Search Results (138)

The global crisis concerning multidrug-resistant microorganisms necessitates the development of innovative antimicrobial strategies that avoid conventional antibiotics and overcome the toxicity and environmental persistence associated with traditional metal-based biocides. This work aims to develop safe and sustainable antibacterial filtration materials by integrating cationic hyperbranched polymer dendrimers (HBP) into electrospun nanofibers. Cationic HBPs were successfully embedded into recycled polyamide 6 nanofibers using industrial needleless electrospinning. Filtration efficiency, assessed against a 0.3 µm paraffin oil aerosol according to EN 149:2001, consistently exceeded 99.8%, meeting and surpassing the FFP3 classification threshold while maintaining low air resistance. The HBP-functionalized nanofibers exhibited pronounced contact-active antibacterial activity against Staphylococcus aureus and Escherichia coli. Quantitative plate count assays confirmed viability reductions of up to 74.1% after 2 h of co-incubation. Crucially, the absence of inhibition zones in agar diffusion tests confirmed that the active polymer was stably embedded within the nanofiber matrix and did not leach. Comprehensive toxicological tests, including cell line and 3D human skin and airway tissue models, confirmed the material’s safety for both dermal and respiratory contact. This study presents a scalable, metal-free, and environmentally responsible next-generation filtration system that combines high mechanical efficiency with active antimicrobial functionality. Full article

Electrospinning has advanced from a lab technique to an industrial method, enabling modern filters that are high-performing, sustainable, recyclable, and non-toxic. This study produced recycled PA6 nanofibers using green solvents and incorporated non-toxic CuO nanoparticles via industrial free-surface electrospinning. Polymer solutions with concentrations of 12.5, 15.0 and 17.5 (w/v)% were electrospun directly onto recyclable polypropylene spunbond/meltblown nonwoven substrates to produce nanofibers with average fiber sizes of 80–250 nm. Electrospinning parameter optimization revealed that the 12.5 wt.% PA6 solution and the 2–3 mm·s⁻¹ winding speed had the optimal performance, attaining 98.06% filtering efficiency and a 142 Pa pressure drop. The addition of 5 wt.% CuO nanoparticles increased the membrane density and reduced the pressure drop to 162 Pa, thereby improving the filtration efficiency to 98.23%. Bacterial and viral filtration studies have demonstrated pathogen retention above 99%. Moreover, antibacterial and antiviral testing has demonstrated that membranes trap and inactivate microorganisms, resulting in a 2.0 log (≈approximately 99%) reduction in viral titer. This study shows that recycled PA6 can be converted into high-performance membranes using green, industrial electrospinning, introducing innovations such as non-toxic CuO functionalization and ultra-fine fibers on recyclable substrates, yielding sustainable filters with strong antimicrobial and filtration performance, which are suitable for personal protective equipment and medical filtration. Full article

Varied types of particulate matter (PM) persist in the environment and exert a harmful impact on public health. The aim of this review article is to explore the key role of membrane technology in the separation of PM from ambient air. Nanofibrous, microporous, Janus, photocatalytic and hollow fiber membranes have found significant utilization in the effective separation of PM. Recent advancements in membrane technology and their key properties such as antibacterial activity, flame retardancy, wettability, thermal stability and reusability have been underscored in this review article. Moreover, the principles of PM separation have been discussed in detail to understand the working pathway of a membrane air filter via physical, chemical or biological approaches. A brief comparison between the conventional air filters and membrane air filters is provided in terms of cost, separation principle and respective merits and demerits to understand the importance of membranes in the realm of PM separation. This study also highlighted the commercial status of PM air filters with respect to their cost and scalability. By focusing on the innovations in membrane filters, this review article has highlighted the futuristic approaches such as green fabrication techniques, highly efficient material incorporation, use of AI/ML, etc., to overcome the challenges associated with conventional air filters. Full article

Acne vulgaris is a prevalent inflammatory disease of the pilosebaceous unit in which Cutibacterium acnes (C. acnes) contributes to lesion initiation and persistence, supporting antibacterial interventions as a component of clinical management. Given the essential role of the 50S large ribosomal subunit—particularly 23S rRNA sites in the peptidyl transferase center and nascent peptide exit tunnel—in C. acnes protein synthesis and viability, targeting the 50S offers an effective path to lead discovery for acne treatment. Here, we present an integrated computational–experimental workflow to identify anti-C. acnes candidates from a 186,659-compound natural product library. Curated 50S/23S ligands trained and validated two ML-QSAR regression models built on different molecular fingerprints (MACCS keys and PubChem 2D) to predict anti-C. acnes activity and rapidly triage the library. Compounds were further screened by ADMET filtering and structure-based docking to 23S rRNA pockets, followed by cluster and interaction analysis. Among six experimental hits, three compounds exhibited MICs against C. acnes of ≤8 μg/mL, with tripterin, a pentacyclic triterpenoid, being the most potent (0.5–2 μg/mL across two acne-relevant strains). Collectively, these results indicate that a 50S ribosomal-focused, multistage computational screening workflow, integrated with in vitro assays, efficiently prioritizes compounds with quantifiable anti-C. acnes activity across a broad range of natural products. Full article

Electrospun fibrous scaffolds based on cellulose acetate (CA), polycaprolactone (PCL), and poly (L-lactic acid) (PLLA) are versatile materials with applications spanning diverse fields, but in their pristine form, they typically lack significant inherent antibacterial properties. To address this limitation and expand their utility, this study explored the incorporation of xylitol, a natural antibacterial sugar alcohol, into these polymer matrices to enhance their physicochemical and antimicrobial properties. Electrospinning was employed to fabricate pristine and xylitol-loaded scaffolds with varying xylitol concentrations. Morphological analysis revealed polymer-dependent changes in fiber diameter and porosity. Mechanical testing assessed the impact of xylitol on tensile properties, while thermal analysis investigated alterations in melting temperature and crystallinity. The antibacterial efficacy against Staphylococcus aureus and Escherichia coli was evaluated using WST assay and live/dead staining. Notably, xylitol significantly enhanced the antibacterial activity against both bacterial species, with a more pronounced and rapid effect observed against S. aureus. The tailored scaffold properties and imparted antimicrobial characteristics highlight the potential of these xylitol-modified electrospun materials: they are easily produced, low-cost, and appropriate for a range of applications (dental applications, filters, masks, wound dressing, and packaging) where preventing bacterial contamination is crucial. Full article

Many viruses, bacteria, and pollen that cause diseases such as COVID-19 are inhaled by humans as aerosols. Therefore, wearing a mask to block pathogen-containing aerosols is crucial for disease prevention. However, current masks have a drawback—residual bacteria on the mask surface can become aerosolized again, spreading infections. To address this, a reusable mask incorporating the antibacterial properties of silver particles should be developed to suppress the immune response to pathogens and pollen that contact the mask surface. This study analyzed protein surface changes in pollen shells following electroless silver plating on polypropylene (PP) filters of KF94 masks using microcurrent. Pore density increased from 7.94% before microcurrent application to 14.8% and 16.9%, depending on the duration of exposure. These results suggest that microcurrents alter pollen surfaces and affect the proteins in pollen shells that trigger hay fever, confirming the potential for preventing pollen allergies. Full article

Particulate matter (PM) suspended in the air has posed significant potential threats to human health. However, current air filters designed to intercept PM are confronted with several challenges, including a complicated preparation process, monotonous protective performance, and uncomfortable wearability. Herein, a novel jet-splitting electrospinning strategy was demonstrated to simply fabricate a hierarchically structured PLA membrane with a high filtration performance, antibacterial performance, and rapid heat dissipation for effective and comfortable air filtering. Formulating a cationic antibacterial surfactant in the PLA solution to tailor the splitting of charged jets enables the simultaneous formation of nanofibers, submicron-fibers, and beads in the hierarchical filtration network by the single-jet electrospinning. Benefiting from the synergistic effect of multi-scale fibers and beads, the hierarchically structured filter exhibited an excellent filtration efficiency of 99.979% and high quality factor of 0.45 Pa⁻¹ against PM_0.3, with a remarkably low pressure drop of 18.7 Pa. Furthermore, the hierarchical structure endowed the filter with excellent stability in filtration performance, even under 20-cyclic and 480 min long-term tests, high-humidity tests with sodium chloride aerosol particles, and the 20-cycle PM_2.5 smoke tests. Simultaneously, the filter also demonstrated remarkable antibacterial performance and an excellent heat dissipation property—all achieved due to its PLA formulation and the hierarchical structure. Full article

Nowadays, utilizing biodegradable and bio-inspired substances and combining them in innovative ways is a prerequisite for obtaining new and useful materials. In this paper, we designed and characterized eco-friendly materials as alternatives for packaging and medical applications. Thus, cellulose fibers of medical gauze or filter paper were coated with a mixed solution containing poly(vinyl alcohol) (PVA), plant-based synthesized silver particles (AgPs), and magnetite (MG). The composites and their components were studied using UV-Vis, FTIR, and Energy-Dispersive X-ray (EDX) spectroscopy, Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM) to evidence the presence, size, surface charge, morphology, and chemical composition of particles in the composites, as well as particle interactions. Their proven hydrophobic and antibacterial character could recommend them for the design of antifouling medical coatings and food packaging. Full article

Aloin, a kind of active phenolic component, is sourced from Aloe vera. Recently, the determination of aloin has received enormous attention, owing to its positive performance (including anti-tumor, antibacterial, detoxification, liver protection, anti-stomach damage, and skin protection activities) and painful side effects (increased carcinogenicity caused by excessive use of aloin) impacting human health. This investigation was inspired by the good fluorescence properties of carbon dots (CDs); CD-based sensors have aroused a great deal of interest due to their excellent sensitivity and selectivity. Thus, it is of great significance to develop novel CD-based sensors for aloin determination. Herein, N,F-CDs were designed and synthesized through a convenient hydrothermal strategy; the synthesized N,F-CDs possessed good fluorescence performance and a small particle size (near 4.3 nm), which demonstrated the successful preparation of N,F-CDs. The resulting N,F-CDs possessed a large Stokes shift and could emit a highly stable green fluorescence. The fluorescence of the N,F-CDs could be effectively quenched by aloin through the inner filter effect. Furthermore, the synthesis procedure was easy to operate. Finally, the N,F-CD-coated test strips were fabricated and combined with a miniaturized fluorimeter for the fluorescence detection of aloin via the inner filter effect for the first time. The N,F-CD-coated test strips were fabricated and used for the fluorescence sensing of aloin, and the results were compared with a typical ultraviolet (UV) method. The N,F-CD-coated test strips exhibited high recovery (96.9~106.1%) and sensitivity (31.8 nM, n = 3), good selectivity, low sample consumption (1 μL), high speed (5 min), good stability, and anti-interference properties. The results indicate that N,F-CD-coated test strips are applicable for the quantitative determination of aloin in bovine serum, orange juice, and urine samples. Full article

Biofloc technology (BFT), traditionally centered on feed supplementation and water purification in aquaculture, harbors untapped multifunctional potential as a sustainable resource management platform. This review systematically explores beyond conventional applications. BFT leverages microbial consortia to drive resource recovery, yielding bioactive compounds with antibacterial/antioxidant properties, microbial proteins for efficient feed production, and algae biomass for nutrient recycling and bioenergy. In environmental remediation, its porous microbial aggregates remove microplastics and heavy metals through integrated physical, chemical, and biological mechanisms, addressing critical aquatic pollution challenges. Agri-aquatic integration systems create symbiotic loops where nutrient-rich aquaculture effluents fertilize plant cultures, while plants act as natural filters to stabilize water quality, reducing freshwater dependence and enhancing resource efficiency. Emerging applications, including pigment extraction for ornamental fish and the anaerobic fermentation of biofloc waste into organic amendments, further demonstrate its alignment with circular economy principles. While technical advancements highlight its capacity to balance productivity and ecological stewardship, challenges in large-scale optimization, long-term system stability, and economic viability necessitate interdisciplinary research. By shifting focus to its underexplored functionalities, this review positions BFT as a transformative technology capable of addressing interconnected global challenges in food security, pollution mitigation, and sustainable resource use, offering a scalable framework for the future of aquaculture and beyond. Full article

In the present study, a quantitative analysis of culturable microflora of car cabin filters was accomplished, with a special focus on bacteria resistant to some antibiotics. The occurrence of antibiotic-resistant bacteria was considered in the filters with activated carbon and filters with antibacterial properties. The minimum inhibitory concentration was evaluated for selected bacterial strains isolated from the filters. It was found that cabin filters after long-time operation are not only heavily contaminated with bacteria and fungi but also constitute a habitat for numerous antibiotic-resistant bacteria. The numbers of culturable bacteria resistant to penicillin, nitrofurantoin, rifampicin, doxycycline, or gentamicin reached 10²–10³ CFU/g of filter material. No relationship was observed between car brand or filter type and the abundance of antibiotics-resistant bacteria. The lower bacterial content of antibacterial filters was not accompanied by a proportionally lower content of resistant microorganisms which may indicate that the present techniques are not sufficient to limit their growth effectively. Pseudomonas sp. isolates from the filter material were not sensitive even in relation to high concentrations of some antibiotics, which confirms their significant resistance potential and may be important in the context of the spread of drug resistance in the vehicles indoors. Full article

Multifunctional water-treatment materials urgently need to be developed to avoid normal organic matter, inorganic anions, resistant bacteria, and hazardous disinfection by-products in conventional drinking water treatment strategies. While quaternary ammonium pyridine resins (QAPRs) possess porous adsorption structures and incorporate antibacterial groups, enabling simultaneous water disinfection and purification, their limited bactericidal efficacy hinders broader utilization. Therefore, a deeper understanding of the structure-dependent antimicrobial mechanism in QAPRs is crucial for improving their antibacterial performance. Hexyl (C₆) was proved to be the optimal antibacterial alkyl in the QAPRs. A new antibacterial quaternary ammonium pyridine resin Py-61 was prepared by more surficial bactericidal N⁺ groups and higher efficient antibacterial hexyl, performing with the excellent antibacterial efficiency of 99.995%, far higher than the traditional resin Py-6C (89.53%). The antibacterial resin Py-61 completed the disinfection of sand-filtered water independently to produce safe drinking water, removing the viable bacteria from 3600 to 17 CFU/mL, which meets the drinking water standard of China in GB5749-2022 (<100 CFU/mL). Meanwhile, the contaminants in sand-filtered water were obviously removed by the resin Py-61, including anions and dissolved organic matter (DOM). The resin Py-61 can be regenerated by 15% NaCl solution, and keeps the reused antibacterial efficiency of >99.97%. As an integrated disinfection–purification solution, the novel antibacterial resin presents a promising alternative for enhancing safety in drinking water treatment. Full article

Water contamination due to microbial proliferation remains a critical global challenge, especially with increasing urbanization, industrial activities, and the use of agrochemicals, and it requires the development of innovative methods for their purification that are not harmful to the environment and humans. In this study, innovative antibacterial nanocomposite coatings, composed of zirconia and silver nanocluster, were developed and deposited via eco-friendly co-sputtering physical vapor deposition (PVD) method onto electrospun polymeric membranes (PCL and PAN-PCL) for water filtration applications. Structural and morphological analyses, including XRD and UV-Vis spectroscopy, confirmed the deposition of a composite coating, consisting of an amorphous zirconia matrix embedding silver nanoclusters, homogeneously distributed on one side of the polymeric fibers. Wettability evaluations showed an increase in hydrophobicity after coating, particularly affecting the filtration performance of the PCL membranes. Antibacterial tests revealed strong inhibition against Staphylococcus epidermidis (Gram-positive) and partial efficacy against Escherichia coli (Gram-negative). Filtration tests of contaminated solutions revealed a 99% reduction in Bacillus subtilis, significant inhibition of Listeria monocytogenes, and limited effect on E. coli, with no bacterial proliferation observed on the coated membranes. These results underscore the effectiveness of ZrO₂/Ag nanocomposites in enhancing microbial control and suggest a promising, scalable strategy for sustainable and safe water purification systems. Full article

Background: QSAR (Quantitative Structure–Activity Relationships) methods have been the basis for the design of new molecules with a certain activity. The great advantage of QSAR methods is that they can predict the pharmacological activity of compounds without the need to obtain or synthesize them previously. Currently, the development of antibiotic resistance by microorganisms is the most important issue in the treatment of infectious diseases. This elevated resistance is associated with expanded morbidity and mortality, as well as an increase in healthcare costs. The development of new molecules with antibacterial activity is therefore urgently needed. Methods: By means of molecular topology, we developed discriminant functions (DF1 and DF2) capable of predicting antibacterial activity. When applied to a database with 6373 chemicals, they selected 266 molecules as candidates, from which 41% have this activity, according to the bibliography. Regression equations determining pharmacokinetic properties such as mean residence time (MRT), volume of distribution (V_D), and clearance (CL) were applied to the selected molecules. Results: We have observed that most antibacterial compounds have pharmacokinetic theoretical values in the intervals 20 > MRT > 0, 3 > V_D > 0, and 500 > CL > 0. We have applied these intervals to our antibacterial model with the objective of finding new antibacterials with a good pharmacokinetic profile. We show that they are an effective tool for discriminating antibacterial compounds, increasing the bibliographic success rate to 50.8, 59, and 61.5%, respectively. When drug-like filters are applied to these new models, the vast majority (89.9–100%) of the selected molecules present antibacterial activity. Conclusions: Considering these results, these new models could avoid the application of drug-likeness filters when searching for new potential antibacterials. All of this proves the usefulness of these mathematical–topological models. Full article

Accelerated urbanization and industrialization have significantly heightened water contamination risks, posing severe threats to public health and ecological balance. Polymeric membranes stand at the forefront of addressing this challenge, revolutionizing water and wastewater treatment. These membranes adeptly remove a broad spectrum of contaminants, including organic compounds and heavy metals, thereby playing a crucial role in mitigating environmental pollution. This research delves into the sophisticated mechanisms of polymeric membranes in filtering out pollutants, with a spotlight on the enhancements brought about by nanotechnology. This includes a detailed examination of their inherent antibacterial properties, showcasing their innovative design and potential for extensive application. The study further investigates advanced techniques like electrochemical processes and membrane distillation, particularly focusing on desalination. These methods are central to the advancement of water purification, emphasizing efficiency and environmental sustainability. However, challenges such as membrane fouling pose significant hurdles, necessitating ongoing research into surface modifications and antifouling strategies. This paper offers a comparative analysis of various membrane technologies, highlighting their manufacturing complexities and efficiency benchmarks. In summation, the paper underscores the importance of continuous innovation in membrane technology, aiming to develop sustainable and effective water treatment solutions. By bridging the gap between basic science and technological advancements, this review aims to guide practitioners and researchers towards a future where clean water is universally accessible, ensuring the preservation of our ecosystems. Full article