Progress in Research of Chitosan Chemical Modification Technologies and Their Applications

Mechanochemical Synthesis of Cross-Linked Chitosan and Its Application as Adsorbent for Removal of Per- and Polyfluoroalkyl Substances from Simulated Electroplating Wastewater

Chitosan is a promising adsorbent for removing a wide range of pollutants from wastewater. However, its practical application is hindered by instability in acidic environments, which significantly impairs its adsorption capacity and limits its utilization in water purification. While cross-linking can enhance the acid stability of chitosan, current solvent-based methods are often costly and environmentally unfriendly. In this study, a solvent-free mechanochemical process was developed using high-energy ball milling to cross-link chitosan with various polyanionic linkers, including dextran sulfate (DS), poly[4-styrenesulfonic acid-co-maleic acid] (PSSM), and tripolyphosphate (TPP). The mechanochemically cross-linked (MCCL) chitosan products exhibited superior adsorption capacity and stability in acidic solutions compared to pristine chitosan. Chitosan cross-linked with DS (Cht-DS) showed the highest Reactive Red 2 (RR2) adsorption capacity, reaching 1559 mg·g-1 at pH 3, followed by Cht-PSSM (1352 mg·g-1) and Cht-TPP (1074 mg·g-1). The stability of MCCL chitosan was visually confirmed by the negligible mass loss of Cht-DS and Cht-PSSM tablets in pH 3 solution, unlike the complete dissolution of the pristine chitosan tablet. The MCCL significantly increased the microhardness of chitosan, with the order Cht-DS > Cht-PSSM > Cht-TPP, consistent with the RR2 adsorption capacity. When tested on simulated rinsing wastewater from chromium electroplating, Cht-DS effectively removed Cr(VI) (98.75% removal) and three per- and polyfluoroalkyl substances (87.40-95.87% removal), following pseudo-second-order adsorption kinetics. This study demonstrates the potential of the cost-effective and scalable MCCL approach to produce chitosan-based adsorbents with enhanced stability, mechanical strength, and adsorption performance for treating highly acidic industrial wastewater containing a mixture of toxic pollutants.

The Low-Waste Grafting Copolymerization Modification of Chitosan Is a Promising Approach to Obtaining Materials for Food Applications

Chitosan takes second place of the most abundant polysaccharides naturally produced by living organisms. Due to its abundance and unique properties, such as its polycationic nature, ability to form strong elastic porous films, and antibacterial potential, it is widely used in the food industry and biomedicine. However, its low solubility in both water and organic solvents makes its application difficult. We have developed an environmentally friendly method for producing water-soluble graft copolymers of chitosan and poly (N-vinylpyrrolidone) with high grafting efficiency and a low yield of by-products. By using AFM, SEM, TGA, DSC, and XRD, it has been demonstrated that the products obtained have changed properties compared to the initial chitosan. They possess a smoother surface and lower thermal stability but are sufficient for practical use. The resulting copolymers have a higher viscosity than the original chitosan, making them a promising thickener and stabilizer for food gels. Moreover, the copolymers exhibit an antibacterial effect, suggesting their potential use as a component in smart food packaging.

Chitosan/Alginate-Based Nanoparticles for Antibacterial Agents Delivery

Nanoparticle systems integrating alginate and chitosan emerge as a promising avenue to tackle challenges in leveraging the potency of pharmacological active agents. Owing to their intrinsic properties as polysaccharides, alginate and chitosan, exhibit remarkable biocompatibility, rendering them conducive to bodily integration. By downsizing drug particles to the nano-scale, the system enhances drug solubility in aqueous environments by augmenting surface area. Additionally, the system orchestrates extended drug release kinetics, aligning well with the exigencies of chronic drug release requisite for antibacterial therapeutics. A thorough scrutiny of existing literature underscores a wealth of evidence supporting the utilization of the alginate-chitosan nanoparticle system for antibacterial agent delivery. Literature reviews present abundant evidence of the utilization of nanoparticle systems based on a combination of alginate and chitosan for antibacterial agent delivery. Various experiments demonstrate enhanced antibacterial efficacy, including an increase in the inhibitory zone diameter, improvement in the minimum inhibitory concentration, and an enhancement in the bacterial reduction rate. This enhancement in efficacy occurs due to mechanisms involving increased solubility resulting from particle size reduction, prolonged release effects, and enhanced selectivity towards bacterial cell walls, stemming from ionic interactions between positively charged particles and teichoic acid on bacterial cell walls. However, clinical studies remain limited, and there are currently no marketed antibacterial drugs utilizing this system. Hence, expediting clinical efficacy validation is crucial to maximize its benefits promptly.

Recent Applications of Chitosan and Its Derivatives in Antibacterial, Anticancer, Wound Healing, and Tissue Engineering Fields

Chitosan, a versatile biopolymer derived from chitin, has garnered significant attention in various biomedical applications due to its unique properties, such as biocompatibility, biodegradability, and mucoadhesiveness. This review provides an overview of the diverse applications of chitosan and its derivatives in the antibacterial, anticancer, wound healing, and tissue engineering fields. In antibacterial applications, chitosan exhibits potent antimicrobial properties by disrupting microbial membranes and DNA, making it a promising natural preservative and agent against bacterial infections. Its role in cancer therapy involves the development of chitosan-based nanocarriers for targeted drug delivery, enhancing therapeutic efficacy while minimising side effects. Chitosan also plays a crucial role in wound healing by promoting cell proliferation, angiogenesis, and regulating inflammatory responses. Additionally, chitosan serves as a multifunctional scaffold in tissue engineering, facilitating the regeneration of diverse tissues such as cartilage, bone, and neural tissue by promoting cell adhesion and proliferation. The extensive range of applications for chitosan in pharmaceutical and biomedical sciences is not only highlighted by the comprehensive scope of this review, but it also establishes it as a fundamental component for forthcoming research in biomedicine.

Fabrication and characterization of a new eco-friendly sulfonamide-chitosan derivative with enhanced antimicrobial and selective cytotoxicity properties

Chitosan (CH) exhibits low antimicrobial activity. This study addresses this issue by modifying the chitosan with a sulfonamide derivative, 3-(4-(N,N-dimethylsulfonyl)phenyl)acrylic acid. The structure of the sulfonamide-chitosan derivative (DMS-CH) was confirmed using Fourier transform infrared spectroscopy and Nuclear magnetic resonance. The results of scanning electron microscopy, thermal gravimetric analysis, and X-ray diffraction indicated that the morphology changed to a porous nature, the thermal stability decreased, and the crystallinity increased in the DMS-CH derivative compared to chitosan, respectively. The degree of substitution was calculated from the elemental analysis data and was found to be moderate (42%). The modified chitosan exhibited enhanced antimicrobial properties at low concentrations, with a minimum inhibitory concentration (MIC) of 50 µg/mL observed for B. subtilis and P. aeruginosa, and a value of 25 µg/mL for S. aureus, E. coli, and C. albicans. In the case of native chitosan, the MIC values doubled or more, with 50 µg/mL recorded for E. coli and C. albicans and 100 μg/mL recorded for B. subtilis, S. aureus, and P. aeruginosa. Furthermore, toxicological examinations conducted on MCF-7 (breast adenocarcinoma) cell lines demonstrated that DMS-CH exhibited greater toxicity (IC50 = 225.47 μg/mL) than pure CH, while still maintaining significant safety limits against normal lung fibroblasts (WI-38). Collectively, these results suggest the potential use of the newly modified chitosan in biomedical applications.

Analysis of molecular structure and topological properties of chitosan isolated from crab shell and mushroom

This investigation aimed to scrutinize the chemical and structural analogies between chitosan extracted from crab exoskeleton (High Molecular Weight Chitosan, HMWC) and chitosan obtained from mushrooms (Mushroom-derived Chitosan, MRC), and to assess their biological functionalities. The resulting hydrolysates from the hydrolysis of HMWC by chitosanase were categorized as chitosan oligosaccharides (csCOS), while those from MRC were denoted as mrCOS. The molecular weights (MW) of csCOS and mrCOS were determined using Matrix-Assisted Laser Desorption Ionization Time-of-Flight (MALDI-TOF) mass spectrometry. Furthermore, structural resemblances of csCOS and mrCOS were assessed utilizing X-ray powder diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy. Intriguingly, no apparent structural disparity between csCOS and mrCOS was noted in terms of the glucosamine (GlcN) and N-acetylglucosamine (GlcNAc) composition ratios. Consequently, the enzymatic activities of chitosanase for HMWC and MRC exhibited remarkable similarity. A topological examination was performed between the enzyme and the substrate to deduce the alteration in MW of COSs following enzymatic hydrolysis. Moreover, the evaluation of antioxidant activity for each COS revealed insignificance in the structural disparity between HMWC and MRC. In summary, grounded on the chemical structural similarity of HMWC and MRC, we propose the potential substitution of HMWC with MRC, incorporating diverse biological functionalities.

A novel injectable thermo/photo dual-crosslinking hydrogel based on modified chitosan for fast sealing open globe injury

Open globe injuries (OGIs) demand immediate attention to prevent further complications and improve vision prognosis. Herein, we developed a thermo/photo dual-crosslinking injectable hydrogel, HBC_m_Arg, for rapidly sealing OGIs in emergency ophthalmic cases. HBC_m_Arg was prepared with arginine and methacrylic anhydride modified hydroxybutyl chitosan (HBC). HBC_m_Arg was initially in liquid form at 25 °C, enabling easy injection at the injury site. After reaching the ocular surface temperature, it underwent reversible heat-induced gelation to achieve in situ transformation. Further, HBC_m_Arg was capable of rapid photocrosslinking under UV light, forming a dual network structure to bolster mechanical strength, thereby facilitating effective OGI closure. Biocompatibility assessments, including in vitro studies with three ocular cell types and in vivo experiments on rabbit eyes, confirmed the safety profile of HBC_m_Arg. Ex vivo and in vivo burst pressure tests demonstrated the hydrogel's ability to promptly restore intraocular pressure and withstand elevated pressures, underscoring its potential for OGI stabilization. Additionally, the suitable degradation of HBC_m_Arg within ocular tissues, coupled with its stability in ex vivo assessments, presented a delicate balance between stability and biodegradability. In conclusion, HBC_m_Arg holds promise for improving emergency ophthalmic care by providing a rapid, effective, and safe way to seal OGIs in critical situations.

Chitosan nanocomposites as a nano-bio tool in phytopathogen control

Chitosan, an economically viable and versatile biopolymer, exhibits a wide array of advantageous physicochemical and biological properties. Chitosan nanocomposites, formed by the amalgamation of chitosan or chitosan nanoparticles with other nanoparticles or materials, have garnered extensive attention across agricultural, pharmaceutical, and biomedical domains. These nanocomposites have been rigorously investigated due to their diverse applications, notably in combatting plant pathogens. Their remarkable efficacy against phytopathogens has positioned them as a promising alternative to conventional chemical-based methods in phytopathogen control, thus exploring interest in sustainable agricultural practices with reduced reliance on chemical interventions. This review aims to highlight the anti-phytopathogenic activity of chitosan nanocomposites, emphasizing their potential in mitigating plant diseases. Additionally, it explores various synthesis methods for chitosan nanoparticles to enhance readers' understanding. Furthermore, the analysis delves into elucidating the intricate mechanisms governing the antimicrobial effectiveness of these composites against bacterial and fungal phytopathogens.

Modification of physicochemical properties of chitosan to improve its pharmaceutical and agrochemical potential applications

Chitosan has received much more attention as a functional biopolymer with applications in pharmaceuticals, agricultural, drug delivery systems and cosmetics. The objectives of present investigation were to carry out modification of chitosan for enhancement of aqueous solubility, which will impart increased solubility and dissolution rate of poorly soluble drug itraconazole (ITZ) and also evaluate the modified chitosan for soyabean seed germination studies. The modification of chitosan was accomplished through the antisolvent precipitation method; employing five carboxylic acids. The resulting products were assessed for changes in molecular weight, degree of deacetylation, solubility and solid state characterization. Subsequently, the modified chitosan was complexed with itraconazole using the co-grinding technique. The prepared formulations were evaluated for solubility, FTIR (Fourier-transform infrared spectroscopy), PXRD (Powder X-ray diffraction), in-vitro dissolution studies. Furthermore the effect of modified chitosan has been evaluated on soybean seed germination. Results demonstrated that, modified chitosan improves self and solubility of itraconazole by six folds. As there was increased degree of deacetylation of chitosan leads to improvement in solubility. The results of FTIR showed the slight shifting of peaks in co-grind formulations of itraconazole. Formulations showed reduction in crystallinity of drug which leads to enhancement in dissolution rate as compared to pure itraconazole. Retention of property of seed germination was observed with modified chitosan at optimum concentration of 3 % w/v, with benefit of enhanced aqueous solubility of chitosan. This positive result paves the way for the advancement of pharmaceutical and agrochemical products employing derivatives of chitosan.

Efficacy of Gentamicin-Loaded Chitosan Nanoparticles Against Staphylococcus aureus Internalized in Osteoblasts

Staphylococcus aureus, the principal causative agent of osteomyelitis, can be internalized by osteoblasts and thereby escape from immune phagocytes and many kinds of antibiotics. To deliver antibiotics into osteoblasts to kill S. aureus in the intracellular environment, we developed gentamicin-loaded chitosan nanoparticles and evaluated their intracellular bactericidal effect. We found decreased numbers of S. aureus cells in infected osteoblasts treated with gentamicin-loaded chitosan nanoparticles. The cytotoxicity of the nanoparticles was evaluated by CCK-8 assay. There was no significant viability decrease at all tested concentrations. In conclusion, our results provide evidence for the potential use of gentamicin-loaded chitosan nanoparticles to enhance the delivery of gentamicin into cells and for their antibacterial effect against internalized S. aureus in the intracellular environment of osteoblasts.

The Chemical Modification to Improve Solubility of Chitosan and Its Derivatives Application, Preparation Method, Toxicity as a Nanoparticles

Chitosan is a functional polymer in the pharmaceutical field, including for nanoparticle drug delivery systems. Chitosan-based nanoparticles are a promising carrier for a wide range of therapeutic agents and can be administered in various routes. Solubility is the main problem for its production and utilization in large-scale industries. Chitosan modifications have been employed to enhance its solubility, including chemical modification. Many reviews have reported the chemical modification but have not focused on the specific characteristics obtained. This review focused on the modification to improve chitosan solubility. Additionally, this review also focused on the application of chitosan derivatives in nanoparticle drug delivery systems since very few similar reviews have been reported. The specific method for chitosan derivative-based nanoparticles was also reported and the latest report of chitosan, chitosan derivative, and chitosan toxicity were also described.

Exploring modified chitosan-based gene delivery technologies for therapeutic advancements

One of the critical steps in gene therapy is the successful delivery of the genes. Immunogenicity and toxicity are major issues for viral gene delivery systems. Thus, non-viral vectors are explored. A cationic polysaccharide like chitosan could be used as a nonviral gene delivery vector owing to its significant interaction with negatively charged nucleic acid and biomembrane, providing effective cellular uptake. However, the native chitosan has issues of targetability, unpacking ability, and solubility along with poor buffer capability, hence requiring modifications for effective use in gene delivery. Modified chitosan has shown that the "proton sponge effect" involved in buffering the endosomal pH results in osmotic swelling owing to the accumulation of a greater amount of proton and chloride along with water. The major challenges include limited exploration of chitosan as a gene carrier, the availability of high-purity chitosan for toxicity reduction, and its immunogenicity. The genetic drugs are in their infancy phase and require further exploration for effective delivery of nucleic acid molecules as FDA-approved marketed formulations soon.

Pharmaceutical applications of chitosan in skin regeneration: A review

Skin regeneration is the process that restores damaged tissues. When the body experiences trauma or surgical incisions, the skin and tissues on the wound surface become damaged. The body repairs this damage through complex physiological processes to restore the original structural and functional states of the affected tissues. Chitosan, a degradable natural bioactive polysaccharide, has attracted widespread attention partly owing to its excellent biocompatibility and antimicrobial properties; additionally, a modified form of this compound has been shown to promote skin regeneration. This review evaluates the recent research progress in the application of chitosan to promote skin regeneration. First, we discuss the basic principles of the extraction and preparation processes of chitosan from its source. Subsequently, we describe the functional properties of chitosan and the optimization of these properties through modification. We then focus on the existing chitosan-based biomaterials developed for clinical applications and their corresponding effects on skin regeneration, particularly in cases of diabetic and burn wounds. Finally, we explore the challenges and prospects associated with the use of chitosan in skin regeneration. Overall, this review provides a reference for related research and contributes to the further development of chitosan-based products in cutaneous skin regeneration.

Recent Advances of Chitosan-Based Hydrogels for Skin-Wound Dressings

The management of wound healing represents a significant clinical challenge due to the complicated processes involved. Chitosan has remarkable properties that effectively prevent certain microorganisms from entering the body and positively influence both red blood cell aggregation and platelet adhesion and aggregation in the bloodstream, resulting in a favorable hemostatic outcome. In recent years, chitosan-based hydrogels have been widely used as wound dressings due to their biodegradability, biocompatibility, safety, non-toxicity, bioadhesiveness, and soft texture resembling the extracellular matrix. This article first summarizes an overview of the main chemical modifications of chitosan for wound dressings and then reviews the desired properties of chitosan-based hydrogel dressings. The applications of chitosan-based hydrogels in wound healing, including burn wounds, surgical wounds, infected wounds, and diabetic wounds are then discussed. Finally, future prospects for chitosan-based hydrogels as wound dressings are discussed. It is anticipated that this review will form a basis for the development of a range of chitosan-based hydrogel dressings for clinical treatment.

Chitosan, chitosan derivatives, and chitosan-based nanocomposites: eco-friendly materials for advanced applications (a review)

For many years, chitosan has been widely regarded as a promising eco-friendly polymer thanks to its renewability, biocompatibility, biodegradability, non-toxicity, and ease of modification, giving it enormous potential for future development. As a cationic polysaccharide, chitosan exhibits specific physicochemical, biological, and mechanical properties that depend on factors such as its molecular weight and degree of deacetylation. Recently, there has been renewed interest surrounding chitosan derivatives and chitosan-based nanocomposites. This heightened attention is driven by the pursuit of enhancing efficiency and expanding the spectrum of chitosan applications. Chitosan's adaptability and unique properties make it a game-changer, promising significant contributions to industries ranging from healthcare to environmental remediation. This review presents an up-to-date overview of chitosan production sources and extraction methods, focusing on chitosan's physicochemical properties, including molecular weight, degree of deacetylation and solubility, as well as its antibacterial, antifungal and antioxidant activities. In addition, we highlight the advantages of chitosan derivatives and biopolymer modification methods, with recent advances in the preparation of chitosan-based nanocomposites. Finally, the versatile applications of chitosan, whether in its native state, derived or incorporated into nanocomposites in various fields, such as the food industry, agriculture, the cosmetics industry, the pharmaceutical industry, medicine, and wastewater treatment, were discussed.

Chitosan scaffolds: Expanding horizons in biomedical applications

Chitosan, a natural polysaccharide from chitin, shows promise as a biomaterial for various biomedical applications due to its biocompatibility, biodegradability, antibacterial activity, and ease of modification. This review overviews "chitosan scaffolds" use in diverse biomedical applications. It emphasizes chitosan's structural and biological properties and explores fabrication methods like gelation, electrospinning, and 3D printing, which influence scaffold architecture and mechanical properties. The review focuses on chitosan scaffolds in tissue engineering and regenerative medicine, highlighting their role in bone, cartilage, skin, nerve, and vascular tissue regeneration, supporting cell adhesion, proliferation, and differentiation. Investigations into incorporating bioactive compounds, growth factors, and nanoparticles for improved therapeutic effects are discussed. The review also examines chitosan scaffolds in drug delivery systems, leveraging their prolonged release capabilities and ability to encapsulate medicines for targeted and controlled drug delivery. Moreover, it explores chitosan's antibacterial activity and potential for wound healing and infection management in biomedical contexts. Lastly, the review discusses challenges and future objectives, emphasizing the need for improved scaffold design, mechanical qualities, and understanding of interactions with host tissues. In summary, chitosan scaffolds hold significant potential in various biological applications, and this review underscores their promising role in advancing biomedical science.

Marine-derived polysaccharides and their therapeutic potential in wound healing application - A review

Polysaccharides originating from marine sources have been studied as potential material for use in wound dressings because of their desirable characteristics of biocompatibility, biodegradability, and low toxicity. Marine-derived polysaccharides used as wound dressing, provide several benefits such as promoting wound healing by providing a moist environment that facilitates cell migration and proliferation. They can also act as a barrier against external contaminants and provide a protective layer to prevent further damage to the wound. Research studies have shown that marine-derived polysaccharides can be used to develop different types of wound dressings such as hydrogels, films, and fibres. These dressings can be personalised to meet specific requirements based on the type and severity of the wound. For instance, hydrogels can be used for deep wounds to provide a moist environment, while films can be used for superficial wounds to provide a protective barrier. Additionally, these polysaccharides can be modified to improve their properties, such as enhancing their mechanical strength or increasing their ability to release bioactive molecules that can promote wound healing. Overall, marine-derived polysaccharides show great promise for developing effective and safe wound dressings for various wound types.

Boiling water resistant fully bio-based adhesive made from maleated chitosan and glucose with excellent performance

Biomass resources are widely considered potential alternatives to formaldehyde-based wood adhesives because of their abundance. In this study, an environmentally friendly biomass adhesive, carboxylated chitosan-glucose (CSC-G), was prepared using chitosan, maleic anhydride, and glucose. The structure and water resistance of the adhesive were analyzed in detail. Maleic anhydride act as a bridge connecting chitosan and glucose, giving the adhesive good water solubility and resistance. The improved water resistance of the CSC-G adhesive was attributed to the formation of covalent cross-linked structures and an increased degree of system cross-linking. Additionally, the curing temperature of the CSC-G adhesive was superior to those of previously reported polyester adhesives. This study not only expands the application scope of fishery waste, but also demonstrates its great potential for the preparation of high-performance plywood.

Antibacterial chitosan-based composite sponge with synergistic hemostatic effect for massive haemorrhage

Uncontrollable acute bleeding and wound infection pose significant challenges in emergency treatment and surgical operations. Therefore, the research and development of highly efficient antibacterial hemostatic agents are of great importance in reducing the mortality rate among patients with massive hemorrhage. In this study, we utilized hydrophobically modified chitosan (HM-CS) and gallic acid chitosan (GA-CS) to create a composite sponge (HM/GA-CS) that exhibits complementary advantages. The composite sponge combines the alkyl chain and polyphenol structure, allowing it to adsorb blood cells and plasma proteins simultaneously. This synergistic effect was confirmed through various tests, including blood cell adhesion, plasma protein barrier behavior, and in vitro hemostatic testing. Furthermore, experiments conducted on a rat liver injury model demonstrated that the composite sponge achieved rapid coagulation within 52 s, resulting in significantly lower bleeding volume compared with traditional gauze. In addition, the incorporation of GA-CS into HM-CS enhanced the antibacterial properties of the composite sponge. The antibacterial rate of the composite sponge against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) reached 100 % and 98.2 %, respectively. To evaluate its biocompatibility, the composite sponge underwent blood compatibility and cell activity tests, confirming its suitability. The HM/GA-CS sponge holds promising applications in managing cases of massive hemorrhage.

Bio-Inspired Self-Healing, Shear-Thinning, and Adhesive Gallic Acid-Conjugated Chitosan/Carbon Black Composite Hydrogels as Suture Support Materials

The occurrence of leakage from anastomotic sites is a significant issue given its potential undesirable complications. The management of anastomotic leakage after gastrointestinal surgery is particularly crucial because it is directly associated with mortality and morbidity in patients. If adhesive materials could be used to support suturing in surgical procedures, many complications caused by leakage from the anastomosis sites could be prevented. In this study, we have developed self-healing, shear-thinning, tissue-adhesive, carbon-black-containing, gallic acid-conjugated chitosan (CB/Chi-gallol) hydrogels as sealing materials to be used with suturing. The addition of CB into Chi-gallol solution resulted in the formation of a crosslinked hydrogel with instantaneous solidification. In addition, these CB/Chi-gallol hydrogels showed enhancement of the elastic modulus (G') values with increased CB concentration. Furthermore, these hydrogels exhibited excellent self-healing, shear-thinning, and tissue-adhesive properties. Notably, the hydrogels successfully sealed the incision site with suturing, resulting in a significant increase in the bursting pressure. The proposed self-healing and adhesive hydrogels are potentially useful in versatile biomedical applications, particularly as suture support materials for surgical procedures.

A drug co-delivery platform made of magnesium-based micromotors enhances combination therapy for hepatoma carcinoma cells

Combination therapy is an emerging strategy to overcome multidrug resistance (MDR) in hepatocellular carcinoma (HCC) chemotherapy treatment. However, the passive diffusion in traditional delivery systems greatly retards the approach and penetration of drugs into hepatocellular carcinoma cells and thus hinders the efficacy of combination therapy. Micro/nanomotors with autonomous locomotion in a tiny scale provide the possibility of tackling this issue. Herein, an active drug delivery micromotor platform delicately designed to load drugs with different physicochemical properties and enhance the drug permeability of cells is demonstrated for HCC chemotherapy treatment. The biocompatible micromotor platform Mg/PLGA/CHI comprised magnesium (Mg) coated with two polymer layers made of poly(lactic-co-glycolic acid) (PLGA) and chitosan (CHI), where the hydrophobic and hydrophilic drugs doxorubicin (Dox) and Curcumin (Cur) were loaded, respectively. The autonomous motion of the micromotors with velocity up to 45 μm s-1 greatly enhanced the diffusion of chemotherapeutic drugs and led to higher extracellular and intracellular drug distribution. Moreover, hydrogen produced during the motion eliminated the excess reactive oxygen species (ROS) in the human hepatocellular carcinoma (HepG2) cells. Compared with inert groups, the absorption of Dox and Cur from the active micromotors was about 2.9 and 1.5 times higher in human hepatocellular carcinoma (HepG2) cells. In addition, the anti-tumor activity also obviously improved at the micromotor concentration of 1 mg mL-1 (cell proliferation was reduced by almost 30%). Overall, this work proposes an approach based on loading different chemotherapy agents on an active delivery system to enhance drug permeability and overcome MDR and provides a potentially effective therapeutic strategy for the treatment of HCC.

Chitosan-dibenzylideneacetone based Schiff base: Evaluation of antimicrobial activity and in-vitro cytotoxicity on MCF-7 and L-132

This study holds significant importance as it explores the synthesis and characterization of two chitosan dibenzylideneacetone Schiff bases. Various analytical techniques, such as UV-visible spectroscopy, FTIR, XRD, TGA, DSC, SEM, and elemental analysis, were employed to thoroughly examine these derivatives. The antimicrobial activity of the chitosan derivatives was evaluated against a range of bacterial and fungal strains, while cytotoxicity tests were conducted on MCF-7, L-132, and VERO cell lines. In the antimicrobial tests, the chitosan derivatives exhibited remarkable antibacterial properties against S. aureus, E. coli, and Pseudomonas aeruginosa, as well as potent antifungal properties against Candida albicans and Aspergillus fumigatus. The cytotoxicity assessment revealed that the dibenzylideneacetone chitosan Schiff base (CHDBA) showed significant effectiveness against the L-132 cell line, surpassing the efficacy of doxorubicin by 2.44 times. Moreover, it exhibited substantial activity against the L-132 and MCF-7 cell lines, with IC50 values of 55.29 μg/mL and 185.8 μg/mL, respectively. Notably, none of the chitosan derivatives demonstrated cytotoxicity towards the normal cell line, indicating their non-toxic nature and safe usability. Based on these findings, it is evident that CHDBA holds promise for further development as a potential treatment option for breast cancer and lung cancer.

Stimulation of the Defense Mechanisms of Potatoes to a Late Blight Causative Agent When Treated with Bacillus subtilis Bacteria and Chitosan Composites with Hydroxycinnamic Acids

Phytophthora infestans is, worldwide, one of the main causal agents of epiphytotics in potato plantings. Prevention strategies demand integrated pest management, including modeling of beneficial microbiomes of agroecosystems combining microorganisms and natural products. Chitooligosaccharides and their derivatives have great potential to be used by agrotechnology due to their ability to elicit plant immune reactions. The effect of combining Bacillus subtilis 26D and 11VM and conjugates of chitin with hydroxycinnamates on late blight pathogenesis was evaluated. Mechanisms for increasing the resistance of potato plants to Phytophthora infestans were associated with the activation of the antioxidant system of plants and an increase in the level of gene transcripts that encode PR proteins: basic protective protein (PR-1), thaumatin-like protein (PR-5), protease inhibitor (PR-6), and peroxidase (PR-9). The revealed activation of the expression of marker genes of systemic acquired resistance and induced systemic resistance under the influence of the combined treatment of plants with B. subtilis and conjugates of chitin with hydroxycinnamates indicates that, in this case, the development of protective reactions in potato plants to late blight proceeds synergistically, where B. subtilis primes protective genes, and chitosan composites act as a trigger for their expression.

Amelioration of Cancer Employing Chitosan, Its Derivatives, and Chitosan-Based Nanoparticles: Recent Updates

The limitations associated with the conventional treatment of cancer have necessitated the design and development of novel drug delivery systems based mainly on nanotechnology. These novel drug delivery systems include various kinds of nanoparticles, such as polymeric nanoparticles, solid lipid nanoparticles, nanostructured lipid carriers, hydrogels, and polymeric micelles. Among the various kinds of novel drug delivery systems, chitosan-based nanoparticles have attracted the attention of researchers to treat cancer. Chitosan is a polycationic polymer generated from chitin with various characteristics such as biocompatibility, biodegradability, non-toxicity, and mucoadhesiveness, making it an ideal polymer to fabricate drug delivery systems. However, chitosan is poorly soluble in water and soluble in acidic aqueous solutions. Furthermore, owing to the presence of reactive amino groups, chitosan can be chemically modified to improve its physiochemical properties. Chitosan and its modified derivatives can be employed to fabricate nanoparticles, which are used most frequently in the pharmaceutical sector due to their possession of various characteristics such as nanosize, appropriate pharmacokinetic and pharmacodynamic properties, non-immunogenicity, improved stability, and improved drug loading capacity. Furthermore, it is capable of delivering nucleic acids, chemotherapeutic medicines, and bioactives using modified chitosan. Chitosan and its modified derivative-based nanoparticles can be targeted to specific cancer sites via active and passive mechanisms. Based on chitosan drug delivery systems, many anticancer drugs now have better effectiveness, potency, cytotoxicity, or biocompatibility. The characteristics of chitosan and its chemically tailored derivatives, as well as their use in cancer therapy, will be examined in this review.

Chitosan-based electrospun nanofibers for encapsulating food bioactive ingredients: A review

Today, society has been more aware of healthy food products and related items containing bioactive compounds, which potentially contribute to human health. Unfortunately, the long-term stability and bioactivity of biologically active compounds against environmental factors compromise their target and effective action. In this way, lab-designed vehicles, such as nanoparticles and nanofibers, provide enough properties for their preservation and suitable delivery. Here, the electrospinning technique acts as an effective pathway for fabricating and designing nanofibers for the entrapments of biomolecules, in which several biopolymers such as proteins, polysaccharides (e.g., maltodextrin, agarose, chitosan), silk, among others, can be used as a wall material. It is likely that chitosan is one of the most employed biomaterials in this field. Therefore, in this review, we reveal the latest advances (over the last 2-3 years) in designing chitosan-based electrospun nanofibers and nanocarriers for encapsulation of bioactive compounds, along with the key applications in smart food packaging as well. Key findings and relevant breakthroughs are a priority in this review to provide a cutting-edge analysis of the literature. Finally, particular attention has been paid to the most promising developments.

Quaternized chitosan (nano)fibers: A journey from preparation to high performance applications

The industrial production of chitosan, initiated over 50 years ago, has transformed its application across diverse industries, agriculture, and medicine. To enhance its properties, numerous chitosan derivatives have been synthesized. The quaternization of chitosan has proven beneficial, as it not only enhances its properties but also imparts water solubility, expanding its potential for a wider range of applications. Specifically, the utilization of quaternized chitosan-based nanofibers has leveraged the synergistic benefits of quaternized chitosan (including hydrophilicity, bioadhesiveness, antimicrobial, antioxidant, hemostatic, and antiviral activities, as well as ionic conductivity) in combination with the distinctive characteristics of nanofibers (such as a high aspect ratio and 3D architecture). This combination has permitted numerous possibilities, spanning from wound dressings, air and water filters, drug delivery scaffolds, antimicrobial textiles, to energy storage systems and alkaline fuel cells. In this comprehensive review, we examine the preparation methods, properties, and applications of various composite fibers containing quaternized chitosan. The advantages and disadvantages of each method and composition are meticulously summarized, while relevant diagrams and figures illustrate the key findings.

Synthesis, Characterization, Properties, and Biomedical Application of Chitosan-Based Hydrogels

The prospective applications of chitosan-based hydrogels (CBHs), a category of biocompatible and biodegradable materials, in biomedical disciplines such as tissue engineering, wound healing, drug delivery, and biosensing have garnered great interest. The synthesis and characterization processes used to create CBHs play a significant role in determining their characteristics and effectiveness. The qualities of CBHs might be greatly influenced by tailoring the manufacturing method to get certain traits, including porosity, swelling, mechanical strength, and bioactivity. Additionally, characterization methods aid in gaining access to the microstructures and properties of CBHs. Herein, this review provides a comprehensive assessment of the state-of-the-art with a focus on the affiliation between particular properties and domains in biomedicine. Moreover, this review highlights the beneficial properties and wide application of stimuli-responsive CBHs. The main obstacles and prospects for the future of CBH development for biomedical applications are also covered in this review.

Anti-Photoaging Effects of Nanocomposites of Amphiphilic Chitosan/18β-Glycyrrhetinic Acid

Improving the transdermal absorption of weakly soluble drugs for topical use can help to prevent and treat skin photoaging. Nanocrystals of 18β-glycyrrhetinic acid (i.e., NGAs) prepared by high-pressure homogenization and amphiphilic chitosan (ACS) were used to form ANGA composites by electrostatic adsorption, and the optimal ratio of NGA to ACS was 10:1. Dynamic light scattering analysis and zeta potential analysis were used to evaluate the nanocomposites' suspension, and the results showed that mean particle size was 318.8 ± 5.4 nm and the zeta potential was 30.88 ± 1.4 mV after autoclaving (121 °C, 30 min). The results of CCK-8 showed that the half-maximal inhibitory concentration (IC50) of ANGAs (71.9 μg/mL) was higher than that of NGAs (51.6 μg/mL), indicating that the cytotoxicity of ANGAs was weaker than that of NGAs at 24 h. After the composite had been prepared as a hydrogel, the vertical diffusion (Franz) cells were used to investigate skin permeability in vitro, and it was shown that the cumulative permeability of the ANGA hydrogel increased from 56.5 ± 1.4% to 75.3 ± 1.8%. The efficacy of the ANGA hydrogel against skin photoaging was studied by constructing a photoaging animal model under ultraviolet (UV) irradiation and staining. The ANGA hydrogel improved the photoaging characteristics of UV-induced mouse skin significantly, improved structural changes (e.g., breakage and clumping of collagen and elastic fibers in the dermis) significantly, and improved skin elasticity, while it inhibited the abnormal expression of matrix metalloproteinase (MMP)-1 and MMP-3 significantly, thereby reducing the damage caused by UV irradiation to the collagen-fiber structure. These results indicated that the NGAs could enhance the local penetration of GA into the skin and significantly improve the photoaging of mouse skin. The ANGA hydrogel could be used to counteract skin photoaging.

A self-gelling powder based on polyacrylic acid/polyacrylamide/quaternate chitosan for rapid hemostasis

In order to improve the hemostatic effect of the hemostatic dressing for non-compressible wounds, unknown bleeding points and irregularly shaped wounds, a self-gelling hemostasis powder based on polyacrylic acid/polyacrylamide/quaternate chitosan (PAA/PAM/QCS) is prepared in this study. When in contact with water, the PAA/PAM/QCS can fuse and rapidly form a stable hydrogel in a short time (< 0.25 min). The PAA/PAM ratio is the main parameter that modulates the formation of the self-gel. The PAA/PAM self-gel can be formed only when the PAA/PAM ratio is 5:5, and the introduction of QCS does not influence the self-gelling behaviors and hydrogel stability. Moreover, the PAA/PAM/QCS self-gel shows good adhesive properties on wet tissue surfaces. In addition, the introduction of QCS improves the antibacterial activity of the self-gelling hemostasis powder. Furthermore, the prepared PAA/PAM/QCS powder can rapidly adsorb lots of blood, aggregate blood cells and platelets. The hemostatic results in vivo show that PAA/PAM/QCS powder is superior to the control group and commercial product groups (chitosan powder) with performance similar to hemostatic zeolite in terms of the amount of bleeding and hemostatic time. Therefore, the PAA/PAM/QCS self-gelling powder shows great application prospects for rapid hemostasis.

Chitosan Oligosaccharide Promotes Junction Barrier through Modulation of PI3K/AKT and ERK Signaling Intricate Interplay in T84 Cells

Chitosan oligosaccharide (COS) is a breakdown product of chitin, a polymer of N-acetyl-D-glucosamine. COS promotes barrier function in intestinal epithelial cells. However, the exact mechanism of COS-induced barrier function remains unknown. This study was aimed to explore the intricate signaling cascades in the junction barrier induced by COS (100 μg/mL) in human intestinal epithelial cells (T84 cells). COS (100 μg/mL) promoted tight junction assembly and increased transepithelial electrical resistance (TEER). COS inhibited FITC-dextran flux in T84 cell monolayers at 2 h, 4 h, 6 h and 24 h post treatment. In addition, the effect of COS on TEER and FITC-dextran flux was abrogated by pre-incubation of wortmannin (2 μM), an AKT (protein kinase B) inhibitor, at 2 h and 4 h post treatment, indicating that COS-induced tight junction integrity was mediated at least in part by AKT activation. COS-induced TEER was amplified at 24 h and 48 h post treatment by pre-incubation with SC79 (2.5 μM), an AKT activator. Moreover, COS induced inhibition of extracellular signal-regulated kinase (ERK) in T84 cells. Wortmannin and SC79 pre-incubation promoted ERK activation and ERK inhibition, respectively, suggesting that COS-induced ERK inhibition was mediated by AKT. Collectively, this study reveals that COS promotes junction barrier integrity via regulating PI3K/AKT and ERK signaling intricate interplay in T84 cell monolayers. COS may be beneficial in promoting junction barrier in intestinal disorders.

Chitosan-Based Biomaterials: Insights into Chemistry, Properties, Devices, and Their Biomedical Applications

Chitosan is a marine-origin polysaccharide obtained from the deacetylation of chitin, the main component of crustaceans’ exoskeleton, and the second most abundant in nature. Although this biopolymer has received limited attention for several decades right after its discovery, since the new millennium chitosan has emerged owing to its physicochemical, structural and biological properties, multifunctionalities and applications in several sectors. This review aims at providing an overview of chitosan properties, chemical functionalization, and the innovative biomaterials obtained thereof. Firstly, the chemical functionalization of chitosan backbone in the amino and hydroxyl groups will be addressed. Then, the review will focus on the bottom-up strategies to process a wide array of chitosan-based biomaterials. In particular, the preparation of chitosan-based hydrogels, organic–inorganic hybrids, layer-by-layer assemblies, (bio)inks and their use in the biomedical field will be covered aiming to elucidate and inspire the community to keep on exploring the unique features and properties imparted by chitosan to develop advanced biomedical devices. Given the wide body of literature that has appeared in past years, this review is far from being exhaustive. Selected works in the last 10 years will be considered.

Physicochemical and Structural Characterization of Alkali-Treated Biopolymer Sphingan WL Gum from Marine Sphingomonas sp. WG

Sphingan WL gum (WL), a kind of exopolysaccharide, is produced by Sphingomonas sp. WG, which was screened from sea mud samples of Jiaozhou Bay by our group. The solubility of WL was investigated in this work. First, 1 mg/mL of WL solution was stirred at room temperature for at least 2 h to obtain a uniform opaque liquid, and further the solution became clear with the increased NaOH and stirring time. Subsequently, the structural features, solubility, and rheological properties of WL before and after alkali treatment were compared systematically. FTIR, NMR, and zeta potential results indicate that the alkali causes acetyl group hydrolysis and carboxyl group deprotonation. XRD, DLS, GPC, and AFM results suggest that the alkali destroys the ordered arrangement and inter- and intrachain entanglement of polysaccharide chains. In the same case, 0.9 M NaOH-treated WL presents better solubility (stirring for 15 min to obtain a clarified solution) but, unsurprisingly, worsens rheological properties. All results demonstrated that the good solubility and transparency of alkali-treated WL will help promote its postmodification and application.

Fucoidan from Fucus vesiculosus: Evaluation of the Impact of the Sulphate Content on Nanoparticle Production and Cell Toxicity

The composition of seaweeds is complex, with vitamins, phenolic compounds, minerals, and polysaccharides being some of the factions comprising their structure. The main polysaccharide in brown seaweeds is fucoidan, and several biological activities have been associated with its structure. Chitosan is another marine biopolymer that is very popular in the biomedical field, owing to its suitable features for formulating drug delivery systems and, particularly, particulate systems. In this work, the ability of fucoidan to produce nanoparticles was evaluated, testing different amounts of a polymer and using chitosan as a counterion. Nanoparticles of 200-300 nm were obtained when fucoidan prevailed in the formulation, which also resulted in negatively charged nanoparticles. Adjusting the pH of the reaction media to 4 did not affect the physicochemical characteristics of the nanoparticles. The IC50 of fucoidan was determined, in both HCT-116 and A549 cells, to be around 160 µg/mL, whereas it raised to 675-100 µg/mL when nanoparticles (fucoidan/chitosan = 2/1, w/w) were tested. These marine materials (fucoidan and chitosan) provided features suitable to formulate polymeric nanoparticles to use in biomedical applications.

Preparation and application of chitosan-based medical electrospun nanofibers

Chitosan is a kind of polysaccharide cationic polymer, which has excellent biocompatibility, biodegradability and biological activity. In recent years, chitosan has been widely used as medical materials because of its non-toxicity, non-immunogenicity and rich sources. This paper reviews chitosan chemistry, the basic principles and influence of electrospinning technology, the blending of chitosan with polyethylene oxide, polyvinyl alcohol, polycaprolactone, polylactic acid, protein, polysaccharide and other polymer materials, the blending of chitosan with oxides, metals, carbon-based and other inorganic substances for electrospinning, the application of chitosan electrospinning nanofibers in medical field and its mechanism in clinical application. In order to provide reference for the in-depth study of electrospinning technology in the field of medical and health.

Chitosan Oligosaccharide Prevents Afatinib-Induced Barrier Disruption and Chloride Secretion through Modulation of AMPK, PI3K/AKT, and ERK Signaling in T84 Cells

Diarrhea is an important adverse effect of epidermal growth factor receptor-tyrosine kinase inhibitors, especially afatinib. Novel antidiarrheal agents are needed to reduce epidermal growth factor receptor-tyrosine kinase inhibitor-associated diarrhea to improve the quality of life and treatment outcome in cancer patients. This study aimed to investigate the anti-diarrheal activity of chitosan oligosaccharide against afatinib-induced barrier disruption and chloride secretion in human intestinal epithelial cells (T84 cells). Chitosan oligosaccharide (100 μg/mL) prevented afatinib-induced barrier disruption determined by changes in transepithelial electrical resistance and FITC-dextran flux in the T84 cell monolayers. In addition, chitosan oligosaccharide prevented afatinib-induced potentiation of cAMP-induced chloride secretion measured by short-circuit current analyses in the T84 cell monolayers. Chitosan oligosaccharide induced the activation of AMPK, a positive regulator of epithelial tight junction and a negative regulator of cAMP-induced chloride secretion. Moreover, chitosan oligosaccharide partially reversed afatinib-induced AKT inhibition without affecting afatinib-induced ERK inhibition via AMPK-independent mechanisms. Collectively, this study reveals that chitosan oligosaccharide prevents the afatinib-induced diarrheal activities in T84 cells via both AMPK-dependent and AMPK-independent mechanisms. Chitosan oligosaccharide represents a promising natural polymer-derived compound for further development of treatment for afatinib-associated diarrheas.