Search Results (954)

This study investigates the synthesis of silver nanoparticles (AgNPs) using Crassula ovata (Jade plant) leaf extract and their subsequent incorporation into chitosan-based nanocomposite films for enhanced antimicrobial activity against four pathogenic microorganisms: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Methicillin-resistant Staphylococcus aureus. Jade AgNPs were chosen for their ease of synthesis, stability, and potent antimicrobial activity. Chitosan encapsulation improved the stability of AgNPs and enhanced their interaction with bacterial cells, leading to improved bactericidal performance. The addition of gentamicin to the nanocomposite further amplified antibacterial activity, reducing the MBC values from 10 to 4 µg/mL for E. coli, 12.5 to 6 µg/mL for P. aeruginosa, 10 to 6 µg/mL for S. epidermidis, and 15 to 8 µg/mL for MRSA, compared to AgNPs alone. Mechanical characterization using dynamic mechanical analysis revealed improved robustness, with storage modulus increasing from approximately 24 MPa for chitosan-AgNPs films to 36 MPa for gentamicin-loaded nanocomposite films, while maintaining elasticity. Overall, these multifunctional nanocomposite films demonstrate strong antimicrobial activity and improved mechanical performance, supporting further evaluation as candidate materials for wound-related antimicrobial applications and localized infection control strategies. Such localized antimicrobial platforms may also contribute to strategies aimed at mitigating antibiotic resistance. Full article

The shift toward sustainable packaging requires biodegradable, active alternatives. This study developed ternary nanohybrids by loading carvacrol (CV) or trans-cinnamaldehyde (tCN) onto zinc oxide/natural zeolite (ZnO/NZ) hybrids, which were incorporated into a poly-L-lactide/tri-ethyl citrate (PLA/TEC) matrix via melt extrusion to produce active films. A key finding was the distinct interaction mechanism: tCN underwent strong chemisorption with ZnO, creating a sustained-release reservoir, while CV was predominantly physisorbed, leading to rapid release. This interfacial divergence dictated functional performance. Antibacterial assessment of nanohybrids revealed that tCN@ZnO/NZ0.25 exhibited the highest inhibition zones against pathogens, correlating with its chemisorbed reservoir. In films, however, CV-based formulations (especially CV@ZnO/NZ0.25) showed superior immediate antioxidant activity (EC₅₀, ~DPPH~ = 34.43 mg/mL) and an 82% reduction in oxygen permeability. In contrast, tCN-based films (especially tCN@ZnO/NZ1.0) demonstrated superior, sustained antibacterial efficacy. In a minced pork preservation study, both films delayed lipid oxidation and preserved heme iron, while the tCN-based film provided better long-term microbial control. This work demonstrates that engineering the nanocarrier–active compound interface enables precise tailoring of release kinetics, which can be optimized for either high immediate antioxidant power or long-term antimicrobial action, depending on specific food preservation requirements. Full article

The use of natural bioactive compounds in edible coatings provides a sustainable approach to reducing food spoilage and meeting consumer demand for safer food preservation. In this study, bioactive extracts from Brassica juncea (green mustard, GM) and Raphanus sativus (radish tango, RT) sprouts were encapsulated into zein/chitosan (Z/CH) microparticles (MPs) using a complex coacervation–based encapsulation approach. The encapsulated microparticles (MPs), characterized by FTIR and UV-Vis spectroscopy, demonstrated a high loading efficiency of up to 90% and maintained their antioxidant activity for up to 168 h. TGA and SEM tests confirmed that the edible films produced by incorporating these microparticles (MPs) into polyvinyl alcohol (PVA) and chitosan (CH) matrices had a more uniform microstructure and enhanced heat stability. The Z/CH/RT6:PVA (1:2) and Z/CH/GM6:CH (1:1) formulations of the films showed significant antioxidant and antibacterial action, with up to 22.4% DPPH inhibition and a 1-log decrease in Salmonella enterica CFU, respectively. Overall, the results underscore the promise of sprout-derived microparticles as components for developing active, biodegradable packaging films with improved functional properties. Full article

Glycerol-(9,10-trioxolane) trioleate (OTOA) is a promising material that combines good plasticizing properties for PLA with profound antimicrobial activity, which makes it suitable for application in state-of-the-art biomedical and packaging materials with added functionality. In this study, the biodegradation kinetics of PLA + OTOA mixed films under soil conditions was assessed over 180 days. Structural and morphological changes that occurred on the surface and in the volume of the films during degradation were scrutinized using DSC, X-ray diffraction, IR, and UV spectroscopy. Morphological changes were assessed using optical and confocal microscopes. The different behavior of the PLA + OTOA blend films during decomposition in soil is explained by their structure and the rate of release of antibacterial OTOA from the PLA matrix. The decomposition rate constants were determined for all films, where k_d for PLA samples is 28 µm·year⁻¹, for samples containing 10% and 30% OTOA k_d is 2 µm·year⁻¹, and for PLA + 50% OTOA samples k_d = 34 µm·year⁻¹. This is explained by changes in the structure and degree of crystallinity of materials during the process of aging in the soil. These results clarify the biodegradation processes of biomaterials containing antibacterial agents in their structure. Full article

This study focuses on the development of antibacterial polymer nanocomposites based on biologically synthesized silver nanoparticles (AgNPs) and polyvinyl alcohol (PVA) as the polymer matrix. Silver nanoparticles were produced using an aqueous extract from dried Lavandula angustifolia (lavender) leaves, which proved to be highly effective in reducing silver ions and stabilizing the resulting nanoparticles. The synthesized AgNPs were characterized by FTIR, UV-Vis, TEM, SEM, and DLS analyses. The nanoparticles were predominantly spherical, with more than 70% having diameters below 20 nm. Subsequently, AgNPs were incorporated into the PVA matrix via an ex situ approach to fabricate nanocomposite fibers and thin films. SEM analysis confirmed successful incorporation and uniform distribution of AgNPs within the polymer structures. The nanocomposites exhibited pronounced antibacterial activity against both Gram-positive (Staphylococcus aureus, Staphylococcus haemolyticus, Streptococcus uberis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria, with nanofibers demonstrating superior performance compared to thin films. These findings highlight the potential of lavender-extract-mediated AgNPs as sustainable functional fillers for the fabrication of eco-friendly antibacterial materials applicable in biomedical and food packaging fields. Full article

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%. Full article

Healthcare-associated infections (HCAIs) remain a significant global challenge, as pathogenic microorganisms can persist on hospital surfaces and medical equipment, contributing to severe infections and epidemic outbreaks. Conventional preventive measures, including disinfection procedures and personal protective equipment, are often insufficient to ensure complete microbial control, prompting interest in innovative antimicrobial surface technologies. This study reports the design, preparation, and comprehensive characterization of chitosan- and poly(ε-caprolactone)-based antibacterial coatings incorporating chlorhexidine-loaded zirconium phosphate (ZrPCHX) nanoparticles. Coatings were deposited by optimized spray and brush techniques to obtain uniform, adherent, and well-defined films. Their morphological, physicochemical, mechanical, and cytocompatibility properties were systematically evaluated, and antibacterial efficacy was assessed against clinically relevant pathogens following ISO 22196:2011 and additional protocols simulating realistic hospital conditions. Both coating systems demonstrated pronounced antibacterial activity, with the PCL-based formulation exhibiting a faster and broader bactericidal effect while maintaining good cytocompatibility. These findings support the potential of the developed nanostructured coatings as sustainable and scalable materials for the active decontamination of high-touch hospital surfaces, offering continuous antimicrobial protection and contributing to a reduction in HCAI incidence. Full article

Chronic and complex wounds, including diabetic foot ulcers, venous leg ulcers, burns and post-surgical defects, remain difficult to manage due to persistent inflammation, impaired angiogenesis, microbial colonization and insufficient extracellular matrix (ECM) remodeling. Conventional dressings provide protection, but they do not supply the necessary biochemical and structural signals for effective tissue repair. This review examines recent advances in hydroxyapatite–collagen (HAp–Col) composite dressings, which combine the architecture of collagen with the mechanical reinforcement and ionic bioactivity of hydroxyapatite. Analysis of the literature indicates that in situ and biomimetic mineralization, freeze-drying, electrospinning, hydrogel and film processing, and emerging 3D printing approaches enable precise control of pore structure, mineral dispersion, and degradation behavior. Antimicrobial functionalization remains critical: metallic ions and locally delivered antibiotics offer robust early antibacterial activity, while plant-derived essential oils (EOs) provide broad-spectrum antimicrobial, antioxidant and anti-inflammatory effects with reduced risk of resistance. Preclinical studies consistently report enhanced epithelialization, improved collagen deposition and reduced bacterial burden in HAp–Col systems; however, translation is limited by formulation variability, sterilization sensitivity and the lack of standardized clinical trials. Overall, HAp–Col composites represent a versatile framework for next-generation wound dressings that can address both regenerative and antimicrobial requirements. Full article

This study aimed to develop an environmentally friendly composite film with effective antibacterial and preservation properties. Silver nanoparticles (AgNPs) were green-synthesized using grape skin extract as a natural reducing agent and incorporated into a PVA/chitosan matrix. The composition of the extract and the structural characteristics of the AgNPs were characterized by UPLC-MS and TEM. The barrier, mechanical performance, antibacterial, and fruit preservation properties of the resulting films were systematically evaluated. The results showed that the incorporation of AgNPs significantly improved the water vapor and oxygen barrier properties of the film and imparted excellent broad-spectrum antibacterial activity. In grape storage experiments, films with higher AgNPs content effectively delayed skin aging and moisture loss, maintaining better visual quality of the fruit. This work provides a green and feasible approach for the preparation of nanoparticle-enhanced antibacterial packaging materials based on natural products, with promising application potential. Full article

Titanium dioxide (TiO₂) thin films were deposited by DC magnetron sputtering and subsequently treated in hot water at 50, 70, and 95 °C for 72 h to investigate the influence of low temperature on their structural optical and functional properties. XRD analysis revealed a progressive transformation from amorphous to anatase phase with increasing treatment temperature, accompanied by an increase in crystallite size from 5.2 to 15.1 nm. FT-IR spectroscopy confirmed enhanced surface hydroxylation and contact angle measurements showed a decrease from 77.4° to 19.7°, indicating a significant improvement in superior wettability. The transmittance spectroscopy revealed a slight narrowing of the optical band gap from 3.34 to 3.21 eV, consistent with improved visible-light absorption. Photocatalytic tests using the Resazurin indicator demonstrated that the film treated at 95 °C exhibited the highest activity, achieving a bleaching time of 245 s three times faster than treated at 50 °C and twice as fast as treated at 70 °C. Under low-intensity solar irradiation, the same sample achieved complete E. coli inactivation within 90 min. These improvements are attributed to increased crystallinity, surface hydroxyl density, and enhanced ROS generation. Overall, this study demonstrates that mild hot-water treatment is an effective, substrate-friendly route to enhance TiO₂ film wettability and multifunctional performance, enabling the fabrication of self-cleaning and antibacterial coatings on fragile materials such as plastics and textiles. Full article

Antibacterial thin-film coatings are of increasing interest for enhancing hygiene in controlled environments such as commercial greenhouses. Phytopathogens including Pseudomonas syringae, and human pathogens such as Escherichia coli, Micrococcus luteus, and Staphylococcus aureus, frequently contaminate greenhouse environments. The present study aimed to develop and evaluate multifunctional magnetron-sputtered glass coatings with strong antimicrobial performance, deposited by physical vapor deposition to achieve precise control of film composition and uniform coverage of large substrates (≥0.25 m²), ensuring industrial-scale applicability. Thin films were fabricated by magnetron sputtering using multi-alloy targets composed of Cu, Sn, Zn, Al, Ni, Fe, Ti, Mn, Nb, or Co. Fourteen distinct coating compositions were characterized using high-resolution transmission electron microscopy, scanning transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Antibacterial performance was evaluated against the following strains: E. coli (PCM 2560), M. luteus (PCM 525), S. aureus (PCM 2602), and P. syringae pv. tomato (IOR2146). Coatings prepared from 90%Cu-10%Sn, 90%Cu-10%Zn, and 80%Cu-20%Ti targets exhibited one of the highest antibacterial efficiencies. These coatings also showed strong mechanical durability and corrosion resistance. Our results indicate that coatings obtained from Cu-based multi-alloy targets by magnetron sputtering are promising candidates for use as durable, antimicrobial inner glass surfaces in future greenhouse applications. Full article

This study aimed to fabricate an active film incorporating limonin (LM) and resveratrol (RES) within a zein/shellac (ZS) matrix for use in strawberry preservation. Zein/shellac composite films embedded with varying concentrations of LM (0–4% w/w) and RES were successfully fabricated using coaxial electrospinning. The prepared films were comprehensively characterized for their mechanical properties, water vapor permeability (WVP), antioxidant capacity (DPPH, ABTS, FRAP), and antibacterial efficacy against E. coli and S. aureus. Mechanical properties and WVP results revealed that the ZSLM4R film exhibited an elongation at break (EBA) of 28.91%, tensile strength (TS) of 0.93 MPa, elastic modulus (EM) of 40.76 MPa, and a WVP of 1.55 g mm/m². h. kPa. Furthermore, LM and RES increased the antioxidant properties of the composite film. ZSLM4R’s free radical scavenging activities against DPPH and ABTS were 68.14% and 89.69%, respectively. The composite film also demonstrated strong antibacterial efficacy against E. coli and S. aureus. When applied to strawberries, ZSLM4R packaging effectively extended the fruit’s shelf life compared to the unwrapped and commercial polyethylene (PE) controls. These obtained results indicate that LM/RES-incorporated zein/shellac composites are a promising eco-friendly packaging alternative for preserving perishable fresh produce and extending its shelf life. Full article

Titanium alloys are widely used for biomedical implants, but their performance is limited by wear, corrosion, and susceptibility to bacterial colonisation. To overcome these drawbacks, multilayer Ti–Cu oxide coatings were deposited on Ti6Al4V substrates using direct current magnetron sputtering. Two multilayer architectures (6 × 2 and 12 × 2 TiO₂/CuO bilayers) were fabricated and evaluated for their structural, mechanical, electrochemical, and biological properties. SEM/EDS and XRD confirmed well-adhered crystalline coatings consisting of rutile/anatase TiO₂ and monoclinic CuO with uniform elemental distribution. The coatings increased surface roughness, improved adhesion, and enhanced hardness by up to ~180% compared to uncoated Ti6Al4V alloy. Compared to the bare substrate, electrochemical testing in simulated body fluid showed higher corrosion resistance of both coated samples, but particularly for the 12 × 2 multilayers. Both architectures provided sustained Cu²⁺ release over seven days without a burst effect. In vitro biological testing showed that both multilayer coatings achieved over 96% inhibition of Gram-positive bacteria such as Staphylococcus aureus and Bacillus subtilis, while exhibiting moderate antibacterial effects against Gram-negative strains (Escherichia coli, Pseudomonas aeruginosa). Despite the presence of copper, MG-63 osteoblast-like cells demonstrated sustained viability and successful extracellular matrix mineralisation, indicating excellent cytocompatibility of the coatings with bone-forming cells. These results demonstrate that multilayer Ti–Cu oxide coatings can effectively balance antibacterial performance, corrosion resistance, mechanical strength, and support bone cell integration, making them a promising strategy for the surface modification of titanium-based biomedical implants. Full article

Phosphorus-modified poly(vinyl alcohol) (PVA) has recently gained increasing attention as a functional polymeric matrix suitable for gel-based systems, owing to its biocompatibility, film-forming ability, and capacity to develop semi-interpenetrating networks. In this work, PVA was chemically modified through the nucleophilic substitution of its hydroxyl groups with the chloride groups of phenyl dichlorophosphate, following a literature-reported method carried out in N,N-dimethylformamide (DMF) as reaction medium, resulting in phosphorus-containing PVA networks (PVA-OP3). Hybrid gel-like films were then prepared by incorporating titanium dioxide nanoparticles (TiO₂ NPs), known for their antimicrobial activity, low toxicity, and high stability. The resulting composites were structurally, morphologically, and thermally characterized using FTIR, SEM, and thermogravimetric analysis. The incorporation of TiO₂ NPs significantly improved the thermal stability, with T₅% increasing from 240 °C for neat PVA-OP3 to 288 °C for the optimal composite, increased the char residue from 4.5% for the neat polymer to 30.1% for PVA-OP3/TiO₂-4, and enhanced antimicrobial activity against both Gram-positive and Gram-negative bacteria. These findings demonstrate that PVA-OP3/TiO₂ hybrid films possess promising potential as advanced biomaterials for biomedical, protective, and environmental applications. Full article

In this work, a novel polyvinyl alcohol/starch (PVA/St)-based composite film was fabricated by integrating citric acid (CA) and silver-loaded biochar (C-Ag) nanofillers to enhance antibacterial functionality. Sorghum straw-derived biochar was loaded with silver nanoparticles (AgNPs) through a green synthesis route using Peucedanum praeruptorum Dunn extract. The successful crosslinking by CA and the uniform incorporation of AgNPs were confirmed by FTIR, XRD, and SEM. Notably, the optimized composite film containing 1.5 g/L C-Ag exhibited strong broad-spectrum antibacterial activity, with inhibition zones of 28 mm against E. coli, 29 mm against S. aureus, and 26 mm against P. aeruginosa, respectively. The high efficacy is attributed to the synergistic effect between the sustained release of Ag⁺ and the CA-induced acidic microenvironment. This work provides a green and high-performance antibacterial material to address the potential microbe contamination. Full article