Synthesis, Chemical and Biomedical Aspects of the Use of Sulfated Chitosan

Functionalized chitosan-inspired (nano)materials containing sulfonic acid groups: Synthesis and application

Nature-inspired chitosan (CS) materials show a high potential for the design/fabrication of sustainable heterogeneous (nano)materials with extraordinary structural/physical features, such as superior biodegradability/biocompatibility, simplicity of chemical modification, environmental safety, high availability, cost-effectiveness, high electrochemical activity, good film-forming ability, and antioxidant, antimicrobial/antibacterial, and anticoagulant activities. Industrialization and growth of industrial wastes or by-products induce an increasing demand for the development of clean, low-cost, and renewable natural systems to minimize or eliminate the utilization of environmentally toxic compounds. The preparation of novel heterogeneous functionalized polysaccharide-inspired bio(nano)materials via chemical modifications of natural CS to improve its physicochemical/biochemical properties has recently become tremendously attractive for many researchers. The most abundantly available and cost-effective functionalized CS-inspired (nano)materials are considerably valuable in terms of the economic aspects of production of (nano)catalysts, (nano)hydrogels, (nano)composite/blend membranes, and thus their commercialization. In this respect, the preparation of functionalized CS-inspired (nano)materials containing -SO3H groups has been represented as a valid alternative to the homogenous unmodified biomaterials for various applications. Sulfonated derivatives of CS-inspired (nano)materials may possess huge surface areas, catalytic activity, adsorption, and biological/biomedical properties. This review article is aimed at the investigation of different methods and potential applications of sulfonated CS-inspired (nano)materials in catalysis, fuel cells, adsorption of ions, membranes, and biological applications.

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.

Thiolated chitosan encapsulation constituted mucoadhesive nanovaccine confers broad protection against divergent influenza A viruses

Influenza A virus (IAV) poses a significant threat to human and animal health, necessitating the development of universal influenza vaccines that can effectively activate mucosal immunity. Intranasal immunization has attracted significant attention due to its capacity to induce triple immune responses, including mucosal secretory IgA. However, inducing mucosal immunity through vaccination is challenging due to the self-cleansing nature of the mucosal surface. Thiolated chitosan (TCS) were explored for mucosal vaccine delivery, capitalizing on biocompatibility and bioadhesive properties of chitosan, with thiol modification enhancing mucoadhesive capability. The focus was on developing a universal nanovaccine by utilizing TCS-encapsulated virus-like particles displaying conserved B-cell and T-cell epitopes from M2e and NP proteins of IAV. The optimal conditions for nanoparticle formation were investigated by adjusting the thiol groups content of TCS and the amount of sodium tripolyphosphate. The nanovaccine induced robust immune responses and provided complete protection against IAVs from different species following intranasal immunization. The broad protective effect of nanovaccines can be attributed to the synergistic effect of antibodies and T cells. This study developed a universal intranasal nanovaccine and demonstrated the potential of TCS in the development of mucosal vaccines for respiratory infectious diseases.

Experimental Early Stimulation of Bone Tissue Neo-Formation for Critical Size Elimination Defects in the Maxillofacial Region

A biomaterial is proposed for closing extensive bone defects in the maxillofacial region. The composition of the biomaterial includes high-molecular chitosan, chondroitin sulfate, hyaluronate, heparin, alginate, and inorganic nanostructured hydroxyapatite. The purpose of this study is to demonstrate morphological and histological early signs of reconstruction of a bone cavity of critical size. The studies were carried out on 84 white female rats weighing 200-250 g. The study group consisted of 84 animals in total, 40 in the experimental group and 44 in the control group. In all animals, three-walled bone defects measuring 0.5 × 0.4 × 0.5 cm3 were applied subperiosteally in the region of the angle of the lower jaw and filled in the experimental group using lyophilized gel mass of chitosan-alginate-hydroxyapatite (CH-SA-HA). In control animals, the bone cavities were filled with their own blood clots after bone trepanation and bleeding. The periods for monitoring bone regeneration were 3, 5, and 7 days and 2, 3, 4, 6, 8, and 10 weeks. The control of bone regeneration was carried out using multiple morphological and histological analyses. Results showed that the following process is an obligatory process and is accompanied by the binding and release of angiogenic implantation: the chitosan construct actively replaced early-stage defects with the formation of full-fledged new bone tissue compared to the control group. By the 7th day, morphological analysis showed that the formation of spongy bone tissue could be seen. After 2 weeks, there was a pronounced increase in bone volume (p < 0.01), and at 6 weeks after surgical intervention, the closure of the defect was 70-80%; after 8 weeks, it was 100% without violation of bone morphology with a high degree of mineralization. Thus, the use of modified chitosan after filling eliminates bone defects of critical size in the maxillofacial region, revealing early signs of bone regeneration, and serves as a promising material in reconstructive dentistry.

Delivery of B. subtilis into Animal Intestine Using Chitosan-Derived Bioresorbable Gel Carrier: Preliminary Results

The oral delivery of bacteria in the human intestine is of great interest because of its potential to correct the gut microbiota and treat inflammatory bowel diseases. The aim of this study was to evaluate sodium N-(2-sulfonatoethyl)chitosan gel cross-linked with glutaraldehyde as a delivery carrier for probiotic bacteria to the gut using in vitro and in vivo experiments. The bacterial test strain was B. subtilis 20. The cytotoxicity of the gel was evaluated via cell culture using flow cytometry and light microscopy. The gel as a delivery system was assessed by the dye release in medium with different pH levels in vitro, and by bacterial titer monitoring in mouse feces using the microbiology method in vivo. Results of an in vitro experiment showed that tested gel has no cytotoxicity. The use of gel as a carrier for bacterial delivery into the intestine was more effective than oral gavage of bacterial suspension. Therefore, gel delivery of bacteria decreased the titer level by up to two times. However, a gavage of bacterial suspension decreased the titer level by over 200 times. Tested gel has the potential to be a carrier for the safe delivery of bacteria to the intestine through the stomach, reducing the rate of the elimination of probiotic bacteria from the intestine.