An overview of carboxymethyl derivatives of chitosan: Their use as biomaterials and drug delivery systems

Recent progress in chitosan-based nanoparticles for drug delivery: a review on modifications and therapeutic potential

Chitosan, obtained from chitin by deacetylation, is a versatile biopolymer known for its biocompatibility, biodegradability and environmental friendliness. Combined with its chemical and physical modifiability, these properties have made chitosan an important material in biomedical and pharmaceutical fields, especially in drug delivery systems. Chitosan-based nanomaterials exhibit enhanced functions through various chemical modifications such as thiolation, acetylation, carboxylation and phosphorylation, as well as through physical and enzymatic approaches. These modifications address inherent limitations such as poor solubility, limited acid resistance and insufficient mechanical strength, expanding the applications of chitosan in tissue engineering, gene therapy, vaccine delivery, wound healing and bioimaging. This review provides an in-depth analysis of the chemical structure, physicochemical properties and modification strategies of chitosan. It also explores current methodologies for preparing chitosan nanoparticles, along with drug loading and release techniques. Various targeting strategies employed in chitosan-based delivery systems are examined in detail. To illustrate the clinical relevance of these approaches, representative examples from recent therapeutic studies are included. Moreover, it highlights future research directions and the innovation potential of chitosan-based materials.

Carboxymethyl Chitosan and Chitosan as a Bioactive Delivery System: A Review

The functionality and mechanism of bioactive agents (BA) in treating various diseases have been studied as a progressive route. Designing an effective delivery system for transferring these molecules and components is a major challenge. For that reason, a wide range of biomaterials has been introduced to deliver BA to the target tissue or cells. Chitosan (CTS) is a nontoxic, biocompatible, biodegradable, and notable point low-cost polymer, and, as a result, can be effectively utilized in the formulation of diverse delivery systems, in biomedical applications. However, CTS has some limitations, such as poor solubility in aqueous and alkaline media, rapid swelling and degradation, and consequence fast release agent. The CTS derivative carboxymethyl chitosan (CMC) is an acceptable candidate for overcoming these limitations. CMC is a high-impact grade for pharmaceutical and biomedical applications because of its nontoxic, biocompatible, biodegradable, gelation, mucoadhesive, antibacterial, and antifungal. CMC bioactivity potentials are related to carboxyl and methyl groups added through chemical modification in the CTS backbone. In this review, the physical and chemical properties of CTS and CMC have been introduced and discussed. Afterward, its biomedical applications with delivery approaches for various BA (drugs, genes, proteins), microfluidic, and cancer have been considered.

Emerging Treatments for Persistent Corneal Epithelial Defects

Persistent corneal epithelial defects (PCEDs) are a challenging ocular condition characterized by the failure of complete corneal epithelial healing after an insult or injury, even after 14 days of standard care. There is a lack of therapeutics that target this condition and encourage re-epithelialization of the corneal surface in a timely and efficient manner. This review aims to provide an overview of current standards of management for PCEDs, highlighting novel, emerging treatments in this field. While many of the current non-surgical treatments aim to provide lubrication and mechanical support, novel non-surgical approaches are undergoing development to harness the proliferative and healing properties of human mesenchymal stem cells, platelets, lufepirsen, hyaluronic acid, thymosin ß4, p-derived peptide, and insulin-like growth factor for the treatment of PCEDs. Novel surgical treatments focus on corneal neurotization and limbal cell reconstruction using novel scaffold materials and cell-sources. This review provides insights into future PCED treatments that build upon current management guidelines.

CMCS-PVA@CA hydrogel dressing: A promoter of wound healing with MRSA virulence attenuation function

Traditional wound dressings, primarily centered on antimicrobial or bactericidal strategies, have inadvertently contributed to the rise of drug-resistant bacterial colonies at wound sites, thus prolonging the healing process. In this study, we developed an innovative hydrogel dressing, CMCS-PVA@CA, incorporating carboxymethyl chitosan (CMCS), polyvinyl alcohol (PVA), and cichoric acid (CA), specifically designed to treat skin wounds infected with methicillin-resistant Staphylococcus aureus (MRSA). Computational biology analyses reveal that CA exerts substantial anti-virulence activity by targeting serine/threonine phosphatase (Stp1), achieving an IC50 of 3.912 μM, thereby mitigating MRSA pathogenicity. Notably, CA lacks intrinsic antibacterial properties, minimizing the risk of fostering drug resistance. Furthermore, CMCS-PVA@CA demonstrates effective wound healing acceleration and meets clinical application standards, with its robust mechanical properties enhancing patient comfort. In essence, this study presents CMCS-PVA@CA as a promising hydrogel dressing offering a viable solution for treating drug-resistant bacterial infections in skin wounds.

Simvastatin-Loaded Chitosan Microspheres as a Biomaterial for Dentin Tissue Engineering

In the present study, chitosan microspheres (MSCH) loaded with different concentrations of simvastatin (2%, 5%, and 10%) were synthesized as a biomaterial for dentin tissue engineering. The microspheres were prepared by emulsion crosslinking method, and simvastatin was incorporated during the process. The microspheres were then physicochemically and morphologically characterized. Scanning electron microscopy and infrared spectroscopy confirmed the spherical morphology of synthesized microspheres and the chemical incorporation of simvastatin into MSCH, respectively. UV-visible absorption confirmed the controlled and continuous release pattern of the drug. To mimic the clinical application in vitro, the microspheres were applied onto three-dimensional (3D) cultures of human dental pulp cells (HDPCs). Cell viability, proliferation, and in situ-mineralized matrix deposition were evaluated. The results indicated no cytotoxic effects for all 3D cultures for all tested biomaterials, with cells being able to proliferate significantly over time. HDPCs showed a significant increase in the deposition of mineralization nodules when 3D cultures were in direct contact with chitosan microspheres in comparison to control; nevertheless, the highest expression was observed for MSCH encapsulated with 5% and 10% simvastatin, which was significantly higher than plain MSCH. Therefore, chitosan microsphere systems loaded with 5%-10% simvastatin provided the development of a controlled release system in bioactive dosages for dentin tissue engineering.

Enhancing the antibacterial activity of ampicillin loaded into chitosan/starch nanocomposites against AMR Staphylococcusaureus

Ampicillin (Amp), an antibiotic, is widely used to treat bacterial infections in humans and livestock, but recently the rate of resistance has increased rapidly. The aim of this work was to enhancing the antibacterial effect of this compound against AMR Staphylococcus aureus via loading Amp into chitosan/starch nanocomposites by spray drying technique. The results showed that the different ratio of chitosan gel and starch gel used in preparing the nanocomposites can affect its properties and performance. The size distribution of the nanocomposite particles was ranging from 122.0 to 816.9 nm. The zeta potential values of the nanocomposites range from +29.47 to +93.07 mV, indicating the stability of the particles and their tendency to repel each other. Ampicillin was loaded into the chitosan/starch nanocomposites with encapsulation efficiency of 70.7-77.3 %, then their releasing and antibacterial effect against AMR S. aureus were investigated. The results indicated that antibacterial activity of chitosan/starch nanocomposites loaded ampicillin was much higher than ampicillin alone. Chitosan/starch nanocomposites loaded ampicillin at concentration 5.0 μg/mL inhibited 88.6 % growth of S. aureus to a similar extent as 7.5 μg/mL of ampicillin alone. Additionally, at same 7.5 μg/mL ampicillin concentration, the nanocomposites loaded ampicillin showed a higher inhibitory rate (93.27 %) compared to ampicillin alone (88.96 %) over a 12 h-period. Especially, the antibacterial activity of chitosan/starch nanocomposites loaded ampicillin still maintained their effectiveness over 48 h (95.43 %) while those the ampicillin decreased down to 85.76 %. This research highlights the potential of using the chitosan/starch nanocomposites as nanocarriers for ampicillin to enhance its antibacterial activity against AMR Staphylococcus aureus. This approach could be a promising strategy to combat antimicrobial resistance.

Medical Applications and Cellular Mechanisms of Action of Carboxymethyl Chitosan Hydrogels

Carboxymethyl chitosan (CMCS) hydrogels have been investigated in biomedical research because of their versatile properties that make them suitable for various medical applications. Key properties that are especially valuable for biomedical use include biocompatibility, tailored solid-like mechanical characteristics, biodegradability, antibacterial activity, moisture retention, and pH stimuli-sensitive swelling. These features offer advantages such as enhanced healing, promotion of granulation tissue formation, and facilitation of neutrophil migration. As a result, CMCS hydrogels are favorable materials for applications in biopharmaceuticals, drug delivery systems, wound healing, tissue engineering, and more. Understanding the interactions between CMCS hydrogels and biological systems, with a focus on their influence on cellular behavior, is crucial for leveraging their versatility. Because of the constantly growing interest in chitosan and its derivative hydrogels in biomedical research and applications, the present review aims to provide updated insights into the potential medical applications of CMCS based on recent findings. Additionally, we comprehensively elucidated the cellular mechanisms underlying the actions of these hydrogels in medical settings. In summary, this paper recapitulates valuable data gathered from the current literature, offering perspectives for further development and utilization of carboxymethyl hydrogels in various medical contexts.

Applications of polysaccharides in enzyme-triggered oral colon-specific drug delivery systems: A review

Enzyme-triggered oral colon-specific drug delivery system (EtOCDDS1) can withstand the harsh stomach and small intestine environments, releasing encapsulated drugs selectively in the colon in response to colonic microflora, exerting local or systematic therapeutic effects. EtOCDDS boasts high colon targetability, enhanced drug bioavailability, and reduced systemic side effects. Polysaccharides are extensively used in enzyme-triggered oral colon-specific drug delivery systems, and its colon targetability has been widely confirmed, as their properties meet the demand of EtOCDDS. Polysaccharides, known for their high safety and excellent biocompatibility, feature modifiable structures. Some remain undigested in the stomach and small intestine, whether in their natural state or after modifications, and are exclusively broken down by colon-resident microbiota. Such characteristics make them ideal materials for EtOCDDS. This article reviews the design principles of EtOCDDS as well as commonly used polysaccharides and their characteristics, modifications, applications and specific mechanism for colon targeting. The article concludes by summarizing the limitations and potential of ETOCDDS to stimulate the development of innovative design approaches.

O-carboxymethyl chitosan in biomedicine: A review

O-carboxymethyl chitosan (O-CMC) is a chitosan derivative produced through the substitution of hydroxyl (-OH) functional groups in glucosamine units with carboxymethyl (-CH2COOH) substituents, effectively addressing the inherent solubility issues of chitosan in aqueous solutions. O-CMC has garnered significant interest due to its enhanced solubility, elevated viscosity, minimal toxicity, and advantageous biocompatibility properties. Furthermore, O-CMC demonstrates antibacterial, antifungal, and antioxidant characteristics, rendering it a promising candidate for various biomedical uses such as wound healing, tissue engineering, anti-tumor therapies, biosensors, and bioimaging. Additionally, O-CMC is well-suited for the fabrication of nanoparticles, hydrogels, films, microcapsules, and tablets, offering opportunities for effective drug delivery systems. This review outlines the distinctive features of O-CMC, offers analyses of advancements and future potential based on current research, examines significant obstacles for clinical implementation, and foresees its ongoing significant impacts in the realm of biomedicine.

A multifunctional chitosan based porous membrane for pH-responsive antibacterial activity and promotion of infected wound healing

Unsatisfactory mechanical and antibacterial properties restricted the solo use of chitosan (CS) as a wound dressing. In this work, a novel CS/hydroxyapatite/ZIF-8 (CS/HAp/ZIF-8, CHZ-10) porous membrane was facilely constructed by in situ loading of ZIF-8 on CS/HAp. The advantages of the three compositions were rationally integrated, and the multifunctionality and practicality of this CS-based dressing were improved. HAp not only improved the mechanical strength and stability of CS, but also promoted cell proliferation and accelerated hemostasis with its released Ca2+. Meanwhile, ZIF-8 enhanced the antibacterial activity of CS by releasing antibacterial Zn2+ in a pH-responsive and sustainable manner, avoiding the bio-accumulation toxicity of heavy metals. Compared with CS/HAp and conventionally used gauze, CHZ-10 exhibited superior coagulation and hemolytic ability, as well as outstanding antibacterial activity against E. coli and S. aureus. Besides, both in vivo observation and histological evaluation demonstrated that CHZ-10 could not only effectively inhibit bacterial infection and reduce inflammation of the wound, but also promote its re-epithelialization, granulation, tissue formation and collagen fibre growth, leading to effectively enhanced wound-healing. This work provides a new method for the easy construction of multifunctional antibacterial dressings based on CS, showing promise for application in clinical wound care.

Microencapsulation of vitamins: A review and meta-analysis of coating materials, release and food fortification

Vitamins are responsible for providing biological properties to the human body; however, their instability under certain environmental conditions limits their utilization in the food industry. The objective was to conduct a systematic review on the use of biopolymers and lipid bases in microencapsulation processes, assessing their impact on the stability, controlled release, and viability of fortified foods with microencapsulated vitamins. The literature search was conducted between the years 2013-2023, gathering information from databases such as Scopus, PubMed, Web of Science and publishers including Taylor & Francis, Elsevier, Springer and MDPI; a total of 49 articles were compiled The results were classified according to the microencapsulation method, considering the following information: core, coating material, solvent, formulation, process conditions, particle size, efficiency, yield, bioavailability, bioaccessibility, in vitro release, correlation coefficient and references. It has been evidenced that gums are the most frequently employed coatings in the protection of vitamins (14.04%), followed by alginate (10.53%), modified chitosan (9.65%), whey protein (8.77%), lipid bases (8.77%), chitosan (7.89%), modified starch (7.89%), starch (7.02%), gelatin (6.14%), maltodextrin (5.26%), zein (3.51%), pectin (2.63%) and other materials (7.89%). The factors influencing the release of vitamins include pH, modification of the coating material and crosslinking agents; additionally, it was determined that the most fitting mathematical model for release values is Weibull, followed by Zero Order, Higuchi and Korsmeyer-Peppas; finally, foods commonly fortified with microencapsulated vitamins were described, with yogurt, bakery products and gummy candies being notable examples.

Chitosan-Derived Nanocarrier Polymers for Drug Delivery and pH-Controlled Release in Type 2 Diabetes Treatment

Diabetes, particularly Type 2 Diabetes Mellitus (T2DM), is a chronic metabolic disorder with high and increasing global prevalence, characterized by insulin resistance and inadequate insulin secretion. Despite advancements in novel drug delivery systems, widespread and systematic treatment of advanced glycation end products (AGEs) remains challenging due to issues like drug toxicity, low water solubility, and uncontrolled release. Thus, developing nanoplatforms with controlled release capabilities has become a major research focus. Due to its excellent biocompatibility and drug delivery properties, chitosan has attracted considerable attention as a typical biopolymer. In this study, we designed and synthesized an intelligent fluorescence-pH sensitive nanopolymer material using chitosan. We loaded drug 1 and chromium phthalocyanine (CrPc) into folic acid-conjugated carboxymethyl chitosan (FA-CMCS) nanocarriers, forming FA-CMCS@1-CrPc. Comprehensive characterization of FA-CMCS@1-CrPc was conducted using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), and gas adsorption analysis (BET). The results indicate that the nanomaterial was successfully synthesized and exhibits excellent specific surface area, biocompatibility, and fluorescence response. Further research revealed that FA-CMCS@1-CrPc not only achieved controlled drug release but also could regulate drug release by adjusting pH. Additionally, due to its strong fluorescence performance, the nanomaterial demonstrated higher detection sensitivity, especially for monitoring the release of 5% trace drugs. An in vitro model of insulin-resistant cells was established to evaluate the effects of the drug delivery system on glucose degradation and AGE-RAGE regulation, providing a foundation for the development of new T2DM drugs.

Biomimetic dentin remineralization using eggshell derived nanohydroxyapatite with and without carboxymethyl chitosan - An in vitro study

The objective of this study was to evaluate the synergistic effect of eggshell-derived nanohydroxyapatite (EnHA) and carboxymethyl chitosan (CMC) in remineralizing artificially induced dentinal lesions. EnHA and CMC were synthesized using simple chemical processes and characterized using FTIR, XRD, HRSEM-EDX, TEM, DLS and TGA/DTA analyses. A total of 64 pre-demineralized coronal dentin specimens were randomly subjected to following treatments (n = 16):artificial saliva (AS), EnHA, CMC, and EnHA-CMC, followed by pH cycling for 7 days. HRSEM-EDX, Vickers-indenter, and micro-Raman analyses were used to assess surface-topography, microhardness, and chemical analysis, respectively. All tested materials demonstrated non-cytotoxicity when assessed on hDPSCs using MTT assay. FTIR, XRD and thermal analyses confirmed the characteristics of both EnHA and CMC. EnHA showed irregular rod-shaped nanoparticles (30-70 nm) with the presence of Ca,P,Na, and Mg ions. Dentin treated with EnHA-CMC exhibited complete tubular occlusion and highest microhardness whereas the AS group revealed the least mineral deposits (p < 0.05). No significant differences were observed between EnHA and CMC groups (p > 0.05). In addition, molecular conformation analysis revealed peak intensities in collagen's polypeptide chains in dentin treated with CMC and EnHA-CMC, whereas other groups showed poor collagen stability. The results highlighted that EnHA-CMC aided in rapid and effective biomineralization, suggesting its potential as a therapeutic solution for treating dentin caries.

Development of bovine serum albumin-modified Fe3O4 embedded in porous α-ketoglutaric acid/chitosan (BSA/Fe3O4@KA/CS): A magnetically targeted hemostatic dressing for deep and irregular wounds

Severe bleeding from deep and irregular wounds poses a significant challenge in prehospital and surgical settings. To address this issue, we developed a novel chitosan-based hemostatic dressing with a magnetic targeting mechanism using Fe3O4, termed bovine serum albumin-modified Fe3O4 embedded in porous α-ketoglutaric acid/chitosan (BSA/Fe3O4@KA/CS). This dressing enhances hemostasis by magnetically guiding the agent to the wound site. In vitro, the hemostatic efficacy of BSA/Fe3O4@KA/CS is comparable to that of commercial chitosan (Celox™) and is not diminished by the modification. In vivo, BSA/Fe3O4@KA/CS demonstrated superior hemostatic performance and reduced blood loss compared to Celox™. The hemostatic mechanism of BSA/Fe3O4@KA/CS includes the concentration of solid blood components through water absorption, adherence to blood cells, and activation of the endogenous coagulation pathway. Magnetic field targeting is crucial in directing the dressing to deep hemorrhagic sites. Additionally, safety assessments have confirmed the biocompatibility and biodegradability of BSA/Fe3O4@KA/CS. In conclusion, we introduce a novel approach to modify chitosan using magnetic guidance for effective hemostasis, positioning BSA/Fe3O4@KA/CS as a promising candidate for managing various wounds.

Static and dynamic adsorption of arsenate from water by Fe3+ complexed with 3-aminopropyltriethoxysilane-modified carboxymethyl chitosan

Fe3+ complexed with 3-aminopropyltriethoxysilane (APTES)-modified carboxymethyl chitosan (CMC) named Fe-ACMC was synthesized by a one-step method at room temperature and pressure. The surface morphology and chemical structure of Fe-ACMC were characterized by SEM-EDS, XRD, BET, FT-IR, XPS, and ζ-potential. In batch adsorption, the optimum pH for arsenate [As(V)] adsorption onto Fe-ACMC was 3-9 with removal efficiency > 99%. The adsorption of As(V) could reach equilibrium within 25 min and the maximum adsorption capacity was 84.18 mg g-1. The pseudo-second-order model fitted well the kinetic data (R2 = 0.995), while the Freundlich model well described the adsorption isotherm of As(V) on Fe-ACMC (R2 = 0.979). The co-existing anions (NO3-, CO32-, and SO42-) exhibited a slight impact on the As(V) adsorption efficiency, whereas PO43- inhibited As(V) adsorption on Fe-ACMC. The real applicability of Fe-ACMC was achieved to remove ca. 10.0 mg L-1 of As(V) from natural waters to below 0.05 mg L-1. The regeneration and reuse of Fe-ACMC for As(V) adsorption were achieved by adding 0.2 mol L-1 HCl. The main adsorption mechanism of As(V) on Fe-ACMC was attributed to electrostatic attraction and inner-sphere complexation between -NH2···Fe3+ and As(V). In fixed-bed column adsorption, the Thomas model was the most suitable model to elucidate the dynamic adsorption behavior of As(V). The loading capacity of the Fe-ACMC packed column for As(V) was 47.04 mg g-1 at pH 7 with an initial concentration of 60 mg L-1, flow rate of 3 mL min-1, and bed height of 0.6 cm.

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.

The application of a 4D-printed chitosan-based stem cell carrier for the repair of corneal alkali burns

BACKGROUND

Corneal alkali burns can lead to ulceration, perforation, and even corneal blindness due to epithelial defects and extensive cell necrosis, resulting in poor healing outcomes. Previous studies have found that chitosan-based in situ hydrogel loaded with limbal epithelium stem cells (LESCs) has a certain reparative effect on corneal alkali burns. However, the inconsistent pore sizes of the carriers and low cell loading rates have resulted in suboptimal repair outcomes. In this study, 4D bioprinting technology was used to prepare a chitosan-based thermosensitive gel carrier (4D-CTH) with uniform pore size and adjustable shape to improve the transfer capacity of LESCs.

METHODS

Prepare solutions of chitosan acetate, carboxymethyl chitosan, and β-glycerophosphate sodium at specific concentrations, and mix them in certain proportions to create a pore-size uniform scaffold using 4D bioprinting technology. Extract and culture rat LESCs (rLESCs) in vitro, perform immunofluorescence experiments to observe the positivity rate of deltaNp63 cells for cell identification. Conduct a series of experiments to validate the cell compatibility of 4D-CTH, including CCK-8 assay to assess cell toxicity, scratch assay to evaluate the effect of 4D-CTH on rLESCs migration, and Calcein-AM/PI cell staining experiment to examine the impact of 4D-CTH on rLESCs proliferation and morphology. Establish a severe alkali burn model in rat corneas, transplant rLESCs onto the injured cornea using 4D-CTH, periodically observe corneal opacity and neovascularization using a slit lamp, and evaluate epithelial healing by fluorescein sodium staining. Assess the therapeutic effect 4D-CTH-loaded rLESCs on corneal alkali burn through histological evaluation of corneal tissue paraffin sections stained with hematoxylin and eosin, as well as immunofluorescence staining of frozen sections.

RESULTS

Using the 4D-CTH, rLESCs were transferred to the alkali burn wounds of rats. Compared with the traditional treatment group (chitosan in situ hydrogel encapsulating rLESCs), the 4D-CTH-rLESC group had significantly higher repair efficiency of corneal injury, such as lower corneal opacity score (1.2 ± 0.4472 vs 0.4 ± 0.5477, p < 0.05) and neovascularization score (5.5 ± 1.118 vs 2.6 ± 0.9618, p < 0.01), and significantly higher corneal epithelial wound healing rate (72.09 ± 3.568% vs 86.60 ± 5.004%, p < 0.01).

CONCLUSION

In summary, the corneas of the 4D-CTH-rLESC treatment group were similar to the normal corneas and had a complete corneal structure. These findings suggested that LESCs encapsulated by 4D-CTH significantly accelerated corneal wound healing after alkali burn and can be considered as a rapid and effective method for treating epithelial defects.

Chitosan-Based Biomaterial in Wound Healing: A Review

Wound healing is an evolving and intricate technique that is vital to the restoration of tissue integrity and function. Over the past few decades, chitosan a biopolymer derived from chitin, became known as an emerging biomaterial in the field of healing wounds due to its distinctive characteristics including biocompatibility, biodegradability, affinity to biomolecules, and wound-healing activity. This natural polymer exhibits excellent healing capabilities by accelerating the development of new skin cells, reducing inflammation, and preventing infections. Due to its distinct biochemical characteristics and innate antibacterial activity, chitosan has been extensively researched as an antibacterial wound dressing. Chronic wounds, such as diabetic ulcers and liver disease, are a growing medical problem. Chitosan-based biomaterials are a promising solution in the domain of wound care. The article analyzes the depth of chitosan-based biomaterials and their impact on wound healing and also the methods to enhance the advantages of chitosan by incorporating bioactive compounds. This literature review is aimed to improve the understanding and knowledge about biomaterials and their use in wound healing.

Chitosan-based promising scaffolds for the construction of tailored nanosystems against osteoporosis: Current status and future prospects

Despite advancements in therapeutic techniques, restoring bone tissue after damage remains a challenging task. Tissue engineering or targeted drug delivery solutions aim to meet the pressing clinical demand for treatment alternatives by creating substitute materials that imitate the structural and biological characteristics of healthy tissue. Polymers derived from natural sources typically exhibit enhanced biological compatibility and bioactivity when compared to manufactured polymers. Chitosan is a unique polysaccharide derived from chitin through deacetylation, offering biodegradability, biocompatibility, and antibacterial activity. Its cationic charge sets it apart from other polymers, making it a valuable resource for various applications. Modifications such as thiolation, alkylation, acetylation, or hydrophilic group incorporation can enhance chitosan's swelling behavior, cross-linking, adhesion, permeation, controllable drug release, enzyme inhibition, and antioxidative properties. Chitosan scaffolds possess considerable potential for utilization in several biological applications. An intriguing application is its use in the areas of drug distribution and bone tissue engineering. Due to their excellent biocompatibility and lack of toxicity, they are an optimal material for this particular usage. This article provides a comprehensive analysis of osteoporosis, including its pathophysiology, current treatment options, the utilization of natural polymers in disease management, and the potential use of chitosan scaffolds for drug delivery systems aimed at treating the condition.

Chitosan-Based Nanocarriers for Pulmonary and Intranasal Drug Delivery Systems: A Comprehensive Overview of their Applications

The optimization of respiratory health is important, and one avenue for achieving this is through the application of both Pulmonary Drug Delivery System (PDDS) and Intranasal Delivery (IND). PDDS offers immediate delivery of medication to the respiratory system, providing advantages, such as sustained regional drug concentration, tunable drug release, extended duration of action, and enhanced patient compliance. IND, renowned for its non-invasive nature and swift onset of action, presents a promising path for advancement. Modern PDDS and IND utilize various polymers, among which chitosan (CS) stands out. CS is a biocompatible and biodegradable polysaccharide with unique physicochemical properties, making it well-suited for medical and pharmaceutical applications. The multiple positively charged amino groups present in CS facilitate its interaction with negatively charged mucous membranes, allowing CS to adsorb easily onto the mucosal surface. In addition, CS-based nanocarriers have been an important topic of research. Polymeric Nanoparticles (NPs), liposomes, dendrimers, microspheres, nanoemulsions, Solid Lipid Nanoparticles (SLNs), carbon nanotubes, and modified effective targeting systems compete as important ways of increasing pulmonary drug delivery with chitosan. This review covers the latest findings on CS-based nanocarriers and their applications.

N-lauric-O-carboxymethyl chitosan: Synthesis, characterization and application as a pH-responsive carrier for curcumin particles

A pH-responsive amphiphilic chitosan derivative, N-lauric-O-carboxymethyl chitosan (LA-CMCh), is synthesized. Its molecular structures are characterized by FTIR, 1H NMR, and XRD methods. The influencing factors are investigated, including the amount of lauric acid (LA), carboxymethyl chitosan (CMCh), N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC), and N-hydroxysuccinimide (NHS), and their molar ratio, reaction time, and reaction temperature on the substitution. The degrees of substitution (DS) of the lauric groups on the -NH2 groups are calculated based on the integrated data of 1H NMR spectra. The optimum reaction condition is obtained as a reaction time of 6 h, a reaction temperature of 80 °C, and a molar ratio of lauric acid to O-carboxymethyl chitosan to N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride to N-hydroxysuccinimide of 1:3:4.5:4.5, respectively. The crystallinity and initial decomposition temperature of LA-CMCh decrease, but the maximum decomposition temperature increases. The crystallinity is reduced due to the introduction of LA and the degree of hydrogen bonding among LA-CMCh molecules. LA-CMCh could self-aggregate into particles, which size and critical aggregation concentration depend on the degree of substitution and medium pH. LA-CMCh aggregates could load curcumin up to 21.70 %, and continuously release curcumin for >200 min. LA-CMCh shows nontoxicity to fibroblast HFF-1 cells and good antibacterial activity against S. aureus and E. coli, indicating that it could be used as an oil-soluble-drug carrier.

Fabrication of affinity-based drug delivery systems based on electrospun chitosan sulfate/poly(vinyl alcohol) nanofibrous mats

Benign electrospinning of chitosan in aqueous medium is an open challenge mainly due to its insolubility in neutral pH and inter- and intramolecular hydrogen bonding interactions. Here, we developed a simple and widely-used methodology to improve the chitosan electrospinnability through the sulfation of chitosan and its further mixing with poly(vinyl alcohol) for the first time. The FTIR, 1H NMR and elemental analyses showed the successful sulfation of chitosan. Furthermore, the viscosity and electrical conductivity measurements revealed the high solubility of chitosan sulfate (CS) in aqueous media. In the next step, a uniform electrospun nanofibrous mat of CS/PVA was fabricated with a fiber diameter ranging from 90 to 340 nm. The crosslinked CS/PVA (50/50) nanofibrous mat as the optimum sample showed a swelling ratio of 290 ± 4 % and a high Young's modulus of 3.75 ± 0.10 GPa. Finally, malachite green (MG) as a cationic drug model was loaded into different samples of chitosan film, CS film, and CS/PVA (50/50) nanofibrous mat and its release behavior was studied. The results of these analyses revealed that the CS/PVA (50/50) nanofibrous mat can successfully load higher contents of the MG and also release it in a sustained manner.

Antimicrobial films fabricated with myricetin nanoparticles and chitosan derivation microgels for killing pathogenic bacteria in drinking water

Pathogenic bacteria in drinking water threaten human health and life. In the work, antimicrobial films composed of myricetin@tannic acid (My@TA) nanoparticles (NPs) and chitosan derivation microgels were developed to kill pathogenic bacteria in drinking water. Hydrophobic My was first made into water soluble My@TA NPs using a solvent exchange method with TA as stabilizer. Polymeric microgels of carboxymethyl chitosan (CMCS)/hydroxypropyltrimethyl ammonium chloride chitosan (HACC) were then fabricated with a blending method. CMCS&HACC/My@TA multilayer films were further deposited on the internal surface of PET bottles by using a layer-by-layer (LbL) assembly technique. The PET bottles coated with the films could effectively kill pathogenic bacteria in water such as S. aureus, E. coli, Staphylococcus epidermidis, Pseudomonas fluorescens, Listeria monocytogenes and methicillin resistant Staphylococcus aureus (MRSA). In addition, CMCS&HACC/My@TA films displayed good antioxidant activity, water resistance, and in vivo biocompatibility with heart, liver, spleen, lung and kidney organs. We believe that the container coated with CMCS&HACC/My@TA films can be applied to prevent microbial contamination of drinking water.

Biologically Derived Nanoarchitectonic Coatings for the Engineering of Hemostatic Needles

Bleeding after venipuncture could cause blood loss, hematoma, bruising, hemorrhagic shock, and even death. Herein, a hemostatic needle with antibacterial property is developed via coating of biologically derived carboxymethyl chitosan (CMCS) and Cirsium setosum extract (CsE). The rapid transition from films of the coatings to hydrogels under a wet environment provides an opportunity to detach the coatings from needles and subsequently seal the punctured site. The hydrogels do not significantly influence the healing process of the puncture site. After hemostasis, the coatings on hemostatic needles degrade in 72 h without inducing a systemic immune response. The composition of CMCS can inhibit bacteria of Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus by destroying the membrane of bacteria. The hemostatic needle with good hemostasis efficacy, antibacterial property, and safety is promising for the prevention of bleeding-associated complications in practical applications.

Review: chitosan-based biopolymers for anion-exchange membrane fuel cell application

Chitosan (CS)-based anion exchange membranes (AEMs) have gained significant attention in fuel cell applications owing to their numerous benefits, such as environmental friendliness, flexibility for structural alteration, and improved mechanical, thermal and chemical durability. This study aims to enhance the cell performance of CS-based AEMs by addressing key factors including mechanical stability, ionic conductivity, water absorption and expansion rate. While previous reviews have predominantly focused on CS as a proton-conducting membrane, the present mini-review highlights the advancements of CS-based AEMs. Furthermore, the study investigates the stability of cationic head groups grafted to CS through simulations. Understanding the chemical properties of CS, including the behaviour of grafted head groups, provides valuable insights into the membrane's overall stability and performance. Additionally, the study mentions the potential of modern cellulose membranes for alkaline environments as promising biopolymers. While the primary focus is on CS-based AEMs, the inclusion of cellulose membranes underscores the broader exploration of biopolymer materials for fuel cell applications.

Enhancing the metal ion binding characteristics and reversal of selectivity of crosslinked chitosan sorbents through functionalisation for targeted applications

In this study, we report optimised synthesis of N-carboxymethylated chitosan (CM-Cts) and its crosslinking to obtain, for the first time, glutaraldehyde crosslinked N-carboxymethylated chitosan (CM-Cts-Glu) as a metal ion sorbent. CM-Cts and CM-Cts-Glu were characterised using FTIR and solid state 13C NMR techniques. As compared to epichlorohydrin, glutaraldehyde was found to be better suited for efficient synthesis of the crosslinked functionalised sorbent. CM-Cts-Glu showed better metal ion uptake properties compared to the crosslinked chitosan (Cts-Glu). Metal ion removal by CM-Cts-Glu was studied in detail under different conditions such as different initial solution concentrations, pH, presence of complexants and competing ions. Further, sorption-desorption kinetics was studied and it was shown that complete desorption and multiple cycles of reuse without any loss in capacity was feasible. The maximum Co(II) uptake obtained for CM-Cts-Glu was found to be 265 μmol/g, while for Cts-Glu it was 10 μmol/g. Metal ion sorption by CM-Cts-Glu was found to be through chelation by the carboxylic acid functional groups present over the chitosan backbone. Utility of the CM-Cts-Glu under complexing decontamination formulations used in nuclear industry was ascertained. While Cts-Glu generally preferred iron over cobalt under complexing conditions, it was shown that the selectivity was reversed in favour of Co(II) in the functionalised sorbent, CM-Cts-Glu. N-carboxylation followed by crosslinking with glutaraldehyde was found to be a feasible approach for the generation of superior chitosan-based sorbents.

Recent advances in carboxymethyl chitosan-based materials for biomedical applications

Chitosan (CS) and its derivatives have been applied extensively in the biomedical field owing to advantageous characteristics including biodegradability, biocompatibility, antibacterial activity and adhesive properties. The low solubility of CS at physiological pH limits its use in systems requiring higher dissolving ability and a suitable drug release rate. Besides, CS can result in fast drug release because of its high swelling degree and rapid water absorption in aqueous media. As a water-soluble derivative of CS, carboxymethyl chitosan (CMC) has certain improved properties, rendering it a more suitable candidate for wound healing, drug delivery and tissue engineering applications. This review will focus on the antibacterial, anticancer and antitumor, antioxidant and antifungal bioactivities of CMC and the most recently described applications of CMC in wound healing, drug delivery, tissue engineering, bioimaging and cosmetics.

Potential Oral Anticancer Therapeutic Agents of Hexahydrocurcumin-Encapsulated Chitosan Nanoparticles against MDA-MB-231 Breast Cancer Cells

Hexahydrocurcumin-encapsulated chitosan nanoparticles (HHC-CS-NPs) were formulated by oil-in-water emulsification and ionotropic gelation and optimized using the Box-Behnken design. The particle size, zeta potential, and encapsulation efficiency of the optimized HHC-CS-NPs were 256 ± 14 nm, 27.3 ± 0.7 mV, and 90.6 ± 1.7%, respectively. The TEM analysis showed a spherical shape and a dense structure with a narrow size distribution. The FT-IR analysis indicated no chemical interaction between the excipients and the drugs in the nanoparticles, but the existence of the drugs was molecularly dispersed in the nanoparticle matrices. The drug release profile showed a preliminary burst release followed by a sustained release under simulated gastrointestinal (GI) and physiological conditions. A stability study suggested that the HHC-CS-NPs were stable under UV light, simulated GI, and body fluids. The in vitro bioaccessibility and bioavailability of the HHC-CS-NPs were 2.2 and 6.1 times higher than those of the HHC solution, respectively. The in vitro evaluation of the antioxidant, anti-inflammatory, and cytotoxic effects of the optimized HHC-CS-NPs demonstrated that the CS-NPs significantly improved the biological activities of HHC in radical scavenging, hemolysis protection activity, anti-protein denaturation, and cytotoxicity against MDA-MB-231 breast cancer cells. Western blot analysis showed that the apoptotic protein expression of Bax, cytochrome C, caspase-3, and caspase-9, were significantly up-regulated, whereas the anti-apoptotic protein Bcl-2 expression was down-regulated in the HHC-CS-NP-treated cells. Our findings suggest that the optimized HHC-CS-NPs can be further developed as an efficient oral treatment for breast cancer.

Advanced Hydrogels Combined with Silver and Gold Nanoparticles against Antimicrobial Resistance

The development of multidrug-resistant (MDR) microorganisms has increased dramatically in the last decade as a natural consequence of the misuse and overuse of antimicrobials. The World Health Organization (WHO) recognizes that this is one of the top ten global public health threats facing humanity today, demanding urgent multisectoral action. The UK government foresees that bacterial antimicrobial resistance (AMR) could kill 10 million people per year by 2050 worldwide. In this sense, metallic nanoparticles (NPs) have emerged as promising alternatives due to their outstanding antibacterial and antibiofilm properties. The efficient delivery of the NPs is also a matter of concern, and recent studies have demonstrated that hydrogels present an excellent ability to perform this task. The porous hydrogel structure with a high-water retention capability is a convenient host for the incorporation of the metallic nanoparticles, providing an efficient path to deliver the NPs properly reducing bacterial infections caused by MDR pathogenic microorganisms. This article reviews the most recent investigations on the characteristics, applications, advantages, and limitations of hydrogels combined with metallic NPs for treating MDR bacteria. The mechanisms of action and the antibiofilm activity of the NPs incorporated into hydrogels are also described. Finally, this contribution intends to fill some gaps in nanomedicine and serve as a guide for the development of advanced medical products.

Mediation of synergistic chemotherapy and gene therapy via nanoparticles based on chitosan and ionic polysaccharides

Nanoparticles (NPs)-based on various ionic polysaccharides, including chitosan, hyaluronic acid, and alginate have been frequently summarized for controlled release applications, however, most of the published reviews, to our knowledge, focused on the delivery of a single therapeutic agent. A comprehensive summarization of the co-delivery of multiple therapeutic agents by the ionic polysaccharides-based NPs, especially on the optimization of the polysaccharide structure for overcoming various extracellular and intracellular barriers toward maximized synergistic effects, to our knowledge, has been rarely explored so far. For this purpose, the strategies used for overcoming various extracellular and intracellular barriers in vivo were introduced first to provide guidance for the rational design of ionic polysaccharides-based NPs with desired features, including long-term circulation, enhanced cellular internalization, controllable drug/gene release, endosomal escape and improved nucleus localization. Next, four preparation strategies were summarized including three physical methods of polyelectrolyte complexation, ionic crosslinking, and self-assembly and a chemical conjugation approach. The challenges and future trends of this rapidly developing field were finally discussed in the concluding remarks. The important guidelines on the rational design of ionic polysaccharides-based NPs for maximized synergistic efficiency drawn in this review will promote the future generation and clinical translation of polysaccharides-based NPs for cancer therapy.

Application of the Composite Fibers Based on Chitosan and Chitin Nanofibrils in Cosmetology

Chitosan and composite fibers containing chitin nanofibrils have been developed for use in cosmetology. The tensile strength of the chitosan multifilaments is 160.6 ± 19.0 MPa, and of the composite multifilaments containing chitin, nanofibrils are 198.0 ± 18.4 MPa. Chitin nanofibrils introduced into the chitosan solution contribute to the creation of a new spatial arrangement of chitosan chains and their denser packing. The studies carried out by optical, scanning electron, and atomic force microscopy has shown that the serum, consisting of a mixture of lactic acid and sodium lactate, contains extended oriented structures—“liquid filaments”. It has been also shown that a mixture of serum and composite fibers based on chitosan and chitin nanofibrils has mucoadhesive, film-forming properties. The introduction of composite fibers containing chitin nanofibrils into the serum promotes the reinforcing effect of liquid filaments, the lifting effect of the film. The obtained composition can be used in cosmetology as a skin care product.

Biodegradable disulfide crosslinked chitosan/stearic acid nanoparticles for dual drug delivery for colorectal cancer

Herein, redox responsive chitosan/stearic acid nanoparticles (CSSA NPs) (≈200 nm) are developed for dual drug delivery. These degradable nanoparticles are prepared based on disulfide (SS) crosslinking chemistry avoiding the use of any external crosslinking agent. CSSA NPs are further loaded with both DOX (hydrophilic) and curcumin (hydrophobic) drugs with ≈86 % and ≈82 % encapsulation efficiency respectively. This approach of combining anticancer therapeutics having different mode of anticancer action allows to develop systems for cancer therapy with enhanced efficacy. In vitro drug release experiments clearly exhibit the low leakage of drug under physiological conditions while ≈98 % DOX and ≈96 % curcumin is released after 136 h under GSH reducing conditions. The cytotoxicity experiments against HCT116 cells demonstrate higher cytotoxicity of dual drug loaded CSSA NPs. In vivo biodistribution experiments with c57bl/6j mice confirms the retention of CSSA NPs in the colon area up to 24 h exhibiting their potential for colorectal cancer therapy.

Development and Evaluation of Amlodipine-Polymer Nanocomposites Using Response Surface Methodology

Introduction. Polymer nanoparticles are a key tool to deliver drugs to specific sites and to increase drug bioavailability. Aim. This research aims to use poly amide-disulfide nanoparticles as drug delivery systems. Method. Amlodipine (Amlop) was used as a model, forming Amlop-polymer nanocomposites. In this work, we investigated the effect of independent variables (polymer, Fe3+, Al3+, and pH) on the dependent variables (loading efficiency (%LE), zeta potential, and particle size). Nanocomposites were prepared by an inotropic method. Nanocomposites were characterized by powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), and a release study. Results. From the XRD data, the Amlop-polymer nanocomposite shows semi crystallinity. In addition, the disappearance of drug peaks indicates that the drug was incorporated between the polymer molecules and was amorphous in behavior. The FTIR for the nanocomposite shows the functional group of the drug, which indicates the incorporation of Amlop into the nanocomposite. From FE-SEM, the results showed that our nanocomposites have an average particle size of approximately 130 nm. The release of amlodipine from the Amlop-polymer nanocomposite was found to be controlled, with approximately 85% within approximately 24 hours. Conclusion. The amide-disulfide polymer nanoparticles are promising carriers for different types of drugs.

Chitosan-based scaffolds as drug delivery systems in bone tissue engineering

The bone tissue engineering approach for treating large bone defects becomes necessary when the tissue damage surpasses the threshold of the inherent regenerative ability of the human body. A myriad of natural biodegradable polymers and scaffold fabrication techniques have emerged in the last decade. Chitosan (CS) is especially attractive as a bone scaffold material to support cell attachment and proliferation and mineralization of the bone matrix. The primary amino groups in CS are responsible for properties such as controlled drug release, mucoadhesion, in situ gelation, and transfection. CS-based smart drug delivery scaffolds that respond to environmental stimuli have been reported to have a localized sustained delivery of drugs in the large bone defect area. This review outlines the recent advances in the fabrication of CS-based scaffolds as a pharmaceutical carrier to deliver drugs such as antibiotics, growth factors, nucleic acids, and phenolic compounds for bone tissue regeneration.

Carboxymethyl chitosan prolongs adenovirus-mediated expression of IL-10 and ameliorates hepatic fibrosis in a mouse model

Effective and safe liver-directed gene therapy has great promise in treating a broad range of liver diseases. While adenoviral (Ad) vectors have been widely used for efficacious in vivo gene delivery, their translational utilities are severely limited due to the short duration of transgene expression and solicitation of host immune response. Used as a promising polymeric vehicle for drug release and nucleic acid delivery, carboxymethyl chitosan (CMC) is biocompatible, biodegradable, anti-microbial, inexpensive, and easy accessible. Here, by exploiting its biocompatibility, controlled release capability and anti-inflammatory activity, we investigated whether CMC can overcome the shortcomings of Ad-mediated gene delivery, hence improving the prospect of Ad applications in gene therapy. We demonstrated that in the presence of optimal concentrations of CMC, Ad-mediated transgene expression lasted up to 50 days after subcutaneous injection, and at least 7 days after intrahepatic injection. Histologic evaluation and immunohistochemical analysis revealed that CMC effectively alleviated Ad-induced host immune response. In our proof-of-principle experiment using the CCl4-induced experimental mouse model of chronic liver damage, we demonstrated that repeated intrahepatic administrations of Ad-IL10 mixed with CMC effectively mitigated the development of hepatic fibrosis. Collectively, these results indicate that CMC can improve the prospect of Ad-mediated gene therapy by diminishing the host immune response while allowing readministration and sustained transgene expression.

O-carboxymethyl chitosan/gelatin/silver-copper hydroxyapatite composite films with enhanced antibacterial and wound healing properties

Wound dressing composite films of O-carboxymethyl chitosan (OCMC) and gelatin were prepared and mixed with hydroxyapatite (HA) composited with Silver (Ag) and Copper (Cu) at different concentrations. The chemical, thermal, morphological, and biological properties of the composite films were studied. The analysis by FTIR confirmed the presence of interactions between gelatin and OCMC, and at the same time, the polymer matrix interactions with Ag-Cu/HA complex. The inclusion of nanoparticle to the composite was associated with an improvement of the thermal stability, morphological roughness, a 9–12% more hydrophobic behavior (composite C1, C5, and C8), increase in antibacterial activity from 23.2 to 33.1% for gram negative bacteria and from 37.28 to 40.59% for gram positive bacteria, and with a cell viability greater than 100% for 24 and 72 h. The films obtained can serve as a wound healing dressing and regenerating biomaterial.

Chitosan and Chitooligosaccharide: The Promising Non-Plant-Derived Prebiotics with Multiple Biological Activities

Biodegradable chitin is the second-most abundant natural polysaccharide, widely existing in the exoskeletons of crabs, shrimps, insects, and the cell walls of fungi. Chitosan and chitooligosaccharide (COS, also named chitosan oligosaccharide) are the two most important deacetylated derivatives of chitin. Compared with chitin, chitosan and COS not only have more satisfactory physicochemical properties but also exhibit additional biological activities, which cause them to be widely applied in the fields of food, medicine, and agriculture. Additionally, due to their significant ability to improve gut microbiota, chitosan and COS are deemed prospective prebiotics. Here, we introduced the production, physicochemical properties, applications, and pharmacokinetic characteristics of chitosan and COS. Furthermore, we summarized the latest research on their antioxidant, anti-inflammatory, and antimicrobial activities. Research progress on the prebiotic functions of chitosan and COS is particularly reviewed. We creatively analyzed and discussed the mechanisms and correlations underlying these activities of chitosan and COS and their physicochemical properties. Our work enriched people's understanding of these non-plant-derived prebiotics. Based on this review, the future directions of research on chitosan and COS are explored. Collectively, optimizing the production technology of chitin derivatives and enriching understanding of their biological functions will shed more light on their capability to improve human health.

Application Progress of Modified Chitosan and Its Composite Biomaterials for Bone Tissue Engineering

In recent years, bone tissue engineering (BTE), as a multidisciplinary field, has shown considerable promise in replacing traditional treatment modalities (i.e., autografts, allografts, and xenografts). Since bone is such a complex and dynamic structure, the construction of bone tissue composite materials has become an attractive strategy to guide bone growth and regeneration. Chitosan and its derivatives have been promising vehicles for BTE owing to their unique physical and chemical properties. With intrinsic physicochemical characteristics and closeness to the extracellular matrix of bones, chitosan-based composite scaffolds have been proved to be a promising candidate for providing successful bone regeneration and defect repair capacity. Advances in chitosan-based scaffolds for BTE have produced efficient and efficacious bio-properties via material structural design and different modifications. Efforts have been put into the modification of chitosan to overcome its limitations, including insolubility in water, faster depolymerization in the body, and blood incompatibility. Herein, we discuss the various modification methods of chitosan that expand its fields of application, which would pave the way for future applied research in biomedical innovation and regenerative medicine.

Recent advances of chitosan-based polymers in biomedical applications and environmental protection

Interest in polymer-based biomaterials such as chitosan and its modifications and also the methods of their application in various fields of science is uninterruptedly growing. Owing to unique physicochemical, biological, ecological, physiological properties, such as biocompatibility, biodegradability, stability in the natural environment, non-toxicity, high biological activity, economic affordability, chelating of metal ions, high sorption properties, chitosan is used in various biomedical and industrial processes. The reactivity of the amino and hydroxyl groups in the structure makes it more interesting for diverse applications in drug delivery, tissue engineering, wound healing, regenerative medicine, blood anticoagulation and bone, tendon or blood vessel engineering, dentistry, biotechnology, biosensing, cosmetics, water treatment, agriculture. Taking into account the current situation in the world with COVID-19 and other viruses, chitosan is also active in the form of a vaccine system, it can deliver antibodies to the nasal mucosa and load gene drugs that prevent or disrupt the replication of viral DNA/RNA, and deliver them to infected cells. The presented article is an overview of the nowaday state of the application of chitosan, based on literature of recent years, showing importance of fundamental and applied studies aimed to expand application of chitosan-based polymers in many fields of science.

Chitosan Nanoparticle-Based System: A New Insight into the Promising Controlled Release System for Lung Cancer Treatment

Lung cancer has been recognized as one of the most often diagnosed and perhaps most lethal cancer diseases worldwide. Conventional chemotherapy for lung cancer-related diseases has bumped into various limitations and challenges, including non-targeted drug delivery, short drug retention period, low therapeutic efficacy, and multidrug resistance (MDR). Chitosan (CS), a natural polymer derived from deacetylation of chitin, and comprised of arbitrarily distributed β-(1-4)-linked d-glucosamine (deacetylated unit) and N-acetyl-d-glucosamine (acetylated unit) that exhibits magnificent characteristics, including being mucoadhesive, biodegradable, and biocompatible, has emerged as an essential element for the development of a nano-particulate delivery vehicle. Additionally, the flexibility of CS structure due to the free protonable amino groups in the CS backbone has made it easy for the modification and functionalization of CS to be developed into a nanoparticle system with high adaptability in lung cancer treatment. In this review, the current state of chitosan nanoparticle (CNP) systems, including the advantages, challenges, and opportunities, will be discussed, followed by drug release mechanisms and mathematical kinetic models. Subsequently, various modification routes of CNP for improved and enhanced therapeutic efficacy, as well as other restrictions of conventional drug administration for lung cancer treatment, are covered.