Search Results (1,329)

Chitosan–gelatin (CG) hybrid hydrogels are widely recognized for their biocompatibility and suitability for soft tissue engineering, wound dressings, and biomedical coatings. Despite this promise, conventional CG systems often exhibit limited mechanical strength, restricted durability, and uncontrolled swelling, which can reduce their clinical relevance. In this study, we introduce an enhanced soft hydrogel platform reinforced with niobium pentoxide (Nb₂O₅) nanoparticles and chemically crosslinked using glutaraldehyde, with citric acid serving as a dissolution medium and processing aid. Three hydrogel variants (G1, G2 and G3) were prepared by adjusting nanoparticle concentration and subsequently evaluated through structural, morphological, swelling, gel-fraction, and rheological analyses. SEM imaging revealed that increasing Nb₂O₅ content produced notable architectural transitions—from smooth porous matrices to nanoparticle-distributed, heterogenous pore structures. XRD, FTIR, and Raman spectroscopy confirmed the structural retention of Nb₂O₅ and its effective interaction with the polymer network. Swelling and gel-fraction measurements demonstrated improved network stability in nanoparticle-loaded systems, with G2 providing the most desirable balance between swelling capacity (298%) and gel fraction (91%). Rheological studies further identified G2 as the most stable and elastic composition, exhibiting strong shear-thinning behavior and high structural recovery. Overall, G2 emerges as the optimal formulation for future biomedical development. Full article

Although probiotics are widely used in the food industry due to their health-promoting effects, their application is often limited by low stability and poor viability under processing, storage, and gastrointestinal conditions. Encapsulation has emerged as a promising strategy to address these issues, offering enhanced protection and controlled release of probiotic strains. This review summarizes recent advances in encapsulation techniques relevant to food applications, including spray drying, freeze drying, coacervation, and liposome formation, as well as novel approaches such as multilayer nanocoatings and dual-core systems. The use of natural biopolymers such as alginate, chitosan, and pectin, along with food-grade synthetic materials, has greatly improved the stability of probiotics in complex food matrices. Furthermore, emerging technologies such as cell-mediated coatings offer improved resistance to gastric acid and oxygen, enhancing probiotic survival through the gastrointestinal tract. These advances contribute to the development of functional foods with better health benefits. However, challenges remain regarding scalability, strain-specific encapsulation efficiency, and regulatory approval. Future research should focus on optimizing food-grade materials, exploring synergistic effects with bioactive compounds, and ensuring consistent performance across food systems. Full article

Background/Objectives: Peri-implantitis is a chronic inflammatory condition affecting tissues surrounding dental implants and is characterized by progressive marginal bone loss that can ultimately lead to implant failure. Reduced vascularization and impaired immune clearance in peri-implant tissues contribute to persistent inflammation and limited therapeutic efficacy. MicroRNAs (miRNAs), particularly miR-21, have emerged as key regulators of inflammatory responses and bone remodeling. The objective of this study was to develop a bioactive dental implant coating capable of locally delivering miR-21 to modulate inflammation and promote peri-implant tissue regeneration, thereby preventing peri-implantitis. Methods: Cationic nanoparticles were synthesized using lecithin and low-molecular-weight polyethylenimine (PEI) as a non-viral delivery system for miR-21. Lecithin was employed to enhance biocompatibility, while PEI functionalization provided a positive surface charge to improve miRNA complexation and cellular uptake. The resulting lecithin–PEI nanoparticles (LEC–PEI NPs) were incorporated into a chitosan-based coating and applied to titanium implant surfaces to obtain a sustained miR-21–releasing system (miR21-implant). Transfection efficiency and biological activity were evaluated in human periodontal ligament fibroblasts (hPDLFs) and compared with a commercial transfection reagent (Lipofectamine). Release kinetics and long-term activity of miR-21 from the coating were also assessed. Results: MiR-21-loaded LEC–PEI nanoparticles demonstrated significantly higher transfection efficiency than Lipofectamine and retained marked biological activity in hPDLFs relevant to peri-implantitis prevention. The chitosan-based nanoparticle coating enabled controlled and sustained miR-21 release over time, supporting prolonged modulation of inflammatory and osteogenic signaling pathways involved in peri-implant tissue homeostasis. Conclusions: The miR21-implant system, based on lecithin–PEI nanoparticles incorporated into a chitosan coating, represents a promising therapeutic strategy for peri-implantitis prevention. By enabling sustained local delivery of miR-21, this approach has the potential to preserve peri-implant bone architecture, modulate chronic inflammation, and enhance the osseointegration of titanium dental implants. Full article

This is the first investigation that attempts to synthesize chitosan-loaded vanillin nanoformulation (vanillin-Nf) as a novel edible coating agent to prolong the storage life of Indian gooseberry (amla). Different concentrations of vanillin were encapsulated into chitosan via ionic gelation approach using sodium tripolyphosphate as a cross-linker. Vanillin-Nf 1:1 (w/v) exhibited maximum loading capacity (2.502 ± 0.008%) and encapsulation efficiency (54.483 ± 1.165%). The physico-chemical characterization of vanillin-Nf through SEM, DLS, FT-IR, and XRD techniques confirmed effective incorporation of vanillin into the chitosan biomatrix and formation of spherical nanocapsules, with a mean particle size of 232.83 nm, zeta potential +69.66 mV, and polydispersity index 0.296. The in vitro release profile of vanillin exhibited a biphasic and regulated release pattern. The application of vanillin-Nf as an edible coating solution on amla (Phyllanthus emblica L.) fruits was highly effective in reducing decay incidence up to 42.84% and extended their shelf-life to 15 days at 25 ± 2 °C. The vanillin-Nf coating significantly reduced weight loss in amla fruits (24.39 ± 1.02%) in comparison to control. In addition, vanillin-Nf coating also helped in preserving the key quality parameters, including pH, chlorophyll content, total soluble solids, total phenols, and antioxidant capacity of Indian gooseberries to a substantial extent at the end of storage. Collectively, our findings indicate that vanillin-Nf coating is an effective post-harvest approach for controlling decay, prolonging shelf-life, and maintaining the nutritional attributes of Indian gooseberries, highlighting its potential for commercial application in the food and agriculture industry. Full article

Background/Objective: Osimertinib (OSI) is a third-generation tyrosine kinase inhibitor approved for non-small cell lung cancer (NSCLC) therapy. OSI is administered orally; this route limits the amount of OSI reaching the tumor in the lungs and is associated with serious systemic toxicity. This study aimed to develop a dry powder inhalable formulation to provide tumor-targeted delivery and minimize systemic toxicity. To the best of our knowledge, this is the first study to prepare and evaluate a dry powder inhalation formulation of OSI. Methods: Chitosan-coated PLGA nanoparticles (PLGA-C NPs) encapsulating OSI were prepared using a single emulsion-solvent evaporation technique. PLGA-C NPs were assembled into respirable nanocomposite microparticles (NCMPs) via spray drying with L-leucine as a carrier. PLGA-C NPs were characterized for particle size, zeta-potential, encapsulation efficiency, and in vitro efficacy in A-549 cell line. NCMPs were evaluated for solid-state properties, aerosolization performance, stability and in vitro release. Results: PLGA-C NPs exhibited a particle size of 145.18 ± 3.0 nm, high encapsulation efficiency and a positive zeta potential. In vitro studies demonstrated a 3.6-fold reduction in IC50 compared to free OSI, superior antimigratory effects and enhanced cell cycle arrest. Solid-state characterization of NCMPs demonstrated drug encapsulation in the polymer without chemical interaction. NCMPs exhibited excellent aerosolization (mass median aerodynamic diameter of 1.09 ± 0.23 μm, fine particle fraction of 73.48 ± 8.6%) and sustained drug release (61.76 ± 3.9% at 24 h). Stability studies confirmed the physicochemical stability integrity. Conclusions: These findings suggest that this novel dry powder inhalable OSI formulation may improve therapeutic outcomes while reducing systemic toxicity. Full article

The development of functional biomaterials based on natural polymers has gained increasing relevance due to the growing demand for sustainable and bioactive alternatives for biomedical and technological applications. In this study, chitosan was obtained from shrimp exoskeletons and used to formulate active films enriched with Mexican propolis, aiming to evaluate the influence of the extract on the physicochemical and functional properties of the resulting biomaterial. Propolis was incorporated into the chitosan film-forming solution at a final concentration of 1.0% (v/v). The propolis employed met the requirements of the Mexican Official Standard NOM-003-SAG/GAN-2017 regarding flavonoid content, total phenolic compounds, and antimicrobial activity; additionally, it was evaluated through antioxidant activity, hemolysis, and acute toxicity (LD₅₀) assays to provide a broader biological and safety assessment. The extracted chitosan exhibited a degree of deacetylation of 74% and characteristic FTIR spectral features comparable to those of commercial chitosan, confirming the quality of the obtained polymer. Chitosan–propolis films exhibited antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans, whereas pure chitosan films showed no inhibitory effect. Thermal analyses (TGA/DSC) revealed a slight reduction in thermal stability due to the incorporation of thermolabile polyphenolic compounds, along with increased thermal complexity of the system. SEM observations demonstrated reduced microbial adhesion and marked morphological damage in microorganisms exposed to the functionalized films. Overall, the incorporation of Mexican propolis enabled the development of a hybrid biomaterial with enhanced antimicrobial performance and potential application in wound dressings and bioactive coatings. 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

Photocatalytic membrane reactors (PMRs) are an innovative technology for water treatment, effectively combining membrane filtration and photocatalysis to enhance contaminant removal while enabling the regeneration of fouled membranes. In this study, a new porous film of chitosan that was impregnated with TiO₂ was developed and coated onto a ceramic support by spin coating to form a new porous immobilized PMR. The formed membrane was tested for two reasons: the removal of methylene blue dye by a dead-end filtration process and to demonstrate its ability to self-regenerate under UV exposure. The selective layer of the membrane was characterized using FTIR spectroscopy, X-ray diffraction, scanning electron microscopy (SEM), and water permeability tests. The results confirmed the formation of an amorphous film with no chemical interaction between chitosan and TiO₂. The membrane exhibited an average water permeability of 10.72 L/m²·h·bar, classifying it as either ultrafiltration (UF) or nanofiltration (NF). Dead-end filtration of methylene blue (10 mg L⁻¹) achieved 99% dye removal based on UV–vis analysis of the permeate, while flux declined rapidly due to fouling. Subsequent UV irradiation removed the deposited dye layer and restored approximately 50% of the initial flux, indicating partial self-regeneration. Overall, spin-coated chitosan–TiO₂ layers on ceramic supports provide high dye removal and photocatalytically assisted flux recovery, and further work should quantify photocatalytic degradation during regeneration. Full article

Background/Objectives: Wound healing represents a pervasive and urgent clinical challenge. Hard-to-heal chronic wounds are frequently complicated by infections, inflammatory responses, and oxidative stress. Currently, wound dressings are broadly categorized into dry and moist types, with moist wound dressings for chronic wounds accounting for approximately 70% of market revenue. Recently, adipose-derived stem cells (ADSCs), which possess self-renewal and multi-lineage differentiation capabilities, have emerged as a promising strategy for promoting tissue regeneration and wound repair. Methods: In this study, we developed a novel luteolin nanoparticle–ADSCs composite hydrogel (GelCA@LUT@ADSCs). This system was constructed by first encapsulating ADSCs within a chitosan/alginate hydrogel (GelCA), followed by coating the hydrogel with luteolin-loaded nanoparticles (LUT@NPs). Results: The sustained release of LUT@NPs from the hydrogel modulates the wound microenvironment, enhancing the pro-healing functions of ADSCs at the wound site. The GelCA hydrogel exhibited excellent biocompatibility. Both in vitro and in vivo results demonstrated that GelCA@LUT@ADSCs treatment effectively reduced inflammation, promoted angiogenesis and collagen deposition, stimulated cell proliferation and migration, and polarized macrophages toward an anti-inflammatory, pro-healing M₂ phenotype, thereby accelerating wound healing. Conclusions: Overall, this innovative therapeutic approach provides a novel strategy for wound management through a synergistic division of labor between pharmaceutical agents and stem cells. Full article

Peri-implant infections pose a significant challenge in dental implantology. This study aimed to develop and characterize a chitosan–vancomycin coating for titanium surfaces, focusing on drug loading, release kinetics, antimicrobial performance, and cytocompatibility. Grade 4 titanium discs were coated with a chitosan film using the dip-coating technique and subsequently loaded with vancomycin through immersion in an aqueous solution. Coating morphology was examined by scanning electron microscopy (SEM). Vancomycin loading was quantified by spectrophotometry, and release kinetics were monitored over 144 h (6-day). Antimicrobial activity was assessed through agar diffusion assays against Staphylococcus aureus. Cytocompatibility was evaluated using human mesenchymal stem cells (hMSCs), whose metabolic activity, adhesion, and morphology were assessed over a 19-day culture period by resazurin assay and SEM. SEM analysis revealed a uniformly distributed, smooth, and crack-free chitosan film, which remained stable after drug loading. The coating exhibited a biphasic release profile, characterized by an initial burst followed by sustained release over six days, which maintained antimicrobial activity, as confirmed by inhibition zones. hMSCs adhered and proliferated on the coated surfaces, displaying normal morphology despite a transient reduction in metabolic activity on vancomycin-containing films. These findings support the potential of chitosan–vancomycin coatings as localized antimicrobial strategies for implant applications, warranting further in vivo and mechanical evaluations. Full article

An optical fiber chemical sensor using a molecularly imprinted chitosan membrane coated on the surface of a bent optical fiber probe was developed for selectively analyzing 4-nitrophenol (4-NP) in water samples. When the sensor probe is exposed to a water sample, the chitosan MIP membrane extracts/concentrates 4-NP from the water sample into the membrane. The 4-NP extracted into the membrane was detected by passing a light beam through the optical fiber and the interaction of the 4-NP in the membrane with an evanescent wave of light guided through the optical fiber was detected as a sensing signal. This sensor detects the intrinsic optical absorption signal of 4-NP itself as a sensing signal. No chemical reagent was needed in analyzing this compound in a sample. The sensor is reversible, can be used for continuous monitoring of 4-NP in a sample, and has a quick response with a response time of 5 min. The sensor has high sensitivity and selectivity because the MIP membrane selectively concentrates 4-NP by 1.4 × 10⁴ times into the membrane from a sample solution, but blocks out interference species, including its isomers and derivatives, from entering the membrane. The sensor achieved a detection limit of 2.5 ng/mL (0.018 µM), which is lower than most reported analytical techniques for analyzing this compound in water samples. This sensor can discriminate 4-NP from its isomers and derivatives, such as 2-NP, 3-NP, 2-Cl-4-NP, and 2,4-di-NP, with a selectivity factor ranging from 104 to 1922. This is the first reported case of an MIP-based optical fiber chemical sensor with the capability of discriminating an organic compound from its closely related positional isomers, which demonstrates the high selectivity nature of the MIP-based optical fiber chemical sensor technique. The sensor has been used for analyzing 4-NP in a standard addition sample. The obtained recovery rate ranged from 93% to 101%, demonstrating the application potential of this sensor in water quality analysis. 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

As an important renewable building material, wood’s flammability significantly limits its application range. This study addresses the environmental pollution issues associated with traditional flame retardants by developing an eco-friendly flame retardant system based on natural biomaterials. Utilizing layer-by-layer self-assembly techniques, sodium phytate, chitosan, sodium alginate, and sodium methyl silicate were sequentially deposited onto the wood surface to construct a multifunctional composite coating. A multifunctional composite coating was constructed on wood surfaces through layer-by-layer self-assembly technology, involving successive deposition of phytic acid sodium, chitosan, sodium alginate, and methyl silicate sodium. Characterization results indicated that the optimized sample WPCSMH achieved a limiting oxygen index of 34.0%, representing a 12% increase compared to untreated wood. Cone calorimetry tests revealed that its peak heat release rate and total heat release were reduced by 57.1% and 25.3%, respectively. Additionally, contact angle measurements confirmed its excellent hydrophobic properties, with an initial contact angle of 111°. Mechanistic analysis reveals that this system significantly enhances flame retardant performance through a synergistic interaction of three mechanisms: gas phase flame retardancy, condensed phase flame retardancy, and free radical scavenging. This research provides a sustainable and innovative pathway for developing environmentally friendly, multifunctional wood-based composites. Full article

Seawater has attracted increasing attention as a promising resource for hydrogen production via electrolysis. However, multivalent ions present in seawater can reduce the efficiency of direct seawater electrolysis (DSWE) by forming inorganic precipitates at the cathode. Bipolar membranes (BPMs) can mitigate precipitate formation by regulating local pH, thereby enhancing DSWE efficiency. Accordingly, this study focuses on the fabrication of a high-performance BPM for DSWE applications. The water-splitting performance of BPMs is strongly dependent on the properties of the catalyst at the bipolar junction. Herein, iron oxide (Fe₃O₄) nanoparticles were coated with cross-linked chitosan to improve solvent dispersibility and catalytic activity. The resulting core–shell catalyst exhibited excellent dispersibility, facilitating uniform incorporation into the BPM. Water-splitting flux measurements identified an optimal catalyst loading of approximately 3 μg cm⁻². The BPM containing Fe₃O₄–chitosan nanoparticles achieved a water-splitting flux of 26.2 μmol cm⁻² min⁻¹, which is 18.6% higher than that of a commercial BPM (BP-1E, Astom Corp., Tokyo, Japan). DSWE tests using artificial seawater as the catholyte and NaOH as the anolyte demonstrated lower cell voltage and stable catholyte acidification over 100 h compared to the commercial membrane. Full article