Micro doi: 10.3390/micro6040097

Authors: Ismayil Safarli

Classical micromechanical models are widely used to estimate composite stiffness, but their transferability to electrospun-fiber-reinforced polymers is uncertain because the reinforcement forms a continuous, often random, network whose effective properties depend on fiber diameter, orientation, architecture, and processing. This study uses six diagnostic case studies from three published composite studies with polyamide 6 (PA6) fibers in poly(ε-caprolactone) (PCL), poly(methyl methacrylate) (PMMA), and poly(lactic acid) (PLA) matrices to test whether the rule of mixtures, Halpin–Tsai, and Tsai–Pagano relations remain predictive when the fiber modulus must be taken from an independent single-fiber study, as is often unavoidable when utilizing data from the literature. With a PA6 single-fiber modulus of 901.65 MPa, all relations fall below the measured moduli. The Reuss–Voigt spread is at most 64 MPa, whereas prediction–experiment differences reach about 4.2 GPa. Uncertainty propagation and sensitivity to density, Halpin–Tsai shape parameter, orientation efficiency, and fiber-modulus choice classify one PLA/PA6 composite as a robust bound violation (required apparent fiber modulus ≥ 166 GPa), a second as a nominal violation, the PCL/PA6 series as input-ambiguous, and the PMMA/PA6 case as inconclusive. The choice of the model is therefore a smaller source of error than the definition of the input phases. A minimum reporting framework is proposed for future micromechanical and data-driven prediction.

Micro doi: 10.3390/micro6040096

Authors: Asmaa Yaseen Mohammad K. Elsaid

The low-energy massive Dirac Hamiltonian of strained monolayer transition metal dichalcogenides (TMDs), including the effects of strain-induced pseudomagnetic fields and intrinsic spin–orbit coupling (SOC), was employed to investigate the electronic and thermodynamic properties of MoS2 and WSe2. The resulting pseudo-Landau-level (PLL) spectrum was obtained and used to calculate the density of states (DOS), Fermi energy, thermal average energy, and pseudomagnetic susceptibility over a wide range of pseudomagnetic fields, temperatures, and carrier concentrations. The results demonstrate that strain-induced pseudomagnetic fields generate discrete PLLs, producing pronounced structures in the DOS and characteristic field-dependent behavior in the thermodynamic quantities. The recalculated generalized pseudofield susceptibility remains positive over the investigated field range and exhibits a pronounced low-field variation followed by a progressively weaker field dependence at higher pseudomagnetic fields. Its magnitude is strongly influenced by both pseudomagnetic field and temperature, reflecting the thermodynamic response of the electronic spectrum to the strain-induced gauge field. Furthermore, the larger intrinsic SOC of WSe2 leads to a more pronounced spin–valley splitting and distinct thermodynamic behavior compared with MoS2. These findings demonstrate that strain-induced pseudomagnetic fields provide an effective route for tailoring the electronic, thermodynamic, and spin–valley properties of monolayer TMDs without an externally applied real magnetic field, opening new opportunities for strain-engineered quantum, spintronic, and valleytronic applications.

Micro doi: 10.3390/micro6040095

Authors: Mitsuhiro Okuda Kornelius Zeth Gabriela Pretre

DNA-binding proteins from starved cells (Dps) are cage-shaped bacterial proteins that sequester iron, suppress oxidative stress, and/or protect DNA through ordered Dps–DNA assembly. The positively charged N-terminal region is considered important for DNA interaction and biocrystallization. In this study, we designed and characterized a Listeria innocua Dps variant carrying seven lysine residues at the N-terminus, designated 7Lys-Dps, to examine the effect of enhanced positive charge on Dps assembly. During overexpression, 7Lys-Dps formed salt-reversible aggregates that were separable from cellular debris by centrifugation and resolubilized with 0.5–1.0 M NaCl. Purified 7Lys-Dps formed transparent crystal-like structures using the hanging-drop vapor diffusion method. These findings indicate that N-terminal lysine tagging modulates Dps solubility and self-assembly, providing a potential strategy for controlling the assembly behavior of Dps-based protein nanocages.

Micro doi: 10.3390/micro6040094

Authors: Sharif H. Zein

Hydrogen is widely regarded as a key component of future low-carbon energy systems, and nanomaterials are central to improving the efficiency and performance of the technologies that will deliver it. Existing reviews typically treat hydrogen production, storage and carbon capture separately; this narrative review compares nanomaterials across these selected domains using qualitative evidence categories and, where the data permit, indicative cost benchmarks. Of the 22 classes assessed, 19 are classified on the maturity axis. Of those, 14 show laboratory evidence only, three reach prototype or pilot evidence and two reach field or commercial evidence in the reviewed application. The remaining three have industrial precedent only in other applications and are not classified on this axis. Across six unmatched storage examples, reported capacities vary substantially, but the data do not support an application-specific maturity relationship. Cost data for nanomaterial-based hydrogen storage are particularly scarce compared with production and carbon capture, where indicative but inconsistently reported benchmarks exist. Commercialisation pathways, hydrogen carrier technologies and environmental, health, safety and life-cycle considerations are also examined alongside the potential contribution to industrial decarbonisation. Key research priorities are identified, including a five-point minimal reporting checklist (TERC) intended to make future cost reporting more comparable.

Micro doi: 10.3390/micro6040093

Authors: Zhenhao Zhou Jie Gao Xiaobing Han

Carbon nanofillers have become a research hotspot in high-performance polymer composites, yet the correlation between filler dimensionality and macroscopic properties remains to be systematically elucidated. This review classifies carbon nanofillers into zero-dimensional (fullerenes, nanodiamonds), one-dimensional (carbon nanotubes, nanofibers), two-dimensional (graphene, nanoplatelets), and three-dimensional (assembled carbon black aggregates, graphene foams, and CNT sponges, whose 0D/1D/2D building blocks are specified where relevant) categories and compares their effects on electrical, mechanical, and thermal properties. The findings reveal that dimensionality significantly influences performance through three important pathways, namely percolation network efficiency, interfacial stress transfer, and thermal transport mechanisms including interfacial thermal resistance and phonon scattering. Zero-dimensional fillers excel in wear resistance, one-dimensional fillers impart optimal impact toughness with high aspect ratio, two-dimensional fillers provide the best tensile strength and modulus enhancement with ultra-high specific surface area, and three-dimensional fillers establish long-range continuous reinforcing networks with interconnected porous structures at low loadings. This review also elucidates the synergistic effects of carbon nanofillers with different dimensionalities, demonstrating that judicious filler combinations can break through the performance ceiling of single-filler systems, and three fundamental synergistic mechanisms (network bridging, network filling, and interlayer intercalation/exfoliation) are identified. This review provides a systematic theoretical framework and experimental basis for filler selection and structural design of high-performance polymer composites.

Micro doi: 10.3390/micro6040092

Authors: Maria Gancheva Ralitsa Velinova Simona Delibaltova Katerina Tumbalova Pavel Markov Hristo Kolev Ivanka Spassova Reni Iordanova Anton Naydenov

SrMoO4 nanoparticles were effectively prepared through direct mechanochemical activation carried out under ambient conditions. In order to improve their catalytic properties, the obtained SrMoO4 was modified with palladium and comprehensively characterized by X-ray diffraction analysis (XRD), N2-physisorption, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Catalytic tests for VOCs were carried out. The XRD patterns showed that the as-synthesized SrMoO4 and Pd/SrMoO4 samples are crystallized in a scheelite-type structure. It was found that the use of SrMoO4 as a catalytic support enables the preparation of a catalytic system with highly dispersed Pd species and strong metal–support interactions. The presence of reduced Mo species on the Pd-modified SrMoO4 catalyst, together with oxygen-deficient surface regions, suggests that the Mo species actively participate in the catalytic process through their redox cycle. The possible coexistence of both Pd2+ and Pd0 species and partially reduced Mo environments further indicates the active involvement of the Pd/SrMoO4 surface in oxygen activation and VOC oxidation, supporting the Mars–van Krevelen mechanism as the most probable reaction route. In addition, the high stability of the material demonstrates the reliability of the Pd-modified SrMoO4 catalyst. Therefore, this material can be considered a promising catalyst in environmental catalysis.

Micro doi: 10.3390/micro6040090

Authors: Abeer Alghamdi Touseef Amna

Bacterial infections, predominantly affecting the gastrointestinal tract and oral cavity, represent a considerable health burden and remain among the leading causes of morbidity and mortality globally. Exploration of therapeutic mediators from medicinal plants continues to be a foundational strategy in modern drug development. The objective of the current study was to synthesize a Mentha arvensis-mediated biogenic iron oxide heterophase nanocomposite as a green therapeutic approach to controlling oral and gastrointestinal (GI) bacteria. Green synthesis is sustainable and an economic alternative for producing nanoparticles, because it is ecologically benign. For the first time native Al-Baha M. arvensis biomass was used for green preparation of mixed-phase iron oxide nanoparticles, and these were characterized by visual observation, X-ray diffraction, scanning electron microscopy, and Energy-Dispersive X-ray and FT-IR spectroscopy. The materialization of a dark brown color preliminarily points toward the establishment of iron oxide heterophase NPs due to reduction by phytochemicals. SEM demonstrated particle sizes approximately ranging between 30 and 80 nm, whereas EDX evidenced the predominance of Fe and O in the nanocomposite. Iron oxide heterophase NPs were also tested against human pathogens. The results displayed effective antibacterial activity, which seems concentration-dependent. The largest zone was recorded for S. aureus, with a size of 25 mm, and the smallest zone for L. garvieae at 100 µg/mL, with a size of 11 mm. The findings of this study indicate that iron oxide heterophase composites possess potential as biogenic antibacterial agents with environmentally friendly properties. Further development and optimization of this nanocomposite could contribute meaningfully to advancements in pharmaceutical and medical areas.

Micro doi: 10.3390/micro6040091

Authors: Ying-Chien Chung Chih-Yu Chen

This study evaluated the microwave-assisted green synthesis of zinc oxide nanoparticles (ZnO NPs) utilizing Melaleuca quinquenervia leaf extract (MQLE) as a sustainable reducing and capping agent. The synthesized bio-capped ZnO NPs exhibited a pure crystalline structure with an average hydrodynamic size of 82.6 nm. The biological profiles of the nanoparticles were systematically evaluated. Results demonstrated that bio-capped ZnO NPs possessed superior antioxidant, antityrosinase, anti-aging, and anti-inflammatory activities compared to chemically synthesized ZnO NPs (Che-ZnO NPs) and raw MQLE. Specifically, bio-capped ZnO NPs effectively suppressed melanin synthesis in human epidermal melanocytes (HEMn) and down-regulated key inflammatory mediators. Biocompatibility assessments based on ISO 10993-5 criteria revealed that bio-capped ZnO NPs maintained high cell viability at their effective working doses, with safe dosage thresholds (viability > 70%) determined at 175 mg/L for CCD966SK, 225 mg/L for HEMn, and 175 mg/L for Raw264.7 cells. The safe doses significantly exceeded the concentrations required for their physiological functions, whereas Che-ZnO NPs displayed prominent cytotoxicity. In conclusion, MQLE-mediated green synthesis provided a safe, biocompatible, and high-performance platform for ZnO NPs, offering great potential for advanced cosmetic and transdermal biomedical applications.

Micro doi: 10.3390/micro6040089

Authors: Abderrahmen Merghni Molka Mrabet Faouzi Ayari

Silver nanoparticles (Ag-NPs), typically sized between 1 and 100 nm, hold considerable promise in biomedicine. Owing to their broad biological activity—most notably their antibacterial action against drug-resistant bacteria—a growing number of research efforts are now directed toward the most environmentally friendly routes for Ag-NP synthesis. Ag-NPs can be prepared through chemical, physical or biological approaches. The chemical route is inexpensive and gives a high yield, but relies on reducing agents and stabilisers that carry a risk of toxicity. Physical methods avoid these chemicals—using a radiation beam as the reducing agent instead—but are energy-intensive and require specialised equipment. These drawbacks have progressively shifted research toward green biosynthesis. In this review, we summarise recent progress in the synthesis of Ag-NPs by physical, chemical and biological approaches and discuss their antimicrobial properties, with particular attention paid to the green synthesis of Ag-NPs from plant-derived (including plant-waste) extracts. Unlike earlier overviews, we compare the three families of methods against the same criteria (control of size and shape, scalability, environmental burden and suitability for biomedical use), relate particle properties to antimicrobial performance, and treat toxicity and bacterial silver resistance in dedicated sections. We further highlight developments published between 2023 and 2026 and outline the main challenges—toxicity, standardisation and scale-up—that will determine whether Ag-NPs can be translated into clinically and industrially viable antimicrobial agents.

Micro doi: 10.3390/micro6040088

Authors: Mili Shah Edwin Pithawala Jolly Shah Hardik Shah

Green synthesis of nanoparticles has emerged as a sustainable and eco-friendly alternative to conventional chemical and physical methods that often involve toxic reagents and energy-intensive processes. In the present study, biosynthesis of silver nanoparticles (AgNPs) using aqueous extracts of dried mushrooms is explored, leveraging naturally occurring bioactive compounds as both reducing and stabilizing agents. The mushroom-mediated synthesis provides a biogenic platform for the formation of stable, small-sized nanoparticles under mild conditions. The successful formation of AgNPs was initially confirmed through UV–visible (UV–Vis) spectroscopy, with distinctive surface plasmon resonance (SPR) peaks observed in the range of 420–450 nm. Further, Fourier Transform Infrared (FTIR) spectroscopy analysis revealed the presence of functional groups such as hydroxyl, carbonyl, and amine, indicating their active participation in the reduction of silver ions and stabilization of nanoparticles. Morphological studies conducted via Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) confirmed the production of spherical nanoparticles with a size distribution ranging from 1 to 2 nm. These findings suggest that mushroom extracts provide a versatile and efficient means of synthesizing AgNPs. The small, stable particle sizes obtained may indicate potential suitability for future biomedical and nanotechnological applications.

Micro doi: 10.3390/micro6040087

Authors: Sathianeson Satheesh M. Prabha Ramzi H. Amran Anand Austin Jeya Kumar

Bacterial diseases are one of the major causative factors for fish mortality and economic losses in aquaculture sector. Most of the pathogenic bacteria exists in biofilms, which offer protection from antibiotics and other infection control measures. In the present study, the antibacterial and antibiofilm activities of green synthesized copper oxide nanoparticles were tested against selected fish pathogens. Copper oxide nanoparticles (CuO-NPs) were synthesized using brown seaweed, Sargassum vulgare, extract. The biosynthesized NPs were characterized using UV-visible spectroscopy analysis, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) analysis, an energy dispersive X-ray analyzer (EDX) and X-ray diffraction (XRD). The SEM examination of morphology revealed predominantly spherical particles with some degrees of aggregation in CuO-NPs. The polycrystalline nature of CuO-NPs was confirmed in the XRD analysis. Furthermore, CuO-NPs exhibited antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH). The prepared NPs also demonstrated antibacterial and biofilm formation inhibition activities against fish pathogens with a maximum biofilm inhibition of 95% against Vibrio anguillarum. Overall, the findings suggest that the S. vulgare mediated CuO-NPs have potential for further investigation in fish disease control in aquaculture due to their antibacterial and biofilm inhibition effects against fish pathogens.

Micro doi: 10.3390/micro6040086

Authors: Chirayu Barapatre Riya Pandey Arjun Thakur Narayanan Latha Ashish Mathur Krishna Kant

Over the past decades, microfabrication technologies have been essential tools in the creation and fabrication of biomedical microfluidic devices useful for diagnostics, biosensing, drug delivery, and organ-on-a-chip applications. Soft lithography is one of the most widely used conventional microfabrication techniques and can achieve a high resolution (~100 nm) and excellent fidelity of the replica but requires a high level of expertise, expensive equipment, and access to cleanrooms, which is not widely available and makes it difficult to scale up and adopt. Moreover, the material limitations and the complicated fabrication steps of conventional lithographic methods limit the fast prototyping of advanced microfluidic platforms. These limitations have been overcome in recent years with the integration of 3D printing and soft lithography, and, now, the rapid, cost-effective, and customizable fabrication of high-quality master molds of PDMS-based microfluidic devices is possible. Modern 3D printing technologies provide great material versatility, design flexibility, high manufacturing efficiency, and a much shorter and lower cost of fabrication. This review critically discusses the recent advancements of the 3D printing-assisted soft lithography method in biomedical microfluidic device fabrication, focusing on fabrication techniques, materials for 3D printing, hybrid fabrication strategies, and representative biomedical applications. Moreover, the current developments of high-resolution additive manufacturing, multi-material fabrication, and eco-friendly manufacturing are discussed, and insights into the future development of next-generation bio-medical microfluidic systems are provided.

Micro doi: 10.3390/micro6040085

Authors: Miao Dan Meng Kummutha A/P Ramesh Wong Charng Choon Saeid Mezail Mawazi

Selecting a microparticle fabrication method requires an understanding of payload compatibility, particle formation, and manufacturing constraints. This review summarizes these considerations and provides guidance on method selection. PubMed, Scopus, and Web of Science databases were searched up to February 2026, supplemented by Google Scholar searches. This structured narrative review compares 16 microparticle fabrication methods, examining their mechanisms, key formulation and process variables, material compatibility, particle properties, release behavior, scalability, and limitations. Representative patented methods are also listed to provide an additional informative technological context. Among the analyzed methods, interfacial dynamics, heat and mass transfer, payload partitioning, and carrier solidification help explain how processing conditions influence particle properties and release. Spray drying and coating are relatively well-established industrial processes. Droplet microfluidics and electrospraying enable precise control over particle size and architecture, though throughput and scale-up remain challenges. Whereas mild aqueous processing may help preserve the integrity of labile biomacromolecules, solvent- and melt-based techniques require careful control of residual solvents and thermal exposure. For long-acting delivery, particular attention must be paid to matrix tortuosity, the changing contributions of diffusion and degradation, and initial burst release. However, direct comparisons are difficult due to differences in formulation parameters and testing conditions. Method selection remains application-dependent. Payload stability, desired particle structure and release profiles, manufacturing constraints, and production scale must all be comprehensively considered. More consistent reporting and direct comparisons under relevant industrial conditions would provide stronger support for these decisions.

Micro doi: 10.3390/micro6040084

Authors: Estefan Monteiro da Fonseca Christine Gaylarde Guy Gaylarde Katherine Gaylarde

Microplastics are increasingly recognized not only as persistent pollutants but also as novel microbial habitats capable of influencing ecological processes across aquatic ecosystems. Although the plastisphere has been extensively described, its broader ecological significance remains poorly integrated within ecosystem theory. Here, we propose the Ecological Infrastructure Framework (EIF), which considers colonized microplastics as persistent mobile substrates that may support microbial communities, create opportunities for biological connectivity and redistribute microbial functional potential across environmental boundaries. The framework integrates material persistence, eco-corona formation, microbial succession, environmental selection and dispersal to examine how plastic-associated communities develop and interact with receiving environments. We further introduce Ecological Filter Compression as a testable hypothesis whereby additional particle-mediated dispersal may modify the relative contributions of dispersal limitation and environmental selection to microbial community assembly. Rather than assuming that colonized particles transport intact functional consortia, the EIF distinguishes physical transport from microbial survival, establishment and the realization of ecological functions. We also examine how microplastics may influence carbon cycling through experimentally demonstrated effects on microbial activity, aggregation and sinking behavior, while considering the additional contribution of mobile microbial functional capacity as a hypothesis requiring direct validation. Potential consequences for ecosystem resilience are similarly expected to depend on environmental context, community composition and disturbance characteristics. By integrating plastisphere ecology with metacommunity theory and ecosystem functioning, this review provides a systems-level framework for evaluating when persistent synthetic particles may contribute to ecological connectivity and generates testable predictions concerning microbial dispersal, community assembly, biogeochemical processes and ecosystem resilience.

Micro doi: 10.3390/micro6040083

Authors: Anuarbek Suychinov Kamil Derbyshev Zhanibek Yessimbekov Dastan Asserzhanov Eleonora Okuskhanova

Foodborne microbial contamination remains a major challenge for the safety and shelf life of poultry and other perishable foods. This study developed a silver nanoparticle (AgNP)-based antimicrobial formulation and evaluated its physicochemical characteristics, antibacterial activity against Escherichia coli, and preliminary concentration-dependent effects on bovine sperm viability. AgNPs were synthesized using a modified glucose–citrate reduction method. UV–Vis measurements showed characteristic surface plasmon resonance maxima within approximately 411–422 nm across the evaluated synthesis experiments. Transmission electron microscopy revealed predominantly quasi-spherical particles with a mean diameter of 23.14 ± 8.31 nm (n = 100), a median diameter of 25.30 nm, and a size range of 5.07–34.88 nm. The mean hydrodynamic radius was 15.47 nm, and the zeta potential was −38.80 ± 0.63 mV, indicating pronounced electrostatic stabilization of the colloidal dispersion. In antibacterial assays, the complete AgNP–chitosan–lactic acid–collagen formulation resulted in complete absence of visible E. coli growth at all tested concentrations, including the lowest evaluated nominal Ag concentration of 6.5 mg/L in the prepared formulation, corresponding to approximately 3.25 µg/mL in the final antibacterial assay mixture, whereas the other tested formulation variants did not achieve complete growth suppression. In the preliminary bovine sperm assay, AgNP dispersion alone caused a concentration-dependent decline in viability, with statistically significant effects observed from 1.37 mg/L onward. These findings demonstrate that the complete multicomponent formulation provides strong antibacterial activity at relatively low nominal Ag concentrations while also highlighting the need for further toxicological and migration assessment. Future studies should validate the formulation in real food matrices and evaluate silver release, migration, and safety under relevant storage and application conditions.

Micro doi: 10.3390/micro6040082

Authors: Yang Liu Yuhan Tao Lili Lu Zhaoxu Meng He Lian Zhou Li

With the exponential growth of global data volume, the physical limitations and high maintenance costs of traditional storage architectures have become increasingly prominent. DNA storage holds value in addressing these issues. However, traditional solid-phase storage media rely on chemical eluents for DNA desorption, which can easily cause the cleavage and fragmentation of nucleic acid chains, thereby interfering with the subsequent sequencing process. This study proposes an electrochemical-controlled DNA adsorption/release strategy based on a conductive composite film made of polylactic acid/polyaniline (PLA/PANI). By adopting the instant alkaline modification and in-situ wet oxidative polymerization process, the problems of interface peeling and collapse of the porous structure were avoided without compromised integrity of the PLA porous framework. Zeta potential analysis indicated that the surface charge of the film could be reversibly converted between +13.01 ± 0.10 mV and −32.53 ± 0.25 mV. Under coordinated optimization of the electrochemical stimulation and pH parameters, the composite film achieved efficient and controllable adsorption and release of DNA. This research provides a new material design concept and technical support for the construction of a green and efficient solid-phase DNA electrochemical-controlled reversible access system.

Micro doi: 10.3390/micro6040081

Authors: Jony Palit Anna Gobetti Giorgio Ramorino Kamol Dey

Hyaluronic acid (HA) has emerged as a promising biopolymer for various biomedical applications due to its biocompatibility, biodegradability, and intrinsic ability to interact with cell surface receptors, making it an attractive candidate for numerous biological processes. Since HA cannot be gelled alone, it must be functionalized through different modification techniques, such as chemical, physical, bio-conjugative, and enzymatic, to activate the various sites present in it. This review analyzes these strategies and applications of HA in different biomedical fields. The first part of the review focuses on the different advanced functionalization strategies of HA, highlighting hydroxyl, amino, and carboxyl group-based reactions, as well as advanced techniques such as oxidation, sulfation, Cu-free click chemistry, thiol–ene coupling, hydrazone formation, bio-conjugation, nano-metal conjugation, and dynamic crosslinking methods. The second part of the review evaluates the use of functionalized HA in the development of advanced biomedical materials, including nano- and microparticles, hydrogels, and mucoadhesive materials with tailored drug release profiles, tissue engineering, skin wound healing, site-specific targeting, and stimuli-responsive behavior. Overall, this review critically consolidates the current advances and future perspectives in the functionalization of HA, underscoring its immense potential to drive the development of biomaterials with diverse biomedical applications.

Micro doi: 10.3390/micro6040080

Authors: Yulduz Yuldosheva Sharif Kiyomov Dilorom Atamurotova Nuriddin Uralov Sardorbek Sodiqov Alisher Ahatov Dilshoda Amanova Dilfuza Yaqubova Bafoyev Abduhamid

Poly(vinyl alcohol) (PVA) has been widely investigated as a matrix for anti-corrosion coatings because of its continuous film-forming ability, relatively low cost, and the versatility of its hydroxyl groups for chemical modification. However, its high affinity for water remains a major limitation for long-term corrosion protection. Consequently, recent research has increasingly focused on cross-linking, nanostructuring, and functional modification of PVA to improve its resistance to moisture and aggressive environments. This review critically examines recent advances in PVA-based anti-corrosion coatings by integrating coating composition, cross-linking chemistry, micro- and nanostructural features, and electrochemical corrosion-protection mechanisms. Particular attention is given to the effects of glutaraldehyde, boric acid, citric acid, epichlorohydrin, and other multifunctional cross-linkers on network structure, mechanical behavior, water resistance, and barrier properties. The roles of urea, glycerol, inorganic fillers, nanomaterials, corrosion inhibitors, and inhibitor-containing nanocontainers are also evaluated in relation to coating durability and corrosion-protection performance. In addition to describing reported approaches, the review critically compares the influence of substrate, PVA characteristics, cross-linking conditions, nanofiller loading, coating architecture, electrolyte, exposure duration, and electrochemical parameters on the reported performance. Particular emphasis is placed on the relationships between cross-linked network structure, nanofiller dispersion, interfacial adhesion, electrolyte transport, and electrochemical response. The review further considers active inhibition, self-healing strategies, and environmental aspects of PVA-based coatings, while identifying limitations related to moisture sensitivity, long-term durability, and inconsistent reporting of experimental parameters. By integrating composition, cross-linking chemistry, structure–property relationships, and electrochemical evidence, this review provides a critical framework for understanding and designing more durable and environmentally compatible PVA-based anti-corrosion coatings.

Micro doi: 10.3390/micro6040078

Authors: Emir Alejandro Hernández-Gómez María Vargas-y Vargas Patricia Quintana-Owen Leydi Carrillo-Cocom Elizabeth Ortiz-Vázquez Jesús Ramón-Sierra Tomás Jesús Madera-Santana

Healing wounds and skin lesions has been practiced since ancient times, and various mechanisms have been used to treat them, ranging from bandages and herbs to ointments and modern alternatives such as dressings. This work aimed to develop bioactive dressings for wound healing. Dressings were prepared using the solution-drained plate technique and comprised 2% (w/v) sodium alginate with varying concentrations of Melipona beecheii honey, up to 5% (w/v). The dressings obtained showed suitable flexibility and elongation as the honey content increased, and had a suitable thickness for skin application, ranging from 0.03 to 0.21 mm. They were also evaluated for barrier, optical, structural, thermal, morphological, bioactive, and cytotoxic properties. The dressings demonstrated good moisture absorption and maintained antimicrobial activity for up to 12 months. Moreover, they retained bioactive compounds, demonstrated strong antioxidant activity, and showed biocompatibility in biological assays. The dressings did not induce cytotoxic effects in human keratinocytes. Dressing with a 2.5% honey concentration exhibited physicochemical and bioactive properties that could improve skin wound healing.

Micro doi: 10.3390/micro6040079

Authors: Avin Sidiq Sehand Arif Bruska Azhdar

Urinary tract infections (UTIs) are a major cause of hospital-acquired infections, and up to 80% of these are linked to urinary catheters. The biofilm formation of uropathogenic E. coli plays a critical role in the development of catheter-associated urinary tract infections (CAUTIs). This study aimed to develop a silicone elastomer material incorporating green-synthesized zinc oxide nanoparticles for potential urinary catheter applications and assess its antibiofilm efficacy against uropathogenic Escherichia coli (UPEC). E. coli was identified by the BD PhoenixTM system and 16S rRNA gene sequencing. ZnO NPs were synthesized through a green method using Crataegus azarolus leaf extract as a biological reducing and stabilizing agent. NPs were incorporated into a silicone matrix at different concentrations (0 wt%, 0.5 wt%, 1 wt% and 1.5 wt%) to produce ZnO-functionalized silicone elastomer specimens for potential urinary catheter applications, and then their antibiofilm activity was assessed through a 96-well microtiter assay. NPs and nanocomposites were characterized through various spectroscopic techniques using XRD, FTIR, and FESEM. In the 1.5 wt% ZnO NPs–silicone elastomer specimen, biofilm formation by E. coli ATCC 25922 and the clinical isolate were significantly reduced by 86.94% and 78.40%, respectively, compared to the control silicone elastomer specimen for potential urinary catheter application. The present findings suggest that green synthesized ZnO NPs provide a promising and biocompatible approach to reducing UPEC biofilm formation when incorporated into silicone elastomer specimens for urinary catheter application. Furthermore, this method may help reduce CAUTIs in clinical settings.

Micro doi: 10.3390/micro6040077

Authors: Reliance Jain Rahul Sippy Salla Nithyanth Kumar Roopesh Kumar Man Mohan Arvind Kumar Patel K. Ganpati Shrinivas Sharma Roopendra Kumar Pathak Sourabh Kumar Soni Sheetal Kumar Dewangan Sandeep Jain

This study investigated the synthesis and microstructural evolution of AlFeCoNi medium-entropy alloy powder processed by ball milling, conventional uniaxial pressing, and vacuum sintering at 900 °C for 1 h. The mechanically milled powder exhibited a refined, irregular particle morphology with a broad size distribution, indicating extensive fracture and cold-welding during milling. SEM (scanning electron microscopy) and EDS (energy-dispersive spectroscopy) observations showed effective elemental mixing of Al, Fe, Co, and Ni, with only limited evidence of large-scale segregation, suggesting that mechanical alloying promoted compositional homogenization. After compaction and sintering, the powder compact exhibited noticeable changes in microstructural continuity and pore morphology, indicating further microstructural evolution during thermal treatment. Overall, the results demonstrate the microstructural evolution of AlFeCoNi MEA during ball milling and subsequent conventional sintering, while further investigation involving quantitative densification measurements and optimization of sintering conditions is required to establish the consolidation behavior and microstructural uniformity of the alloy.

Micro doi: 10.3390/micro6040076

Authors: Muhammad Rif’an Arie Aryanto Karlisa Priandana Waras Nurcholis

Chitosan films and interfaces are increasingly used in micro- and nanosensors, yet the contribution of chitosan is often obscured by hybrid architectures. This systematic evidence map and curated critical review evaluated fabrication routes, micro-/nanoscale structures, functional roles, transduction mechanisms, analytical validation, reporting completeness, and device readiness. Searches of Scopus, PubMed, and IEEE Xplore yielded 15,058 database records. After deduplication, 8832 unique database-derived records underwent rule-based evidence mapping: Core Primary Candidate (n = 2617), Contextual Evidence (n = 3096), Manual Review (n = 1318), and Exclude (n = 1801). A separately assembled curated full-text subset contained 73 unique records, including 32 unique additions to the database-derived corpus. Full-text adjudication of this curated subset identified 26 studies meeting the strict CORE criteria, 17 boundary experimental studies, eight contextual experimental/material studies, 18 review/contextual sources, two methodological sources, and two exclusions. The detailed critical synthesis and reporting-completeness assessment were restricted to the 26 CORE studies assessed within this curated subset and should not be interpreted as an exhaustive synthesis of all 2617 automated candidate records. Within the 26-study curated CORE subset, reporting completeness was highest for response definition (26/26, 100.0%) and functional-role reporting (25/26, 96.2%), but lower for chitosan identity and selectivity/interference (17/26, 65.4% each) and stability (13/26, 50.0%). The assessed studies indicate that strong analytical performance in hybrid architectures generally reflected the complete sensing system rather than chitosan alone. The proposed role–structure–transduction–evidence framework supports clearer component attribution, within-platform comparison, validation, and device-readiness assessment within the evidence set examined.

Micro doi: 10.3390/micro6030075

Authors: Rostyslav Marunych Dorota Bartusik-Aebisher Klaudia Dynarowicz Barbara Smolak David Aebisher

Protoporphyrin IX (PpIX) occupies a unique nexus in photodynamic therapy (PDT) by bridging the endogenous metabolism of heme biosynthesis with highly efficient, light-induced cytotoxicity. Administered via its precursor 5-aminolevulinic acid (5-ALA) or its derivatives, intracellularly generated PpIX undergoes intersystem crossing upon irradiation to predominantly initiate Type II photochemistry. This process yields singlet oxygen and ancillary reactive oxygen species (ROS) characterized by a strict, nanometer-scale radius of molecular attack. Consequently, the spatiotemporal kinetics of PDT are dictated by the precise subcellular compartmentalization of PpIX within the mitochondria, mitochondrial-associated membranes (MAMs), endoplasmic reticulum, lysosomes, and plasma membrane. Beyond inducing direct biomolecular damage, PpIX-PDT operates as a localized selector of complex signaling networks, orchestrating organelle communication, redox-mediated pathways, and cell fate adaptations. This comprehensive review systematically delineates the metabolic parameters governing intracellular PpIX accumulation, the biophysical mechanisms driving its excitation, and the subsequent cascade from primary oxidative stress to downstream signaling responses. Crucially, we present a novel, integrated framework that seamlessly connects upstream transporter kinetics and metabolic flux directly to downstream immunogenic and therapeutic outcomes. Ultimately, these multifaceted properties establish 5-ALA-mediated PpIX-PDT as a powerful theranostic platform, advancing pathway-oriented and personalized strategies to optimize modern anticancer interventions.

Micro doi: 10.3390/micro6030074

Authors: Sebastián Guzmán-León Carlos Gregorio Barreras-Urbina Tomás Jesús Madera-Santana Lorena Armenta-Villegas Maritza Lizeth Álvarez-Ainza José Agustín Tapia-Hernández Itzel Yanira López-Peña Francisco Rodríguez-Félix

Curcuma longa L. rhizomes contain curcuminoids and other compounds of interest, but their incorporation into aqueous systems is limited by poor dispersibility and chemical instability. This study formulated gelatin–Curcuma longa L. extract nanoparticles by coaxial electrospraying. A dried hydroethanolic extract was obtained from commercial Curcuma longa L. powder by ultrasound-microwave-assisted extraction (UMAE), with a mean gravimetric yield of 12.46 ± 1.47%. Because the recovered material was not purified or quantified by a compound-specific method, it is described as Curcuma longa L. extract rather than curcumin. Gelatin solutions at 8 and 10% (w/v) were used as the outer feed, whereas extract solutions at 0.1, 0.5, and 1.0% (w/v) were used as the inner feed. The precursor solutions showed near-Newtonian behavior. The 8% gelatin–0.5% extract formulation exhibited predominantly spherical morphology, a hydrodynamic diameter of 266.27 ± 0.57 nm, and the lowest PDI (0.24 ± 0.01). FTIR-ATR results were consistent with non-covalent interactions, mainly hydrogen bonding. These findings support coaxial electrospraying as a suitable method for preparing gelatin–Curcuma longa L. extract nanoparticles.

Micro doi: 10.3390/micro6030073

Authors: Selin Sagbas Suner Mehtap Sahiner Evrim Umut Nurettin Sahiner

Graphitic carbon nitrides (g-C3N4) are well-known fluorescent nanosheets that are photoactive under the UV–visible light range and could generate reactive oxygen species (ROS) upon appropriate light exposure. Therefore, these materials are generally favored in diagnostic applications for bioimaging and light-activated treatments simultaneously, e.g., theranostic applications in cancer treatments. Here, the natural polymer, hyaluronic acid (HA), was physically crosslinked with trivalent metal ions such as Gd(III) or Fe(III) ions in the presence of boron (B)- or sulfur (S)-doped graphitic carbon nitride (g-C3N4) nanosheets to attain spherical light-sensitive g-C3N4@HA-M(III) (M: G(III) or Fe(III) ions) composite microparticles. The g-C3N4@HA-M(III) particles were in the 0.5–20 μm size range, which is injectable for possible intravenous administration. No significant toxicity was determined for g-C3N4@HA-Gd(III) particles up to 500 μg/mL concentration on L929 fibroblast cells; for example, g-C3N4@HA-Fe(III) particles could be used in vivo applications safely up to 100 μg/mL concentration with no toxicity. The g-C3N4-based materials exhibited strong fluorescence at λex 380 nm, and S-doped g-C3N4@HA-Gd(III) particles provided the highest emission intensity for possible cell imaging applications as a diagnostic tool material. Especially, S-doped g-C3N4@HA-M(III) particles delivered photoinduced anticancer activity on SKMEL 30 skin cancer cells after 30 min of UV-A treatment at 6.88 mW/cm2 irradiance and 12.38 J/cm fluence via the reactive oxygen species (ROS) production capability. In addition to the targeting ability of HA-M(III) particles, the photoinduced anticancer activity of g-C3N4@HA-M(III) particles, e.g., on SKMEL 30 melanoma cells, offer great alternatives to toxic chemo- or radiotherapy. Furthermore, HA-Gd(III)-based particles show the highest signal intensity with better proton relaxation times and the highest proton longitudinal relaxivity. Overall, HA-Gd/Fe(III) particles with heteroatom-doped g-C3N4 revealed excellent assets with enhanced MRI capabilities in addition to specific targeted cancer treatments and photoinduced therapy for multifaceted theranostic applications.

Micro doi: 10.3390/micro6030072

Authors: Praveen Kumar Annagowni Renuka Gudepu Swati Dahariya Aditya Velidandi

Biofilm-associated infections represent a critical challenge in modern medicine, accounting for approximately 80% of all microbial infections and demonstrating up to 1000-fold higher antimicrobial resistance compared to planktonic bacteria. The extraordinary recalcitrance of biofilms stems from a complex interplay of physical barriers (extracellular polymeric substance matrix), chemical gradients (pH and oxygen heterogeneity), and biological defenses (persister cells and horizontal gene transfer), rendering conventional antibiotics largely ineffective. This comprehensive review highlights the transformative potential of antimicrobial nanoformulations in overcoming these formidable barriers through strategic design principles and diverse mechanisms of action. Evidence demonstrates that rationally engineered nanocarriers achieve improvements in bacterial killing, biofilm biomass reduction, and colony-forming unit reductions compared to free antibiotics. Advanced stimuli-responsive systems exploiting biofilm-specific triggers (acidic pH, bacterial enzymes, elevated ATP) and externally applied stimuli (near-infrared photothermal therapy, ultrasound sonodynamic therapy) enable on-demand therapeutic activation with unprecedented precision, achieving >99.999% bacterial elimination and near-complete biofilm eradication. Despite these remarkable advances, clinical translation remains hindered by challenges in scalability, comprehensive safety evaluation, and regulatory pathway navigation. This review establishes a consolidated evidence base for the design of next-generation antimicrobial nanoformulations, highlights their potential to address biofilm-associated infections, and identifies key knowledge gaps and translation barriers that must be addressed to realize their therapeutic promise.

Micro doi: 10.3390/micro6030071

Authors: Awad Kadim Shaalan Al-Khalidy Ali Jabbar Abd Al-Hussain Alkawaz Maryam Sabah Naser Ali Jalil Obaid

Introduction: Catheter-associated urinary tract infections (CAUTIs) caused by multidrug-resistant (MDR) uropathogens pose a management challenge due to bacterial biofilm formation and crystalline encrustation, especially those associated with Proteus mirabilis, which result in persistent infections and catheter obstructions. Current catheter surface coatings against CAUTIs target either the initial stages or later phases of such pathologies separately. Aim: We report the design and characterization of a novel polyfunctional coating comprised of polydopamine (PDA), genipin-crosslinked chitosan (GCS), and ZnO nanoparticles capable of blocking bacterial attachment, biofilm formation, and mineral encrustation. Methods: PDA-coated silicon surfaces were functionalized with genipin-crosslinked GCS/ZnO nanocomposites and studied by means of TEM, XRD, FTIR, SEM, AFM, water contact angle measurements, and zinc ion release tests. Antibacterial, antibiofilm, anti-encrustation, and hemocompatibility activities were then assessed. Results: ZnO nanoparticles were spherical, with an average particle size of 34.6 ± 8.2 nm and a highly crystalline hexagonal wurtzite structure. Coatings containing ZnO nanoparticles retained hydrophilic surface properties and released Zn2+ ions steadily. The G5 coating (containing 0.2% ZnO) demonstrated an ability to decrease bacterial adherence by >4 log10 CFU, lower biofilm biomass by 80–90% (p < 0.001), prevent mineral deposition by 67–70% caused by Proteus mirabilis, and keep catheter patency for 14 days. Hemolysis was within the ISO 10993-4 acceptance criteria. Conclusions: A rationally designed combination of PDA, genipin-crosslinked GCS, and ZnO nanoparticles provided a multifunctional coating with potent antibacterial, antibiofilm, anti-encrustation, and initial hemocompatibility activity, serving as a proof-of-concept platform for further cytotoxicity assessment, mechanical durability studies, and preclinical evaluations prior to clinical implementation.

Micro doi: 10.3390/micro6030070

Authors: Muhammad Umar Fareed Musaddaq Azeem Ahmad Fraz Nesrine Amor Hafiz Muhammad Asad Ali Muhammad Tayyab Noman

Sports e-textiles have emerged as a key component of wearable technology, enabling real-time physiological monitoring and enhanced athletic performance. However, the integration of conventional batteries into sportswear is constrained by their rigidity, weight, limited flexibility, and safety concerns. Textile-integrated supercapacitors have therefore attracted considerable attention as a promising energy storage solution owing to their lightweight design, rapid charge–discharge capability, long cycle life, and excellent mechanical flexibility. This review critically examines recent advances in supercapacitor-based energy storage for sports e-textiles, with emphasis on electrode materials, textile substrates, fabrication and integration strategies, electrochemical performance, and practical applications in sportswear. Particular attention is given to the effects of textile architecture, flexibility, washability, mechanical durability, sweat resistance, and long-term operational stability on device performance. The review also discusses the major challenges limiting commercial adoption, including durability, scalable manufacturing, user comfort, and environmental sustainability. Finally, future research directions are proposed to accelerate the development of high-performance, sustainable, and commercially viable textile energy storage systems for next-generation intelligent sportswear. This review provides a comprehensive reference for researchers, textile engineers, and wearable technology developers working on advanced energy storage solutions for smart sports apparel.

Micro doi: 10.3390/micro6030069

Authors: Diana Anghel Gheorghe Ilia Vlad Chiriac Dana Vlascici

A Ni/Cu-containing phosphinate material based on 2-carboxyethyl(phenyl)phosphinic acid was synthesized under hydrothermal conditions and characterized using FT-IR (Fourier Transform Infrared Spectroscopy), SEM (Scanning Electron Microscopy) and EDAX (Energy Dispersive X-ray Analysis) analysis. The FT-IR spectra suggest the coordination of the phosphinate group to the metal, while SEM revealed compact aggregated particles of the compound. EDAX analysis confirmed the simultaneous presence of both Ni(II) and Cu(II) metals in the synthesized material. DFT (Density Functional Theory) calculations performed on the corresponding mononuclear Ni-CEPPA and Cu-CEPPA models indicated that the Cu complex possesses a smaller HOMO–LUMO energy gap (2.72 eV) than the Ni analog (3.43 eV), suggesting higher electronic reactivity. The obtained material was preliminarily evaluated for Methylene Blue removal, exhibiting an adsorption capacity of 170.24 mg/g. These results suggest that mixed Ni/Cu phosphinate materials may represent potential candidates for adsorption-related applications.

Micro doi: 10.3390/micro6030068

Authors: Rajashekhara Bhari Sharanesha Deepti Virupakshappa Maram Alagla Zeyad Alkwaifali Faisal Alotaibi

Background/Objectives: Nanotechnology has become a transformative area in modern dentistry, providing new opportunities for better diagnosis, targeted drug delivery, improved restorative materials, antimicrobial treatments, and tissue regeneration. This scoping review outlines the scope, key developments, and future directions of nanotechnology use across all dental specialties, highlights emerging innovations, and identifies major translational challenges and research priorities. Methods: This review followed the Joanna Briggs Institute (JBI) methodology for scoping reviews and adhered to the PRISMA-ScR guidelines. These guidelines, originally by Arksey and O’Malley (2005) and later updated by Levac et al. (2010) and Peters et al. (2020, 2021), guided the process. The Population, Concept, and Context (PCC) framework guided the eligibility criteria. Included studies were primary research or reviews reporting nanotechnology applications in any dental specialty, published in English, with no date restriction. Excluded were non-peer-reviewed sources, conference abstracts without full text, studies unrelated to dental applications, and non-English publications. A comprehensive literature search was conducted across PubMed/MEDLINE, Scopus, and Web of Science. After screening titles and abstracts and reviewing full texts, 133 studies were included. Results: The included studies covered a wide range of fields such as restorative dentistry, implantology, periodontology, endodontics, drug delivery, tissue regeneration, oral diagnostics, antimicrobial applications, prosthodontics, orthodontics, and emerging technologies like nanorobotics and graphene-based systems. The most commonly reported nanomaterials were silver nanoparticles (AgNPs), calcium phosphate nanoparticles (CaP NPs), and polymeric nanoparticles such as PLGA and chitosan. Additionally, there was a notable increase in publications starting from 2019. Conclusions: Nanotechnology offers transformative possibilities in every area of dentistry. Nonetheless, challenges such as nanotoxicology safety, regulatory alignment, and effective clinical application need resolution. Essential steps include standardized characterization, gathering long-term safety data, and establishing international regulatory standards to ensure safe adoption of nano dentistry.

Micro doi: 10.3390/micro6030067

Authors: Pisutsaran Chitichotpanya Nattaya Vuthiganond Penwisa Pisitsak Manthana Jariyaboon Chayanisa Chitichotpanya

The emergence of antibiotic-resistant Vibrio parahaemolyticus poses a challenge to sustainable shrimp aquaculture and highlights the need for effective antibacterial alternatives. In this study, silver nanoparticles were biosynthesized using Eri silk fibroin (ESF) as both a reducing and stabilizing biopolymer. Eri silkworms can be reared on cassava leaves, an abundant agricultural by-product in Thailand, thereby supporting waste valorization and the circular bioeconomy. Optimal synthesis was achieved at an AgNO3-to-ESF weight ratio of 1:4, 60 °C, and 4 h, yielding 82.8% ESF-AgNPs with a particle size of 10.8 ± 2.3 nm and a polydispersity index of 0.19 ± 0.01. TEM, XRD, and XPS confirmed the formation of well-dispersed metallic Ag0. The particles remained colloidally stable for at least four weeks. ESF-AgNPs exhibited minimum inhibitory and bactericidal concentrations of 12.5 and 25 µg/mL, respectively; inhibited biofilm formation by 52.45–99.98%; and increased intracellular reactive oxygen species generation. After 72 h, silver release reached 5.70% in deionized water and 9.30% in TSB containing 3% NaCl. Artemia franciscana survival remained 96.2% after 24 h at the MBC. These findings support ESF as a sustainable platform for producing antibacterial and antibiofilm AgNPs with a preliminary safety margin, although further in vivo efficacy and chronic-toxicity studies are required before practical application.

Micro doi: 10.3390/micro6030066

Authors: Irnik Dionisiev Vladimira Videva Daniela Karashanova Velichka Strijkova Ivalina Avramova Peter Rafailov Dimitre Dimitrov Vera Marinova

Two-dimensional transition metal dichalcogenides (TMDCs) require highly controllable and scalable synthesis methods for successful integration into next-generation optoelectronic technologies. This study presents a modified two-step thermally assisted conversion approach for synthesizing 2D tungsten diselenide (WSe2) by introducing an intermediate UV–ozone treatment. Magnetron-sputtered tungsten films are exposed to UV–ozone, converting the precursor into a uniform, dense layer of amorphous tungsten trioxide (WO3) prior to the selenization process via chemical vapor deposition. X-ray photoelectron spectroscopy and Raman spectroscopy confirm the complete phase transition from the oxidized precursor to the 2H-WSe2 crystal lattice. Morphological evaluations utilizing transmission electron microscopy and atomic force microscopy demonstrate that the ozonated precursors yield highly uniform, triangular flakes exceeding 5 µm in lateral size, effectively eliminating the unreacted WO3 phases observed in untreated samples. Furthermore, the intermediate oxidation step finetunes the electronic band structure; the resulting WSe2 exhibits an enhanced p-type character with a valence band maximum shift to 0.35 eV, a tuning attributed to residual oxygen doping. Optical characterizations reveal significantly improved transmittance in the visible spectrum, accompanied by excitonic absorption shifts indicative of reduced layer dimensionality. This intermediate ozonation strategy provides a highly effective pathway for producing high-quality WSe2 nanosheets with tailored structural and optoelectronic properties.

Micro doi: 10.3390/micro6030065

Authors: Ali A. Al-Allaq Hussein A. Hassan Hidayet M. Hidayet Abdullah A. Abdulhakeem Zain Al-Abeden Q. Ahmad

Drug delivery systems based on nanoparticles have emerged as promising approaches for overcoming the blood–brain barrier (BBB), a major obstacle to treating disorders of the central nervous system (CNS). There are several reasons why conventional therapies fail, including poor brain penetration, rapid drug clearance, and nonspecific distribution. This review critically evaluates recent advances in nanoparticle-mediated BBB targeting, focusing particularly on in vivo findings. As part of this review, lipid-based, polymeric, metallic, dendrimeric, exosome-inspired, and magnetic nanoparticles are discussed in conjunction with their transport mechanisms. The review compares their therapeutic efficacy, biodistribution, targeting ability, and safety across a variety of neurological conditions. Additionally, emerging technologies are discussed, including biomimetic nanoparticles, stimuli-responsive systems, artificial intelligence, and personalized nanomedicine. Additionally, this review critically discusses the major barriers to clinical translation, including biosafety, manufacturing, and regulatory challenges. As a result, this review provides an updated perspective on current progress and future prospects for developing effective brain-targeted nanomedicine.

Micro doi: 10.3390/micro6030064

Authors: Thita Sonklin Shivakumar Chedurupalli Dhanunjaya Munthala Nutthaphat Luangjiranotai Pattanaphong Janphuang James K. C. Raju Soodkhet Pojprapai Sanong Suksaweang

This study investigates the acoustic response of ZnO-based SAW devices fabricated on ZnO/Si and ZnO/SiO2/Si substrates through a combined finite element analysis and experimental approach. Two-dimensional FEA was used to analyze scattering parameters, three-dimensional FEA was used to determine eigenfrequencies and mode shapes, and ZnO thin films were deposited by RF magnetron sputtering with interdigital transducers defined by UV lithography. The ZnO/SiO2/Si device exhibited Rayleigh and Sezawa-type mode resonances at 145 MHz (4350 m/s) and 234 MHz (7020 m/s), respectively, in close agreement with simulation, while the ZnO/Si device resonated at 166 MHz with a phase velocity of 4980 m/s. Incorporation of the Au sensing layer improved signal transmission by approximately 2 dB, consistent with modeling predictions. For biosensing evaluation, the device was functionalized with a thiolated ssDNA probe targeting the EGFR L858R point mutation, a clinically relevant lung cancer biomarker. Probe immobilization and target hybridization were confirmed by contact angle measurements and resonance frequency shifts, with the sensor demonstrating a linear detection range of 0.1 to 0.6 µM and LOD of 0.09 µM. These findings establish an integrated framework of acoustic modeling, microfabrication, and biofunctionalization for ZnO-based SAW biosensors toward label-free nucleic acid detection.

Micro doi: 10.3390/micro6030063

Authors: Yang Ping Hao Xu Shuang Bao Muhammad Qaiser Zakaria Zhenzhou Zhang Jingwen Yu Xuyue Wang Renjing Chen Yinlong Pan Heng Zhu

The growing demand for efficient and sustainable energy-storage systems has intensified efforts to develop materials capable of delivering both high power output and reliable capacity retention. Conventional supercapacitors excel in rapid charge–discharge processes and offer outstanding cycling durability; however, their inherently low energy density limits large-scale use. In contrast, batteries provide high energy densities but typically display slower power response and poorer rate capability. Consequently, hybrid storage systems that merge capacitive and faradaic mechanisms have emerged as a compelling strategy to overcome these shortcomings. In this study, a SrS/polyaniline (SrS/PANI) nanocomposite was fabricated via hydrothermal synthesis and evaluated as an electrode material for hybrid supercapacitor architectures. Structural and morphological characterisation confirmed the formation of a nanoscale composite with well-integrated phases. Electrochemical performance was first evaluated in a three-electrode half-cell configuration, where the optimized SrS/PANI (50/50 wt%) electrode delivered a GCD-derived specific capacity of 580 C g−1 at 0.4 A g−1. The electrode was then assembled into an asymmetric two-electrode device, which achieved an energy density of 18 Wh kg−1, a power density of 2980 W kg−1, and 75% capacity retention after 1000 cycles. Overall, the findings indicate that the SrS/PANI composite exhibits improved charge-storage behaviour arising from the combined contribution of redox-active SrS and the conducting-polymer component PANI, underscoring its promise for hybrid energy-storage applications.

Micro doi: 10.3390/micro6030062

Authors: George Kenanakis

Additive manufacturing [AM; three-dimensional (3D) printing] is reshaping heterogeneous photocatalysis by enabling architected materials and devices that span from centimeter-scale monoliths to micro- and lab-on-chip reactors. Heterogeneous photocatalysts have traditionally been deployed as powders or simple coatings, which offer high activity but suffer from mass-transfer limitations, poor light utilization and difficult recovery. Three-dimensional (3D) printing now allows precise control over macroscopic geometry, internal channel networks and micro-/nano-scale surface texturing, creating structured photocatalysts and microreactors that can be tailored for specific photon and flow fields. In contrast to recent reviews that primarily survey materials development or additive-manufacturing routes, this work focuses on photocatalytic microreactors and lab-on-chip devices as multi-scale reactors in which catalyst composition, architected geometry, photon management and hydrodynamics are co-designed across length scales. We summarize three-dimensional 3D-printed photocatalytic systems based on polymer–oxide composites, ceramic scaffolds such as zinc oxide (ZnO)/titanium dioxide (TiO2) clay monoliths, and laser-written titanium dioxide (TiO2) nano-architectures, with particular emphasis on microfluidic and lab-on-chip implementations fabricated by fused deposition modeling (FDM), direct ink writing (DIW), stereolithography (SLA), digital light processing (DLP) and laser direct writing (LDW). Based on the literature data and representative case studies, we examine how architected lattices, sponges and microreactor chips affect key performance metrics—apparent rate constants, apparent quantum yield (AQY) and space–time yield (STY)—for the degradation of dyes, antibiotics, detergents and other emerging contaminants in realistic matrices, and we compile reported values to illustrate emerging performance trends and limitations. Representative case studies highlight 3D-printed manganese-doped zinc oxide (Mn:ZnO)-decorated sponges used as modular cartridges for greywater and detergent treatment, as well as laser-written titanium dioxide (TiO2) nano-photocatalysts integrated into microchannels to couple structured light fields with controlled residence times. Finally, we outline materials and process challenges—including ultraviolet (UV) aging of polymer supports, the energy intensity of ceramic sintering and the lack of standardized testing protocols—and identify future research directions formulti-scalee modeling and techno-economic evaluation of three-dimensional (3D)-printed photocatalytic microreactors and devices.

Micro doi: 10.3390/micro6030061

Authors: Héctor Guillermo Bustamante-Armenta Dora Evelia Rodríguez-Félix María Mónica Castillo-Ortega Yedith Soberanes-Duarte Erika Silva-Campa Lerma Hanaiy Chan-Chan Arturo Zizumbo-López Hisila del Carmen Santacruz-Ortega

Herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) cause recurrent skin infections that are difficult to treat because of the limited solubility and permeability of acyclovir (ACV). This study developed electrospun polymeric membranes based on polycaprolactone (PCL), poly(lactic acid) (PLA), and cellulose acetate (CA) as controlled ACV delivery systems using uniaxial and coaxial fiber architectures. In the coaxial configuration, ACV-loaded PCL was used as the core and a PLA/CA blend as the shell. Continuous, randomly oriented, bead-free fibers with diameters ranging from 0.68 ± 0.32 µm to 1.45 ± 0.57 µm were obtained. Spectroscopic and thermal analyses confirmed successful drug incorporation, polymer compatibility, and good thermal stability. Coaxial membranes exhibited improved mechanical properties compared with uniaxial systems. Drug release studies showed a prolonged, pH-dependent profile, with greater ACV release at pH 7.3 than at pH 5.5, indicating the effective modulation of drug diffusion by the shell layer. Release kinetics were mainly governed by diffusion and anomalous transport mechanisms. All membranes maintained a cell viability above 80%, demonstrating good in vitro cytocompatibility. These findings support the potential of coaxial electrospun membranes for controlled antiviral drug delivery in skin applications.

Micro doi: 10.3390/micro6030060

Authors: Maria Baikousi Foteini Tsiogka Alexandros Parodos Nikolaos Pantiskas Constantinos E. Salmas Michael A. Karakassides

This study demonstrates the rapid microwave-assisted upcycling of diverse bio-wastes—including aloe vera industrial leaf waste (av), corn cob agricultural residues (cc), and soft slaughterhouse (sh) by-products (pork liver, lung, and heart) into high-surface-area activated carbons for efficient hexavalent chromium removal via ZnCl2-activated microwave pyrolysis. To process the challenging high-moisture animal organs, a hybrid approach combining microwave-assisted hydrothermal pre-treatment with subsequent ZnCl2-activated microwave pyrolysis was developed to promote chemical dehydration and aromatic network development. Structural characterization by N2 porosimetry, FT-IR, Raman, and XRD confirmed the formation of stable, amorphous porous networks, with surface development strongly dependent on both precursor type and pyrolysis temperature. The materials exhibited high specific surface areas (BET) of 1442, 1120, and 775 m2/g for cc, av, and sh, respectively, and they also demonstrated high water dispersibility. Cr(VI) adsorption data were best described by the Langmuir isotherm model, while thermodynamic analysis confirmed the spontaneous and endothermic adsorption process. The maximum adsorption capacities (qmax) at pH 3 were 157, 112, and 71 mg/g for the activated carbons derived from cc, av, and sh, respectively. Agricultural-derived carbons exhibited superior adsorption performance, whereas all materials remained competitive, demonstrating a potential sustainable circular-economy strategy for waste valorization.

Micro doi: 10.3390/micro6030059

Authors: Xuqiao Zhao Zijian Wang Jiaxuan Li Changxu Chen Wei Miao Xi Cui Zhou Li

Electrical cues are essential regulators of tissue repair processes such as wound healing, nerve regeneration, and bone remodeling. Implantable electrical stimulation systems have therefore attracted increasing interest; however, conventional devices typically rely on external power supplies or batteries, leading to limitations including bulky system integration, finite lifetime, mechanical mismatch, and elevated risks of infection and revision surgery. Herein, we propose a conceptual classification of implantable electrical stimulation materials based on their relationship with electric charges, categorizing them into charge-storing materials, charge-conducting materials, and charge-generating materials. Among these, charge-generating materials represent an emerging class capable of autonomously converting endogenous mechanical, chemical, thermal, or optical energy into electrical signals, enabling self-powered and self-sustained electrical stimulation without external energy input. This review systematically summarizes the underlying mechanisms, material design strategies, and recent advances of representative charge-generating systems, including piezoelectric, triboelectric, and electrochemical materials. Their applications in tissue repair are critically discussed, highlighting unique advantages in device miniaturization, long-term operation, and intelligent responsiveness. Finally, current challenges and future perspectives are outlined to guide the development of next-generation self-powered bioelectronic therapies.

Micro doi: 10.3390/micro6030058

Authors: Jain A. R. Tony Benedict Suthan Ramakrishna Pillai Aishwarya Kumaraswamy Pushpa Kumari John Solomon Israel Mohan Raj Manoharan Ayyanar Subbiah Rajesh Munusamy

This study examines the impacts of key abrasive water jet machining (AWJM) parameters on the machinability of AA7175–15 wt.% ZrB2 metal matrix composites produced via a two-step stir casting route. Jet pressure (100–300 MPa), traverse speed (70–130 mm/min), standoff distance (3–5 mm), and abrasive flow rate (250–450 g/min) were systematically varied to evaluate their effects on surface roughness (Ra), kerf taper angle (KA), and material removal rate (MRR). The experimental setup was designed using response surface methodology based on a central composite design (RSM–CCD), enabling both interaction and curvature effects to be assessed. Analysis of variance indicates that jet pressure exerts the strongest influence on MRR, which may be attributed to the increased kinetic energy and penetration capability of abrasive particles at higher pressures. In contrast, traverse speed was found to play a dominant role in controlling surface roughness and kerf geometry. As traverse speed increased, Ra and kerf taper angle tended to rise, likely due to reduced jet–material interaction time and incomplete erosion of the hard ZrB2-reinforced matrix. Abrasive flow rate contributed positively to MRR up to higher levels, although its effect appeared secondary compared to jet pressure. Regression models developed for all machining responses showed strong predictive performance, with coefficients of determination exceeding 0.95 and statistically insignificant lack-of-fit, suggesting adequate representation of the underlying process behaviour within the investigated parameter range. Scanning electron microscopy of the machined surfaces revealed erosion features such as abrasive ploughing, particle pull-out, and striation formation. These surface morphologies are consistent with the observed variations in Ra and kerf characteristics and reflect the combined ductile–brittle erosion response of the composite. Overall, the study identifies optimised AWJM parameter combinations that can improve both surface quality and machining efficiency when processing AA7175–ZrB2 composites.

Micro doi: 10.3390/micro6030057

Authors: Alibala Aliyev Ulviyya Hasanova Silvia Buroni Altunay Aliyeva Aygun Israyilova

Clays, historically employed in traditional medical practices, have recently gained prominence within contemporary biomedical science, especially in the context of wound healing, due to advancements in nanotechnology and materials science. This review article investigates the physicochemical characteristics, biological processes, and therapeutic functions of clay materials—including bentonite, halloysite nanotubes, palygorskite, sepiolite, and synthetic clays like Laponite—in diverse wound-healing applications. These materials play a crucial role in the wound-healing process, including stopping bleeding, controlling inflammation, protecting against infection, and rebuilding tissue. They work through both passive and active methods. The layered or fibrous structure of these materials allows for efficient drug loading, controlled release, and mechanical support when used in hydrogels, films, and advanced drug delivery systems. Preclinical and initial clinical investigations have substantiated the biocompatibility, antimicrobial properties, and regenerative capabilities of these systems, although they have also revealed several challenges concerning toxicity, regulatory categorization, and standardization. Consequently, clay-based systems present a potentially valuable multifunctional platform for advancing next-generation wound-treatment therapies, necessitating additional translational and clinical research.

Micro doi: 10.3390/micro6030056

Authors: Jain A. R. Tony Benedict Barath Srinivas Prabakaran Janardhan Kamath Sreenarayan Venkatachalam Subramanyam Muhammed Anaz Khan Ajith Raj Rajendran

This study investigates the mechanical and thermal properties of epoxy composites reinforced with aluminum nanoparticles (Al NPs), titanium nanoparticles (Ti NPs), and chopped E-Glass fibers, individually and in hybrid combinations. Thirteen compositions were systematically fabricated and characterized, spanning pure epoxy (PRC0), Al NP-series (PRA1–3), Ti NP-series (PRT1–3), Al NP/E-Glass hybrid series (PRAG1–3), and Ti NP/E-Glass hybrid series (PRTG1–3). The investigation evaluates the effects of these reinforcements on tensile strength, flexural strength, Shore D hardness, thermogravimetric stability, and microstructure. The PRTG2 composite (2 wt% Ti NP + 2 wt% E-Glass fiber) achieved the highest tensile strength of 80 MPa (33.3% improvement over pure epoxy) and the highest flexural strength of 115 MPa (43.75% improvement). These results demonstrate the superior reinforcing efficiency of Ti nanoparticles over Al nanoparticles and the synergistic benefit of combining nanoparticle and fiber reinforcements within a single epoxy matrix.

Micro doi: 10.3390/micro6030055

Authors: Irina Nikulin Volker Kible Jonathan Seybold André Bülau Stephan Knappmann

For the development of a novel optical sensor technology, diffraction grating microstructures were manufactured on a silicon surface. The principle of operation of the sensor technology is based on rotatory encoder technology, developed at Hahn-Schickard. It is based on a convolution of a Gaussian laser beam at a diffraction grating, generating sine and cosine signals resulting from the movement of the diffraction grating. Applying this approach to silicon is new and places technological challenges, which are overcome using a proprietary nanoimprint lithography (NIL) process. The process development, which was done on bulk silicon, is discussed, and its capability of producing operational optical grating microstructures is verified by moving the bulk silicon chips with the grating over an opto-electronic module using a piezo stage in an automated control and data acquisition setup. The noise measured in a 16-bit setup was below 2.8 nm RMS, and the linearity error was 100 nm RMS. Compared to the traveled distance (320 µm), this is less than 350 ppm. Furthermore, the chips with the grating were refined to a MEMS-accelerometer chip by introducing etched spring structures. This setup then was verified using different miniaturized interpolator boards.

Micro doi: 10.3390/micro6030054

Authors: Mudda Deepak Ullinga Ramesh Mylapalli Hariprasad Reddy Obili M. Hussain Christian M. Julien

In material research, heteroatom doping in a host lattice is regarded as an effective method to modify the structural and electronic properties of the materials, consequently enhancing their electrochemical performance. This study represents the microstructural and electrochemical properties of lanthanum-doped Li4Ti5O12 (Li4Ti5−xLaxO12, x = 0.02, 0.04, and 0.06) using a hydrothermal method. The findings indicate that all three compositions demonstrate a comparable crystallite phase, free from discernible impurities, and exhibit a flake-like morphology. The Li4Ti4.96La0.04O12 sample exhibited a cubic spinel structure with flake-like morphology, a low crystallite size of 9.7 nm and a reasonably good electrical conductivity of 3.56 × 10−6 S cm−1. In order to delve deeper into the supercapacitive behavior, the electrochemical characteristics of the electrodes were assessed through cycling voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS). Notably, the Li4Ti4.96La0.04O12 electrode demonstrated exceptional electrochemical performance, achieving a specific capacitance of 461 F g−1 at 1 A g−1. Furthermore, it exhibited commendable cycling stability with approximately 80% capacitance retention after 5000 cycles and around 89% Coulombic efficiency, highlighting its potential as a noteworthy electrode material for energy storage applications.

Micro doi: 10.3390/micro6030053

Authors: José Luis Pompa-Ramos Francisco Rodríguez-Félix Dora Evelia Rodríguez-Félix José Agustín Tapia-Hernández Miguel Angel Robles-García Silvia Elena Burruel-Ibarra Teresa del Castillo-Castro María Jesús Moreno-Vásquez Karla Hazel Ozuna-Valencia Alejandra Montserrat Preciado-Saldaña Beatriz Montaño-Leyva Carlos Gregorio Barreras-Urbina Ricardo Aly López-Cruz

The development of sustainable biopolymer-based active packaging materials is essential to replace single-use petroleum-derived plastics and reduce food deterioration. In this study, chitosan-based films incorporating green-synthesized silver microparticles (Ag microparticles) obtained from pecan nutshell extract rich in phenolic compounds were developed as multifunctional materials with antioxidant and antibacterial properties. Films were prepared by the casting method using chitosan solutions at different concentrations (1.5–2.5% w/v), with Ag microparticles incorporated at 0.25% (w/v). The phenolic profile of the extract (gallic acid, catechin, ferulic acid, and ellagic acid), determined by UPLC-DAD, confirmed its role as a reducing and stabilizing agent during Ag microparticle synthesis. All film-forming solutions exhibited non-Newtonian pseudoplastic behavior, and variations in viscosity and consistency were directly reflected in the mechanical behavior of the films. Strong antioxidant activity, mainly governed by single-electron transfer mechanisms, was observed in ABTS, DPPH, and FRAP assays. The films also showed pronounced antibacterial activity, achieving complete inhibition of Listeria monocytogenes. Finally, it is concluded that film mechanical properties are strongly governed by the rheological behavior of the chitosan-based film-forming solutions. The resulting chitosan-Ag microparticle films combine suitable mechanical behavior with antioxidant activity and antibacterial effects against Listeria monocytogenes, suggesting their potential for future application in active food-packaging systems.

Micro doi: 10.3390/micro6030051

Authors: Ayşenur Bezelya Berrin Küçüktürkmen Hande Yüce

The production of polymeric nanoparticles using microfluidic systems holds great potential for controlled drug delivery applications. In this study, the effects of flow parameters and surfactant properties on the characteristics of PLGA (Poly (lactic-co-glycolic acid)) nanoparticles were systematically investigated. First, the total flow rate (TFR) and flow rate ratio (FRR) were optimized to ensure stable droplet formation. Subsequently, the effects of different surfactant types (anionic, cationic, and nonionic) and their varying concentrations were evaluated. Using the selected parameters, capsaicin-loaded PLGA nanoparticles were successfully produced. The particles were prepared using a microfluidic platform, and the organic phase was subsequently removed via solvent evaporation. The resulting formulations were comprehensively characterized in terms of particle size, polydispersity index (PDI), zeta potential, and encapsulation efficiency (%EE). Additionally, the in vitro release profiles and cytotoxicity of capsaicin-loaded nanoparticles were evaluated. This study aimed to elucidate the decisive role of surfactant parameters in the microfluidic production of PLGA nanoparticles and to contribute to the development of optimized and reproducible formulations.

Micro doi: 10.3390/micro6030052

Authors: Mozhgan Jirehnezhadyan Fatemeh Norouzi Hamidreza Ghaderi Jafarbeigloo Zahra Abpeikar Mohsen Safaei Ahmad Reza Farmani Arash Goodarzi

Background: Taurine is a bioactive amino acid that has great potential for wound healing, but it struggles with poor skin penetration and quick clearance. This study aimed to develop taurine-loaded nanoliposomes (Nlp-Tau) to enable sustained local delivery and improve effectiveness. Methods: Nlp-Tau were prepared using thin-film hydration. We characterized them for size, charge, shape, encapsulation efficiency (EE%), loading efficiency (LE%), and in vitro release. Also, its biocompatibility on human foreskin fibroblasts (HFF) with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT assay) has been assessed. In vitro wound healing potential was further evaluated using a scratch assay. Results: Optimized Nlp-Tau showed favorable properties, including an average hydrodynamic diameter of about 282 nm, a polydispersity index of 0.2, a strong negative zeta potential of −31.3 mV, and a spherical shape. However, transmission electron microscopy (TEM) images revealed diameters of about 142 nm and 194 nm for the drug-free and taurine-loaded particles, respectively. Additionally, EE% and LE% were 20% and 2.5%, respectively. In vitro release in PBS (pH 7.4) followed Higuchi kinetics, showing sustained release over 72 h. Nlp-Tau displayed excellent biocompatibility, with HFF viability significantly higher than other groups at concentrations up to 7 mg/mL. Importantly, in the scratch assay, Nlp-Tau treatment resulted in just 6.8% of the wound area remaining after 48 h, which outperformed free taurine at 10.7%. Conclusions: The Nlp-Tau system we developed offers a stable, biocompatible, and effective delivery method for sustained taurine release. It demonstrates greatly improved in vitro wound closure and shows strong potential for future wound care applications.

Micro doi: 10.3390/micro6030050

Authors: Hemayet Hossain Snigdha Sharmin Binte Sayeed Md. Al Muktadir Sojib Ahmed Mostafizor Rahman Md. Hasan Ali Sadia Islam Ria Milon Mia Tajmir Hossain Badhon Golam Ahsan Md. Mosharof Hosen Md. Shahidur Rahman Chowdhury Md. Mahfujur Rahman

Microplastics (MPs) and nanoplastics (NPs) have become pervasive environmental contaminants, raising growing concern regarding their potential accumulation within the human body and associated health risks. MP particles can translocate into systemic circulation and multiple organs, necessitating a comprehensive evaluation of current human biomonitoring data. This comprehensive review aimed to synthesize current evidence on the occurrence, distribution, detection technologies, exposure reduction and potential health implications of microplastics in human biological samples. The reviewed literature confirms the presence of microplastics in blood, placenta, amniotic fluid, umbilical cord blood, breast milk, semen, urine, and selected tissues including cardiovascular, renal, and reproductive samples. Detection frequencies in some matrices exceeded 70–90%, with polymer types such as polyethylene, polypropylene, polystyrene, and polyethylene terephthalate most commonly identified. Reported particle sizes ranged from nanometer-scale fragments to particles over 100 µm, indicating both systemic circulation and potential tissue retention. Spectroscopic techniques such as μFTIR and μRaman dominate polymer identification, while thermoanalytical approaches such as Py-GC/MS provide quantitative polymer confirmation. Emerging evidence suggests associations with oxidative stress, inflammatory responses, endothelial dysfunction, and impaired reproductive parameters, although causal relationships remain uncertain due to methodological heterogeneity and limited longitudinal data. This review provides an integrated overview of current human exposure evidence, identifies analytical gaps, and highlights the urgent need for harmonized detection frameworks and longitudinal risk assessment studies to inform public health policy and future biomonitoring strategies.

Micro doi: 10.3390/micro6030049

Authors: Liangtian Li Shuangquan Wen Junfeng Xiong

Magnetically actuated microrobots have exhibited broad application prospects in biomedical fields. To advance their clinical application, extensive research has attempted to enhance the navigation robustness of microrobots in the body. In the vascular environment, microrobots are easily obscured by blood cells and disturbed by fluid flow, leading to the failure of external sensors and the formation of navigation blind zones. However, most existing navigation methods are based on ideal environment assumptions and struggle to address the challenges posed by navigation blind zones. The study proposes a navigation framework integrating Extended Kalman Filter (EKF) and a Proportional–Integral–Derivative (PID) controller. The EKF fuses sensor measurements and the microrobot kinematic model to sustain continuous state estimation when sensors fail inside blind zones. The simulation results show that this navigation framework achieves pixel-level positioning accuracy under ideal conditions and a 100% navigation success rate. In the presence of blind zone interference, this navigation framework can effectively suppress the divergence of position errors and significantly improve navigation robustness. The study proposes a theoretical framework for microrobot navigation in vascular blind zones. Further physical prototype experiments are required to verify its practical performance.

Micro doi: 10.3390/micro6030048

Authors: Yanfang Zhang Jinggang Hao Conggui Huang Yue Dong Quanhua Chen Ke Fang Dongjie Qian Guoling Xiao

The κ-phase gallium oxide (κ-Ga2O3) has emerged as a promising material for next-generation electronic devices owing to its ultra-wide band gap, remarkable spontaneous polarization and unique ferroelectricity. We have investigated the two-dimensional electron gas (2DEG) characteristics and device performance of κ-Ga2O3/GaN HEMTs via numerical simulations. The κ-Ga2O3/GaN heterostructure exhibits a significantly enhanced 2DEG density (~1.05 × 1014 cm−2), which is nearly an order of magnitude higher than that of conventional AlGaN/GaN HEMTs, due to the strong polarization effect. For a barrier thickness of 25 nm, the κ-Ga2O3/GaN HEMT exhibits a maximum drain current density (ID,max) of 4.40 A/mm at VGS = 2 V and a peak transconductance (gm,max) of 0.45 S/mm, accompanied by a steep subthreshold swing (SS) of 63.2 mV/decade. Furthermore, we find that the absolute value of threshold voltage increases with the barrier thickness and the peak transconductance decreases with the increase in barrier thickness. When the thickness reaches 40 nm, the 2DEG density becomes saturated with a value of 1.12 × 1014 cm−2. Moreover, by incorporating a p-type GaN cap layer into the κ-Ga2O3/GaN heterostructure, a normally off operation is achieved, with a positive threshold voltage as the acceptor concentration exceeds 8.0 × 1017 cm−3. These results highlight the potential of κ-Ga2O3/GaN heterostructures for high-performance power electronic applications.

Micro doi: 10.3390/micro6030047

Authors: Vusala Nabi Jafarova Aynur N. Jafarova Jihad H. Asad Ayisha J. Ahmadova Resul S. Rehimov Rahila A. Hasanova Fariz Guliyev

In this work, the structural, electronic, charge-transfer, thermal, and magnetic properties of pristine and Fe-doped silicon carbide nanosheets (SiCNShs) were systematically investigated using spin-polarized density functional theory (DFT) within the Local Spin Density Approximation including Hubbard correction (LSDA + U). A 4 × 4 SiCNSh supercell containing 80 atoms was considered, where Fe atoms were substitutionally introduced at carbon sites to evaluate dopant-induced modifications in the nanosheet. Structural optimization, energy convergence, force minimization, and stress evolution analyses confirm that Fe incorporation preserves the structural integrity of the SiCNSh and leads to energetically stable configurations. The calculated defect formation energy (−7.44 eV/atom) demonstrates the thermodynamic feasibility of Fe substitution, while ab initio molecular dynamics (AIMD) simulations at 300 K verify the thermal stability of the energetically favorable Fe-doped configuration. Electronic-structure calculations reveal that pristine SiCNSh exhibits a nonmagnetic semiconducting nature with a band gap of approximately 2.4 eV, whereas Fe incorporation significantly modifies the electronic structure through pronounced Fe–3d/C–2p/Si–3p orbital hybridization. The band gap is reduced to approximately 1.1 eV for the single-Fe-doped system and further decreases to 0.53/0.51 eV (spin-up/spin-down) in the double-Fe configuration, while preserving semiconducting behavior. Spin-polarized band structure and density of states analyses demonstrate clear spin asymmetry near the Fermi level, indicating strong dopant-induced spin polarization and exchange interactions. Charge-density difference and Bader charge analyses reveal substantial dopant-induced charge redistribution characterized by electron depletion around Fe atoms, enhanced electron accumulation on neighboring carbon atoms, and partial charge neutralization of nearby Si atoms, resulting in a more localized covalent Si–C–Fe bonding environment. Mulliken spin population analysis further demonstrates robust ferromagnetic ordering, where the Fe dopant acts as the dominant magnetic center with strong induced spin polarization extending into neighboring Si and C atoms. Comparison between ferromagnetic (FM) and antiferromagnetic (AFM) configurations confirms that the 2Fe@C-doped SiCNSh stabilizes in a ferromagnetic ground state, exhibiting a favorable FM–AFM energy difference of 0.216 eV. Based on the mean-field approximation, the Curie temperature was estimated to be approximately 837 K, indicating strong magnetic stability significantly above room temperature. The present findings collectively demonstrate that Fe incorporation effectively tailors the electronic and magnetic properties of SiCNSh through band-gap engineering, spin-symmetry breaking, and stabilization of high-temperature ferromagnetism. These combined characteristics establish Fe-doped SiCNShs as promising candidates for spintronic devices, magnetic semiconductors, spin injectors, spin filters, and non-volatile magnetic memory applications.

Micro doi: 10.3390/micro6030046

Authors: Yang Ping Shuang Bao Muhammad Naeem Tabassam Hao Xu Zhenzhou Zhang Yinlong Pan Heng Zhu Saad Aslam Naveed Ahmad

Two-dimensional (2D) materials have emerged as a key platform for next-generation electronics due to their atomic thickness and tunable properties. Iron disulfide (FeS2), known as pyrite, with a bandgap of ~0.95 eV, is suitable for solar energy applications. However, its performance is limited by defects in bulk crystals. Reducing FeS2 to a single layer eliminates bulk defects and enables strain engineering of the bandgap. In this study, First-principles density functional theory (DFT) calculations are performed using the CASTEP code and the PBEsol functional to examine the structural, electronic, and optical properties of a distorted 1T′-phase FeS2 monolayer. Full geometry optimization yields lattice parameters a′ = 17.594 Å, b′ = 3.20231 Å, c′ = 5.28091 Å, and Fe–S bond angles of ~75.8° and ~98.2°, confirming symmetry-breaking distortion. The monolayer is dynamically stable, showing no imaginary modes in the phonon dispersion, and remains structurally intact up to 1000 K in molecular dynamics simulations. The unstrained system has an indirect bandgap of 0.70 eV, with the valence band maximum at the Γ point (dominated by S-p states) and conduction band minimum near the X point (Fe-d states). Under mechanical strain (±4%), the bandgap decreases significantly: from 0.70 eV to 0.44 eV under +4% tensile strain along the y-axis, and to 0.53 eV under −4% compressive strain. Biaxial strain causes weaker modulation, reducing the gap to 0.66 eV (+4%) and 0.62 eV (−4%). Optical absorption exceeds 104 cm−1 for photon energies above the bandgap, with tensile strain causing redshifts and compressive strain inducing blueshifts. These findings demonstrate that 2D FeS2 is mechanically robust, electronically tunable, and optically active, making it a promising candidate material for flexible strain sensors and photovoltaic devices. This work is intended to motivate and inform future synthesis efforts.

Micro doi: 10.3390/micro6020045

Authors: Rostyslav Marunych Dorota Bartusik-Aebisher Barbara Smolak Klaudia Dynarowicz David Aebisher

Photodynamic therapy (PDT) represents a promising non-antibiotic strategy for addressing bacterial and fungal infections, particularly in the context of increasing antimicrobial resistance and biofilm-associated disease. PDT is based on the light-induced activation of photosensitizers, leading to the generation of reactive oxygen species (ROS), including singlet oxygen (1O2), which induce oxidative damage to multiple microbial targets. Unlike conventional antimicrobial drugs that often act through specific molecular pathways, antimicrobial PDT produces simultaneous damage to membranes, proteins, nucleic acids, and extracellular biofilm components, thereby reducing the probability of resistance development. This review critically analyzes the cellular, biochemical, and biophysical determinants that govern PDT selectivity toward bacterial and fungal cells in comparison with mammalian host tissues. Particular attention is given to photosensitizer localization, membrane interactions, photobleaching, oxygen dependence, light penetration, and the balance between Type I and Type II photochemical mechanisms. The review provides a comparative overview of major molecular photosensitizer classes, including phenothiazines, porphyrins, chlorins, phthalocyanines, xanthene dyes, natural polyphenols, endogenous compounds, and advanced targeted photosensitizers. In addition, this review distinguishes molecular photosensitizers from nanotechnology-based platforms and delivery systems. Nanoparticles, polymeric carriers, hydrogels, and light-activated coatings are discussed not only as photosensitizer delivery tools, but also as systems that modulate aggregation, improve localization, enhance biofilm penetration, and enable surface-confined ROS generation. ROS are capable of causing phototoxic effects wherever they are located. Unless selectively accumulated by target organisms, there can be systemic phototoxicity. Overall, PDT should be regarded as a modular antimicrobial platform in which photosensitizer chemistry, formulation, light delivery, oxygen availability, and infection biology must be co-optimized. Although further studies are required to address clinical translation, regulatory complexity, material safety, and standardized treatment protocols, PDT offers a scientifically robust and clinically relevant approach that may complement conventional antibacterial and antifungal therapies, especially in localized, biofilm-associated, and device-related infections.

Micro doi: 10.3390/micro6020044

Authors: Tolga Duran Necip Atar

The adsorption of aromatic hydrocarbons from liquid paraffin is essential because of their harmful nature, long-lasting presence, and detrimental effects on the quality of the product. In this study, we investigated the adsorption of naphthalene from liquid paraffin by using a nanoclay-based adsorbent prepared from boron enrichment process waste. The characterization of the prepared adsorbent was carried out by using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS) and N2 adsorption–desorption techniques, which confirmed the development of a layered nanostructure containing boron that possesses a porous and high-surface-area format appropriate for the adsorption. The hydrothermal treatment significantly increased the BET surface area from 35.42 to 112.15 m2/g, indicating the successful formation of a porous nanostructure. The kinetic and isotherm parameters of the adsorption process were calculated from experimental data. The adsorption of naphthalene followed pseudo-second-order kinetics and the isotherm fit well to the Langmuir model. Adsorption experiments revealed that the optimum adsorption performance was achieved at pH 4.0, and equilibrium was reached within 90 min. The adsorption kinetics were best described by the pseudo-second-order model (R2 > 0.99), while the equilibrium data showed excellent agreement with the Langmuir isotherm model (R2 = 0.995), suggesting monolayer adsorption. The maximum adsorption capacity of BNC was determined as 365.20 mg/g, which was more than twice that of the raw BEW (247.59 mg/g). Thermodynamic analysis indicated that the adsorption process was spontaneous at lower temperatures and exothermic, with a ΔH° value of −15.42 kJ/mol for BNC. The results suggest that the adsorption occurs through a multi-step process, beginning with external film diffusion, followed by pore diffusion and surface interaction. Based on the kinetic, isotherm, and spectroscopic data, a supramolecular adsorption mechanism is suggested, which encompasses π-π interactions, van der Waals forces, and surface complexation between naphthalene and the nanoclay structure. These results indicate that boron enrichment process waste-derived nanoclay is a sustainable, economical, and efficient adsorbent for removing naphthalene from liquid paraffin.

Micro doi: 10.3390/micro6020043

Authors: Bo Pan Yang Liu Furong Cao Lei Li Hao Liu Yongyuan Li Haibo Zhao Yizhong Cao Wushuang Bai

Hydrogen sulfide (H2S) is a contaminant for water quality, which can affect the eyes, respiratory system, and central nervous system, and may also cause damage to multiple organs such as the heart. Therefore, rapid and sensitive detection of trace H2S is of great importance. In this work, a novel gold nanoparticle/2D porphyrin metal–organic framework nanocomposite (Au NPs/2D Cu-TCPP MOF) was prepared, and a novel electrochemical sensing method was established for the rapid determination of H2S by differential pulse voltammetry (DPV). In 0.1 M PBS (pH 7.0), the detection limit of H2S is as low as 0.03 μM, the linear range is 0.1–10 μM, and the response time is about 7 s. In addition, this method exhibits good stability and reproducibility, which can be applied to the rapid detection of H2S in mine water samples. This study provides a reference for the development of new detection methods for H2S in various complex environments.

Micro doi: 10.3390/micro6020042

Authors: Afia Sultana Qingyue Wang Miho Suzuki Christian Ebere Enyoh Md. Sohel Rana Weiqian Wang Anunobi Chinazo Ndidiamaka

Microplastic (MP) contamination in terrestrial ecosystems has emerged as a critical environmental concern, particularly in agricultural soils influenced by anthropogenic activities. This study investigated the depth-wise distribution, polymer composition, and associated ecological and human health risks of MPs in homestead agricultural soils across four regions of Bangladesh representing different levels of industrialization: Narayanganj (old industrial), Savar (moderate industrial), Gazipur (emerging industrial), and Mymensingh (non-industrial). Soil samples were collected from two depth intervals (0–20 cm and 21–50 cm), and MPs were extracted using density separation, identified through microscopic analysis, and characterized via ATR-FTIR spectroscopy. A diverse range of MP morphologies and polymers was detected, with irregular particles and fragments dominating the composition. Polypropylene (PP), high-density polyethylene (HDPE), and polyethylene terephthalate (PET) were the most abundant polymers, reflecting widespread domestic, industrial, and agricultural plastic usage. MP abundance was consistently higher in surface soils, indicating dominant surface inputs, although vertical migration into subsoil layers was evident. Spatial analysis revealed higher MP contamination in industrial regions, particularly Narayanganj and Savar, compared to the non-industrial reference site. Ecological risk assessment indicated low risk levels across all regions; however, significant spatial variability was observed. Human exposure assessment demonstrated that inhalation was the primary pathway, followed by dermal contact and ingestion, with children exhibiting higher exposure levels than adults. Lifetime average daily dose (LADD) and carcinogenic risk estimates remained below acceptable thresholds, suggesting minimal immediate health risks. Nevertheless, the persistence, mobility, and cumulative nature of MPs highlight potential long-term concerns. Therefore, this study provides comprehensive insights into the sources, distribution, and risks of MPs in homestead agricultural soils and underscores the need for improved waste management practices, sustainable agricultural strategies, and long-term monitoring to mitigate environmental and human health impacts.

Micro doi: 10.3390/micro6020041

Authors: Rebecca Sikkema Igor Zhitomirsky

This investigation addressed challenges in the delivery of poorly soluble drugs, and the colloidal processing of polymer–ceramic composites by fabrication of advanced supramolecular hydrogels. Polygalacturonic acid (PGA) polymer and 18β-glycyrrhetinic acid (GA) drug, both characterized by poor aqueous solubility, were selected as model building blocks for supramolecular hydrogels. Meglumine (MG) served as a multifunctional component in the gels, acting as a building block as well as an alkalizing and solubilizing agent for PGA and GA. Investigations revealed gel formation mechanisms, which were based on the electrostatic interactions of deprotonated anionic carboxylic groups of PGA and GA with protonated amino groups of MG and the hydrogen bonding of PGA polymer and GA molecules. The feasibility of the fabrication of PGA-MG and GA-MG gels opened an avenue for the fabrication of PGA-GA-MG gels. The composite gels provided a platform for drug delivery, and the kinetics of drug release from the composite gels containing MG excipient were investigated. Composite gels were obtained from colloidal dispersions, containing bioceramics, such as hydroxyapatite, silica, and titania, and bioglass in the PGA solutions in the presence of MG. The results of this investigation pave the way for the fabrication of novel supramolecular and composite gels loaded with various functional materials.

Micro doi: 10.3390/micro6020040

Authors: Edith Dube

Phytochemical-assisted green synthesis of silver nanoparticles offers a sustainable alternative to conventional fabrication routes by utilising plant-derived metabolites as multifunctional reducing, capping, and stabilising agents. Polyphenols, flavonoids, tannins, alkaloids, and related biomolecules mediate the reduction of Ag+ to Ag0 under mild conditions while controlling nucleation, growth, and surface stabilisation, thereby dictating nanoparticle size, morphology, and colloidal stability. This review establishes clear links between phytochemical composition and the mechanistic pathways governing nanoparticle formation and biofunctional performance. Variations in extract chemistry influence electron transfer dynamics, surface functionalisation, and physicochemical properties, ultimately modulating biological activity. Enhanced antimicrobial and antioxidant effects arise from synergistic interactions between the silver core and phytochemical capping layers, promoting membrane disruption, reactive oxygen species generation, and biomolecular interference. Despite promising applications in antimicrobial coatings, food preservation, agriculture, and anticancer systems, key challenges remain, including compositional variability, limited mechanistic standardisation, and insufficient toxicological evaluation. Nonetheless, phytochemical-assisted synthesis provides a tunable and sustainable platform for AgNP production, aligning nanomaterial design with green chemistry principles while enabling multifunctional bioactivity. By integrating phytochemical composition, mechanistic synthesis pathways, and structure–activity relationships across diverse applications, this review provides a critical framework for the rational design, standardisation, and scalable development of next-generation phytochemical-mediated AgNP systems.

Micro doi: 10.3390/micro6020039

Authors: Hedi Ben Ahmed Maxim Pryazhnikov Jessica Pirogovskaya Sergey Zharkov Il’ya Bril’ Andrey Minakov

Magnesium oxide (MgO) nanoparticles, recognized for their versatile applications from catalysis to biomedicine, require synthesis methods that offer precise control over their properties while ensuring safety and scalability. This study explores a safer, industrially viable adaptation of the polyacrylamide gel synthesis route by utilizing magnesium sulfate (MgSO4) instead of conventional nitrates to mitigate explosion risks during calcination. A systematic study was conducted to evaluate the influence of key synthesis parameters, such as crosslinker ratio, initiator concentration, precursor loading, calcination conditions (including temperature, time, and heating rate), pH, and the use of chelating agents (EDTA and citric acid), on the purity, morphology, size distribution, and colloidal stability of the synthesized MgO nanoparticles. Characterization via X-ray spectroscopy XRF and XRD, acoustic spectroscopy, nitrogen physisorption (BET), electronic microscopy SEM and TEM and dispersion stability analysis revealed that polymeric cell volume (controlled by crosslinker and initiator) significantly influences size distribution, while chelating agents in alkaline environments drastically reduce particle size to ~20 nm and alter morphology to platelets (EDTA) or polygonal shapes (citric acid). Crucially, a low heating rate (2.5 °C/min) was found to yield smaller particles (~30 nm) and higher purity. This work provides a comprehensive blueprint for the tailored, safe, and scalable synthesis of MgO nanoparticles with targeted properties for specific technological applications.

Micro doi: 10.3390/micro6020038

Authors: Emanuela Cutuli Pasquale Memmolo Biagio Mandracchia Maide Bucolo

This work presents the Smart-Reflex-Scope, a compact and accessible smartphone-based microscope with integrated reflective illumination developed for on-chip analysis of microparticle dynamics. In this work, the platform is specifically employed to characterize size-dependent microparticle motion within a microchannel. The Smart-Reflex-Scope simultaneously functions as an illumination source and imaging unit by integrating a reversed smartphone camera lens, a custom reflex module, a microfluidic chip, and a precision Z-axis translation stage for focal adjustment. The optical performance was quantitatively evaluated in terms of equivalent focal length, magnification, and object-plane spatial resolution, providing a comprehensive assessment of the system’s microscale imaging capabilities. A comparative design study was conducted between two configurations: Design-1, based on normal reflection, and Design-2, based on angular reflection. The two approaches were analyzed with respect to illumination uniformity and imaging performance to identify the optimal configuration for enhanced visualization. Experimental validation was performed using synthetic microparticles with diameters of 6μm and 20μm, enabling assessment of the system’s ability to resolve and dynamically track micrometric objects of different sizes. The results demonstrate reliable detection and size-dependent dynamic characterization. A two-factor statistical ANOVA analysis confirmed the significance of the observed differences between microparticle groups under the tested experimental conditions (p-value <0.0001). Overall, the proposed platform represents a scalable and miniaturized microscopy solution bridging conventional benchtop instruments and portable analytical devices.

Micro doi: 10.3390/micro6020037

Authors: Masanori Sakamoto Akari Nakata Misa Shimizu Ayuka Tagashira Hideyuki Hirazawa Yugo Imai Hazuki Saka Kokona Okabe

Conventional organic and inorganic ultraviolet (UV) filters often face limitations related to photostability, skin penetration, and potential toxicity arising from their photocatalytic activity. In this study, graphitic carbon nitride (g-C3N4) was investigated as a candidate biocompatible UV-shielding pigment. g-C3N4 powders were synthesized via thermal polymerization using urea and melamine as precursors. The melamine-derived samples exhibited a dense, block-like morphology with a strong yellow coloration and poor spreadability. In contrast, the urea-derived samples formed a distinctive porous and rounded structure. This morphology, originating from multistage gas evolution during polymerization, significantly reduced the static friction coefficient, resulting in a smoother texture and improved skin adaptability. Preliminary biological evaluation indicated high cell viability in cytotoxicity tests. Combined with the observed low photocatalytic activity, these findings suggest a favorable biocompatibility profile for topical applications. Overall, the results demonstrate that precursor engineering using urea enables the synthesis of high-performance g-C3N4 pigments with improved texture, desirable optical properties, and reduced biological reactivity.

Micro doi: 10.3390/micro6020036

Authors: Manita Saini Syed Arman Rabbani Mohamed El-Tanani Shrestha Sharma Rakesh Kumar

Fungal infections remain a major and growing global health concern, particularly in immunocompromised populations and in settings where antifungal resistance is increasing. Imidazole antifungals continue to play an important role in the treatment of superficial and mucocutaneous mycoses because they inhibit lanosterol 14α-demethylase (CYP51), a key enzyme in ergosterol biosynthesis. This mechanism disrupts fungal membrane integrity and underlies their clinical utility. However, the effectiveness of imidazoles is increasingly limited by resistance mechanisms such as CYP51 mutations, efflux pump overexpression, and biofilm-associated tolerance. In parallel, several biopharmaceutical constraints, including poor aqueous solubility, limited tissue penetration, short residence time, and variable local drug exposure, further reduce therapeutic performance. This review critically examines the medicinal chemistry, mechanism of action, and resistance biology of imidazole antifungals, while also highlighting the role of pharmacokinetic and pharmacodynamic limitations in treatment failure. Particular attention is given to emerging drug delivery approaches, including lipid-based systems, vesicular carriers, nanocarriers, and other advanced topical formulations, which are being developed to improve solubility, enhance tissue retention, and sustain antifungal exposure at the site of infection. By integrating resistance mechanisms with formulation science, the review provides a translational perspective on how imidazole antifungals may be optimized for improved clinical utility and resistance management.

Micro doi: 10.3390/micro6020035

Authors: Tomasz Blachowicz Guido Ehrmann Johannes Fiedler Reinhard Kaschuba Andrea Ehrmann

Freeform optics belong to the increasingly important elements in optical research and industry, which pose several challenges regarding design and highly precise manufacturing. First being used in cameras and for focusing, nowadays freeform optics are used in a broad range of applications, from lighting to LiDAR, from endoscopy to photovoltaics, and from astronomical instruments to quantum cryptography. Designing freeform optics can be based on different theories and methods. Fabrication is possible by mechanical methods, such as diamond turning or high-precision milling, often followed by different polishing techniques, as well as laser-based techniques, mainly applying different lithographic techniques. Here, we give an overview of recent design and optimization methods, production methods used during the last years, and applications of freeform optics, including the possibility to combine freeform optics with tunability for different applications. We describe the opportunities of new applications as well as common problems and give an outlook towards future directions of research and development.

Micro doi: 10.3390/micro6020034

Authors: Vladimir Georgiev Evgeni Ivanov Todor Batakliev Rumiana Kotsilkova

The present work investigates the composition-dependent thermoresistive behavior of polylactic acid/polycaprolactone (PLA/PCL) composites reinforced with 4 wt.% graphene nanoplatelets (GNP), prepared by twin-screw extrusion at PLA/PCL ratios of 95/5, 70/30, 60/40, and 30/70 wt.%/wt.%. Their morphology, thermal properties, and structure were characterized by scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and wide-angle X-ray diffraction. Thermoresistive measurements over four cycles (30–130 °C) revealed two distinct regimes: PLA-rich compositions exhibited a stable, monotonic positive temperature coefficient (PTC) response after the first conditioning cycle, with TCR values up to 0.38% °C−1, whereas compositions with 40–70 wt.% PCL displayed a non-monotonic PTC-to-NTC transition linked to PCL melting and subsequent conductive network rearrangement. The magnitude of both PTC and NTC responses increased systematically with PCL content. These results demonstrate that the thermoresistive characteristics of biodegradable PLA/PCL/GNP composites, including the sign, magnitude, and switching temperature of the TCR, can be effectively tuned through blend composition, offering a practical route for designing thermally responsive sensing materials.

Micro doi: 10.3390/micro6020033

Authors: Diego Pádua de Almeida Paula Zambe Azevedo Ramila Cristiane Rodrigues Elisa de Paula Reis Lima Paulo Cesar Stringueta Pedro Henrique Campelo Evandro Martins

The increasing incidence of foodborne diseases and the limitations of conventional preservation methods have driven the search for safer, more effective, and sustainable antimicrobial strategies. In this context, essential oil nanoemulsions have emerged as promising alternatives to synthetic preservatives due to their broad-spectrum antimicrobial activity, natural origin, and potential applicability across diverse food matrices. This study critically examines the mechanisms of action of essential oils against pathogenic and spoilage microorganisms and discusses how their incorporation into nanoemulsions can overcome limitations such as low volatility, poor solubility, and chemical instability. The physicochemical principles governing the formation and stability of these nanoemulsions are addressed, alongside the influence of food matrix components (proteins, lipids, polysaccharides, pH, and ionic strength) on antimicrobial efficacy. Evidence from real food systems indicates that nanoemulsions often outperform free essential oils, although the magnitude of the effect strongly depends on matrix complexity and processing or storage conditions. The review further discusses critical aspects related to toxicity, safety, bioaccessibility, sensory acceptance, and regulatory considerations, as well as emerging evidence on adaptive responses and antimicrobial resistance risks associated with sublethal exposure to essential oil nanoemulsions. It is concluded that, despite their considerable technological potential, the industrial application of essential oil nanoemulsions requires further systematic studies in real foods, standardized protocols, and integrated risk assessments to ensure efficacy and safety under practical conditions.

Micro doi: 10.3390/micro6020032

Authors: Reiko Kohsaka Saho Komatsu Akiko Haruyama Toshiaki Ara Akihiro Kuroiwa Nobuo Yoshinari Atsushi Kameyama

The effects of different surface pretreatments on the microtensile bond strength (µTBS) between a bulk-fill resin-based composite cavity base material (Bulk Base HARD II) and 4-META/MMA-TBB resin (Super-Bond EX), which is often used as a luting agent for indirect dental restorations, were investigated. Six experimental treatments were established: 10% citric acid/3% ferric chloride conditioner (10-3), self-etching primer (Teeth Primer; TP), silane coupling agent (M&C Primer; MC), 10-3+MC, TP+MC, and a control group with no treatment. The µTBS was measured after 1 week (immediate group) and 6 months (aged group) of water storage. There were no significant differences in µTBS among the immediate subgroups. However, the aged 10-3+MC group exhibited the highest bond strength, significantly outperforming the control group. On the other hand, the µTBS of the aged TP group was significantly lower than those of both aged 10-3 and 10-3+MC. MC alone did not enhance bond strength, and its application after TP led to a nonuniform surface morphology, raising concerns about adhesive stability. Failure mode analysis indicated that cohesive failure within the luting cement was predominant, with mixed failures being more frequent in the aged TP group. Overall, MC may not be necessary, and 10-3 conditioning does not adversely affect bond strength. Based on the results of this in vitro study, the most effective clinical practice entails pretreatment of the prepared cavity employing a citric acid/ferric chloride conditioner.

Micro doi: 10.3390/micro6020031

Authors: Joseph B. Bernstein Tsuriel Avraham Bin Wang

Bias temperature instability (BTI) degradation is commonly described using empirical power-law kinetics; however, extraction of the time exponent and projection of lifetime remain highly sensitive to baseline definition and data representation. In conventional approaches, the threshold voltage shift is referenced to an initial value that cannot be measured simultaneously with stress, introducing uncertainty that can produce apparent curvature and variability in the extracted exponent. In this work, a baseline-independent linearization method is applied to representative published datasets spanning advanced silicon, SiC MOSFETs, and GaN power devices. By analyzing the measured degradation trajectories directly in a transformed time coordinate, the method removes curvature associated with baseline ambiguity and enables consistent extraction of the effective power-law exponent. Across all material systems examined, the extracted exponent exhibits systematic dependence on applied stress once baseline effects are reduced. This behavior challenges the commonly assumed constant-exponent formulation used in conventional lifetime projections and shows that even modest variations in the exponent can produce large differences in projected time-to-failure. A transformed lifetime representation based on TTFn is introduced, in which the influence of exponent variation is separated from the intrinsic voltage and temperature acceleration of the degradation rate. In this representation, the extracted acceleration parameters become more stable and physically interpretable. This formulation is consistent with standard reliability frameworks, including JEDEC JEP122G, in which the time exponent enters directly into the lifetime expression. These results demonstrate that baseline-independent analysis provides a unified framework for interpreting BTI degradation across disparate semiconductor technologies and suggest that explicit treatment of stress-dependent exponents is required for physically consistent lifetime modeling.

Micro doi: 10.3390/micro6020030

Authors: Martina Schwager Niklas Käfer Jenni Richter Hannes Reggel

The hydrogen evolution reaction (HER) plays a central role in electrochemical hydrogen production and requires catalysts that combine high activity with reduced noble metal usage. In this work, palladium nanoparticles (PdNPs) were deposited onto silver nanowire-modified graphite electrodes (Pd/AgNW/C) to investigate the influence of Pd loading on HER kinetics and catalytic efficiency. The electrodes were prepared by constant-current electrodeposition and characterized using polarization measurements and electrochemical impedance spectroscopy (EIS). The direct current (DC) results showed a pronounced enhancement of HER activity in the presence of Pd, while the highest mass-specific activity was observed at low Pd loadings. Increasing the Pd content further increased the overall current but reduced the catalytic efficiency when normalized to the Pd mass. EIS measurements revealed two contributions to the impedance response associated with processes occurring on different timescales. With increasing cathodic overpotential, both the charge transfer resistance and the low-frequency resistance decreased markedly, indicating accelerated reaction kinetics. The combined DC and alternating current (AC) analyses suggest that the silver nanowire network facilitates efficient electron transport and promotes a favorable dispersion of Pd nanoparticles at low loadings, enabling efficient HER catalysis with reduced noble metal usage.

Micro doi: 10.3390/micro6020029

Authors: Rifat Hussain Chowdhury Shunya Okamoto Takayuki Shibata Tuhin Subhra Santra Moeto Nagai

Resin 3D-printed molds are being increasingly favored for PDMS microfluidics across many disciplines. However, resin diversity, as well as secret manufacturer formulations, leads to a lack of standardization when using 3D printing for microscale applications. The impact of physical resin properties, both in its monomeric concoction and polymerized lattices at 100 µm or lower scales, needs quantification. We tested the performance of locally available resin formulations, isolating the impact of resin pigments and how it impacted the resin’s properties and performance. Lower resin viscosity improved feature fidelity (edge filleting < 25 µm) and improved resolution limit for recessed features, while cured polymer mechanical strength impacted the limit for positive mold features. We combined our findings to fabricate quality negative and positive mold structures in the mold and determined the best protocols associated with limitations during the fabrication of such structures. The methodologies in this study are expected to be widely applicable across various resin types and simplify the adoption of 3D printing protocols for specific feature fabrication in microscale molds for PDMS devices.

Micro doi: 10.3390/micro6020028

Authors: Mareni Arishima Shigehisa Aoki Sayaka Masaike Takayuki Narita

Vascularization remains a central challenge in thick tissue engineering. Building on our prior demonstration that carbonate buffer concentration governs multi-channel collagen gel (MCCG) architecture and perfusion culture performance, this study aimed to establish non-contact, orthogonal control of pore size and density in riboflavin-sensitized Type I collagen hydrogels via UV irradiation intensity and preparation temperature. UV intensity was modulated by varying the source-to-sample distance (25–52 mm); preparation temperature was set at 5, 25, or 40 °C; gelation kinetics were quantified using a vial-tilt assay. Pore area fraction ranged from 0.9% to 8.6% and Young’s modulus from 16 to 49 kPa depending on UV dose. Higher preparation temperatures accelerated gelation and produced smaller, more densely distributed pores, consistent with kinetically arrested phase separation. NIH/3T3 fibroblasts cultured on intermediate- and low-intensity UV scaffolds achieved >80% confluency by Day 7, with three-dimensional tissue-like organization and directionally aligned cellular bundles within large pores; cell metabolic activity, assessed by CCK-8 assay, remained consistently high throughout the culture period. These results demonstrate that UV irradiation intensity and preparation temperature are independently tunable, non-contact parameters for reproducible fabrication of collagen scaffolds with tunable vascular-like pore networks, complementing and extending the chemical (buffer concentration) design space of MCCG-based perfusion culture systems.

Micro doi: 10.3390/micro6020027

Authors: Sahin Demirci Jorge H. Torres Seneshaw Tsegaye Nurettin Sahiner

The widespread use of herbicides such as paraquat and glyphosate is a serious environmental and health concern due to their persistence, mobility, and toxicity in aquatic ecosystems. Composites of alginic acid (Alg) are prepared with carbonaceous materials such as graphene oxide (GO), carbon particles (CPs), porous carbon particles (PCPs), carbon black (CB), and carbon nanotubes (CNTs) were synthesized and evaluated as sorbents for the removal of cationic herbicide paraquat and the anionic herbicide glyphosate. The resulting Alg-based beads are environmentally safe because of the materials used during their preparation, such as a biopolymer, Alg, carbonaceous substances (GO, CPs, PCPs, and CB) as composite moieties, and Ca(II) ions as cross-linkers. The Alg–bead composite possessed strong swelling ability ranging from 1700% to 2500%, which led to swollen beads of spherical shape and an average diameter of 3 mm, each containing 20% of carbonaceous materials. Amongst all Alg-based beads prepared for paraquat and glyphosate removal from the aquatic environment, the highest adsorption capacity was attained for Alg–porous carbon particle (Alg-PCP) composites. The Alg-PCP beads were capable of adsorbing 85.7 ± 2.9 mg/g and 31.6 ± 2.2 mg/g from 50 mL of 250 ppm solutions of paraquat and glyphosate, respectively. In contrast, bare Alg beads adsorbed only 39.7 ± 1.8 mg/g and 12.9 ± 1.7 mg/g, respectively. A 250 mg Alg-PCP bead composite achieved a 91% removal of paraquat from a 50 mL solution containing 250 ppm of paraquat. These results show that Alg–PCP can be used to mitigate herbicide contamination in water, protecting aquatic ecosystems and addressing associated environmental and health risks.

Micro doi: 10.3390/micro6020026

Authors: Yudai Oda Masaki Miyamoto Shogo Miyata

Mechanical confinement plays an important role in regulating tumor growth and invasion; however, the quantitative, time-resolved, three-dimensional evaluation of confined tumor spheroids remains technically challenging. In this study, we developed a custom-built selective plane illumination microscopy (SPIM)-based monitoring platform for long-term volumetric imaging of tumor spheroids under mechanically confined conditions. This system integrates a culture housing unit and a transparent cuvette-based spheroid culture method optimized for SPIM observation. Colorectal adenocarcinoma-derived cell spheroids were embedded in agarose gels with defined concentrations to modulate the stiffness of the surrounding matrix. Bright-field imaging and viability analyses confirmed sustained spheroid growth without necrotic core formation over a 4-day culture period, demonstrating that the SPIM-based system maintained the physiological culture conditions. Three-dimensional imaging using SPIM enabled a quantitative evaluation of spheroid growth and anisotropic invasion. Volumetric expansion was observed under all confinement conditions. Notably, increasing the matrix stiffness enhanced both the volumetric growth rate and anisotropic invasion, indicating stiffness-dependent directional growth under mechanical confinement. The developed SPIM-based platform has the potential to serve as a practical tool for the time-resolved three-dimensional analysis of tumor spheroid growth and may provide a useful approach for investigating the mechanobiological regulation of tumor progression in confined microenvironments.

Micro doi: 10.3390/micro6020025

Authors: Sonia J. Bailón-Ruiz Yarilyn Cedeño-Mattei Nayeli Colón-Dávila Luis Alamo-Nole

The environmental persistence of β-lactam antibiotics represents a growing ecological concern, requiring materials capable of combined adsorption and catalytic degradation. Herein, pure ZnS and 1% Fe-doped ZnS nanoparticles were synthesized via microwave-assisted treatment and evaluated for the removal of ceftaroline fosamil from aqueous media. Transmission electron microscopy revealed quasi-spherical nanoparticles below 10 nm, while selected area electron diffraction confirmed a face-centered cubic structure retained after Fe incorporation. UV-Vis spectroscopy showed similar absorption edges (~316 nm), indicating negligible band-gap variation, whereas photoluminescence analysis demonstrated strong emission quenching in Fe-ZnS, indicating suppressed electron–hole recombination. Point-of-zero charge measurements (pHPZC ≈ 4.6 for ZnS; 4.5 for Fe-ZnS) indicated negatively charged surfaces under circumneutral conditions, influencing interfacial interactions with the antibiotic. Adsorption experiments followed the Langmuir isotherm model, with Fe-ZnS exhibiting a higher maximum adsorption capacity (156 mg g−1) compared to ZnS (115 mg g−1). Under UV irradiation (302 nm), Fe-ZnS achieved near-complete degradation at a catalyst loading of 500 ppm. Liquid chromatography–mass spectrometry analysis revealed the transformation of ceftaroline fosamil (m/z 685.01) into ceftaroline (m/z 605.05) via phosphate group loss, followed by the formation of intermediate fragments at m/z 492.08 and 308.03, associated with cleavage of the thiadiazol-amine moiety and subsequent opening of the cephalosporin ring. After extended irradiation, these intermediates diminished, and a fragment at m/z 356.01 was detected, suggesting further breakdown through thioether bond cleavage. These results support a degradation pathway involving sequential dephosphorylation and fragmentation of the cephalosporin core. Overall, the enhanced performance of Fe-ZnS arises from the synergistic interplay between surface charge characteristics and dopant-modulated charge carrier dynamics, highlighting its potential for antibiotic remediation in aquatic environments.

Micro doi: 10.3390/micro6020024

Authors: Sashka Alexandrova Anna Szekeres Evgenia Valcheva Mihai Anastasescu Hermine Stroescu Madalina Nicolescu Mariuca Gartner

Nitridation of different materials using ion implantation is of considerable interest for many applications. As electronic components, oxynitride (SiOxNy) layers exhibit beneficial properties such as precise compositional variability, refractive index tunability, oxidation resistance, and low mechanical stress. In the present study we investigate nanoscale SiOxNy synthesized using ion implantation methods. To introduce N+ ions into a shallow Si subsurface region, both conventional ion beam implantation and plasma immersion ion implantation with subsequent high-temperature treatment in dry O2 are used. The optical and morphological properties and chemical bonding of formed SiOxNy layers were studied by applying spectroscopic ellipsometry in the range of VIS-Near IR (SE) and IR (IR-SE), Raman spectroscopy and Atomic Force Microscopy (AFM). Monte Carlo modeling of implant profiles contributed to understanding physical and chemical processes and predicted different influences of the incorporated N+ ions on the oxidation mechanism, confirmed by the thickness dependence of SiOxNy/Si layers obtained from the SE data analysis. IR-SE spectral analysis established the formation of Si-O, Si-N, Si-N-O and Si-Si chemical bonds in the grown layers. The occurrence of amorphization of the Si crystal lattice due to incorporation of high-energy N+ ions into the Si lattice is confirmed by the Raman and ellipsometry results. The free Si atoms can congregate, forming nanocrystalline clusters. AFM imaging revealed that both implantation methods left the surface of the resulting SiOxNy layers considerably smooth with similar roughness parameter values. The results of the studies imply that the technological approaches used allow the production of high-quality nanoscale silicon oxynitride films with appropriate tunable composition and properties for possible application in advanced electronic devices for nanoelectronics, optoelectronics and sensor applications.

Micro doi: 10.3390/micro6020023

Authors: Victor Petrov Timofey Grishin Alexandra Starnikova

This study investigates the properties of ZnO nanorod-based sensors and ZnO nanorods modified with tin dioxide (ZnO/SnO2) and gold (ZnO/Au) nanoclusters and their response to low concentrations of carbon monoxide (CO). It was demonstrated that the ZnO/SnO2(3) nanorod-based sensor exhibited the highest sensitivity (S = 1.64) to 10 ppm CO, while the ZnO/Au(3) sensor displayed the shortest response (69–207 s) and recovery (203–233 s) times. This behavior can be explained by ZnO/Au and ZnO/SnO2 nanostructures having low activation energies (0.23–0.25 eV) and high potential barrier values (0.37–0.43 eV). Sensors based on ZnO/Au and ZnO/SnO2 nanorods demonstrate sensitivity to 10 ppm CO at 250 °C and at 200 °C. In contrast, ZnO nanorod-based sensors are sensitive to 2 ppm CO at 250 °C.

Micro doi: 10.3390/micro6010022

Authors: Jude N. Ike Raymond Tichaona Taziwa

Over the past two decades, organic semiconductors have attracted significant research interest due to their advantageous features, including low-cost fabrication, lightweight properties, and portability, for photonic device applications. In this study, nickel sulfide doped with cobalt (NiS/Co) nanocomposites were successfully synthesized via a wet-chemical processing technique and used as a dopant in the active layer of thin-film organic solar cells (TFOSCs). The poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) blend was used as the active layer in this investigation. The devices were fabricated with NiS/Co nanocomposites at 1 wt%, 2 wt%, and 3 wt% in the active layer to determine the optimal dopant concentration. However, the experimental evidence clearly showed that the solar cell’s performance depends on the concentration of the NiS/Co nanocomposites. As a result, the highest power conversion efficiency (PCE) recorded in this experimental work was 6.11% at a 1% doping concentration, compared with 2.48% for the pristine reference device under AM 1.5G illumination (100 mW/cm2) in ambient conditions. The optical and electrical properties of the active layers are found to be strongly influenced by the inclusion of NiS/Co nanocomposites in the medium. However, the device doped with 1 wt% NiS/Co nanocomposite exhibits the highest absorption intensity, consistent with the better performance observed in this study, which can be attributed to the localized surface plasmon resonance (LSPR) effect. The optical and morphological characteristics of the synthesized NiS/Co nanocomposites were comprehensively analyzed using high-resolution transmission electron microscopy (HRTEM), high-resolution scanning electron microscopy (HRSEM), and additional complementary techniques.

Micro doi: 10.3390/micro6010021

Authors: Warlen Monfardini João Victor Vieira João Batista Fogagnolo Juliano Soyama

Laser processing has been widely investigated as an effective approach for improving surface properties and consolidating advanced materials, particularly complex alloys such as titanium aluminides (TiAl). In this study, laser surface remelting was applied to binary (Ti-45Al) and ternary (Ti-45Al-2Co and Ti-45Al-2Ni) alloys produced by powder metallurgy via blended elemental (BE) and pre-alloyed (PA) powder routes. Laser powers of 50 and 100 W were employed, resulting in a high-energy-density surface remelting regime applied to both green compacts and sintered samples with relatively high initial porosity, under an argon-controlled atmosphere. Microstructural and phase analyses were performed using scanning electron microscopy (SEM) and X-ray diffraction (XRD), while mechanical behavior was assessed by instrumented microindentation. Laser processing promoted the formation of a dense and homogeneous surface layer, approximately 150 μm thick, accompanied by significant microstructural refinement and enhanced hardness and elastic modulus. While rapid solidification led to crack formation in laser-treated sintered samples, the green compacts exhibited defect-free modified layers. Overall, the results demonstrate that laser surface remelting is an effective strategy for enhancing the surface integrity and mechanical performance of TiAl alloys processed by powder metallurgy.

Micro doi: 10.3390/micro6010020

Authors: Iosif Galanakis

Employing ab initio electronic structure methods, in this study, I examine the effect of order on the spin gapless semiconducting behavior of the Mn2CoAl Heusler compound. The occurrence of atomic disorder in general destroys the spin gapless semiconductivity observed in the inverse XA lattice structure; however, in some cases, novel magnetic configurations emerge. In the case of structures derived from the XA structure, where only Mn-Co or Mn-Al atoms are mixed, Mn2CoAl alloy presents a half-metallic magnetic character. In the case of full disorder (A2 lattice structure), where atoms occupy all sites with the same probability, the ground state is an antiferromagnetic metallic one. The L21 and B2 lattice structures, where Mn atoms occupy both sites of a similar local environment, correspond to a ferromagnetic state of very high spin magnetic moment per formula unit. The present study encompasses a much larger variety of disordered structures in comparison with other studies in the literature. It concludes that the control and minimization of the concentration of impurities at anti-sites is imperative to achieving optimal performance in spintronic devices based on spin gapless semiconducting Mn2CoAl.

Micro doi: 10.3390/micro6010019

Authors: Evangelia Dimeli Dimitrios I. Anyfantis Athanasios Sigalos Alexandros Banis Dimitrios Niarchos

This work investigates the fabrication and performance of axially compressed isotropic epoxy-bonded NdFeB-type magnets produced from melt-spun powders with partial substitution of (Nd,Pr) by (La,Ce). Four alloy compositions were synthesized and processed into bonded magnets using two powder-to-binder weight ratios (95:5 and 96.5:3.5). Structural analysis confirms that all substituted alloys retain the tetragonal Nd2Fe14B phase (up to ~95 wt%) even at high substitution levels, while the lattice parameters decrease slightly with increasing (La,Ce) content. Microscopy analysis confirms a homogeneous distribution of the binder phase around the powder particles, demonstrating uniform binder–powder integration. Thermal analysis reveals composition-dependent Curie temperatures and enhanced crystallization onset in highly substituted powders. Magnetic measurements on both powders and bonded magnets show that increasing substitution leads to a gradual reduction in remanence, coercivity, and energy product, though all samples maintain strong hard-magnetic behavior. Increasing the powder fraction to 96.5 wt.% significantly improves all magnetic parameters due to higher magnetic-phase density and enhanced interparticle coupling, yielding bonded magnets with densities up to ~80% of the theoretical value. The resulting magnets achieve competitive performance, uniform field distribution and isotropic magnetization with (BH)max values about 65 kJ/m3, a coercivity around 660 kA/m, and superior thermal stability compared with commercial bonded NdFeB magnets. Overall, partial substitution with light rare-earth elements (La,Ce) provides a cost-effective route to high-density bonded NdFeB magnets that combine strong magnetic performance, enhanced thermal stability, and suitability for lightweight, complex-shaped industrial applications. Surprisingly, the coefficients of the temperature variation of coercivity and (BH)max are much better compared to the commercial NdFeB bonded magnets.

Micro doi: 10.3390/micro6010018

Authors: Julia Rieber Tiziano A. Schweizer Gabor Kadler Gabriella Meier Bürgisser Pietro Giovanoli Johanna Buschmann

Background: Surgical tendon rupture repair suffers from scar formation, leading to tendons with inferior mechanics and consequently to re-ruptures, as well as from adhesion formation to the surrounding tissue, reducing the range of motion. In an approach of re-purposing the phytochemical Bakuchiol to be incorporated in the polymer DegraPol® (DP), we fabricated a novel implant material by emulsion electrospinning. Methods: To characterize the emulsion electrospun novel materials, we used Scanning Electron Microscopy (SEM) to determine the fiber diameter and pore size. In addition, we used Fourier Transformed Infrared Spectroscopy (FTIR). Finally, we planted the materials onto the chorioallantoic membrane of the chicken embryo (CAM assay) to assess tissue integration and collagen expression. Results: While the pure DP meshes were very well integrated in the CAM assay and showed a significantly higher collagen deposition within the scaffold, the DP + Bakuchiol meshes exhibited poor tissue integration, showing rather the beginning of a fibrous encapsulation. Conclusions: The novel electrospun material DP + Bakuchiol could be used as an anti-adhesion barrier to prevent tendon adhesion.

Micro doi: 10.3390/micro6010017

Authors: Xuening Zhao Kangyu Liu Jiaying Yuan Yuming Li

One-dimensional alumina nanorods have garnered significant attention due to their unique physical and chemical properties, which hold great promise for applications in catalysis, sensing, and other fields. However, the precise control over the morphology and properties of these nanorods remains a challenge, particularly in achieving a high specific surface area and desirable crystallinity. In this work, we explored the hydrothermal synthesis of alumina nanorods, focusing on the effects of structure-directing agents. It was observed that extending the hydrothermal time and optimizing the temperature led to the formation of nanorods with enhanced crystallinity and specific surface area. The addition of urea and different structure-directing agents significantly influenced the morphology and properties of the nanorods. Furthermore, density functional theory (DFT) calculations revealed the underlying mechanisms of how these structure-directing agents affect the adsorption and growth of alumina nanorods on different crystal planes. Our findings suggest that by carefully tuning these parameters, it is possible to achieve alumina nanorods with optimized properties. This work not only provides a systematic approach to the synthesis of alumina nanorods but also opens up new possibilities for the development of advanced materials with tailored properties for a wide range of applications.

Micro doi: 10.3390/micro6010016

Authors: Arjun Thakur Shreeji Pandit Abhishek Singh Ashish Mathur Krishna Kant

Microfluidics provides precise control of microscale fluid transport and has become central to biomedical, pharmaceutical, and industrial technologies. However, conventional fabrication methods such as photolithography and soft lithography require cleanroom facilities, use costly materials, and offer limited capability for constructing complex or multi-material architectures. This review highlights emerging manufacturing strategies, focusing on polymer-based micro-milling as an accessible and cost-effective alternative for microfluidic device production. Advances in micro-milling now enable the fabrication of microchannels and functional features with improved dimensional accuracy and surface quality, while additive manufacturing offers complementary rapid prototyping and design flexibility. Micro-milling is particularly promising for rapid prototyping of polymeric biosensor chips designed for point-of-care diagnostics. The technique supports diverse materials and eliminates reliance on cleanroom processing. Critical parameters, including tool geometry, spindle speed, and feeding rate, strongly influence fidelity and surface roughness, which directly affect biosensor sensitivity. Despite its advantages, challenges such as tool wear, burr formation, and limits on minimum feature size continue to hinder reproducibility. Recent progress in toolpath optimization, hybrid additive–subtractive methods, and real-time process monitoring shows the potential to overcome these barriers. Overall, micro-milling offers a scalable and economical route for fabricating accessible microfluidic and biosensing platforms, with future work needed to standardize processes and improve integration with surface functionalization methods.

Micro doi: 10.3390/micro6010015

Authors: Christian Ebere Enyoh Qingyue Wang

The rapid and selective discrimination of microplastics (MPs) is a critical analytical challenge, particularly as current carbon quantum dot (CQD)-based sensors often rely on single-wavelength “turn-on/off” or staining mechanisms that lack polymer-specific resolution. This work addresses these limitations by presenting a mechanism-driven fluorescence sensing platform using ultra-fine polyamide-derived carbon quantum dots (PACQDs; ~1.4 nm) to identify three prevalent MPs: polyamide (PA), polypropylene (PP), and polyethylene terephthalate (PET). Excitation–emission matrix (EEM) spectroscopy reveals polymer-specific photophysical responses: PAMPs and PPMPs induce fluorescence enhancement of 11.66% and 11.43%, respectively, whereas PETMPs cause net quenching (−4.61%) alongside a distinct, red-shifted emission band. Despite a common scatter-dominated peak at 290/308 nm, quantitative discrimination is achieved via integrated intensity and red/blue emission ratios (0.0137 for PAMPs, 0.0098 for PPMPs, and 0.0072 for PETMPs). Multivariate analysis reinforces this discrimination. Parallel factor analysis (PARAFAC) resolves the EEM data into three fluorescent components representing the intrinsic CQDs core and two interaction-induced surface states with a rank 3 model reducing the relative reconstruction error from 0.1625 to 0.1285. Principal component analysis (PCA) yields clear separation of the polymer classes, with the first two principal components capturing ~88% of the total spectral variance. ATR–FTIR spectroscopy provides direct molecular evidence for the underlying mechanisms: amide–amide coupling and interfacial rigidification for PAMPs; hydrophobic interaction without spectral shifts for PPMPs; and a synergistic interaction involving hydrogen bonding and π–π stacking for PETMPs. In particular, these polymer-specific fluorescence fingerprints are largely preserved in tap water, despite elevated background intensity and partial contrast attenuation, demonstrating the resilience of the EEM–chemometric approach under realistic matrix conditions. Collectively, the strong agreement between fluorescence metrics, multivariate signatures, and interfacial chemistry establishes a robust structure–property framework and positions PACQDs as a rapid, label-free, and matrix-tolerant platform for reliable microplastic discrimination in environmental analysis.

Micro doi: 10.3390/micro6010014

Authors: László Égerházi Erika Griechisch Tamás Szörényi

Wire explosion (WE) inherently generates particle ensembles spanning the nano- to microscale, posing challenges for conventional characterization methods in terms of capturing the full particle population. To address this issue, spectrophotometric analysis combined with algorithmic spectrum reconstruction based on Mie theory and constrained distribution models were employed to characterize copper WE products formed in aqueous surroundings within the 4–12 kV discharge voltage range. Three independent fitting strategies, specifically a semimanual fitting, an evolutionary algorithm, and a grid search, were applied to retrieve the size distributions and relative shares of copper and copper oxide particles as a function of discharge voltage. Based on experimental and theoretical findings, lognormal and normal distributions across the 10–300 nm diameter range were assumed as constraints for oxide and metallic fractions, respectively. The reconstructed metallic copper population exhibited mean diameters ranging from 123 to 181 nm, while oxidized fractions followed lognormal distributions centred near 10 nm mode diameters. Voltage-dependent trends revealed an optimal discharge regime between 6 kV and 8 kV, where the exploded fraction reached approximately 63% and the metallic mass share exceeded 80%. These results confirmed that spectrophotometry represents an essential tool for the quantitative characterization of such complex, wide-range systems.

Micro doi: 10.3390/micro6010013

Authors: Navaratnarajah Kuganathan Tharmarajah Manoranjan

The functionalization of molecules on C60 is a promising engineering approach, as non-covalently governed fullerene surfaces facilitate reversible host–guest recognition, tunable electronic communication, and conformationally adaptive molecular adsorption. In this work, spin-resolved simulations using density functional theory (DFT) were conducted to examine the interaction between a newly identified arylalkanone isolated from the medicinal species Myristica ceylanica and the nanocarbon framework of C60 fullerene, including doped configurations incorporating group III elements (B, Al, Ga, In and Tl). The results indicate that the arylalkanone binds to pristine C60 through an exothermic, energetically favourable binding process, supporting thermodynamically viable molecular uptake. Among the doped models, B substitution exhibits the greatest overall thermodynamic preference; however, Al doping produces the most pronounced enhancement in binding energy, identifying the Al-doped configuration as the most effective surface-uptake architecture in relative terms. Across all complexes, a small amount of charge transfer is noted, signifying weak yet persistent electronic coupling between the ligand and the carbon carrier. Additionally, all doped fullerenes demonstrate induced magnetic behaviour, a property of increasing relevance in spintronics research, suggesting that these complexes may hold future value in spin-dependent electronic and molecular-recognition-guided nanoscale biomedical engineering.

Micro doi: 10.3390/micro6010012

Authors: Heyi Wei Yang Zou Xuecheng Qu Xi Cui Zhou Li

Nanomaterials have emerged as a pivotal driving force in the field of biomedicine due to their unique physicochemical properties. This article systematically reviews the design, synthesis, and characterization of novel nanomaterials, with a focus on their application advances in three key areas: targeted drug delivery, tissue engineering and regenerative medicine, and disease diagnosis and sensing. In drug delivery, nanocarriers enable precise drug targeting and controlled release through surface functionalization and stimuli-responsive design. In tissue engineering, nanocomposite scaffolds mimic the structure and function of the natural extracellular matrix, providing an ideal microenvironment for tissue repair. In disease diagnosis, nanomaterials significantly enhance the sensitivity and specificity of biosensors, promoting the development of real-time, non-invasive, and ultra-early detection technologies. The article further summarizes current challenges in the clinical translation of nanomedicine and envisions its future trends toward intelligence, personalization, and the integration of diagnosis and therapy.

Micro doi: 10.3390/micro6010011

Authors: Ewelina Musielak Agnieszka Feliczak-Guzik Aleksandra Majchrzak-Celińska Anna Rybarczyk Violetta Krajka-Kuźniak

Malignant gliomas, including glioblastoma multiforme (GBM) and grade 4 astrocytoma, are the most common types of brain tumors in adults. Standard treatment for gliomas includes adjuvant chemotherapy, typically based on temozolomide, combined with radiotherapy. However, its effectiveness is severely hindered by the limited ability of drugs to cross the blood–brain barrier and by the hyperactivation of the canonical Wnt signaling pathway, which drives tumor cell survival. Therefore, innovative drug combinations and novel delivery strategies are crucial for overcoming these barriers. Polymeric micelles represent a promising approach for enhancing drug delivery to brain tumors. This study aimed to obtain micelles containing cannabidiol (CBD), celecoxib (CELE), and temozolomide (TMZ), as well as their combinations, and to verify their anti-glioma properties. The study involved optimizing the micelle composition, incorporating active ingredients, and assessing the temporal stability of the resulting nanocarriers under varying temperature conditions. The GBM cell line U-138 MG and astrocytoma cell line U-87 MG were used to evaluate the biologic effects of the tested micelles. Cytotoxicity was assessed using the MTT assay, and flow cytometry was used to analyze the effect of the micelles on apoptosis. Western blot analysis was employed to assess the impact of the tested nanoformulations on the Wnt/β-catenin signaling pathway. The optimized micelles demonstrated strong cytotoxic and proapoptotic effects, accompanied by attenuation of the Wnt/β-catenin pathway. These preliminary findings support the therapeutic potential of polymeric micelles for treating malignant gliomas; however, further in vitro and in vivo studies are required to confirm their clinical applicability.

Micro doi: 10.3390/micro6010010

Authors: Luis Alamo-Nole Glorimar Rivera-Rodriguez

The production of quantum dots (QDs) has increased due to their wide variety of commercial products and applications. QDs can be dangerous in the environment because their small size can encourage their incorporation into living systems. In this project, ZnS and ZnSSe were synthesized under microwave irradiation, generating a water-stable nanomaterial. The bandgap energies calculated using the UV-Vis spectra were 3.81 and 3.86 eV for ZnS and ZnSSe QDs, respectively, indicating that the selenium worked as a dopant agent. The photoluminescence analysis shows narrow emission peaks, confirming a low size distribution, and the selenium doping generated a blue shift. The crystal size of both nanomaterials was around 7 nm. The cellular toxicity of these nanomaterials was evaluated using Chinese Hamster Ovary (CHO) Cells (a standard mammalian cell model). The results suggest that ZnS and ZnSSe QDs slightly affect the viability of CHO Cells, but Zn2+ decreases the viability at concentrations higher than 20 mg/L. The content of zinc inside cells (by ICP-OES) suggested that QDs can enter cells more easily than Zn2+. Therefore, the decrease in cell viability caused by Zn2+ outside the cells is likely due to its effect on cell membrane integrity, suggesting that these nanomaterials are less toxic than bulk materials.

Micro doi: 10.3390/micro6010009

Authors: Abbass Akhdar Amine Geneste Asfaw Zegeye Bénédicte Prélot Jerzy Zajac

Fe-oxyhydroxides can incorporate toxic metals during the formation of mineral phases in soils and sediments, thereby potentially altering the environmental reactivity of metals and impacting the microbial communities. In this study, isothermal microcalorimetry has been used to monitor the metabolic activity of Pseudomonas putida KT2440 exposed to pure ferrihydrite and to Pb-, Cd-, and As-bearing ferrihydrites under oxygen-limited conditions. Calorimetric measurements of the integral heat released during the exponential growth were combined with the analysis of dissolved iron and heavy metals, as well as the glucose uptake, to understand how heavy metal incorporation modifies mineral reactivity and microbial heat output. Pure ferrihydrite decreased the integral heat by about 45%, primarily due to glucose and phosphate depletion, Fe(III) leaching, and mineral–cell aggregation. Heavy metal dopants were found to modulate nutrient availability, surface charge, and Fe solubilization, which, in turn, influenced the integral heat. Pb-Fh generated the highest ferrihydrite dissolution and metabolic heat, with a maximum effect at intermediate substitution levels. As-Fh induced moderate Fe release and metabolic activity, consistent with the enhanced phosphate sorption and lowered surface charge. Cd-bearing Fh showed minimal reactivity and yielded the lowest heat output. Microcalorimetry was proven useful for unraveling microbe–mineral interactions in complex contaminated environments.

Micro doi: 10.3390/micro6010008

Authors: Kuikui Zhang Lezhou Fang Can Xu Weiwei Zhou Xiaoqiu Deng Chenkun Shan Quanling Zhang Lijia Pan

Regenerative medicine is increasingly leveraging the synergies between bioinspired conductive biomaterials and 3D/4D bioprinting to replicate the native electroactive and hierarchical microenvironments essential for functional tissue restoration. However, a critical gap remains in the intelligent integration of these technologies to achieve dynamic, responsive tissue regeneration. This review introduces a “bioinspired material–printing–function” triad framework to systematically synthesize recent advances in: (1) tunable conductive materials (polymers, carbon-based systems, metals, MXenes) designed to mimic the electrophysiological properties of native tissues; (2) advanced 3D/4D printing technologies (vat photopolymerization, extrusion, inkjet, and emerging modalities) enabling the fabrication of biomimetic architectures; and (3) functional applications in neural, cardiac, and musculoskeletal tissue engineering. We highlight how bioinspired conductive scaffolds enhance electrophysiological behaviors—emulating natural processes such as promoting axon regeneration cardiomyocyte synchronization, and osteogenic mineralization. Crucially, we identify multi-material 4D bioprinting as a transformative bioinspired approach to overcome conductivity–degradation trade-offs and enable shape-adaptive, smart scaffolds that dynamically respond to physiological cues, mirroring the adaptive nature of living tissues. This work provides the first roadmap toward intelligent electroactive regeneration, shifting the paradigm from static implants to dynamic, biomimetic bioelectronic microenvironments. Future translation will require leveraging AI-driven bioinspired design and organ-on-a-chip validation to address challenges in vascularization, biosafety, and clinical scalability.

Micro doi: 10.3390/micro6010007

Authors: Ryosuke Nakamura Rie Togawa Daisuke Koizumi Masataka Kawarasaki Keishi Iohara Michiyo Honda

Dental caries is a major global health issue associated with biofilm formation by Streptococcus mutans (S. mutans). Conventional antimicrobials often fail to eliminate biofilms due to their structural resistance, highlighting the need for new strategies. This study investigated the antibacterial and antibiofilm effects of protamine peptides (PPs), which are cell-penetrating antimicrobial peptides derived from salmon protamine, alone and in combination with antimicrobial agents. Antimicrobial susceptibility was evaluated using alamarBlue® and colony count assays, while biofilm formation was analyzed using crystal violet staining, confocal microscopy, and extracellular polysaccharide (EPS) quantification. PP exhibited moderate antibacterial activity but strongly suppressed EPS accumulation and biofilm development, leading to a flattened biofilm structure. Cotreatment with ε-poly-L-lysine (PL) significantly enhanced antibacterial and antibiofilm effects compared with either agent alone, whereas this effect was not observed with other cationic polymers. Fluorescence imaging revealed that PL promoted the intracellular localization of PP without increasing membrane damage, indicating a cooperative mechanism by which PL enhances membrane permeability and PP targets intracellular sites. These findings demonstrate that combining a cell-penetrating peptide with a membrane-active agent is a novel approach to overcome bacterial tolerance. The PP–PL combination effectively suppressed S. mutans growth and biofilm formation through dual action on membranes and EPS metabolism, offering a promising basis for the development of peptide-based preventive agents and biofilm-resistant dental materials.

Micro doi: 10.3390/micro6010006

Authors: Nurettin Sahiner Sahin Demirci Betul Ari Selin S. Suner Mehtap Sahiner Olgun Guven

A facile and single-step synthesis of poly(L-Cysteine) (p(L-Cys)) particles through microemulsion polymerization using tetrakis(hydroxymethyl) phosphonium chloride (THPC) as crosslinker is accomplished for the first time. The L-Cys:THPC ratio in p(L-Cys) particles was calculated as 80:20% (by weight) with elemental analyses, and the generation of p(L-Cys) particles was confirmed. SEM imaging revealed a popcorn-like morphology of the p(L-Cys) particles with a 1–20 µm particle size range. The isoelectric point of p(L-Cys) particles was determined at pH 1.15 via zeta potential measurements. The hydrolytic degradation of p(L-Cys) particles was determined as about 85% within 3 h (by weight). The p(L-Cys) particles displayed excellent blood compatibility with a hemolysis % ratio of <2.3% and a blood clotting index of 95% at 1 mg/mL concentration. Moreover, cell compatibility tests up to 50 mg/mL against L929 fibroblast cells exhibited about 90% cell viability for p(L-Cys) particles versus 58% for L-Cys molecule. The antimicrobial efficacy of the L-Cys molecules was notably enhanced in p(L-Cys) particles, exhibiting a 5-fold reduction in minimal bactericidal concentration (MBC) values against E. coli (Gram-negative, ATCC 8739) and a 2-fold reduction against S. aureus (Gram-positive, ATCC 6538). Additionally, the antioxidant capacity of p(L-Cys) particles was retained somewhat, measured as 0.14 ± 0.01 µM versus 2.25 ± 0.03 µM Trolox equivalent/g for L-Cys. Therefore, p(L-Cys) particles are versatile and offer a unique avenue for immense biomedical use.

Micro doi: 10.3390/micro6010005

Authors: Azam Ali Muhammad Zaman Khan Sana Rasheed Rimsha Imtiaz

Integrating antibacterial fabrics into wearable technology represents a transformative advancement in healthcare, fashion, and personal hygiene. Antibacterial fabrics, designed to inhibit microbial growth, are gaining prominence due to their potential to reduce infections, enhance durability, and maintain cleanliness in wearable devices. These fabrics offer effective antimicrobial properties while retaining comfort and functionality by incorporating nanotechnology and advanced materials, such as silver nanoparticles, zinc oxide, titanium dioxide, and graphene. The production techniques for antibacterial textiles range from chemical and physical surface modifications to biological treatments, each tailored to achieve long-lasting antibacterial performance while preserving fabric comfort and breathability. Advanced methods such as nanoparticle embedding, sol–gel coating, electrospinning, and green synthesis approaches have shown significant promise in enhancing antibacterial efficacy and material compatibility. Wearable technology, including fitness trackers, smart clothing, and medical monitoring devices, relies on prolonged skin contact, making the prevention of bacterial colonization essential for user safety and product longevity. Antibacterial fabrics address these concerns by reducing odor, preventing skin irritation, and minimizing the risk of infection, especially in medical applications such as wound dressings and patient monitoring systems. Despite their potential, integrating antibacterial fabrics into wearable technology presents several challenges. This review provides a comprehensive overview of the key antibacterial agents, the production strategies used to fabricate antibacterial textiles, and their emerging applications in wearable technologies. It also highlights the need for interdisciplinary research to overcome current limitations and promote the development of sustainable, safe, and functional antibacterial fabrics for next-generation wearable.

Micro doi: 10.3390/micro6010004

Authors: Asma Gzaiel Khalil Aouadi Aurélien Besnard Yoann Pinot Corinne Nouveau Faker Bouchoucha Yahya Agzenai Ben Salem Amina Guessabi Boudjemaa Bouaouina

This paper investigates the properties of zirconium oxide thin films deposited on Ti6Al4V and Si substrates via oblique angle deposition, using varying out-of-plane θ (15 to 85°) and in-plane Φ (0 and 180°) substrate orientations. ZrO2 films have garnered significant interest due to their antibacterial properties and mechanical performance. The aim is to engineer surfaces capable of inhibiting bacterial growth while maintaining excellent mechanical integrity. The methodology combines experimental deposition by DC magnetron sputtering with multi-scale simulations using SRIM and SIMTRA. Structural analyses were conducted via X-ray diffraction, while microstructure and surface morphology were examined using scanning electron microscopy and atomic force microscopy. Nanoindentation tests were performed to assess hardness and elastic modulus. Results revealed that increasing the incidence angle α from 7 to 74° significantly affected surface morphology, microstructure, film thickness, and columnar tilt. The hardness and Young’s modulus of the films exceeded those of Ti6Al4V, for incidence angle α between 7 and 50°, but decreased with the increasing incidence angle α. Furthermore, the films exhibited strong antibacterial activity against Gram-positive pathogens (Staphylococcus aureus), particularly at the highest incidence angle α, with inhibition rates exceeding 90%.

Micro doi: 10.3390/micro6010003

Authors: Haider Jaafar Chilabi Luqman Chuah Abdullah Waleed Al-Ashtari Azizan As’arry Hanim Salleh Eris E. Supeni

The growing need for self-powered Internet of Things networks has raised interest in converting abundant waste into reliable energy harvesters despite long-standing material and technology challenges. As demand for environmentally friendly self-powered IoT devices continues to rise, attention toward green waste as an eco-friendly energy source has strengthened. However, its direct utilisation in high-performance energy harvesters remains a significant challenge. Driven by the growing need for renewable sources, the triboelectric nanogenerator has emerged as an innovative technology for converting mechanical energy into electricity. In this work, the design, fabrication, and characterisation of a rotating triboelectric energy harvester as a prototype device employing date seed waste as the tribopositive layer are presented. The date seeds particles, measuring 1.2 to 2 mm, were pulverised using a grinder, mixed with epoxy resin, and subsequently applied to the grating-disc structure. The coated surface was machined on a lathe to provide a smooth surface facing. The performance of the prototype was evaluated through a series of experiments to examine the effects of rotational speed, the number of grating-disc structures, the epoxy mixing process, and the prototype’s influence on the primary system, as well as to determine the optimal power output. An increase in rotational speed (RPM) enhanced power generation. Furthermore, increasing the number of gratings and pre-mixing of epoxy with the biomaterial resulted in enhanced output power. Additionally, with 10 gratings, operating at 1500 rpm, and a 24 h pre-mixing method, the harvester achieved maximum voltage and power outputs of 129 volts and 1183 μW at 7 MΩ.

Micro doi: 10.3390/micro6010002

Authors: Irene Méndez-Mesón Alba Sebastián-Martín Mónica Grande-Alonso Rafael Ramírez-Carracedo Rafael Moreno-Gómez-Toledano Antonio Peña-Fernández

Contemporary knee prostheses rely predominantly on a metal–polyethylene bearing couple, which—despite substantial advances in material engineering—continues to generate polymeric wear particles over time. While the local biological effects of polyethylene debris, such as inflammation and osteolysis, are well-characterised, their potential systemic implications remain insufficiently explored. In this review, we synthesise multidisciplinary evidence to evaluate the generation, biological behaviour, and systemic dissemination of polyethylene-derived nano- and microplastics (NMPs) released from knee prostheses. We also contextualise prosthetic wear within the broader toxicological framework of NMP exposure, highlighting translocation pathways, interactions with immune and metabolic systems, and potential multi-organ effects reported in recent experimental and clinical studies. Current findings suggest that prosthetic wear may represent an under-recognised internal source of NMP exposure, with possible implications for long-term patient health. A clearer understanding of the systemic behaviour of prosthetic-derived NMPs is essential to guide future biomonitoring studies, improve prosthetic materials, and support the development of safer, more biocompatible implant designs.

Micro doi: 10.3390/micro6010001

Authors: Edgar B. Sousa N. F. Cunha Joel Borges Michael Belsley

We demonstrate that pulsed laser annealing induces plasmonic gold nanoparticles in ZnO thin films, monitored in real-time via pulse-by-pulse spectroscopy. Initially embedded gold nanoparticles (smaller than 5 nm) in sputtered ZnO films were annealed using 532 nm pulses from a Q-switched Nd:YAG laser while monitoring transmission spectra in situ. A plasmonic resonance dip emerged after ~100 pulses in the 530–550 nm region, progressively deepening with continued exposure. Remarkably, different incident energies converged to a thermodynamically stable optical state centered near 555 nm, indicating robust nanoparticle configurations. After several hundred laser shots, the process stabilized, producing larger nanoparticles (40–200 nm diameter) with significant surface protrusion. SEM analysis confirmed substantial gold nanoparticle growth. Theoretical modeling supports these observations, correlating spectral evolution with particle size and embedding depth. The protruding gold nanoparticles can be functionalized to detect specific biomolecules, offering significant advantages for biosensing applications. This approach offers superior spatial selectivity and real-time process monitoring compared to conventional thermal annealing, with potential for optimizing uniform nanoparticle distributions with pronounced plasmonic resonances for biosensing applications.

Micro doi: 10.3390/micro5040060

Authors: Alibala Aliyev Aygun Israyilova Ulviyya Hasanova Zarema Gakhramanova Aida Ahmadova

The process of wound healing is intricate and regulated by a network of cellular, molecular, and biochemical pathways. Acute wounds progress via distinct phases of hemostasis, inflammation, proliferation, and remodeling. Chronic wounds frequently cease to heal and exhibit resistance to conventional therapies. These types of injuries are frequently attributed to diabetes, infection, or senescence. Existing therapies are constrained due to their ineffectiveness against bacteria, inability to promote regeneration, and inadequate control over medication release. Nanotechnology presents novel methods to overcome these challenges by providing multifunctional platforms that enable biological repair and medicinal delivery. Nanoparticles, which combat germs and modulate the immune system, in addition to being intelligent carriers that react to pH, oxidative stress, or enzymatic activity, provide targeted and adaptive wound therapy. Nanocomposite hydrogels are particularly advantageous as biointeractive dressings due to their ability to maintain wound moisture while facilitating regulated drug delivery. Recent advancements indicate their potential to aid in tissue regeneration, enhance therapy precision, and address issues related to safety and translation. Nanotechnology-based approaches, especially smart hydrogels, give significant promise to transform the future of wound care due to their flexibility, adaptability, and efficiency.

Micro doi: 10.3390/micro5040059

Authors: Luca Banchelli Rosen Mitrev Vladimir Stavrov Borislav Ganev Todor Todorov

This paper presents a theoretical and experimental investigation of the amplitude–frequency response of a triple-microcantilever system designed for real-time ultra-low mass detection. The present study focuses on the unfunctionalized configuration to clarify the intrinsic electromechanical behavior of this system. Starting with analytical expressions, output voltage amplitude–frequency responses are derived for a Wheatstone-bridge-based readout circuit and used to analyze the relationship between the resonant frequencies and mechanical amplitude–frequency responses of the three microcantilevers and the resulting electrical response. The extrema and zero-crossing points of the output voltage do not trivially coincide with the individual resonance peaks or their intersection points; this offers more freedom for defining strong detection criteria. A specialized experimental setup has been developed and used to measure the frequency response of a fabricated triple-microcantilever prototype; good agreement with the theoretical predictions has been found within the operating range. Initial humidification tests confirm the high sensitivity of the microsystem against small added masses, corresponding to an estimated detection limit on the order of 10−16 kg for the unfunctionalized device. In this way, the present work confirms the validity of the proposed triple-microcantilever configuration for ultra-low mass sensing and outlines its potential for future application in pathogen detection upon surface functionalization.

Micro doi: 10.3390/micro5040058

Authors: Jexairys Sostre-Figueroa Amanda Rodríguez-Cadiz Sonia J. Bailón-Ruiz

Zinc oxide (ZnO) nanoparticles are widely used in cosmetics, coatings, and industrial formulations due to their UV-absorbing and antimicrobial properties; however, their increasing release into aquatic systems has raised concerns about potential ecological risks. This study evaluates the acute toxicity of pure and silver-doped ZnO (Ag-ZnO) nanoparticles using Artemia salina as a marine model organism. Nanoparticles were synthesized via a reflux-assisted method and characterized by UV–Vis spectroscopy, HRTEM, ED, FTIR, and EDX analyses, confirming a crystalline wurtzite structure, particle sizes of 10–30 nm, and successful incorporation of 5% Ag. Silver doping produced a slight blue shift in the absorption edge and minor lattice distortions, indicating modifications in the electronic structure. Toxicity assays revealed clear concentration- and time-dependent decreases in nauplii survival. Dose–response modeling showed LC50 values of 358 ppm (24 h) and 64 ppm (48 h) for pure ZnO, whereas Ag-ZnO exhibited LC50 values of 607 ppm (24 h) and 28 ppm (48 h). These results indicate that Ag doping does not enhance short-term toxicity but markedly increases toxicity after prolonged exposure. Overall, the findings highlight the need to consider both nanomaterial composition and exposure duration in ecotoxicological assessments and provide relevant data for evaluating the environmental impact of doped nanomaterials in marine systems.