Search Results (645)

Surface modification of zinc oxide nanoparticles (ZnO NPs) with organosilane capping agents represents an effective strategy to control their physicochemical and biological properties. In this work, we report for the first time the use of halogenosilanes, namely (3-chloropropyl)trimethoxysilane (CPTMS), (3-bromopropyl)trimethoxysilane (BPTMS) and (3-iodopropyl)trimethoxysilane (IPTMS), for the surface functionalization of ZnO NPs obtained by chemical precipitation. Structural and morphological characterization (PXRD, TEM, SEM-EDX and FTIR) confirmed successful surface modification and revealed a significant particle size reduction from ~31 nm for unmodified ZnO to ~8 nm for BPTMS-modified ZnO (ZnO_b). The biological evaluation showed that halogenosilane-modified ZnO NPs exhibit enhanced cytotoxic activity against prostate cancer cell lines (PC3 and 22Rv1), with ZnO_b displaying the highest activity, likely associated with improved cellular uptake and increased reactive oxygen species (ROS) generation. In contrast, antimicrobial assays revealed only moderate bactericidal effects against Escherichia coli and Staphylococcus aureus at relatively high concentrations (≥1250 µg mL⁻¹), while no significant activity was observed against Pseudomonas aeruginosa, Burkholderia contaminans or Candida spp, within the tested range. These findings suggest that halogenosilane functionalization modulates the biological profile of ZnO nanoparticles by enhancing anticancer effects while also influencing microbiocidal activity, highlighting the role of surface chemistry in tuning biological selectivity. The present study supports the concept that rational surface engineering of ZnO-based nanoplatforms can be exploited to favor tumor-targeted activity over broad-spectrum antimicrobial effects, providing new perspectives for the design of application-oriented nanomaterials. Full article

The strategy of enhancing biocatalytic activity through the modification of natural cells with nanomaterials has overcome the intrinsic catalytic bottlenecks of bacteria, making significant contributions to energy production and pollution treatment. However, chemically engineered biocatalyst systems remain in their early stages of development. Herein, we report a simple and straightforward strategy for constructing an efficient biocatalyst by incorporating carbon quantum dots (CDs) into Escherichia coli (E. coli) to enhance the oxygen reduction reaction (ORR) at the cathode of microbial fuel cells (MFCs). The introduction of CDs significantly accelerates extracellular electron transfer and metabolic activity, markedly increases intracellular adenosine triphosphate (ATP) levels, and promotes substrate utilization. Furthermore, the engineered E. coli exhibits enhanced surface adhesion and increased electronegativity. Electrochemical measurements demonstrate superior ORR activity, delivering a maximum current density of 3.1 mA·cm⁻² and an onset potential of 0.67 V, outperforming many previously reported biocatalysts. When applied in an MFC system, the modified biocatalyst achieves a maximum power density of 325 μW·cm⁻², placing it among the highest-performing systems reported to date. This work provides a facile and cost-effective approach for improving MFC performance and offers a promising design strategy for next-generation biohybrid catalysts. Full article

Cosmetic preservatives should have reduced percutaneous absorption to lower the risk of systemic exposure and skin irritation. In this work, previously synthesized galactosylated derivatives of common cosmetic preservatives were comparatively evaluated for transdermal permeation and preliminary toxicity. Escherichia coli β-galactosidase was used to enzymatically modify several of the commonly used cosmetic preservatives to produce their corresponding galactosylated derivatives: benzyl alcohol β-d-galactopyranoside 7, 2-phenoxyethanol β-d-galactopyranoside 8, chlorphenesin β-d-galactopyranoside 9, 1,2-hexanediol β-d-galactopyranoside 10, 1,2-octanediol β-d-galactopyranoside 11, and 2-phenylethyl β-d-galactopyranoside 12. HPLC and NMR spectroscopy were used to analyze the previously synthesized derivatives. The Franz diffusion cell assay was used to evaluate skin penetration. 2-Phenoxyethanol (PE), chlorphenesin (CPN), and 2-phenylethanol (PhE), showed measurable skin penetration, with flux values ranging from 3.82 to 7.34 µg·h⁻¹·cm⁻² and permeability coefficients (Kp) between 1.38 and 3.00 × 10⁻³ cm·h⁻¹. In contrast, their galactosylated derivatives showed markedly reduced permeation under the same experimental conditions. Moreover, brine shrimp lethality assays indicated that galactosylated derivatives had significantly higher LD₅₀ values (1.6–2.1 mg/mL) than their parent compounds (0.1–0.79 mg/mL), suggesting lower cytotoxicity. These findings suggest that enzymatic galactosylation can significantly decrease skin permeability and the toxicity of cosmetic preservatives, highlighting its potential approach to improve the safety of cosmetic components. Full article

Polyphenolic compounds extracted from Taraxacum officinale (dandelion) were used as natural chelating ligands to synthesize copper–polyphenol complexes, which were subsequently immobilized on sericite to obtain hybrid organic–inorganic materials. The complexes were prepared under controlled pH and temperature conditions, yielding structures with different Cu–polyphenol ratios. Structural characterization confirmed the formation of Cu(II)–polyphenol chelates, partial reduction to Cu(I) species at higher pH values, and the deposition of mixed Cu₂O/CuO phases on the layered sericite substrate. Copper–polyphenol superstructures, copper nanoparticles, and copper oxide crystallites were heterogeneously distributed depending on synthesis conditions and metal–ligand ratios. The hybrid materials exhibited modified optical properties, combining the intrinsic reflectance of sericite with UV absorption from polyphenols and copper species. When incorporated into an emulsion matrix, the materials showed promising UV-screening performance, with SPF-equivalent values ranging from 7 to 33 depending on concentration. Antimicrobial evaluation demonstrated that copper–polyphenol complexes displayed enhanced activity against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Candida albicans compared to the natural extract, while sericite-supported hybrids retained selective efficacy, particularly against Gram-positive bacteria and C. albicans. These results indicate the potential of dandelion-derived copper complexes and their sericite hybrids as multifunctional bioactive agents for cosmetic dermatology applications. Full article

Waterborne polyurethane (WPU) is widely used in flexible films and textile finishing, but its intrinsic flammability, severe melt dripping, and sensitivity to polar additives restrict its fire-safe applications. Herein, a phosphorous acid-protonated chitosan (PCS) was designed as an emulsion-adaptable bio-based modifier and incorporated into cationic WPU via a facile aqueous blending route, yielding transparent multifunctional composite films and flame-retardant textile coatings. Unlike conventional flame-retardant WPU systems that rely on reactive monomers or suffer from poor emulsion compatibility, this work proposes an emulsion-compatible strategy based on PCS, enabling the simultaneous integration of dispersion stability, flame retardancy, and antibacterial functionality within a single system. PCS could be stably accommodated in the WPU latex without visible precipitation or demulsification after centrifugation, and the resulting films preserved a continuous matrix structure with uniformly distributed PCS-rich nanodomains. Rheological analyses revealed that the polar groups of PCS established strong intermolecular associations with urethane segments, strengthening the physical network. The char residue at 700 °C increased from 0.7 wt% for neat WPU to 32.7 wt% for WPU/PCS-5. Meanwhile, WPU/PCS-5 achieved a limiting oxygen index of 35.4% and a UL-94 V-0 rating, while its peak heat release rate and total heat release were reduced by 73.4% and 41.8%, respectively. The composite films also showed nearly complete antibacterial efficiency against Escherichia coli and Staphylococcus aureus. As a textile coating, WPU/PCS-5 enabled immediate self-extinguishing of cotton fabric, increased the limiting oxygen index from 18.5% to 27.2%, and reduced the damaged length from 30.0 to 11.0 cm. This work demonstrates that an emulsion-compatible strategy based on PCS can effectively integrate dispersion stability, fire safety, multifunctionality, and coating applicability into WPU materials. Full article

Introduction: Plazomicin, a novel, semi-synthetic aminoglycoside designed to overcome most aminoglycoside-modifying enzymes (AMEs), represents a therapeutic alternative to traditional aminoglycosides for complicated urinary-tract infections (cUTIs). In this review, we sought to evaluate the available data on drug resistance. Methods: We performed a thorough search across four databases (PubMed, Embase, Scopus, and Web of Science) from their inception to 4 November 2025 to identify relevant studies. The published Clinical and Laboratory Standards Institute (CLSI) antimicrobial susceptibility breakpoints for Enterobacterales were applied. Results: Fifty-five studies, out of a total of 905 records originally identified, were eligible for data extraction and analysis, yielding antimicrobial susceptibility data for 80,159 clinical isolates. The overall resistance of consecutive Enterobacterales isolates to plazomicin was 0–9.4%, and specifically for Escherichia coli and Klebsiella spp. isolates were up to 4.7% and 15.2%, respectively. Among selected isolates with specific resistance mechanisms, the resistance of carbapenem-resistant Enterobacterales (CRE) was 1.8–67.6%, and specifically for carbapenem-resistant E. coli and Klebsiella spp. isolates, 0–10% and 0.3–90%, respectively. Among multi-drug-resistant (MDR) isolates, up to 24.6% of MDR Klebsiella spp. isolates and up to 15% of MDR E. coli isolates were resistant to plazomicin. Among non-fermenting Gram-negative bacteria, the MIC₉₀ values were consistently high. Conclusions: The demonstrated high activity of plazomicin against consecutive Enterobacterales isolates and the considerable, yet variable, activity against selected resistant isolates suggest its consideration as a valuable option in the treatment of complicated urinary-tract infections. Full article

Forward osmosis (FO) membranes have garnered widespread research interest in water treatment, yet their permeability–selectivity trade-off, internal concentration polarization, and membrane fouling remain critical challenges. Herein, a chitooligosaccharide/polydopamine (COS/PDA) co-deposition strategy was proposed to modify polyethersulfone (PES) substrates for constructing high-performance thin-film composite (TFC) FO membranes. COS suppressed excessive PDA aggregation, reduced substrate roughness, and improved substrate hydrophilicity. This substrate modification regulated interfacial polymerization by increasing the adsorption capacity for m-phenylenediamine (MPD) while slowing its diffusion rate, thereby forming thinner, smoother, and more densely crosslinked polyamide (PA) layers. The optimized C₄P₁-TFC membrane delivered water fluxes of 42.2 and 23.5 L m⁻² h⁻¹ in pressure-retarded osmosis (PRO) and FO modes, respectively, representing 43.1% and 40.2% improvements over the pristine membrane. Its specific salt flux decreased to 0.07 and 0.15 g L⁻¹ in the two modes, respectively, suggesting enhanced selectivity. Meanwhile, the C₄P₁-TFC membrane showed antibacterial rates of 85.7% against Escherichia coli and 86.9% against Staphylococcus aureus, together with improved antifouling performance against bovine serum albumin and lysozyme. This work presents a simple and effective co-deposition approach for simultaneously improving the separation, antibacterial, and antifouling performance of TFC FO membranes, showing promising potential for practical applications. Full article

A novel water treatment agent, ethylenediamine–benzenesulfonic acid-modified polyaspartic acid (PASP-S), was controllably synthesized using an amino ring-opening reaction. The controllable synthesis methods, conditions for polymerization degree, and the molecular weight of the new polymer were explored. The structure was characterized using Fourier-transform infrared spectroscopy (FT-IR), ¹H nuclear magnetic resonance (¹H-NMR), and gel permeation chromatography (GPC). The scale inhibition, corrosion inhibition, and fluorescence properties of the new polymer, as well as the corresponding mechanisms, were investigated using static scale inhibition tests, electrochemical measurements, X-ray photoelectron spectroscopy (XPS), density functional theory (DFT), and frontier molecular orbital (FMO) theory. The results indicate that PASP-S exhibits strong Ca²⁺ chelation ability and can effectively inhibit CaCO₃ and CaSO₄ scaling. At 50 mg/L, the scale inhibition efficiency for Ca₃(PO₄)₂ reaches 99.50%. At 30 mg/L, its corrosion inhibition efficiency is 33.19% higher than that of PASP. Unexpectedly, the polymer shows remarkable selective antibacterial activity. At 100 mg/mL, the inhibition rate against Escherichia coli (E. coli) is 71%, while no obvious inhibition is observed for Bacillus cereus. A good linear relationship is found between fluorescence intensity and concentration. Mechanistic studies demonstrate that PASP-S adsorbs on the scale surface, suppressing crystal growth and distorting crystal morphology. Meanwhile, it forms a protective film on the electrode surface, thus reducing the dissolution and corrosion of carbon steel. Full article

N⁶-methyladenine and N⁶,N⁶-dimethyladenine are the heterocyclic bases present in the RNA of eukaryotic and bacterial cells and play important regulatory roles. How the degradation of such modified nucleic acids, and the subsequent demethylation of modified heterocyclic bases, occurs in the bacterium Escherichia coli is not established. Here, we investigated the growth of adenine auxotroph strains in a minimal M9 medium supplemented with either N⁶-methyladenine or N⁶,N⁶-dimethyladenine. We found that N⁶-methyladenine supported the growth of ∆purH::Km but not that of the ∆purA::Km strain, whereas N⁶,N⁶-dimethyladenine did not support the growth of either adenine auxotroph. Similar experiments performed using structurally related 2-amino-N⁶-methylpurine and 2-amino-N⁶,N⁶-dimethylpurine bases—using ∆guaA::Km, ∆guaB::Km, and ∆purH::Km guanine auxotrophs—demonstrated that growth of only the ∆guaB::Km mutant was supported by 2-amino-N⁶-methylpurine but not by its dimethylated counterpart. We expressed and purified C-teminus 6xHis tagged E. coli adenine/adenosine deaminases AdeC and Add and tested their substrate specificity. We demonstrated that AdeC protein does not catalyse deamination of either N⁶-methyl- or N⁶,N⁶-dimethyladenine, whereas Add catalyses deamination of N⁶-methyl- but not that of N⁶,N⁶-dimethyladenosine. Based on our findings, biochemical pathways leading to the demodification and return into metabolism of N⁶-methyladenine and 2-amino-N⁶-methylpurine in E. coli are proposed. Full article

This study focuses on the application of photocatalysis for air pollution, targeting both chemical and biological contaminants. The selected target compounds were 3-methylbutan-1-ol (C₅H₁₂O), a volatile organic compound abundantly generated in the food industry, and Escherichia coli, representing a relevant bacterial indicator commonly encountered in such industrial environments and effectively embodying a biological threat. In this work, a series of experiments was conducted in a batch reactor using a novel TiO₂-based photocatalytic system integrating metal wires, namely copper (Cu) and silver (Ag), woven into an optical fiber support. A comparative evaluation of photocatalytic performance across different media was carried out for the removal of 3-methylbutan-1-ol, as well as for E. coli deactivation. The results demonstrated notable performance of the TiO₂-Cu medium for chemical treatment, achieving 97% removal efficiency after 85 min at an inlet concentration of 28 mg·m⁻³. Similarly, significant antibacterial activity was observed with 5.50 log reduction in colony-forming units (CFU) after 2.5 h. The photocatalytic performance of TiO₂-Cu supports was further validated under different operating conditions, including relative humidity levels ranging from 20% to 60% and concentration range from 5–30 mg·m⁻³. Finally, this study also includes a comparison between the TiO₂-Cu support and conventional photocatalytic systems based on TiO₂, particularly for simultaneous (combined) treatment of chemical and biological contaminants, with promising and encouraging outcomes. Full article

In this study, a hierarchical design strategy is introduced for tuning the release of rosmarinic acid (RA) from electrospun poly(L-lactide) (PLA) fibrous materials via surface engineering with chitosan/hyaluronic acid (Ch/HA) polyelectrolyte complexes (PECs). RA was selectively incorporated within the fiber bulk, the PEC coating, or both, enabling control over its spatial distribution. The PEC coating, formed by sequential dip coating, was shown to act as a diffusion-regulating layer with a dual role—either retarding RA release or promoting rapid initial release when functioning as a surface-associated reservoir. As a result, the release kinetics could be systematically tuned depending on the coating architecture and RA localization. Thorough characterization confirmed successful coating formation, enhanced surface hydrophilicity, and improved mechanical performance. All RA-loaded materials retained high antioxidant activity and exhibited pronounced antibacterial and antifungal effects against Staphylococcus aureus, Escherichia coli, and Candida albicans. This work introduces PEC-modified electrospun systems as a versatile platform for the rational design of multifunctional fibrous biomaterials with controlled release profiles, with potential applications in wound healing and drug delivery. Full article

Two phenylacetaldehyde dehydrogenases, originating from Escherichia coli K-12 (FeaB-K-12) and Sphingopyxis fribergensis Kp5.2 (FeaB-Kp5.2), were immobilized on powdery silica carrier with various functionalization. First, the suitability of these carriers for application in combination with phenylacetaldehydes and phenylacetic acids was studied. Out of two carriers functionalized differently, mesoporous cellular foam, whose surface was modified with 3-glycidyloxypropyl groups (MCF-G), showed promising results. Hence, this carrier was further tested at 17 different immobilization conditions. Despite both enzymes showing high immobilization efficiency, the initial activities were relatively low compared to the free enzymes. Interestingly, the immobilized FeaB-Kp5.2 on MCF-G-Kw showed about 80% of retained activity after two months of incubation at 0 °C, indicating that the immobilization enhances the stability of this enzyme. In contrast, no changes in the temperature stability of FeaB-Kp5.2 due to immobilization could be noted. However, relative enzyme activities towards all three substituted phenylacetaldehydes could be increased by the immobilization to approximately 130%. The most active and stable powdery immobilizate was MCF-G-Kw-FeaB-Kp5.2 at pH 8. In addition, FeaB-Kp5.2 was also immobilized and tested on monolith silica carrier for continuous catalysis to produce phenylacetic acids. Full article

Magnesium alloys exhibit promising application prospects in medical orthopedic implants. However, their practical applications are limited by rapid corrosion, suboptimal osseointegration, and implant-related infections. Although conventional drug-eluting polymer coatings can provide various biological functions, the uncontrolled drug release often compromises long-term therapeutic efficacy. In this study, a self-healing Mg-poly(ε-caprolactone) (PCL)@OHF coating is designed and prepared on WE43 Mg by spin coating to achieve ultrasound-triggered release of osthole. OHF consists of osthole-loaded hollow mesoporous silica nanoparticles (HMSs) modified with Pluronic F127. Drug release studies show that the nanocapsules respond to ultrasound stimulation, with the cumulative release increasing from 39.94% to 75.93% after 7 days. Furthermore, the coating demonstrates intrinsic self-healing capacity upon thermal treatment at 50 °C. Electrochemical and immersion tests reveal that the composite coating provides good barrier protection for the WE43 Mg alloy, evidenced by a decrease in corrosion current density from 2.04 × 10⁻⁶ to 5.94 × 10⁻⁷ A/cm². In vitro biological assays confirm the antibacterial efficacy against Staphylococcus aureus and Escherichia coli, as well as the ability to promote osteogenic differentiation. The results reveal a surface modification strategy that combines self-healing, anticorrosion, and on-demand drug release, offering a promising approach for advanced orthopedic implants. Full article

The growing need for sustainable strategies to reduce agro-industrial waste has stimulated interest in valorizing winery by-products as sources of high-value bioactive compounds. Wine lees, rich in phenolic compounds with well-documented antimicrobial activity, remain largely underutilized in the development of functional materials. In most cases, incorporation of bioactive agents relies on physical adsorption, which often results in weak adhesion and limited durability. In this study, phenolic extracts derived from wine lees and grape seed extract were incorporated into bacterial cellulose (BC) to develop bioactive materials with antimicrobial and antioxidant functionality. Two strategies were investigated: (i) direct immersion of BC in phenolic extracts and (ii) incorporation of extracts in BC membranes pre-modified with carboxymethyl cellulose (CMC) to enhance phenolic affinity and retention. The resulting materials were characterized for total phenolic content, antioxidant activity, and antimicrobial performance against bacterial strains (Escherichia coli, Salmonella Typhimurium, and Staphylococcus aureus). CMC-pretreated membranes significantly enhanced phenolic incorporation and antimicrobial performance, achieving a 99.9% reduction in E. coli after 24 h, while S. Typhimurium and S. aureus counts were below the detection limit (LOD < 1.0 log₁₀ CFU/mL). These findings demonstrate the potential of wine lees as a sustainable source of bioactive compounds for the development of antimicrobial cellulose-based materials, supporting circular bioeconomy strategies and their potential application in food packaging. Full article

In this research, PLA biocomposites reinforced with 20 wt% flax fibers modified with 1, 5, 10, and 20% concentrations of trans-cinnamic acid (TC) were prepared. The materials were systematically characterized to evaluate their structural, thermal, viscoelastic, surface, and functional properties. Thermal stability and phase transitions were analyzed using thermogravimetric analysis (TG) and differential scanning calorimetry (DSC), while viscoelastic behavior and molecular relaxation processes were investigated by dynamic mechanical analysis (DMA). To elucidate failure mechanisms and interfacial quality, fracture surface morphology after tensile testing was observed using scanning electron microscopy (SEM). Surface wettability was determined through water contact angle measurements, and antibacterial activity against Escherichia coli and Staphylococcus aureus was evaluated to assess the functional potential of the developed biocomposites. The results demonstrated that moderate fiber modification improved interfacial adhesion and enhanced thermo-mechanical performance. The highest contact angles were observed for 5% and 10% TC concentrations, indicating increased surface hydrophobicity, while strong antibacterial activity (R ≥ 6) was achieved for 10% and 20% TC. The research confirms that trans-cinnamic acid concentration governs multiple structure–property relationships, enabling controlled tuning of mechanical reinforcement and antibacterial functionality. Full article