Search Results (236)

This study systematically investigated the oxidation of chitosan using the TEMPO/NaClO/NaBr catalytic system under varying experimental conditions, namely temperature, reaction time, and pH, in order to optimize the oxidation process. Response surface methodology (RSM) was employed to determine the optimal parameters for maximizing the efficiency of the reaction. The structural modifications to the chitosan following oxidation were confirmed using Fourier-transform infrared spectroscopy (FTIR), alongside additional analytical techniques, which validated the successful introduction of carbonyl and carboxyl functional groups. Solvent-cast films were prepared from both native and oxidized chitosan in order to evaluate their functional performance. The antibacterial activity of these films was assessed against Gram-negative (Salmonella) and Gram-positive (Streptococcus faecalis) bacterial strains. The oxidized chitosan films exhibited significantly enhanced antibacterial effects, particularly at shorter incubation periods. In addition, antioxidant activity was evaluated using DPPH radical scavenging and ferrous ion chelation assays, which both revealed a marked improvement in radical scavenging ability and metal ion binding capacity in oxidized chitosan. These findings confirm that TEMPO-mediated oxidation effectively enhances the physicochemical and bioactive properties of chitosan, highlighting its potential for biomedical and environmental applications. Full article

In the rapidly evolving field of biomedical engineering, hydrogels have emerged as highly versatile biomaterials that bridge biology and technology through their high water content, exceptional biocompatibility, and tunable mechanical properties. This review provides an integrated overview of both natural and synthetic hydrogels, examining their structural properties, fabrication methods, and broad biomedical applications, including drug delivery systems, tissue engineering, wound healing, and regenerative medicine. Natural hydrogels derived from sources such as alginate, gelatin, and chitosan are highlighted for their biodegradability and biocompatibility, though often limited by poor mechanical strength and batch variability. Conversely, synthetic hydrogels offer precise control over physical and chemical characteristics via advanced polymer chemistry, enabling customization for specific biomedical functions, yet may present challenges related to bioactivity and degradability. The review also explores intelligent hydrogel systems with stimuli-responsive and bioactive functionalities, emphasizing their role in next-generation healthcare solutions. In modern medicine, temperature-, pH-, enzyme-, light-, electric field-, magnetic field-, and glucose-responsive hydrogels are among the most promising “smart materials”. Their ability to respond to biological signals makes them uniquely suited for next-generation therapeutics, from responsive drug systems to adaptive tissue scaffolds. Key challenges such as scalability, clinical translation, and regulatory approval are discussed, underscoring the need for interdisciplinary collaboration and continued innovation. Overall, this review fosters a comprehensive understanding of hydrogel technologies and their transformative potential in enhancing patient care through advanced, adaptable, and responsive biomaterial systems. Full article

This study addresses the challenge of chitosan (CS) being difficult to dissolve in water due to its highly ordered crystalline structure. Chitosan is modified with chloroacetic acid to reduce its crystallinity and enhance its water solubility. Through single-factor experiments, the optimal conditions for preparing carboxymethyl chitosan film (CMCS) were determined: under conditions of 50 °C, a cellulose substrate (CS) concentration of 18.75 g/L, a NaOH concentration of 112.5 g/L, and a chloroacetic acid concentration of 18.75 g/L, the reaction proceeded for 5 h. Under these conditions, the resulting carboxymethyl chitosan film exhibited the best flocculation effect, forming chitosan films in water that had flocculation activity toward mung bean starch protein wastewater. The successful introduction of carboxyl groups at the N and O positions of the chitosan molecular chain, which reduced the crystallinity of chitosan and enhanced its water solubility, was confirmed through analysis using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The prepared carboxymethyl chitosan film (CMCS) was applied in the flocculation recovery of protein. Through single-factor and response surface experiments, the optimal process conditions for flocculating and recovering protein with CMCS were determined: a CMCS dosage of 1.1 g/L, a reaction time of 39.6 min, a reaction temperature of 42.7 °C, and a pH of 5.2. Under these conditions, the protein recovery rate reached 56.97%. The composition and amino acid profile of the flocculated product were analyzed, revealing that the mung bean protein flocculated product contained 62.33% crude protein. The total essential amino acids (EAAs) accounted for 52.91%, non-essential amino acids (NEAAs) for 47.09%, hydrophobic amino acids for 39.56%, and hydrophilic amino acids for 12.67%. The ratio of aromatic to branched-chain amino acids was 0.31, and the ratio of basic to acidic amino acids was 1.68. These findings indicate that the recovered product has high surface activity and good protein stability, foaming ability, and emulsifying properties. Full article

Nanotechnology has revolutionized dermocosmetic innovation by improving the stability, bioavailability, and efficacy of active ingredients. In this study, we developed and optimized a novel xanthan gum-based hydrogel containing quercetin-loaded chitosan lactate nanoparticles for antioxidant and antimicrobial skincare applications. Chitosan was converted to its lactate form to enhance water solubility and enable nanoparticle formation at physiological pH via ionic gelation with citric acid. The formulation was optimized using Box–Behnken response surface methodology to achieve minimal particle size and maximal zeta potential. The final gel was structured with xanthan gum as the gelling polymer, into which the optimized nanoparticles were incorporated to create a stable and bioactive hydrogel system. Encapsulation efficiency was measured separately to assess the effectiveness of drug loading. The optimized nanoparticles exhibited a mean diameter of 422.02 nm, a zeta potential of +29.49 mV, and a high quercetin encapsulation efficiency (76.9%), corresponding to the proportion of quercetin retained in the nanoparticle matrix relative to the total amount initially used in the formulation. Antioxidant assays (TAC, DPPH, and reducing power) confirmed superior radical-scavenging activity of the nanoformulation compared to the base hydrogel. Antibacterial tests showed strong inhibition against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, with MIC values comparable to streptomycin. Accelerated stability studies demonstrated excellent physicochemical and microbiological stability over 60 days. This natural, bioactive, and eco-friendly formulation represents a promising platform for next-generation cosmeceuticals targeting oxidative stress and skin-related pathogens. Full article

The development of antibacterial coatings for biomedical applications is crucial to prevent implant-associated infections (IAIs). In this study, we designed and evaluated a multilayer coating based on chitosan (CHI), polyacrylic acid (PAA), and triclosan (TCS) using the layer-by-layer (LbL) self-assembly technique. The successful incorporation of TCS was confirmed by Fourier-transform infrared (FTIR) spectroscopy. Surface roughness and topography were analyzed using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Additionally, the pH-dependent behavior of PAA/CHI films was studied to assess its effect on TCS loading. According to disk diffusion assays, coatings assembled at pH 5 (PAA5/CHI5/TCS) exhibited the strongest antibacterial activity, with inhibition zones of 60.0 ± 0.0 mm for S. aureus and 33.67 ± 1.5 mm for E. coli. The long-term stability of the coatings was evaluated by measuring the antibacterial activity after 1, 10, 20, 30, and 40 days, with results confirming that antimicrobial properties and structural integrity were preserved over time. Furthermore, TCS release kinetics were assessed under physiological (pH 7.4) and acidic (pH 5.5) conditions, revealing enhanced release at pH 5.5. These findings highlight the potential of this multilayer system for biomedical applications requiring both stability and pH-responsive drug release. Full article

This study aimed to design dual-responsive chitosan–polylactic acid nanosystems (PLA@CS NPs) for controlled and targeted ledipasvir (LED) delivery to HepG2 liver cancer cells, thereby reducing the systemic toxicity and improving the therapeutic selectivity. Two formulations were developed utilizing ionotropic gelation and w/o/w emulsion techniques: LED@CS NPs with a size of 143 nm, a zeta potential of +43.5 mV, and a loading capacity of 44.1%, and LED-PLA@CS NPs measuring 394 nm, with a zeta potential of +33.3 mV and a loading capacity of 89.3%, with the latter demonstrating significant drug payload capacity. Since most drugs work through interaction with DNA, the in vitro affinity of DNA to LED and its encapsulated forms was assessed using stopped-flow and other approaches. They bind through multi-modal electrostatic and intercalative modes via two reversible processes: a fast complexation followed by a slow isomerization. The overall binding activation parameters for LED (cordination affinity, K_a = 128.4 M⁻¹, K_d = 7.8 × 10⁻³ M, ΔG = −12.02 kJ mol⁻¹), LED@CS NPs (K_a = 2131 M⁻¹, K_d = 0.47 × 10⁻³ M, ΔG = −18.98 kJ mol⁻¹) and LED-PLA@CS NPs (K_a = 22026 M⁻¹, K_d = 0.045 × 10⁻³ M, ΔG = −24.79 kJ mol⁻¹) were obtained with a reactivity ratio of 1/16/170 (LED/LED@CS NPs/LED-PLA@CS NPs). This indicates that encapsulation enhanced the interaction between the DNA and the LED-loaded nanoparticle systems, without changing the mechanism, and formed thermodynamically stable complexes. The drug release kinetics were assessed under tumor-mimetic conditions (pH 5.5, 10 mM GSH) and physiological settings (pH 7.4, 2 μM GSH). The LED@CS NPs and LED-PLA@CS NPs exhibited drug release rates of 88.0% and 73%, respectively, under dual stimuli over 50 h, exceeding the release rates observed under physiological conditions, which were 58% and 54%, thereby indicating that the LED@CS NPs and LED-PLA@CS NPs systems specifically target malignant tissue. Release regulated by Fickian diffusion facilitates tumor-specific payload delivery. Although encapsulation did not enhance the immediate cytotoxicity compared to free LED, as demonstrated by an in vitro cytotoxicity in HepG2 cancer cell lines, it significantly enhanced the therapeutic index (2.1-fold for LED-PLA@CS NPs) by protecting non-cancerous cells. Additionally, the nanoparticles demonstrated broad-spectrum antibacterial effects, suggesting efficacy in the prevention of chemotherapy-related infections. The dual-responsive LED-PLA@CS NPs allowed controlled tumor-targeted LED delivery with better selectivity and lower off-target toxicity, making LED-PLA@CS NPs interesting candidates for repurposing HCV treatments into safer cancer nanomedicines. Furthermore, this thorough analysis offers useful reference information for comprehending the interaction between drugs and DNA. Full article

Ulcerative colitis (UC) is a multifactorial disorder, and conventional oral berberine (BBR) suffers from poor colonic targeting. This study aimed to develop a colon-targeted microparticle system (BBR-ES MPs) based on chitosan (CS) and Eudragit S-100 to enhance BBR delivery efficiency and therapeutic efficacy in UC. Methods: BBR-CS nanocarriers were prepared via ionotropic gelation and coated with Eudragit S-100 to form pH/enzyme dual-responsive MPs. Colon-targeting performance was validated through in vitro release assays. SPF-grade male KM mice (Ethics Approval No.: JMSU-2021090301) with dextran sulfate sodium (DSS)-induced UC were divided into normal, model, BBR, and BBR-ES MPs groups. Therapeutic outcomes were evaluated by monitoring body weight, disease activity index (DAI), colon length, histopathology, inflammatory cytokines (IL-1β, IL-6, TNF-α, IL-10), and myeloperoxidase (MPO) activity via ELISA. Gut microbiota diversity was analyzed using 16S rRNA sequencing. Results: BBR-ES MP treatment significantly reduced DAI scores (p < 0.01), restored colon length, downregulated pro-inflammatory cytokines (IL-1β, IL-6, TNF-α; p < 0.05), and upregulated anti-inflammatory IL-10. Microbiota analysis revealed that the Bacteroidetes/Firmicutes ratio, which decreased in the model group, was restored post-treatment, with alpha/beta diversity approaching normal levels. BBR-ES MPs outperformed free BBR at equivalent doses. Conclusion: BBR-ES MPs achieved colon-targeted drug delivery via pH/enzyme dual-responsive mechanisms, effectively alleviating UC inflammation and modulating gut dysbiosis, offering a safe and precise therapeutic strategy for UC management. Full article

UV-cured methacrylated chitosan (MCHIT) hydrogels were achieved in the presence of silanised tellurium-doped silica bioactive glass (BG-Te-Sil) to produce an antimicrobial and osteoconductive scaffold for tissue engineering applications. Methacrylation of chitosan enabled efficient crosslinking, and the curing process was evaluated by means of Fourier-transform infrared spectroscopy (FTIR) and photorheology analyses. Compressive testing on crosslinked hydrogels showed that the silanised, bioactive, doped glass increased the hydrogel’s elastic modulus by up to 200% compared to unreinforced controls. Antibacterial assays against Staphylococcus aureus ATCC 43300 revealed a significant (p < 0.05) reduction in bacterial metabolic activity for hydrogels containing 50 wt% of the Te-doped bioactive glass. In vitro cytocompatibility with human bone-marrow mesenchymal stem cells demonstrated sustained viability and uniform distribution at 72 h (live/dead staining, AlamarBlue). Under H₂O₂-induced oxidative stress, reinforced hydrogels downregulated pro-inflammatory genes (TNF-α, IFN-γ, IL-1β, and PGES-2). These results suggest that the presence of the silanised bioactive glass can significantly enhance mechanical stability, antibacterial properties, and anti-inflammatory responses without affecting cytocompatibility, making these hydrogels promising for tissue engineering applications. Full article

This study aimed to develop a green and sustainable composite polysaccharide gel with antioxidant activity and freshness-monitoring properties. Blueberry pomace was repurposed to extract anthocyanins (BA), which were incorporated into chitosan (CS)/polyvinyl alcohol (PVA) and starch (S)/PVA matrices to prepare pH-indicating composite polysaccharide gels. The anthocyanin solution exhibited significant colorimetric responses to pH 2–14 buffer solutions. Comparative analyses revealed distinct performance characteristics: the CS/PVA-BA gel showed optimal elongation at break, low hydration (8.33 ± 0.57% water content), and potent antioxidant activity (DPPH: 73.59 ± 0.1%; ABTS: 77.47 ± 0.1%), whereas the S/PVA-BA gel demonstrated superior tensile strength and pH-responsive sensitivity. Structural characterization via FT-IR and SEM confirmed molecular compatibility between BA and polymeric matrices, with anthocyanins enhancing intermolecular hydrogen bonding. Applied to chilled beef (4 °C) freshness monitoring, the CS/PVA-BA gel exhibited color transformations from magenta-red (initial spoilage at 48 h: TVB-N > 15 mg/100 g, TVC > 4.0 lg CFU/g) to bluish-gray (advanced spoilage by day 6), correlating with proteolytic degradation metrics. These findings established a multifunctional platform for real-time food quality assessment through anthocyanin-mediated color changes in the composite gels, coupled with preservation activity, highlighting their significant potential as intelligent active packaging in the food industry. Full article

Hydrogels are three-dimensional polymeric systems, being able to accommodate different categories of bioactive agents and act as promising drug delivery systems in many different biomedical applications. Due to their extended 3D network, hydrogels exhibit many advantages, such as extensive loading capacity and controlled drug release profiles, combined with characteristics such as biocompatibility and biodegradability, due to their constructive polymeric biomaterials. Moreover, hydrogels are capable of being administered via different routes of administration, including systemic and topical ones, due to their tunable characteristics. Stimuli-responsive hydrogels are characterized as smart biomaterials, while environmental stimuli, such as pH, can be employed to trigger on-demand drug release from the hydrogels via the provocation of conformational changes. In the present study, an emphasis on the pH-responsive hydrogels is taking place through various literature cases in drug delivery, wound healing, and some alternative applications, including implantation, oral administration, etc., wherein many different polymeric derivatives have been utilized. Moreover, the role of each used polymer or polymeric combination with other functional biomaterials, their mode of structure formation (for example, crosslinking), and their content release mechanism are highlighted, as well as the therapeutic effect of the hydrogels on different pathological conditions, as promising candidates for pharmaceutical applications. Full article

The hyperglycemic microenvironment in diabetic wounds predisposes them to bacterial infections, sustains chronic inflammation, and hinders therapeutic efficacy. In this study, antibiotic-loaded fast-crosslinked hybrid nanogel wound dressings (florfenicol nanogels) based on Schiff’s base bond were obtained through N, O-carboxymethyl chitosan (N, O-CMCS) and oxidized hyaluronic acid (OHA). The successfully prepared florfenicol N, O-CMCS/OHA nanogels exhibited obvious pH- and HAase-responsiveness release, which allowed it to quickly release florfenicol at infected wounds to exert on-demand antibacterial activity, as well as accelerate diabetic bacterial-infected wound healing. The nanogel dressings showed excellent antibacterial activity by destroying the bacterial cell membrane and wall. More specifically, the glucose oxidase in the dressings can catalyze the breakdown of high-concentration glucose, generating abundant ROS that directly cause cellular damage. According to the results of wound healing, the dressings showed satisfactory anti-inflammatory and therapeutic effects for the full-thickness mouse skin defect wounds. The nanogel dressings are anticipated to be excellent wound dressings to synergistically overcome the theraputic difficulty of diabetic bacterial wounds. Full article

pH-sensitive hydrogels are important soft biomaterials as they mimic biological organisms by altering their properties in response to small pH changes in biological fluids. In this work, novel chitosan (Cs) hydrogels were developed using an innovative dual curcumin (Cur) encapsulation system. Cur was loaded into poloxamer 407 micelles and incorporated into citric acid (CA) cross-linked Cs hydrogels using a central composite design. The hydrogels were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), rheological tests, and in vitro experiments, such as hemolysis and cytotoxicity assays. FTIR confirmed cross-linking between Cs and CA, while DSC suggested interactions between Cur-loaded micelles and the hydrogel matrix. Rheological analysis revealed gel-like behavior, with G′ consistently higher than G, and temperature influenced hydrogel properties. SEM showed a denser network when Cur-loaded micelles were incorporated, slowing Cur release. At physiological pH (7.4), 75% of Cur was released after 7 days, while 84% was released at pH 5.5, showing pH-responsive behavior. Cytotoxicity tests showed over 80% viability of VERO CCL-81 cells (0.2–20 ppm hydrogel). This dual-encapsulation system provides a simple and effective platform for loading lipophilic drugs into pH-responsive hydrogels. Full article

Background/Objectives: Due to the challenges faced by anticancer therapeutics, such as poor selectivity and metabolic degradation, novel delivery systems are needed to mitigate the adverse effects of chemotherapy. The management of chronic wounds is often overlooked and affects patients mentally and physically. The application of hydrogels can reduce deficiencies in drug delivery and wound healing due to their similarity to the extracellular matrix and stimuli-responsive properties. Methods: A chitosan (CS) hydrogel, cross-linked to gold nanoparticles (AuNPs), followed by the encapsulation of 5-fluorouracil (5-FU), was formulated. The physicochemical properties, drug release profiles, cytotoxicity, and wound healing in vitro were analyzed. Results: Fourier transform infrared spectroscopy and a UV-visible peak at 530 nm confirmed their successful synthesis. Transmission electron microscopy revealed spherical NPs of 89.31 nm, while scanning electron microscopy confirmed the porous network surface of the hydrogels. The thermogravimetric analysis demonstrated enhanced stability for the CS-Au hydrogel, while a non-Newtonian shear-thinning property was evident from rheology. Drug release showed a sustained, pH-dependent release with specificity for the acidic cancer microenvironment. The cytotoxicity assay demonstrated a specificity of the CS-Au-5-FU hydrogel for the cancer cells (HeLa and MCF-7) and diminished cytotoxicity in the non-cancer cells (HEK293). The scratch assay illustrated a complete closure of the wounds in HEK293 cells at low concentrations (15.63 and 31.25 µg/mL). Conclusions: The positive findings from this study confirm the potential of these CS-Au hydrogels to function as smart in vitro delivery systems and scaffolds for wound healing, warranting additional optimizations and in vivo studies. Full article

Background/Objectives: Nanocarrier particle design for treating chronic pulmonary diseases presents several challenges, including anatomical and physiological barriers. Drug-repurposing technology using monodispersed spherical silica is one of the innovative ways to deliver drugs. In the present study, the anticancer potential of combinational cisplatin/ribavirin was explored for targeted lung cancer therapeutics. Methods: Monodispersed spherical silica (80 nm) capable of diffusing into the tracheal mucus region was chosen and doped with 10 wt% superparamagnetic iron oxide nanoparticles (SPIONs). Subsequently, it was wrapped with chitosan (Chi, 0.6 wt/vol%), functionalized with 5% wt/wt cisplatin (Cp)/ribavarin (Rib) and angiotensin-converting enzyme 2 (ACE-2) (1.0 μL/mL). Formulations are based on monodispersed spherical silica or halloysite and are termed as (S/MSSiO₂/Chi/Cp/Rib) or (S/Hal/Chi/Cp/Rib), respectively. Results: X-ray diffraction (XRD) and diffuse reflectance UV-visible spectroscopy (DRS-UV-vis) analysis of S/MSSiO₂/Chi/Cp/Rib confirmed the presence of SPION nanoclusters on the silica surface (45% coverage). The wrapping of chitosan on the silica was confirmed with a Fourier transformed infrared (FTIR) stretching band at 670 cm⁻¹ and ascribed to the amide group of the polymer. The surface charge by zetasizer and saturation magnetization by vibrating sample magnetometer (VSM) were found to be −15.3 mV and 8.4 emu/g. The dialysis membrane technique was used to study the Cp and Rib release between the tumor microenvironment and normal pH ranges from 5.5 to 7.4. S/MSSiO₂/Chi formulation demonstrated pH-responsive Cp and Rib at acidic pH (5.6) and normal pH (7.4). Cp and Rib showed release of ~27% and ~17% at pH 5.6, which decreases to ~14% and ~3.2% at pH 7.4, respectively. To assess the compatibility and cytotoxic effect of our nanocomposites, the cell viability assay (MTT) was conducted on cancer lung cells A549 and normal HEK293 cells. Conclusions: The study shows that the designed nanoformulations with multifunctional capabilities are able to diffuse into the lung cells bound with dual drugs and the ACE-2 receptor. Full article

In this study, a new edible gel of Perilla essential oil (PE)/grape seed extract (GSE)–chitosan/gelatin was prepared, and it was applied to the preservation of silver carp. By establishing a fuzzy mathematical model, using a single-factor experiment and Box–Behnken response surface optimization combined with matlab analysis, the optimum preparation conditions of composite gel films were determined: the addition of PE (p < 0.01) was 6.91 μL/mL, the addition of GSE (p < 0.05) was 0.45 mg/mL, and the addition of gelatin (p > 0.05) was 1.63%. Under these conditions, the composite gel films exhibited an excellent water vapor barrier and mechanical properties. Using Fourier-transform infrared spectroscopy (FTIR) analysis, it was found that the addition of PE enhanced or weakened the absorption peaks, indicating the molecular interaction between PE and the substrate. Scanning electron microscopy (SEM) observed that the surfaces of the composite gel films with added PE were smooth, but there were a few pores in the cross-section. X-ray diffraction (XRD) analysis showed that PE had good compatibility with other components. The fresh-keeping experiment showed that the composite gel films could significantly prolong the fresh-keeping period of grass carp. After 10 days of storage at 4 °C, compared with the blank group (without plastic wrap) and the control group (with composite gel film, no PE added), the experimental group (with composite gel films, PE added) showed better fresh-keeping effect in terms of sensory score, moisture content, pH value, TBARS value, and TVB-N value (p < 0.05). Correlation analysis further confirmed the positive effects of composite gel films on water content, pH value, TVB-N, and other quality indexes of silver carp, indicating that the composite gel films will have broad application prospects in the food preservation field. This study provides an innovative basis and theoretical basis for the development and application of natural polysaccharide/protein composite edible film, which is helpful to promote the development of green food-packaging materials. Full article