Does the use of chitosan contribute to oxalate kidney stone formation?

Towards sustainable microplastic cleanup: Al/Fe ionotropic chitosan hydrogels for efficient PET removal

Chitosan (CHI) was modified with iron and aluminum salts to create ionotropic beads, Fe-CHI and Al-CHI, for the removal of polyethylene terephthalate microplastics (PET-MP) from water. Infrared spectroscopy revealed reduced hydrogen bonding associated with N-H vibration of CHI (3500-3100 cm-1) due to the interaction with the metal ions, and absorption peaks between 500 and 916 cm⁻1 predominantly due to metal-oxygen stretching vibrations. The swelling behavior of the beads increased with temperature but decreased as pH and metal doping concentration increased. Conductivity and PET-MP removal efficiency improved with higher metal ion concentrations, with Al-CHI exhibiting greater swelling and conductivity compared to Fe-CHI. The highest efficiency for MP remediation was recorded at low pH levels. MP adsorption decreased with rising temperatures and varied with pH changes due to protonation and deprotonation reactions of CHI, along with the various cationic and anionic species formed by the metals. At pH 7, MP removal by Fe-CHI beads declined as the doping concentration increased, attributed to specific Fe species that emerged at this pH. The zeta potential measurements showed that both the beads and the MP were in an unstable range at low pH but shifted towards stability at higher pH levels. Re-adsorption efficiencies exceeded 70% for both low and high-doped Fe-CHI and Al-CHI beads when tested with ~ 40 MP/mL of MP suspension over three different cycles. Overall, the use of ionotropic CHI beads offers a promising, eco-friendly method for effectively reducing PET-MPs in water.

Development of chitosan/hydrolyzed collagen interaction product-based microparticles for the treatment of respiratory tract infections

Respiratory tract infections (RTIs) represent a significant global health issue, particularly for vulnerable population, such as children, the elderly, or patients with immunosuppression. In this context, the aim of the present work was the development of Chitosan/Hydrolyzed Collagen-based microparticles (Mps) as a pulmonary drug delivery system (PDDS) for the treatment of RTIs. Mps were produced via spray-drying and composed of chitosan (Cs), one of the most widely used polysaccharides in PDDS, and hydrolyzed collagen (HC), another promising material for the development of PDDS that has not yet been fully explored. The formation of an interaction product between Cs and HC occurred during the spray-drying process and was confirmed by infrared spectroscopy and thermal analysis. Mps were characterized in terms of morphology, particle size, zeta potential, aerodynamic performance, swelling behavior and biodegradation profile in simulated lung fluid. Mps biocompatibility was also assessed on adenocarcinomic human alveolar basal epithelial (A549) cells. Finally, Mps were characterized in vitro for antibacterial properties and their ability to inhibit bacterial adhesion to S. aureus and P. aeruginosa. An enhanced antibacterial effect was observed for Mps with respect to the pristine materials (Cs and HC) and their physical mixture. Moreover, Mps were also able to inhibit bacteria adhesion to epithelial cells.

Comparison on the performance of green and conventional magnetic chitosan-based composites in the removal of complex dyes: Synergetic effect, experimental and theoretical studies

The presence of complex dyes, which possess four or more aromatic rings, is pervasive in environmental matrices. Nanomaterials offer a promising avenue for their removal. In this study, we synthesized novel magnetic nanocomposites comprising nanochitosan (nCS) and iron nanoparticles through the application of green and conventional protocols. In the preparation of the green composite, designated as G-nCS@FeNPs, eucalyptus leaves extract and proanthocyanidins were employed as reducing and crosslinking agents, respectively. In contrast, the conventional composite, designated as C-nCS@FeNPs, utilized ammonia and glutaraldehyde as the reducing and crosslinking agents, respectively. The G-nCS@FeNPs exhibited a more electropositive surface, and prominent magnetic properties. The zeta potential measurements of the G-nCS@FeNPs (ranging from +36 to +30 mV) were more positive than those of the C-nCS@FeNPs (+35 to -2.79 mV). Additionally, the C content in C-nCS@FeNPs was less (36.4 %) than in G-nCS@FeNPs (57.2 %), which is likely due to the higher nanochitosan content and the presence of proanthocyanidins in the green nanocomposite. The G-nCS@FeNPs exhibited a tridimensional porous structure, whereas the conventional composite appeared to form a CS film with an uneven surface and embedded FeNPs. G-nCS@FeNPs demonstrated remarkable potential as an adsorbent material for the removal of anionic reactive dyes, namely orange 122 (RO122) and red 250 (RR250). It exhibited an exceptional adsorption capacity of 3005 mg.g-1 for RO122. A DFT study revealed that the RO122 molecule displays enhanced reactivity towards the adsorbent surface. Moreover, experiments conducted in saline media and XPS and FTIR analyses post-adsorption indicated that 78.8 % of the interactions between RO122 and the adsorbent are based on electrostatic and ion exchange, while the remaining 22.2 % are attributed to π-π and hydrogen bonds. Also, G-nCS@FeNPs demonstrated a synergistic effect on the removal of the cationic dye safranin in multicomponent systems, exhibiting an increase in removal capacity from 0 to 169 mg.g-1.

Enhancing Bioactivity of Titanium-Based Materials Through Chitosan Based Coating and Calcitriol Functionalization

Titanium (Ti)-based materials are favored for hard tissue applications, yet their bioinertness limits their success. This study hypothesizes that functionalizing Ti materials with chitosan nano/microspheres and calcitriol (VD) will enhance their bioactivity by improving cellular activities and mineralization. To test this, chitosan particles were applied uniformly onto Ti surfaces using electrophoretic deposition (EPD) at 20 V for 3 minutes. VD was then loaded onto the coated surfaces, and the release profile of VD was monitored. Human fetal osteoblastic cells (hFOB) were cultured on the VD-loaded Ti surfaces. Cellular activities such as proliferation, Alkaline phosphatase (ALP) activity, osteogenic gene expression (runt-related transcription factor 2 (Runx2), collagen type 1 (Col I), osteocalcin ( OCn), osteopontin (OP)), and mineralization were assessed. Von Kossa staining was performed to analyze mineralization, and the expression of cell adhesion proteins (N-cadherin (NC), integrin alpha V (IaV), integrin beta 3, (Ib3)) was measured. The results showed that approximately 50% of the VD released over 50 hours. The chitosan coating increased surface roughness three-fold, and this, combined with VD release, resulted in reduced cell proliferation but increased ALP activity, suggesting enhanced differentiation. VD-functionalized Ti surfaces showed statistically significant differences in osteogenic gene expressions, particularly on rougher surfaces. Additionally, the expression of cell adhesion proteins (NC, IaV, Ib3) was upregulated on VD-containing coated surfaces. Von Kossa analysis revealed that surface roughness significantly enhanced mineralization, particularly on VD-free surfaces by day 7, while mineralization on VD-containing bare surfaces started on day 14. These findings demonstrate that VD-loaded chitosan coatings significantly enhance the biocompatibility and bioactivity of Ti-based materials, highlighting their potential for applications in bone regeneration.

Green approach to synthesis polymer composites based on chitosan with desired linear and non-linear optical characteristics

The current study used sustainable and green approaches to convey polymer composites with desired optical properties. The extracted green tea dye (GTD) enriched with ligands was used to synthesize zinc metal complexes. Green chitosan biopolymer incorporated with green synthesized metal complex using casting technique was used to deliver polymer composites with improved optical properties. The FTIR-ATR was used to identify the functional groups of the GTD, pure CS, and functional groups surrounding the synthesized zinc metal complex. Distinguished ATR bands were observed in green tea dye spectra, such as OH, C = O, and NH functional groups ascribed to various polyphenols. The ATR bands of the zinc metal complex compared to GDT established that GDT is crucial to capturing zinc cations and producing the Zn2+-metal complex. The broadness of the bands observed in CS-based composites inserted with the Zn2+- metal complex confirms strong interaction among the components of polymer composites. The XRD achievements confirm that CS films with different Zn2+- metal complex concentrations transferred to an amorphous composite. The XRD pattern of composite films establishes that the zinc metal complex scarified the crystalline phases of chitosan. Linear optical properties such as absorption, refractive index (n), and optical dielectric parameters were improved. The absorption edge of the composite's films shifted to lower photon energies. Various models were used to determine the optical band gap. The band gap drops from [Formula: see text] when chitosan is loaded with a 36% Zn2+-metal complex. The Spitzer-Fan method is used to get the dielectric constant, and the Drude Lorentz oscillator model was used to calculate vital optical parameters, including N/m*, τ, and µopt. The W-D single oscillator model was used to determine the Eo and Ed parameters. The values of optical moments (M-1 and M-3) were calculated with the help of the W-D model. The oscillator's strength ([Formula: see text]) and wavelength ([Formula: see text]) were determined via the Sellmeier model using the linear refractive index. The first-order nonlinear ( [Formula: see text]), second-order non-linear ([Formula: see text]) and third-order nonlinear optical susceptibility ([Formula: see text]) were determined for all the films.

New insights into chitosan-Ag nanocomposites synthesis: Physicochemical aspects of formation, structure-bioactivity relationship and mechanism of antioxidant activity

Herein, a novel approach to the controlled formation of chitosan-Ag nanocomposites (NCs) with different structures and tunable chemical/biological properties was proposed. The chitosan-Ag NCs were obtained using hydrothermal synthesis and varying the concentrations of components. The hypothesis of chitosan-Ag NC synthesis using polysaccharide coils as a "microreactor" system was confirmed. A comparative analysis of the physicochemical characteristics of the NCs with single-core-shell and multi-core-shell structures was carried out, and the "structure-property" relationship was revealed. The obtained NCs exhibited excellent antiradical properties, comparable to the activity of phenolic acids: the IC50 values were 0.051, 0.022, and 0.019 mg/mL for CS7, CS5, and caffeic acid, respectively. A mechanism for the antiradical activity of chitosan-Ag NCs was discussed. The redox activity of the NCs was found to be 11.4 and 2.3 mg ABTS per 1 mg of Ag in CS5 and CS7, respectively. The proposed environmentally friendly one-pot, one-step synthesis of silver nanoparticles inside chitosan "microreactors" represents an innovative approach to designing hybrid materials with nanoscale control of desired structure and properties. These findings pave the way for further optimization of biopolymer‑silver nanostructures for various biomedical and industrial applications, including the design of a new type of hybrid catalysts such as nanozymes.

Films Based on Chitosan/Konjac Glucomannan Blend Containing Resveratrol for Potential Skin Application

Biopolymers represent a significant class of materials with potential applications in skin care due to their beneficial properties. Resveratrol is a natural substance that exhibits a range of biological activities, including the scavenging of free radicals and anti-inflammatory and anti-aging effects. In this study, chitosan/konjac glucomannan resveratrol-enriched thin films were prepared. The enrichment of biomaterials with active ingredients is a common practice, as it allows the desired properties to be obtained in the final product. To characterize the films, several analyses were performed, including infrared spectroscopy, imaging of the samples by SEM and AFM techniques, swelling analysis in pH 5.5 and 7.4, mechanical and antioxidant assays, contact angle measurements, and determination of the resveratrol release profile under the skin mimicking conditions. Resveratrol incorporation into the matrices resulted in modifications to the chemical structure and film morphology. The mechanical characteristics of films with additives were found to undergo deterioration. The sample containing 10% of resveratrol exhibited a higher swelling degree than other films. The resveratrol-modified films demonstrated a notable antioxidant capacity, a reduced contact angle, and enhanced wettability. The resveratrol release occurred rapidly initially, with a maximum of 84% and 56% of the substance released depending on the sample type. Thus, the proposed formulations have promising properties, in particular good swelling capacity, high antioxidant potential, and improved wettability, and may serve as skin dressings after further investigation.

Development of a Sustainable Flexible Humidity Sensor Based on Tenebrio molitor Larvae Biomass-Derived Chitosan

This study presents the fabrication of a sustainable flexible humidity sensor utilizing chitosan derived from mealworm biomass as the primary sensing material. The chitosan-based humidity sensor was fabricated by casting chitosan and polyvinyl alcohol (PVA) films with interdigitated copper electrodes, forming a laminate composite suitable for real-time, resistive-type humidity detection. Comprehensive characterization of the chitosan film was performed using Fourier-transform infrared (FTIR) spectroscopy, contact angle measurements, and tensile testing, which confirmed its chemical structure, wettability, and mechanical stability. The developed sensor exhibited a broad range of measurements from 6% to 97% relative humidity (RH), a high sensitivity of 2.43 kΩ/%RH, and a rapid response time of 18.22 s with a corresponding recovery time of 22.39 s. Moreover, the chitosan-based humidity sensor also demonstrated high selectivity for water vapor when tested against various volatile organic compounds (VOCs). The superior performance of the sensor is attributed to the structural properties of chitosan, particularly its ability to form reversible hydrogen bonds with water molecules. This mechanism was further elucidated through molecular dynamics simulations, revealing that the conductivity in the sensor is modulated by proton mobility, which operates via the Grotthuss mechanism under high-humidity and the packed-acid mechanism under low-humidity conditions. Additionally, the chitosan-based humidity sensor was further seamlessly integrated into an Internet of Things (IoT) framework, enabling wireless humidity monitoring and real-time data visualization on a mobile device. Comparative analysis with existing polymer-based resistive-type sensors further highlighted the superior sensing range, rapid dynamic response, and environmental sustainability of the developed sensor. This eco-friendly, biomass-derived, eco-friendly sensor shows potential for applications in environmental monitoring, smart agriculture, and industrial process control.

Protein-Polymer Conjugates as Biocompatible and Recyclable ATRP Catalysts

Atom transfer radical polymerization (ATRP) is a leading method for creating polymers with precise control over molecular weight, yet its reliance on metal catalysts limits its application in metal-sensitive and environmental contexts. Addressing these limitations, we have developed a recyclable, biocompatible, robust, and tunable ATRP catalyst composed of a protein-polymer-copper conjugate, synthesized by polymerizing an L-proline-based monomer onto bovine serum albumin and complexing with Cu(II). The use of this conjugate catalyst maintains ATRP's precision while ensuring biocompatibility with bothEscherichia coli and HEK 293 cells, and its high molecular weight allows for easy recycling through dialysis. Therefore, our efforts extend ATRP's applicability across diverse fields, including biotechnology and green chemistry, marking a significant advance toward environmentally friendly and safe polymerization technologies.

Effects of Gamma Irradiation on Structural, Chemical, Bioactivity and Biocompatibility Characteristics of Bioactive Glass-Polymer Composite Film

Gamma irradiation is an effective technique for biocomposite films intended for application in tissue engineering (TE) to ensure sterility and patient safety prior to clinical applications. This study proposed a biocomposite film composed of natural polymer chitosan (CS) and synthetic polymer poly-Ɛ-caprolactone (PCL) reinforced with sol-gel-derived bioactive glass (BG) for potential application in TE. The BG/PCL/CS biocomposite film was sterilized using 25 kGy gamma rays, and subsequent changes in its characteristics were analyzed through mechanical and physical assessment, bioactivity evaluation via immersion in simulated body fluid (SBF) and biocompatibility examination using human primary dermal fibroblasts (HPDFs). Results indicated a homogeneous distribution of BG particles within the BG/PCL/CS polymer matrix which enhanced bioactivity, and the polymer blend provide a structurally stable film. Gamma irradiation induced an increase in the film's surface roughness due to photo-oxidative degradation; however, this did not adversely affect the integrity of glass particles and polymer chains. In vitro assessments demonstrated hydroxyapatite formation on the film's surface, suggesting bioactivity. Biocompatibility testing confirmed enhanced cell adhesion and proliferation. These multifunctional properties highlight the potential of the fabricated BG/PCL/CS biocomposite film for TE and regenerative medicine applications.

Molecular insights into the anti-cancer activity of chitosan-okra mucilage polymeric nanocomposite doped with nano zero-valent iron against multi-drug-resistant oral carcinoma cells

Recent advances in nanotechnology, particularly those utilizing polymeric nanocomposites, have garnered significant attention for their effectiveness and biocompatibility in cancer diagnosis and treatment. In this study, a chitosan-okra mucilage polymeric nanocomposite doped with nano zero-valent iron (CS-OM-nZVI), synthesized using green chemistry principles, was evaluated for its anti-cancer activity against drug-resistant oral carcinoma cells (KBChR). The nanocomposite was created from chitosan, mucilage derived from okra biomass, and nano zerovalent iron particles synthesized through chemical reduction. The resulting nanocomposite exhibited a highly stable, crystalline nanoscale structure with excellent stability. Anti-cancer activity was assessed by measuring cell viability, apoptosis induction, oxidative stress markers, DNA fragmentation, and performing in silico docking studies between the components of the polymeric nanocomposite (CS-OM-nZVI) and key proteins involved in carcinoma pathogenesis. The nanocomposite demonstrated significant anticancer activity, with an IC50 of 600 μg/mL, indicating notable effects on cell viability. It also induced significant morphological changes associated with apoptosis, such as chromatin condensation and nuclear fragmentation. Additionally, the nanocomposite had a marked effect on oxidative stress markers, particularly catalase and superoxide dismutase activity. In silico docking studies revealed that the polymeric composite modulates and enhances both intrinsic and extrinsic apoptotic pathways, confirmed by chitosan's binding to Caspase-3. This study suggests that the prepared nanocomposite is a promising anti-cancer agent against drug-resistant oral carcinoma cells, demonstrating a significant impact on cancer cell viability.

Fabrication and evaluation of chondroitin sulfate based hydrogels loaded with chitosan nanoparticles for oral delivery of vildagliptin

Vildagliptin is a drug of choice in type II diabetes mellitus that suffers from limitations like short half-life with reduced bioavailability. To improve the therapeutic performance of vildagliptin, this study aimed to synthesize chitosan nanoparticles (NPs) loaded hydrogel by using biological polysaccharides like sodium alginate (SA) and chondroitin sulfate (CS). The NPs were prepared by ionic gelation method and various characterization tests like surface morphology, size and zeta potential, entrapment efficiency, and in-vitro drug release studies were performed. Results indicated that NPs were round in geometry with an average particle size of 213 nm, having drug encapsulation efficiency of 65 % and controlled drug release within 6-8 h. The optimized NPs (F2) loaded hydrogel showed a good dynamic swelling with gel fraction of 96 %. The hydrogels released 96 % of vildagliptin in 72 h via a non-Fickian diffusion mechanism. The optimized formulation was thermally stable. Formulation showed greater swelling at slight basic pH 7.4 as compared to acidic medium. Moreover, acute toxicity study results demonstrated that the developed NPs loaded hydrogel were safe for oral delivery. The overall results suggested that vildagliptin-loaded NPs loaded hydrogel can serve as an alternative novel dosage form for oral controlled drug delivery.

Cross-linked chitosan as biomacromolecular adsorbents for adsorption of precious metal-chloride complexes from aqueous media

Precious metal recovery from secondary sources has received significant attention due to the reduced availability of precious metals from conventional sources. Herein, chitosan (CHT) was modified via cross-linking with glutaraldehyde (glu) to yield CHT-glu adsorbents with improved physicochemical and adsorption properties with precious metal ions (Au(III) and Pd(II)). CHT-glu adsorbents were prepared at variable glu ratios and characterized via complementary spectral (IR, 13C solids NMR, XPS) and thermogravimetry methods. The adsorbents display remarkably enhanced properties relative to CHT upon incremental cross-linking, which includes structural stability in acidic media, greater porosity and surface area with unparalleled adsorption at pH 2. The highest metal-ion uptake capacity for the CHT-glu adsorbent system was 1322 mg/g (Au(III)) and 1337 mg/g (Pd(II)). Electrostatic and chelation interactions govern the adsorption mechanism of gold and palladium species by CHT-glu, as supported by XPS results. The CHT-glu systems display superior solid phase extraction properties for the recovery of precious metals from acidic leachate, which is relevant to sustainable metal recovery from tailings or industrial wastewater effluent.

Glatiramer acetate in situ forming gel, a new approach for multiple sclerosis treatment

BACKGROUND

Glatiramer acetate (GA), a commonly used treatment for multiple sclerosis (MS), requires long-term frequent injections to ensure its effectiveness. This often leads to adverse effects, patient noncompliance, and economic inefficiency.

OBJECTIVES

In this study, poloxamer, as a thermosensitive polymer modified by chitosan (CS) and hyaluronic acid (HA), was employed to prepare an in situ forming prolonged release formulation of GA to overcome the problems derived from frequent repeated injections and to enhance the patient compliance.

METHODS

The sol-gel formulation was produced through a cold method and optimized using design of experiments. The final product was characterized in terms of gelation time (GT), rheological behaviors, morphological properties, assay, and drug release kinetics.

RESULTS

The in vitro release rate of GA during the first 24 h was quite rapid, but then it continued at a slower rate of 0.05 mg ml-1h-1. The in vivo analysis after the subcutaneous injections showed lower levels of IL-5, IL-13, and uric acid (UA) in mice treated with the gel formulation compared with those receiving free GA in the first few days. However, after 10 days, significantly higher concentrations were detected, which continued to increase slowly.

CONCLUSION

It can be concluded that the designed thermosensitive sol-gel formula is capable of extending the effectiveness of GA and can be considered as a promising sustained release formulation for the treatment of MS.

Strontium doped 58S bioglass incorporated chitosan/gelatin porous scaffold for bone tissue engineering applications

Bioglass (Bg) is accepted as a revolutionary material, and doping with strontium (Sr) ions in the Bg network exhibits improved biofunctionality towards bone tissue regeneration and inhibits osteoclast formation. Keeping this in view, the present study focused on the development of chitosan (CS)/gelatin (GE) porous scaffolds incorporated with Sr-doped Bg nanoparticles (nSrBg) for bone tissue engineering applications. The SEM analysis of the fabricated scaffold exhibited that it possessed a homogenous microstructure with an interconnected porous network having pore sizes of 100-300 μm. A swelling of <6-fold and a degradation rate under 50 % were achieved. The compression test revealed that nSrBg improved the strength of the composite to 1.15 MPa. In vitro bioactivity assays suggested the presence of nSrBg enhanced the bone-like deposition of the apatite layer, which possessed cell-supportive properties, allowing the cells to attach and proliferate over the scaffold surface. MTT assay and live-dead staining revealed that the nSrBg enhanced the proliferation of the cells up to 0.48 OD. The ALP assay suggested that the nSrBg addition improved the osteogenic potential until 0.70 OD. Overall, the fabricated scaffold showed superior mechanical and biological properties that can be a promising platform for bone tissue regeneration.

Applications of three-dimensional whey protein amyloid fibril-based hybrid aerogels in oil/water separation and emulsion separation

Environmental contamination from oil spills and industrial wastewater poses long-term risks to ecosystems and human health. Amyloid fibrils' superior stiffness and stability, outstanding biocompatibility and biodegradability, versatile functional groups, and high specific surface area make them promising sustainable adsorbents. This study is aimed at examining the application of three-dimensional polysaccharide-modified whey protein amyloid fibril (WPIAF) aerogels in oil/water separation and emulsion separation. The WPIAF aerogel was first synthesized through the salting out method coupled with lyophilization, then modified using carboxymethyl cellulose (CMC) or chitosan (CS). Our results showed that WPIAF aerogels exhibited increased mechanical properties and surface hydrophobicity after polysaccharide modification. The CS-modified WPIAF aerogels showed better oil adsorption capacities, oil adsorption capability, and reusability than WPIAF aerogel and CMC-modified WPIAF aerogels. Furthermore, the applicability of polysaccharide-modified WPIAF aerogels in a continuous oil/water separation system was demonstrated. Finally, the separation efficiencies of polysaccharide-modified WPIAF aerogels were determined to be over 90 % in various emulsion systems, and the possible separation mechanism was further investigated. This study provides a nice example of applying amyloid-based aerogels for oil/water separation and emulsion separation.

Study on Fabrication and Properties of Polyvinyl Alcohol/Chitosan Nanofibers Created from Aqueous Solution with Acetic Acid and Ethanol by the Electrospinning Method

The development of nanofibers with incorporated biologically active molecules with a targeted mode of action is a current research trend. Potential materials for the development of such systems include poly(vinyl alcohol) (PVA) and chitosan (CS) nanofibers, which are traditionally fabricated by the electrospinning of aqueous solutions of these polymers with acetic acid. To improve drug integration, ethanol was added to the binary-solvent system. This results in several important data: noticeable shifts in the solvent system's solubility parameter, the interaction of the various component forces, and optical and rheological properties of the PVA-CS solution. The use of ethanol in the electrospun solution also contributes to adjusting the solubility parameters of the solution in the Teas graph, maintaining the "fh - fd" in the optimal region for the fabrication of PVA-CS nanofibers. Increasing the efficiency of PVA-CS nanofiber fabrication by electrospinning is quite difficult due to the requirements of solution parameters, technological parameters, and environmental parameters; however, this efficiency was increased in this work by 2 to 3 times with a more optimal PVA-CS nanofiber morphology. These results demonstrate that aqueous solution containing 4% PVA, 3% CS, 15% ethanol, and 45% acetic acid is optimal for increasing the nanofiber fabrication productivity, improving the morphology and diameter of PVA-CS nanofibers without changing in chemical bonds. The XRD spectrum revealed that the alterations in the crystal lattice and diameter of the PVA-CS nanofibers led to the variation in their thermal and tensile properties.

New Composite Materials Based on PVA, PVP, CS, and PDA

In this work, new materials based on the blends of polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), chitosan (CS), and polydopamine (PDA) have been prepared. Fourier Transform Infrared Spectra have been conducted to verify the presence of individual components in the composite materials. EDX elemental analysis showed a clear view of the element's presence in the composite materials, with the maximum values for carbon and oxygen. Atomic force microscopy (AFM) was used to observe the surface topography and measure the surface roughness. In the case of the individual polymers, CS presented the higher value of surface roughness (Rq = 3.92 nm and Ra = 3.02 nm), and surface roughness was found to be the lowest in the case of polyvinyl pyrrolidone (PVP), and it was with values (Rq = 2.34 nm and Ra = 0.95 nm). PVA films presented the surface roughness, which was with the value (Rq = 3.38 nm and Ra = 2.11 nm). In the case of composites, surface roughness was highest for the composite based on PVA, PVP, and CS, which presented the value (Rq = 11.91 nm and Ra = 8.71 nm). After the addition of polydopamine to the polymeric composite of PVA, PVP, and CS, a reduction in the surface roughness was observed (Rq = 7.49 nm and Ra = 5.15 nm). The surface roughness for composite materials was higher than that of the individual polymers. The addition of PDA to polymeric composite (PVA/PVP/CS) led to a decrease in Young's modulus. The elongation percentage of the polymeric films based on the PVA/PVP/CS/PDA blend was higher than that of the blend without PDA (9.80% vs. 5.68% for the polymeric composite PVA/PVP/CS). The surface of polymeric films was hydrophilic. The results from the MTT assay showed that all tested specimens are non-toxic, and it was manifested by a significant increase in the viability of L929 cells compared with control cells. However, additional studies are required to check the biocompatibility of tested samples.

Electrocapacitive removal of Na and Cd ions from contaminated aqueous solution using Fe3O4-poly (3,4-ethylenedioxythiophene) poly(styrene sulfonate) modified chitosan nanosheets

Chitosan nanosheets (NS) stabilized on poly (3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT: PSS) was functionalized using Fe3O4 to capacitively remove chloride ions and toxic cadmium ions at optimized pH, concentration, and number of charging cycles. The synthesis procedure was investigated by Fourier transform infrared spectroscopy (FTIR), X-Ray Diffractometer (XRD), Transmission Electron Microscope (TEM), Scanning Electron Microscope - Energy Dispersive X-ray Spectroscopy (SEM-EDS), and Brunauer-Emmett-Teller (BET). The analyses confirms increase in surface area of the nanocomposite from 41 to 132 m2/g and a decrease in crystallinity from 75.3 to 66.9% after nanosheet formation. The highest sorption exchange capacity (SEC) for this work, 93% CdCO3 removal is achieved at 100 CDI cycles while 82% NaCl removal was achieved at 80 cycles. The SEC% increased with pH during Na ion deionization and decreased with pH during Cd removal. The works shows that chitosan is able to impart advanced structural properties to Fe3O4 and PEDOT and is able to reduce reverse migration of ions from electrodes to bulk solution, leading to higher SEC performance.

Chitosan adorned with ZIF-67 on ZIF-8 biocomposite: A potential LED visible light-assisted photocatalyst for wastewater decontamination

The current investigation has utilized a simple and constructive stratified method to synthesize a binary (Cs/Z-8: chitosan (Cs) and zeolitic imidazolate framework-8 (Z-8)) and ternary Cs/Z-8/Z-67 (Z-67: ZIF-67) biocomposites at room temperature. A certain amount of Cs/Z-8 (0.05, 0.1, and 0.2 g) was used to prepare ternary biocomposites (denoted as Cs/Z-8/Z-67-0.05, Cs/Z-8/Z-67-0.1, and Cs/Z-8/Z-67-0.2, respectively). The synthesized materials were characterized. Through the adornment Cs, a non-toxic biopolymer, with Z-8 and Z-67, the desired efficacy in removing pollutants (TCN: Tetracycline, AB92: Acid Blue 92, and MB: Methylene Blue) was achieved under LED visible light. TCN removal in the presence of visible light by Cs, Z-8, Cs/Z-8, Cs/Z-8/Z-67-0.05, Cs/Z-8/Z-67-0.1, and Cs/Z-8/Z-67-0.2 was 22.6 %, 47.3 %, 69.0 %, 77.0 %, 95.5 %, and 65.0 %, respectively. The trapping test showed that TCN degradation by adding ascorbic acid, methanol, and IPA was 44.8 %, 66.9 %, and 78.5 %, respectively. It could be concluded that the O2- play the decisive role for the destruction of TCN. The reusability of Cs/Z-8/Z-67-0.1 as a photocatalyst indicated that it had the capability to preserve its stability and performance for three successive cycles of use (95.5 %, 89.0 %, and 84.0 %). Also, Cs/Z-8/Z-67 had dye degradation ability (39.0 % for Methylene Blue and 81.0 % for Acid Blue 92).

Enhancement of oral bioavailability of celastrol by chitosan microencapsulated porous starch carriers

Celastrol demonstrates significant potential in immunomodulatory applications; however, its low oral bioavailability presents a substantial obstacle to its clinical translation. Here, we combined porous starch with chitosan to develop an efficacious microencapsulation system aimed at enhancing the oral absorption of celastrol. Microcapsule carrier for celastrol was formulated Through the utilization of chitosan-coated porous starch particle technology and Subsequent evaluations of the morphology and release kinetics of microcapsules. The impact of microencapsulation on the enhanced absorption of celastrol was assessed through Caco-2 cell uptake experiments and in vivo pharmacokinetic studies. FT-IR analysis revealed the stable presence of celastrol in an amorphous state within the microcapsules, facilitated by hydrogen-bonding interactions between celastrol and porous starch. Simulated release experiments indicated that the chitosan coating improved the stability and extended the release of celastrol. Cell experiments, as well as in vivo distribution and pharmacokinetic investigations, demonstrated that the chitosan microencapsulation strategy significantly enhanced cellular uptake and in vivo absorption of celastrol, resulting in notably higher bioavailability compared to conventional formulations. This study successfully demonstrated the remarkable efficacy of chitosan microencapsulated porous starch carriers in enhancing the oral bioavailability of celastrol, revealing novel potential applications for these two food-grade materials in delivery systems.

Lignin microparticle coatings for enhanced wet resistance in lignocellulosic materials

The widespread use of synthetic plastics in packaging materials poses significant environmental challenges, prompting the search for biobased, biodegradable, and non-toxic alternatives. This study focuses on improving high-yield pulps (HYPs) as sustainable materials for packaging. Enhancing wet strength and barrier properties of papers from bleached chemi-thermomechanical pulps (BCTMPs) is crucial for their application in water- and air- resistant wrappers. Traditional wet strength agents raise environmental and health concerns; therefore, this research explores the use of lignin, in the form of microparticles (LMPs), as a natural biopolymer that offers a safer alternative. However, the low viscosity of LMPs hampers their dispersion as a coating, requiring thickening agents (such as cationic starch (CS), chitosan (CH) or sodium alginate) for an effective coating formulation. Results demonstrate a synergistic effect of LMP coatings with CH or CS, enhanced by hot-pressing at 260 °C for 30 s, which improves dry and wet mechanical properties and decreases air permeability. The use of LMPs as a water-resistant interlayer between BCTMP paper sheets further improves the wet tensile index to 40 kN·m/kg for CH + LMPs and 23 kN·m/kg for CS + LMPs interlayer, representing 55 and 38 % of their respective dry tensile indices.

Cotton-like antibacterial polyacrylonitrile nanofiber-reinforced chitosan scaffold: Physicochemical, mechanical, antibacterial, and MC3T3-E1 cell viability study

Bio-scaffolds, while mimicking the morphology of native tissue and demonstrating suitable mechanical strength, enhanced cell adhesion, proliferation, infiltration, and differentiation, are often prone to failure due to microbial infections. As a result, tissue engineers are seeking ideal scaffolds with antibacterial properties. In this study, silver nanoparticles (AgNPs) were integrated into cotton-like polyacrylonitrile nanofibers via a polydopamine (PDA) interlayer (Ag@p-PAN). These Ag@p-PAN nanofibers were then incorporated into the chitosan (CS) matrix, developing an antibacterial CS/Ag@p-PAN composite scaffold. The composite scaffold features an interconnected porous morphology with fiber-infused pore walls, improved water absorption and swelling properties, a controlled degradation profile, enhanced porosity, better mechanical strength, strong antibacterial properties, and excellent MC3T3-E1 cell viability, adhesion, proliferation, and infiltration. This study presents a novel method for reinforcing CS-based scaffolds by incorporating bioactive nanofibers, offering potential applications in tissue engineering and other biomedical fields.

Removal of acetyl-rich impurities from chitosan using liquefied dimethyl ether

Chitosan, recognized for its excellent biodegradability, biocompatibility, and antibacterial properties, has several potential applications, particularly in the biomedical field. However, its widespread use is hindered by inherent limitations such as low mechanical strength and safety concerns arising from a low degree of deacetylation and the presence of impurities. This study aimed to introduce an innovative purification method for chitosan via liquefied dimethyl ether (DME) extraction. The proposed technique effectively addresses the challenges associated with chitosan by facilitating deacetylation and impurity removal. Liquefied DME is emerging as the extraction solvent of choice owing to its advantages, such as low boiling point, safety, and environmental sustainability. The degree of deacetylation of chitosan was extensively evaluated using thermogravimetric-differential thermal analysis, Fourier transform infrared spectroscopy, X-ray diffraction, intrinsic viscosity measurements, solid-state nuclear magnetic resonance spectroscopy and X-ray photoelectron spectroscopy, and elemental analysis. The solubility of chitosan in liquefied DME was investigated using Hansen solubility parameters. This study contributes to the improvement of the safety profile of chitosan, thereby expanding its potential applications in various fields. The use of liquefied DME as an extraction solvent proved to be efficient in addressing the existing challenges and is consistent with the principles of safety and environmental sustainability.

Surface modification of surgical suture by chitosan-based biocompatible hybrid coatings: In-vitro anti-corrosion, antibacterial, and in-vivo wound healing studies

This work aims to develop chitosan-based biocompatible hybrid coatings on synthetic surgical sutured by direct current electrophoretic deposition (DC-EPD) method. The chitosan (CS), curcumin (CR), aloe-vera (AV), and 2-aminothiazolidin-4-one-5-ethanoic acid (AT) were used as suspensions of varying combinations and compositions (A-I). Each suspension has a further 05 samples (Aa-Ae-Ia-Ie) at selected DC-EPD set parameters (2-10 V, t; 240 s, D; 1 cm). Potentiodynamic polarization measurements (PDP) were carried out in the ringer solution. Among all samples, Ed (CS, 1.6 g/L; 8 V) and Hb (CS-CR-AT, 1.6 g/Leach; 4 V) have shown greatest corrosion inhibition efficiency (IEPDP: 99 %), least corrosion rates (CR; 0.001 mm/y and 0.017 mm/y, respectively), and least corrosion current density (Icorr.; 0.01 A cm-2). SEM and FTIR further confirmed these two best coatings stable and corrosion resistant before and after performing corrosion test, while the coating thickness by profilometry test was found to be greater (16.28 μm) for Hb. Mechanical stress and strain of bare and coated samples were found to have no significant difference. Antibacterial activity revealed greater resistance of Hb against S. aureus as compared to Ed. In-vivo incision wound model study further revealed better healing and less inflammation with coated sutures with comparatively enhanced wound healing effect of Hb coated suture.

Fabrication of gallic acid containing poly(vinyl alcohol)/chitosan electrospun nanofibers with antioxidant and drug delivery properties

Chitosan-based nanofibers with excellent properties are attractive materials for specific industrial applications of contemporary interest. This work aims to fabricate functional nanofibers based on poly(vinyl alcohol)/chitosan (CS) with an antioxidant and model drug molecule, gallic acid (GA), by electrospinning, followed by cross-linking through glutaraldehyde (PVA-CS-GAs). PVA-CS-GAs were electrospun at two different concentrations by the adjustment of the CS feeding ratio. The detailed characteristics of the as-prepared electrospun nanofibers were elucidated by Fourier Transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), water contact angle (WCA) measurements, thermogravimetric and differential scanning calorimetry (TGA and DSC) analyses. SEM images indicated that the average fiber diameter distribution was in the range of 90-110 nm. The results show that morphology, mean diameter, wettability, and thermal characteristics of the composite nanofibers were affected by the CS feeding ratio. Although the increase in the amount of polar -OH groups with the addition of GA caused an improvement in the hydrophilicity and thermal stability of the electrospun nanofibers, it also caused a decrease in the thermal transition temperatures. Furthermore, antioxidant tests based on DPPH radical scavenging ability and in vitro release studies demonstrated that the cross-linked PVA-CS-GA composite nanofibers have good antioxidant activity and a pH-dependent drug release rate, indicating their potential for implementation in wound healing and drug delivery applications.

Crop resilience enhancement through chitosan-based hydrogels as a sustainable solution for water-limited environments

Frequent droughts significantly affect agricultural productivity and highlight the need for effective solutions to improve water availability for crops. This study investigates the potential of chitosan-based hydrogels, biodegradable biopolymers known for their water-retaining properties, to improve soil moisture and promote plant growth during drought periods. Chitosan hydrogels were synthesized using Pluronic F127 and compared with chitosan and chitosan in combination with sodium alginate (CS/Alg-Na). Comprehensive chemical characterizations were performed by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and field emission scanning electron microscopy (FESEM). The CS/Pl-F127 hydrogels showed high porosity and a water absorption capacity of 81.5 %, while the CS/Alg-Na exhibited a denser network with a capacity of 93.35 % and improved mechanical strength. Plants in the CS/Pl-F127 hydrogel had a shoot elongation rate of 5.9 mm/day on Day 9, which continued until Day 40. In contrast, shoot elongation in the CS/Alg-Na hydrogel peaked at 7.1 mm/day on Day 20 and maintained growth under drought conditions until Day 33. These results show that all chitosan-based hydrogels improve water use efficiency. CS/Alg-Na provides the best support for plant growth under drought conditions, followed by CS/Pl-F127 and pure chitosan.

Investigation of Microstructure and Physical Characteristics of Eco-Friendly Piezoelectric Composite Thin Films Based on Chitosan and Ln2O3-Doped Na0.5Bi0.5TiO3-BaTiO3 Nanoparticles

This paper investigates the synthesis and characterization of eco-friendly piezoelectric composite thin films composed of chitosan and Ln2O3-doped Na0.5Bi0.5TiO3-BaTiO3 (NBT-BT) nanoparticles. The films were fabricated using a solution-casting technique, successfully embedding the particles into the chitosan matrix, which resulted in enhanced piezoelectric properties compared to pure chitosan. Characterization methods, such as photoluminescence spectroscopy and piezo-response force microscopy (PFM) which revealed strong electromechanical responses, with notable improvements in piezoelectric performance due to the inclusion of NBT-BT nanoparticles. X-ray diffraction (XRD) analysis revealed a pure perovskite phase with the space group R3c for NBT-BT and NBT-BT-Ln particles. Scanning electron microscopy (SEM) images showed a non-uniform distribution of NBT-BT particles within the chitosan matrix. The results also suggest that the incorporation of rare earth elements further enhances the electrical and piezoelectric properties of the composites, highlighting their potential in flexible and smart device applications. Overall, these findings underscore the potential of chitosan-based composites in addressing environmental concerns while offering effective solutions for energy harvesting and biomedical applications.

The Properties of Thin Films Based on Chitosan/Konjac Glucomannan Blends

In this work, blend films were prepared by blending 2% chitosan (CS) and 0.5% konjac glucomannan (KGM) solutions. Five ratios of the blend mixture were implemented (95:5, 80:20, 50:50, 20:80, and 5:95), and a pure CS film and a pure KGM film were also obtained. All the polymeric films were evaluated using FTIR spectroscopy, mechanical testing, SEM and AFM imaging, thermogravimetric analyses, swelling and degradation analyses, and contact angle measurements. The CS/KGM blends were assessed for their miscibility. Additionally, the blend films' properties were evaluated after six months of storage. The proposed blends had good miscibility in a full range of composition proportions. The blend samples, compared to the pure CS film, indicated better structural integrity. The surface structure of the blend films was rather uniform and smooth. The sample CS/KGM 20:80 had the highest roughness value (Rq = 12.60 nm). The KGM addition increased the thermal stability of films. The blend sample CS/KGM 5:95 exhibited the greatest swelling ability, reaching a swelling degree of 946% in the first fifteen minutes of the analysis. Furthermore, the addition of KGM to CS improved the wettability of the film samples. As a result of their good mechanical properties, surface characteristics, and miscibility, the proposed CS/KGM blends are promising materials for topical biomedical and cosmetic applications.

Green nanotechnology for the enhancement of antibacterial properties in lining leather: MgO-chitosan nanocomposite coating

Antimicrobial nanomaterials have received a lot of interest in recent years due to their potential to fight against microbial degradation, a common problem in leather products. In this study, a nanocomposite was synthesized with MgO nanoparticles prepared by Aloe vera leaf extract and chitosan (CS), as an innovative solution to this problem. Three nanocomposite samples (C1, C2, and C3) were formulated with varying ratios of MgO and chitosan and evaluated for antimicrobial efficacy against Escherichia coli and Bacillus subtilis. Leather treated with MgO/Chitosan nanocomposite (MgO/Chitosan-1:1) exhibited substantial inhibition zones of 13 mm and 12 mm against E. coli and B. subtilis, respectively. Characterization of MgO nanoparticles, chitosan, and MgO/CS nanocomposite was performed through FTIR, XRD, SEM, TGA, and cytotoxicity tests. The average particle size and crystallite size of MgO nanoparticles were found as 136 nm and 10.3 nm, respectively and a weight loss of 67 % for MgO/CS nanocomposite in thermogravimetric analysis. FTIR confirmed the successful incorporation of MgO nanoparticles into the chitosan matrix, evidenced by the presence of characteristic functional groups. Application of nanocomposite onto lining leather via spraying resulted in finished leather with improved color rub fastness, perspiration fastness, and thermal stability compared to untreated leather. In comparison to dry color rub fastness, wet color rub fastness was notably improved by the MgO/CS nanocomposite, with gray scale ratings ranging from 4/5 to 5. Perspiration fastness was marginally enhanced by the MgO/CS coating, with gray scale ratings ranging from 4/5 to 5 for both grain and flesh samples. Specifically, the coated leather exhibited a water vapor permeability (WVP) of 9.94 mg cm-2.hr-1 that was lower than both uncoated (12.37 mg cm-2.hr-1) and PVA-coated (11.22 mg cm-2.hr-1) leather. This study presents a promising solution to the challenge of microbial degradation in leather products and highlights the potential of natural sources for synthesizing functional nanocomposites with diverse applications in materials science and biotechnology.

Dual Antimicrobial Activity of HTCC and Its Nanoparticles: A Synergistic Approach for Antibacterial and Antiviral Applications Through Combined In Silico and In Vitro Studies

N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC), a quaternized chitosan derivative, has been shown to exhibit a broad spectrum of antimicrobial activity, especially against bacteria and enveloped viruses. Despite this, molecular docking studies showing its atomic-level mechanisms against these microorganisms are scarce. Here, for the first time, we employed molecular docking analyses to investigate the potential antibacterial activity of HTCC against Staphylococcus aureus and its antiviral activity against human immunodeficiency virus 1 (HIV-1). According to the findings, HTCC exhibited promising antibacterial activity with high binding affinities; however, it had limited antiviral activity. To validate these theoretical outcomes, experimental studies were conducted. Different derivatives of HTCC were synthesized and characterized using NMR, XRD, FTIR, and DLS. The in vitro assays validated the potent antibacterial efficacy of HTCC against S. aureus, whereas the antiviral studies did not show good antiviral activity. However, our research also revealed a promising avenue for further exploration of the antimicrobial activity of HTCC nanoparticles (NPs), since, thus far, no studies have been conducted to show the antiviral activity of HTCC NPs against HIV-1. The nanosized HTCC exhibited superior antiviral performance compared to the parent polymers, with complete (100%) inhibition of HIV-1 viral activity at the highest tested concentration (0.33 mg/mL).

Enhanced Photodetection Performance of WSe2/V2O5 Nanocomposite on Flexible Substrate: Synergistic Advantages and Improved Efficiency

The two-dimensional (2D) chalcogenide WSe2/V2O5 composite nanostructures were synthesized using the hydrothermal method and extensively characterized with various spectroscopic techniques. X-ray diffraction analysis confirmed the hexagonal crystal structure exhibiting space symmetry of P63/mmc. Scanning electron microscopy images provided insights into the irregular and nonuniform morphology. Optical spectrum analysis indicated a band gap value of 2.01 eV for 15% WSe2/V2O5 nanostructures, as determined by the Wood and Tauc equation. Photoluminescence (PL) excitation spectra at emission wavelengths of 550 and 750 nm exhibited broad emission attributed to self-trapped excitons for V2O5 and WSe2 nanostructures. Under excitation at λexc = 365 nm, PL emission spectra displayed distinct peaks at 550 and 750 nm, demonstrating the ability to emit vivid red light. A device optimized for photoresponsivity (R) of approximately 7.80 × 10-1 A W-1 and detectivity (D) of around 8.65 × 1011 Jones, and quantum efficiency of approximately 3.42 × 10-2 A W-1 were achieved at a wavelength of 390 nm while using a lamination sheet as a substrate. These findings underscore the capability of devices for efficient photoconversion at specified wavelengths, indicating potential applications in sensing, imaging, and optical communication. The photoresponsivity of the device remained stable at 3.38 × 10-3 A W-1 at 0° and 3.09 × 10-3 A W-1 at 55° bending angle. This indicates the resilience of device to mechanical strain, making it ideal for flexible and wearable sensor applications. The structural, morphological, and optical characterizations confirm the suitability of luminescent WSe2/V2O5 chalcogenide for practical optoelectronic applications, especially in display technologies.

Modelling methacrylated chitosan hydrogel properties through an experimental design approach: from composition to material properties

Hydrogels of biopolymers are gradually substituting synthetic hydrogels in tissue engineering applications due to their properties. However, biopolymeric hydrogels are difficult to standardize because of the intrinsic variability of the material and the reversibility of physical crosslinking processes. In this work, we synthesized a photocrosslinkable derivative of chitosan (Cs), namely methacrylated chitosan (CsMA), in which the added methacrylic groups allow the formation of hydrogels through radical polymerization triggered by UV exposure. We then performed a systematic study to link the physical properties of the materials to its preparation parameters to standardize its preparation according to specific applications. We studied the properties of CsMA solutions and the derived hydrogels using a statistical method, namely, response surface method, which allowed us to build empirical models describing material properties in terms of several selected processing factors. In particular, we studied the viscosity of CsMA solutions as a function of CsMA concentration, temperature, and shear rate, while hydrogel compression modulus, morphology, degradation and solubilization were investigated as a function of CsMA concentration, photoinitiator concentration and UV exposure. CsMA solutions resulted in shear thinning and were thus suitable for extrusion-based 3D printing. The CsMA hydrogel was found to be highly tunable, with a stiffness in the 12-64 kPa range, and was stable over a long timeframe (up to 60 days). Finally, the possibility to engineer hydrogel stiffness through an empirical model allowed us to hypothesize a number of possible applications based on the mechanical properties of several biological tissues reported in the literature.

Incorporation of montmorillonite into microfluidics-generated chitosan microfibers enhances neuron-like PC12 cells for application in neural tissue engineering

The complexity in structure and function of the nervous system, as well as its slow rate of regeneration, makes it more difficult to treat it compared to other tissues. Neural tissue engineering aims to create an appropriate environment for nerve cell proliferation and differentiation. Fibrous scaffolds with suitable morphology and topography and better mimicry of the extracellular matrix have been promising for the alignment and migration of neural cells. On this premise, to improve the properties of the scaffold, we combined montmorillonite (MMT) with chitosan (CS) polymer and created microfibers with variable diameters and varied concentrations of MMT using microfluidic technology and tested its suitability for the rat pheochromocytoma cell line (PC12). According to the findings, CS/MMT 0.1 % compared to CS/MMT 0 % microfibers showed a 201 MPa increase in Young's modulus, a 68 mS/m increase in conductivity, and a 1.4-fold increase in output voltage. Analysis of cell mitochondrial activity verified the non-toxicity, resulting in good cell morphology with orientation along the microfiber. Overall, the results of this project showed that with a low concentration of MMT, the properties of microfibers can be significantly improved and a suitable scaffold can be designed for neural tissue engineering.

An Easy-to-Handle Route for Bicomponent Porous Tubes Fabrication as Nerve Guide Conduits

Over the past two decades, the development of nerve guide conduits (NGCs) has gained much attention due to the impellent need to find innovative strategies to take care of damaged or degenerated peripheral nerves in clinical surgery. In this view, significant effort has been spent on the development of high-performance NGCs by different materials and manufacturing approaches. Herein, a highly versatile and easy-to-handle route to process 3D porous tubes made of chitosan and gelatin to be used as a nerve guide conduit were investigated. This allowed us to fabricate highly porous substrates with a porosity that ranged from 94.07 ± 1.04% to 97.23 ± 1.15% and average pore sizes-estimated via X-ray computed tomography (XCT) reconstruction and image analysis-of hundreds of microns and an irregular shape with an aspect ratio that ranged from 0.70 ± 0.19 to 0.80 ± 0.15 as a function of the chitosan/gelatin ratio. More interestingly, the addition of gelatin allowed us to modulate the mechanical properties, which gradually reduced the stiffness-max strength from 0.634 ± 0.015 MPa to 0.367 ± 0.021 MPa-and scaffold toughness-from 46.2 kJ/m3 to 14.0 kJ/m3-as the gelatin content increased. All these data fall into the typical ranges of the morphological and mechanical parameters of currently commercialized NGC products. Preliminary in vitro studies proved the ability of 3D porous tubes to support neuroblastoma cell (SH-SY5Y) adhesion and proliferation. In perspective, the proposed approach could also be easily implemented with the integration of other processing techniques (e.g., electrospinning) for the design of innovative bi-layered systems with an improved cell interface and molecular transport abilities.

Bio-inspired magnetic chitosan/Iron oxide macromolecules for multiple anionic dyes adsorption from aqueous media

Organic anionic dyes are major water pollutants due to their low degradability caused by complex aromatic structures. Not only do they exert toxic, mutagenic, teratogenic, tumorigenic, and genotoxic effects, but they also decrease fertility and cause irritation to the skin and respiratory system in humans. This long-term toxicity has detrimental effects on aquatic organisms and their surroundings, resulting in an imbalanced ecosystem. In this study, a Cs@Fe3O4 magnetic biosorbent was synthesised to uptake three anionic dyes and characterised for FTIR, BET/BJH, XRD, TGA, VSM, and FESEM analyses. The biosorbent average surface area was confirmed to be 52.6524 m2/g, with average pore sizes of 7.3606 nm and 6.9823 nm for adsorption-desorption processes, respectively. Batch adsorption studies pH values, contact times, temperature, initial dye concentrations, and adsorbent dosages were examined. Several isotherm and kinetic models were studied to determine the adsorption mechanism. The adsorption data of these dyes at equilibrium was observed to match Langmuir's isotherm and pseudo-second-order kinetic models. The thermodynamic study revealed that the adsorption process for these dyes was an exothermic reaction. Maximum adsorption capacities for congo red, methyl orange, and metanil yellow were 117.77 mg/g, 137.77 mg/g, and 155.57 mg/g, respectively. The reusability of recovered Cs@Fe3O4 after dye adsorption was evaluated up to five continuous adsorption-desorption cycles for its possible industrial applications.

The role of chitosan grafted copolymer/zeolite Schiff base nanofiber in adsorption of copper and zinc cations from aqueous media

The objective of this research was to develop and assess chitosan-grafted copolymer/HZSM5 zeolite Schiff base nanofibers for Cu2+ and Zn2+ adsorption from aqueous media. Nanofibers were prepared via electrospinning and characterized using XRD, FTIR, 1H NMR, FESEM, TGA, BET, and XPS. The study evaluated the effect of unmodified HZSM5 and Schiff base functionalization on adsorption capacities. Incorporating 10.0 wt% zeolite Schiff base as the optimum content into the chitosan-grafted copolymer significantly enhanced adsorption, achieving increases of 98.2 % for Zn2+ and 42.2 % for Cu2+. Specifically, Zn2+ adsorption increased from 27.6 to 54.7 mg/g, and Cu2+ from 67.1 to 95.4 mg/g. Factors such as temperature, pH, adsorption time, and initial cation concentration were analyzed. Kinetic studies revealed a double-exponential model, and isotherm analysis indicated a good fit with the Redlich-Peterson model, showing maximum monolayer capacities of 310.1 mg/g for Cu2+ and 97.8 mg/g for Zn2+ (pH 6.0, 240 min, 45 °C). The adsorption thermodynamics indicated a spontaneous and endothermic adsorption. Reusability tests showed minimal capacity loss (4.91 % for Cu2+ and 5.59 % for Zn2+) after five cycles. The nanofiber displayed greater selectivity for Cu2+ over Zn2+ in multi-ion systems and real electroplating wastewater, highlighting its potential for targeted heavy metal removal.

Physicochemical characterization of antioxidant film based on ternary blend of chitosan and Tulsi-Ajwain essential oil for preserving walnut

This study focuses on changes in the physiochemical properties of chitosan film when incorporated with a blend of essential oils of Tulsi and Ajwain. The essential oil blend-loaded films showed a decrement in transparency. Tulsi essential oil decreased the moisture content, swelling capacity, and water solubility. However, adding Ajwain along with Tulsi essential oil led to a significant increase in these properties. Meanwhile, the water vapor transmission rate didn't change significantly due to non-polar constituents in Tulsi essential oil, except when only Ajwain essential oil was present. The mechanical properties showed that the tensile strength of films increased with the addition of Tulsi essential oil (14.95 MPa to 31.27 MPa) but decreased further with increasing Ajwain oil concentration in films (32.13 MPa to 15.89 MPa). On the other hand, an increment in percent elongation at break (8.26 % to 24.02 %) was observed due to the excellent plasticization effect of Ajwain essential oil. Antioxidant activity was observed for the Tulsi essential oil-containing films and increased significantly with adding Ajwain essential oil. Finally, walnuts were packed in the active film. The active film showed better antioxidant activity against the oxidation of oil in walnuts, which the FTIR of the packed product confirmed.

A crayfish chitosan-based bioactive film to treat vaginal infections: A sustainable approach

Polymicrobial communities are seen to be a sign of health, but they can turn detrimental when an excess of pathogenic species leads to recurring vaginal infections. This microbiological imbalance may decrease women's fertility, increasing also the risk of infection by Human Papillomavirus (HPV) and/or other sexually transmitted infections (STIs). There is a worldwide need for smart/sustainable solutions to tackle these types of infections. Hereupon, we investigated, as a potential solution, the use of crayfish chitosan-based membrane as a mucoadhesive, antimicrobial, biocompatible and biodegradable material. Chitosan was chemically extracted with a process yield of ca. 63 % and a degree of deacetylation of ca. 65 %. Further chitosan was characterized by FTIR, DSC, XRD and zeta potential. Antimicrobial and antioxidant activities were tested by microbicide concentration and ABTS methods. The extracted chitosan was confirmed to be antioxidant and antimicrobial against Escherichia coli, Candida albicans, Staphylococcus aureus (methicillin resistant and susceptible strains). Vaginal films using chitosan extracted from crayfish shells were produced by solvent casting, and the biological profile was tested in simulated vaginal fluid as a proof of concept. The main data showed that the vaginal films prepared were active against several microorganisms responsible for vaginal infections, demonstrating their potential in the field.

Selenium nanoparticle-functionalized injectable chitosan/collagen hydrogels as a novel therapeutic strategy to enhance stem cell osteoblastic differentiation for bone regeneration

Stem cells are an essential consideration in the fields of tissue engineering and regenerative medicine. Understanding how nanoengineered biomaterials and mesenchymal stem cells (MSCs) interact is crucial for their role in bone regeneration. Taking advantage of the structural stability of selenium nanoparticles (Se-NPs) and biological properties of natural polymers, Se-NPs-functionalized, injectable, thermoresponsive hydrogels with an interconnected molecular structure were prepared to identify their role in the osteogenic differentiation of different types of mesenchymal stem cells. Further, comprehensive characterization of their structural and biological properties was performed. The results showed that the hydrogels undergo a sol to gel transition with the help of β-glycerophosphate, while functionalization with Se-NPs significantly enhances their biological response through stabilizing their polymeric structure by forming Se-O covalent bonds. Further results suggest that Se-NPs enhance the differentiation of MSCs toward osteogenic lineage in both the 2D as well as 3D. We demonstrated that the Se-NPs-functionalized hydrogels could enhance the differentiation of osteoporotic bone-derived MSCs. We also focused on specific cell surface marker expression (CD105, CD90, CD73, CD45, CD34) based on the exposure of healthy rats' bone marrow-derived stem cells (BMSCs) to the Se-NP-functionalized hydrogels. This study provides essential evidence for pre-clinical/clinical applications, highlighting the potential of the nanoengineered biocompatible elastic hydrogels for bone regeneration in diseased bone.

Influence of Chitosan on the Viability of Encapsulated and Dehydrated Formulations of Vegetative Cells of Actinomycetes

This study focuses on developing an encapsulated and dehydrated formulation of vegetative actinobacteria cells for an efficient application in sustainable agriculture, both as a fungicidal agent in crop protection and as a growth-stimulating agent in plants. Three strains of actinobacteria were used: one from a collection (Streptomyces sp.) and two natives to agricultural soil, which were identified as S3 and S6. Vegetative cells propagated in a specific liquid medium for mycelium production were encapsulated in various alginate-chitosan composites produced by extrusion. Optimal conditions for cell encapsulation were determined, and cell damage from air-drying at room temperature was evaluated. The fresh and dehydrated composites were characterized by porosity, functional groups, size and shape, and their ability to protect the immobilized vegetative cells' viability. Actinomycetes were immobilized in capsules of 2.1-2.7 mm diameter with a sphericity index ranging from 0.058 to 0.112. Encapsulation efficiency ranged from 50% to 88%, and cell viability after drying varied between 44% and 96%, depending on the composite type, strain, and airflow. Among the three immobilized and dried strains, S3 and S6 showed greater resistance to encapsulation and drying with a 4 L·min-1 airflow when immobilized in coated and core-shell composites. Encapsulation in alginate-chitosan matrices effectively protects vegetative actinobacteria cells during dehydration, maintaining their viability and functionality for agricultural applications.

Preparation and Characterization of Chitosan/Starch Nanocomposites Loaded with Ampicillin to Enhance Antibacterial Activity against Escherichia coli

Chitosan/starch nanocomposites loaded with ampicillin were prepared using the spray-drying method by mixing various ratios of chitosan and starch. The morphology of chitosan/starch nanoparticles was studied using a scanning electron microscope (SEM), and the zeta potential value and size distribution were determined by a Nanoparticle Analyzer. The results show that the chitosan/starch nanocomposites have a spherical shape, smooth surface, and stable structure. Nanoparticle size distribution ranged from 100 to 600 nm, and the average particle size ranged from 300 to 400 nm, depending on the ratio between chitosan and starch. The higher the ratio of starch in the copolymer, the smaller the particle size. Zeta potential values of the nanocomposite were very high, ranging from +54.4 mV to +80.3 mV, and decreased from 63.2 down to +37.3 when loading with ampicillin. The chitosan/starch nanocomposites were also characterized by FT-IR to determine the content of polymers and ampicillin in the nanocomposites. The release kinetics of ampicillin from the nanocomposites were determined in vitro using an HPLC profile for 24 h. The loading efficiency (LE) of ampicillin into chitosan/starch nanoparticles ranged from 75.3 to 77.3%. Ampicillin-loaded chitosan/starch nanocomposites were investigated for their antibacterial activity against antibiotic-resistant Escherichia coli in vitro. The results demonstrate that the antibacterial effectiveness of nanochitosan/starch loading with ampicillin against E.coli was 95.41%, higher than the 91.40% effectiveness of ampicillin at the same concentration of 5.0 µg/mL after 24 h of treatment. These results suggest that chitosan/starch nanocomposites are potential nanomaterials for antibiotic drug delivery in the pharmaceutical field.

Anti-Helicobacter pylori activity of nanocomposites from chitosan/broccoli mucilage/selenium nanoparticles

Helicobacter pylori can infect most people worldwide to cause hazardous consequences to health; the bacteria could not easily be controlled or disinfected. Toward exploring of innovative biocidal nanoformulations to control H. pylori, broccoli seeds (Brassica oleracea var. italica) mucilage (MBS) was employed for biosynthesizing selenium nanoparticles (MBS/SeNPs), which was intermingled with chitosan nanoparticles (NCT) to generate bioactive nanocomposites for suppressing H. pylori. The MBS could effectually generate and stabilize SeNPs with 13.61 nm mean diameter, where NCT had 338.52 nm mean diameter and positively charged (+ 39.62 mV). The cross-linkages between NCT-MBS-SeNPs were verified via infrared analysis and the nanocomposites from NCT:MBS/SeNPs at 1:2 (T1), 1:1 (T2) and 2:1 (T3) ratios had mean diameters of 204, 132 and 159 nm, respectively. The entire nanomaterials/composites exhibited potent anti- H. pylori activities using various assaying methods; the T2 nanocomposite was the utmost bactericidal agent with 0.08-0.10 mg/L minimal concentration and 25.9-27.3 mm inhibition zones. The scanning microscopy displayed the ability of nanocomposite to attach the bacterial cells, disrupt their membranes, and completely lyse them within 10 h. The NCT/MBS/SeNPs nanocomposites provided effectual innovative approach to control H. pylori.

Hesperidin Nanoformulation: A Potential Strategy for Reducing Doxorubicin-Induced Renal Damage via the Sirt-1/HIF1-α/VEGF/NF-κB Signaling Cascade

Hesperidin (Hes) functions as a strong antioxidant and anti-inflammatory to guard against damage to the heart, liver, and kidneys. Nevertheless, due to its restricted solubility and bioavailability, a delivery method is required for it to reach a specific organ. In this study, ion gelation was used to synthesize a chitosan/hesperidin nanoformulation. Numerous characterization techniques, such as zeta potential, particle size, XRD, TEM, SEM, and FTIR analyses, were used to corroborate the synthesis of hesperidin nanoparticles (Hes-NPs). Male albino mice were given a pretreatment dose of 100 mg/kg, PO, of Hes or Hes-NPs, which was administered daily for 14 days before the induction of doxorubicin nephrotoxicity on the 12th day. Kidney function (urea and creatinine levels) was measured. Lipid peroxidation (MDA) and antioxidant enzyme (CAT and SOD) activities were estimated. TNF-α, IL-1β, and VEGF content; histopathological examination of kidney tissue; and immunohistochemical staining of NF-κB, Caspase-3, BAX, Bcl-2, and TGF-β1 were evaluated. The gene expressions of Sirt-1, Bcl-2, VEGF, HIF1-α, and Kim-1 were also considered. The results showed that pretreatment with Hes or Hes-NPs reduced doxorubicin's nephrotoxic effects, with Hes-NPs showing the greatest reduction. Kidney enzyme and MDA content were lowered in response to the Hes or Hes-NP pretreatment, whereas antioxidant enzyme activities were increased. Hes or Hes-NP pretreatment suppressed the levels of TNF-α, IL-1β, VEGF, NF-κB, Caspase-3, BAX, and TGF-β1; however, pretreatment increased Bcl-2 protein levels. Furthermore, the gene expressions of Sirt-1, Bcl-2, VEGF, HIF1-α, and Kim-1 were considerably higher with Hes-NP than with Hes treatment. These results suggest that Hes-NP treatment might reduce DOX-induced nephrotoxicity in mice via modulating Sirt-1/HIF1-α/VEGF/NF-κB signaling to provide antioxidant, anti-inflammatory, and anti-apoptotic effects.

Selenium Nanoparticles Synergize with a KRAS Nanovaccine against Breast Cancer

Selenium (Se) is an element crucial for human health, known for its anticancer properties. Although selenium nanoparticles (SeNPs) have shown lower toxicity and higher biocompatibility than other Se compounds, bare SeNPs are unstable in aqueous solutions. In this study, several materials, including bovine serum albumin (BSA), chitosan, polymethyl vinyl ether-alt-maleic anhydride, and tocopherol polyethylene glycol succinate, are explored to develop stable SeNPs and further evaluate their potential as candidates for cancer treatment. All optimized SeNP are spherical, <100 nm, and with a narrow size distribution. BSA-stabilized SeNPs produced under acidic conditions present the highest stability in medium, plasma, and at physiological pH, maintaining their size ≈50-60 nm for an extended period. SeNPs demonstrate enhanced toxicity in cancer cell lines while sparing primary human dermal fibroblasts, underscoring their potential as effective anticancer agents. Moreover, the combination of BSA-SeNPs with a nanovaccine results in a strong tumor growth reduction in an EO771 breast cancer mouse model, demonstrating a three-fold decrease in tumor size. This synergistic anticancer effect not only highlights the role of SeNPs as effective anticancer agents but also offers valuable insights for developing innovative combinatorial approaches using SeNPs to improve the outcomes of cancer immunotherapy.

Fabrication and characterization of polyvinyl alcohol-chitosan composite nanofibers for carboxylesterase immobilization to enhance the stability of the enzyme

Electrospinning stands out as a flexible and viable method, presenting designed nanoscale materials with customized properties. This research demonstrates the immobilization of carboxylesterase protein Ha006a, reported for its adequacy in pesticide bioremediation by utilizing the electrospinning strategy. This strategy was utilized to create nanofibers by incorporating variable mixtures of biodegradable and cost-effective polyvinyl alcohol (PVA)-chitosan (CS) nanofiber solution (PVA100, PVA96, PVA94, PVA92 and PVA90). All the mixtures were electrospun at a reliable voltage of 21 kV, maintaining a gap of 12 cm from the nozzle. The Ha006a, sourced from Helicoverpa armigera, was consolidated into the optimized PVA90 polymer mixture. The electrospun nanofibers experienced comprehensive characterization utilizing distinctive microscopy and spectroscopy procedures counting FESEM, TGA, XRD and FTIR. The comparative investigation of the esterase property, ideal parameters and stability of the unbound and bound/immobilized Ha006a was scrutinized. The results uncovered an essential elevation in the ideal conditions of enzyme activity post-immobilization. The PVA-CS control nanofiber and Ha006a-PVA-CS showed a smooth structure, including an average breadth of around 170.5 ± 44.2 and 222.5 ± 66.5 nm, respectively. The enzyme-immobilized nanofibers displayed upgraded stability and comprehensive characterization of the nanofiber, which guaranteed genuineness and reproducibility, contributing to its potential as a potent device for bioremediation applications. This investigation opens the way for the manufacture of pesticide-resistant insect enzyme-based nanofibers, unlocking their potential for assorted applications, counting pesticide remediation and ensuring environmental sustainability.

Nanocellulose@gallic Acid-Based MOFs: A Novel Material for Ecofriendly Food Packaging

The development of an effective food packaging material is essential for safeguarding against infections and preventing chemical, physical, and biological changes during food storage and transportation. In the present study, we successfully synthesized an innovative food packaging material by combining chitosan (CH), nanocellulose (NC), and a gallic acid-based metal-organic framework (MOF). The CH films were prepared using different concentrations of NC (5 and 10%) and MOFs (1.5, 2.5, and 5%). Various properties of prepared films, including water solubility (WS), moisture content (MC), swelling degree, oxygen permeability, water vapor permeability (WVP), mechanical property, color analysis, and light transmittance, were studied. The chitosan film with a 5% NC and 1.5% MOF (CH-5% NC-1.5% MOF) exhibited the least water solubility, moisture content, and water vapor permeability, indicating the overall stability of the film. Additionally, this film demonstrated low oxygen permeability, as indicated by a peroxide value of 18.911 ± 4.009, ensuring the effective preservation of packaged contents. Notably, this synthesized film exhibited high antioxidant activity, resulting in an extended duration of 52 days. This antioxidant activity was further validated by the preservation of apple slices for 9 days in a CH-5% NC-1.5% MOF film. The findings of the study suggest that the developed films can provide a promising and environmentally friendly solution for active food packaging.

Exploring the Feasibility of Polysaccharide-Based Mulch Films with Controlled Ammonium and Phosphate Ions Release for Sustainable Agriculture

Bio-based polymers are a promising material with which to tackle the use of disposable and non-degradable plastics in agriculture, such as mulching films. However, their poor mechanical properties and the high cost of biomaterials have hindered their widespread application. Hence, in this study, we improved polysaccharide-based films and enriched them with plant nutrients to make them suitable for mulching and fertilizing. Films were produced combining sodium carboxymethyl cellulose (CMC), chitosan (CS), and sodium alginate (SA) at different weight ratios with glycerol and CaCl2 as a plasticizer and crosslinker, respectively, and enriched with ammonium phosphate monobasic (NH4H2PO4). A polysaccharide weight ratio of 1:1 generated a film with a more crosslinked structure and a lower expanded network than that featuring the 17:3 ratio, whereas CaCl2 increased the films' water resistance, thermal stability, and strength characteristics, slowing the release rates of NH4+ and PO43-. Thus, composition and crosslinking proved crucial to obtaining promising films for soil mulching.

Spatiotemporally Controlled Release of Etamsylate from Bioinspired Peptide-Functionalized Nanoparticles Arrests Bleeding Rapidly and Improves Clot Stability in a Rabbit Internal Hemorrhage Model

Achieving rapid clotting and clot stability are important unmet goals of clinical management of noncompressible hemorrhage. This study reports the development of a spatiotemporally controlled release system of an antihemorrhagic drug, etamsylate, in the management of internal hemorrhage. Gly-Arg-Gly-Asp-Ser (GRGDS) peptide-functionalized chitosan nanoparticles, with high affinity to bind with the GPIIa/IIIb receptor of activated platelets, were loaded with the drug etamsylate (etamsylate-loaded GRGDS peptide-functionalized chitosan nanoparticles; EGCSNP). Peptide conjugation was confirmed by LCMS, and the delivery system was characterized by DLS, SEM, XRD, and FTIR. In vitro study exhibited 90% drug release till 48 h fitting into the Weibull model. Plasma recalcification time and prothrombin time tests of GRGDS-functionalized nanoparticles proved that clot formation was 1.5 times faster than nonfunctionalized chitosan nanoparticles. The whole blood clotting time was increased by 2.5 times over clot formed under nonfunctionalized chitosan nanoparticles. Furthermore, the application of rheometric analysis revealed a 1.2 times stiffer clot over chitosan nanoparticles. In an in vivo liver laceration rabbit model, EGCSNP spatially localized at the internal injury site within 5 min of intravenous administration, and no rebleeding was recorded up to 3 h. The animals survived for 3 weeks after the injury, indicating the strong potential of the system for the management of noncompressible hemorrhage.