Chitosan is derived from chitin through deacetylation. Extensive research has focused on extracting chitin from affordable sources. Commercially available chitosan products are primarily derived from α-chitin, extracted from crustacean exoskeletons, which are rich in inorganic material. In contrast, β-chitosan is derived from β-chitin sourced from cephalopods such as squid pens with negligible mineral content. This natural purity of β-chitin sources eliminates the need for aggressive chemical demineralisation, making the production process more environmentally friendly. Despite promising attributes, β-chitosan has received limited attention in the scientific literature compared to α-chitosan. A comprehensive literature search was conducted to address this knowledge gap by providing an extensive review to elucidate the structural and functional distinctions of β-chitosan. The article evaluates its biomedical efficacy, highlighting antibacterial activity against multidrug-resistant pathogens in preclinical models. The antioxidant, antitumor, and anticoagulant properties are also discussed. The findings demonstrate the potential of β-chitosan as a versatile, high-performance, and sustainable biopolymer for advanced biomedical applications.

Chitinolytic enzymes catalyze the hydrolysis of chitin, the second polysaccharide in nature and the main component of the cell wall of fungi and the cuticle of arthropods. Besides a growing attention in medicine, environmental management, and the food industry, these enzymes are increasingly considered for applications in crop protection based on their active role in the control of fungal pathogens and insect pests. Although many fungal biocontrol agents are known to share this potential, species in the genus Talaromyces stand out for their widespread occurrence as components of the plant mycobiome, as both endophytes and rhizosphere associates. An overview of the current knowledge on chitin degrading enzymes of these fungi, their properties, and potential applications in biocontrol is offered in this paper.

Chronic wounds represent a rapidly growing challenge for global healthcare. Bacterial infections remain one of the most important factors contributing to the persistence of chronic wounds. In this context, chitosan and honey have regained prominence as promising natural supportive therapy agents. This article provides a comprehensive narrative review aimed at determining the effects of chitosan- and honey-based hydrogel dressings on the wound-healing process. The Scopus, Web of Science, and Medline (PubMed) databases were searched. The review included 19 basic and preclinical studies that met the established inclusion criteria. No clinical studies were found in this area of research. It was found that chitosan and honey, as components of hydrogel systems, exhibit combined antibacterial and wound-healing properties for the treatment of chronic wounds, including burns and ulcers. They exhibited high antibacterial activity against, among others, Staphylococcus aureus and Escherichia coli strains. Preclinical studies demonstrated favourable biocompatibility and low cytotoxicity toward skin cells.

This review article provides an overview of recent advances in chitosan-based hydrogels, highlighting the motivation for their development in the context of the transition to sustainable polymeric materials and the limitations associated with synthetic polymers. The review integrates the major areas of application of chitosan hydrogels, with a focus on biomedicine and pharmaceuticals (wound dressings, drug delivery platforms, tissue engineering matrices, haemostatic and antimicrobial systems), but also on emerging uses in the food industry (active/smart biodegradable packaging, edible coatings and nutrient delivery systems), agriculture (controlled delivery of nutrients/agrochemicals and soil conditioning), environmental protection (pollutant adsorption, heavy metal sensing, and solar desalination), aquaculture and electronics/bioelectronics (flexible sensors, bioelectronic interfaces, electrolytes and energy storage components). In addition, transdisciplinary applications in forensics (fingerprint visualisation and explosives detection) and aeronautics/aerospace (CO₂ capture, lightweight multifunctional materials for electromagnetic/thermal/acoustic protection) are discussed. Overall, the paper highlights the structure-property-function relationship of chitosan hydrogels and outlines research directions for optimising mechanical performance, degradation control and integration into advanced applications.

Chitosan-biosurfactant (CS-BS) systems represent an emerging class of hybrid bio-based materials with applications in environmental, biomedical, and agricultural fields. Despite extensive research on each component individually, their combined behaviour remains poorly understood, particularly regarding structure-function relationships. This review analyses the physicochemical interactions between chitosan and biosurfactants, focusing on electrostatic attraction, hydrophobic association, and interfacial activity. These interactions influence colloidal stability, delivery efficiency, and biological performance. Most CS-BS systems function as co-formulated hybrids rather than well-defined supramolecular complexes, although evidence of structured assemblies is emerging. The combination enhances antimicrobial activity, pollutant removal, and plant growth responses, with delivery-driven synergy identified as a key mechanism. However, limited structural characterisation and a lack of systematic parameter studies remain major challenges for rational design and scalable implementation.

Chitosan, a naturally derived cationic polysaccharide obtained through the partial deacetylation of chitin, has emerged as one of the most versatile biopolymers in food science. Owing to its biodegradability, biocompatibility, non-toxicity, and multifunctional biological activities, chitosan has found increasing application in the development of functional foods. Beyond its traditional role as a food preservative or coating material, chitosan is now widely studied as a technological and bioactive ingredient that can improve nutritional value, the bioavailability of functional compounds, gut health, and metabolic outcomes. This review focuses on its use in the formulation of functional foods. Special emphasis is placed on emerging food technologies, including encapsulation systems, probiotic and nutraceutical delivery, nano- and micro-structured foods, and sustainable processing strategies. Current challenges, regulatory aspects, and future perspectives for chitosan-based functional foods are also discussed.

Chitosan is increasingly effective in biomedical applications, especially as a wound-healing material. The above-mentioned effectiveness is due to its interesting biological properties and effect on human tissues. In wound healing, chitosan initiates recovery during the haemostasis stage, primarily through charge-mediated blood coagulation. Advancement to the next stages (such as the inflammatory, proliferative, and remodelling phases) depends solely on the successful and timely process of blood coagulation. Chitosan materials, such as films, nanofibers, and sponges, are expanding their applications in wound healing. Chitosan wound dressings were used to promote blood coagulation. They also led to support for the reduction of pro-inflammatory cytokine levels. Chitosan wound dressings were also effective in the proliferation and remodelling phase. In short, the objective of this study was to probe the potential of chitosan materials in terms of their use for wound healing over the past few years.

Chitosan-based materials are widely investigated as sustainable adsorbents for environmental remediation due to their biodegradability, abundance, and functional versatility. This review summarises recent advances (2015–2025) in the use of chitosan and its derivatives for the removal of organic and inorganic pollutants from aqueous systems. The correlation of material structure, modification strategies, and removal efficiency are discussed, focusing on adsorption, chelation, and flocculation mechanisms. Special attention is given to hybrid and bio-integrated systems that enhance treatment efficiency through synergistic effects. Key challenges, such as limited stability, reduced performance in complex matrices, and scalability barriers, are critically evaluated. Regeneration, reusability, and life-cycle considerations are also addressed. The findings highlight the need for more application-oriented and system-level methods in future research by highlighting both the promise and present limits of chitosan-based materials. The findings indicate that chitosan-based materials demonstrate both potential and existing limitations. Future investigations should concentrate on application- and system-level approaches.

In recent years, the polymer nanocomposites containing carbon nanotubes have been the subject of intense research. Chitosan-based systems are particularly promising due to the unique biological properties of this polysaccharide. This article presents the results of research on thermosensitive chitosan hydrogels containing single-walled carbon nanotubes. Biomaterials were prepared from chitosan lactate and chitosan chloride solutions using β-glycerol phosphate disodium salt pentahydrate as the cross-linking agent. A preliminary characterisation of the developed systems was performed. The nanocomposite hydrogels were analysed using Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Additionally, the cytotoxicity of the biomaterials against normal human BJ fibroblasts was assessed using the resazurin assay. The studies suggest that chitosan hydrogels containing carbon nanotubes may be promising solutions for biomedical applications.

Chitosan/poly(vinyl alcohol)/gelatin (CHS/PVA/GEL) hydrogels represent attractive two-dimensional (2D) biomaterial interfaces for directing stem cell behaviour in vitro. In this study, a CHS/PVA/GEL hydrogel was fabricated via solvent casting and rendered suitable for biological application through steam sterilisation (autoclaving). Physicochemical properties were evaluated by assessing uniformity, swelling capacity, and 21-day gravimetric stability in differentiation-relevant media. Biological performance was examined using human dental pulp stromal cells (hDPSCs), including verification of mesenchymal cell identity, cytocompatibility testing using extract-based MTT and LIVE/DEAD assays, together with direct-contact LIVE/DEAD assessment, and adhesion analysis. hDPSCs were subsequently differentiated into insulin-producing cells using a three-stage induction protocol over a 15-day differentiation workflow. Morphological changes, dithizone staining, and glucose-stimulated insulin secretion were used to assess differentiation. The hydrogel demonstrated cytocompatibility and supported cell adhesion. At the same time, differentiation yielded robust glucose responsiveness, with insulin secretion increasing from 627.4 μUI/mL per 1·10⁵ cells (3.3 mM glucose) to 4121.3 μUI/mL per 1·10⁵ cells (16.7 mM glucose), corresponding to an approximately 6.6-fold increase. These findings highlight the CHS/PVA/GEL hydrogel as a stable planar substrate that enables strong functional outcomes.

Heavy metal contamination of water remains a major environmental problem. This study compares the efficiency and selectivity of chitosan (CTS), pectin (PCT), and sodium alginate (ALG) hydrogel beads prepared via coagulation for the removal of Cu²⁺, Ni²⁺, and Co²⁺ from aqueous solutions at concentrations of 10, 50, and 100 mg/L. CTS showed the highest selectivity for Cu²⁺, achieving a capacity of 25.3 mg/g at 100 mg/L. PCT was most effective at higher concentrations, with adsorption capacities of 61.8, 25.9 and 20.4 mg/g for Cu²⁺, Ni²⁺, and Co²⁺ ions, respectively, whereas ALG exhibited greater ion removal from solutions of low metal concentrations. The study demonstrates that biopolymer-based hydrogels, particularly chitosan, hold strong potential for future water treatment and critical metal hydrometallurgy, aligning with the concept of urban mining.

This work aimed to investigate the electrostriction effect of two types of chitosan-zinc oxide films (CS-ZnO): non-neutralised - obtained by mixing CS and ZnO in acetic acid, and neutralised - films immersed in a NaOH solution. The X-ray, SEM, FTIR, AFM, weight, polarisation, and dielectric spectroscopy measurements indicate that these two films have different structures. In non-neutralised films, the chelation effect is observed due to the Zn²⁺ ions formed from ZnO under acidic conditions, causing an increase in the CS chain's dimension. In neutralised films, Zn²⁺ ions precipitate as nanoparticles (NPs). The difference in the structure is the reason for the difference in electrostrictive properties, a variation in the orientation of polymer chains in an electric field. Furthermore, the electrostriction coefficient M₃₃ obtained for neutralised films with ZnO nanoparticles (5.8·10^-1 m²/V²) is similar to or higher than that for poly(vinylidene fluoride)(PVDF)-based nanocomposites. CS-ZnO NP nanocomposite films are a promising option for biomedical applications.

Chitin-based filament yarns have great potential for use in biomedical and technical textiles. However, their processing and applicability are severely limited by poor solubility and inefficient solvent removal, restricting scalable manufacturing. This study investigates the development and scale-up of a wet spinning process for chitin yarns using the ionic liquid 1-ethyl-3-methylimidazolium propionate (EMIMOPr). Solvent removal during monofilament spinning was investigated using Fourier-transform infrared spectroscopy and thermogravimetric analysis to examine its dependence on filament diameter, coagulation temperature, and residence time. The results demonstrated that solvent removal is governed by mass transport processes, with residual solvent potentially persisting in the filament core under laboratory-scale conditions. Based on these insights, multifilament spinning on a pilot scale was successfully implemented, enabling efficient solvent removal during coagulation and washing stages. The resulting yarns exhibited homogeneous morphology and consistent textile-mechanical properties. This process provides a promising platform for the large-scale production of chitin filament yarns for advanced biomedical and technical applications.

The paper presents thermodynamic studies on enzymatic chitosan deacetylation based on the action of intracellular chitin deacetylase (EC 3.5.1.41) from Absidia orchidis vel coerulea. Based on those studies, the entropy and enthalpy of formation of the enzyme-substrate complex (ES; ∆H° = 81.386 kJ/mol, ∆S° = 220.73 J/(mol·K)) as well as product formation (P+E; ∆H^# = 75.15 kJ/mol, ∆S^# = 78.13 J/(mol·K)) were determined. Based on their values, the Gibbs free energy for each step was calculated. It was shown that neither the formation of the enzyme-substrate complex (ES) nor the formation of the product (P) is spontaneous in the investigated range of temperatures (35–50 °C). Possible reasons for the lack of spontaneity and for the comparison with the chemical process were discussed in the paper.

Mucor is a genus of fungi belonging to the Mucorales, the most important order of zygospore-forming fungi. Mucor species are attracting growing interest due to their distinctive features, which make them excellent models for genetic studies, and also due to their wide industrial applications. They are a source of lipids, pigments, biosurfactants, and numerous enzymes, including proteases, lipases, cellulases, chitinases, and chitosanases. However, information regarding the isolation of intracellular chitosanolytic and chitinolytic enzymes from different Mucor species remains limited, and species-specific requirements for enzyme extraction have not been sufficiently investigated. In this context, the aim of this study was to develop a method for extracting intracellular proteins produced by Mucor racemosus CH52 and Mucor hiemalis CH80 and to confirm their activity in chitosan and chitin hydrolysis. Detergent lysis (Triton X-100, 0.5% w/v) was found to be the most effective method for isolating these enzymes from M. racemosus CH52 cells. In the case of the second strain, the best results were obtained by freezing and grinding biomass, combined with lysis using detergent (Triton X-100, 0.5% w/v). These methods enabled the production of cell-free extracts with high protein content and chitosanase and chitinase activities. The results demonstrated species-dependent differences in enzyme recovery and indicated the importance of developing tailored extraction strategies for individual Mucor species.

Reducing sulfur dioxide (SO₂) while maintaining clarity and compositional stability remains a key challenge in white winemaking. This study evaluated fungal chitosan (CHIT) derived from Aspergillus niger as an alternative fining/stabilising agent for ‘Solaris’ (Vitis vinifera L.) white wine, compared with sodium bentonite (BENT), under two free-SO₂ regimes. After fermentation, wines were subjected to one of three treatments: no fining (NF/CTRL), bentonite, or chitosan, followed by SO₂ adjustment at 30–35 mg/L (SO_{2_std}) or 15–18 mg/L (SO_{2_low}), cold stabilisation, and bottle storage. Across variants, pH remained stable, whereas acetic acid concentration increased during storage, reaching the highest value in NF/CTRL-SO_{2_low}. Both fining agents markedly improved clarity. Bentonite caused the greatest reduction in total polyphenols, whereas chitosan-treated wines retained higher levels, particularly CHIT-SO_{2_std}. Chitosan was also associated with more favourable SO₂ retention under reduced dosing. Overall, fungal chitosan provided effective clarification, better preservation of total polyphenols than bentonite, and more favourable SO₂ retention, supporting its potential use in reduced-SO₂ white wine production.

This study evaluated the effects of fungal-derived chitosan (CHIT) and bentonite (BENT), applied under standard and reduced SO₂ regimes, on total copper and iron concentrations, protein stability, and the post-storage trained-panel sensory profile of ‘Solaris’ white wine across successive processing stages and after 60 days of storage. The experimental design included fining treatments, determination of Cu and Fe concentrations, assessment of protein stability, and sensory evaluation after storage. Chitosan provided the most consistent reduction in both Cu and Fe and was associated with a more favourable trained-panel sensory profile after storage, while also achieving protein stability under the applied heat-test criterion. Bentonite delivered the greatest safety margin for protein stabilisation and the lowest final turbidity; however, under reduced SO₂, it was associated with stronger panel-perceived oxidative character and aldehydic notes/browning after storage. Overall, the findings indicate that fining-agent selection is a key determinant of SO₂-reduction strategies for white wine production, although longer storage trials, combined with direct oxidative-marker analysis, are needed to confirm long-term oxidative and aroma stability.

Silver nanoparticles (AgNPs) stabilised by chitosan were synthesised via high-frequency ultrasound (620 kHz). The effects of pH (3–4) and the AgNO₃-to-chitosan molar ratio on nanoparticle formation, size, and colloidal stability were systematically evaluated. Acoustic cavitation generated highly reactive radical species, enabling efficient reduction of Ag⁺ to Ag⁰ without external reducing agents. UV-Vis spectroscopy confirmed nanoparticle formation, revealing surface plasmon resonance (SPR) bands at 405–410 nm (pH 3) and 420–425 nm (pH 4), indicating metal core diameters of 35–50 nm and pronounced pH-dependent structural variations. Dynamic light scattering showed hydrodynamic diameters of 100–250 nm. Notably, systems prepared at pH 3 exhibited a higher ζ-potential (~ +45 mV) and enhanced colloidal stability compared to those prepared at pH 4. These findings highlight high-frequency sonication as a clean and effective route for the additive-free synthesis of chitosan-stabilised AgNPs, with pH-driven polymer conformation playing a key role in controlling nanoparticle size and long-term stability.

Micropropagation of habitat-specialised species requires protocols that support shoot multiplication while maintaining plantlet quality. This study evaluated how cytokinins and selected low molecular weight chitosan fractions modify in vitro shoot growth and leaf colour of Dorycnium germanicum. Nodal explants were cultured on Murashige and Skoog medium supplemented with BAP or zeatin, or with chitosan fractions (CH_3.33kDa or CH_8kDa) applied at 0.5–2.0 mg/L. The highest number of newly formed shoots was observed with BAP at 1.0 mg/L, whereas 2.0 mg/L promoted shoot elongation but resulted in fewer new shoots. The response to chitosan depended mainly on the tested fraction, with concentration-associated differences within each fraction. CH_8kDa, particularly at 1.0 mg/L supported shoot elongation, while CH_3.33kDa reduced shoot length and shifted CIE L*a*b* parameters away from the control profile. Overall, chitosan should be considered a supportive additive rather than a substitute for cytokinin-based shoot multiplication in preliminary conservation-oriented micropropagation of D. germanicum.

Microplastic contamination in water is a global problem, and its removal via membrane separation is considered one of the best solutions. Polymers traditionally used pose a threat if becoming the source of this exact pollutant. Chitosan was investigated for the production of microfiltration membranes potentially dedicated to water filtration in a dead-end regime. Two variants of phase inversion, coupled with neutralisation of the chitosan salt, were tested. Mechanical strength, surface wettability, morphology, and the separation efficiency of polyvinyl chloride microplastics were investigated. Membranes produced by precipitation from the concentrated solution proved to be suitable for the filtration application, contrary to those made as dried films produced with porogenic agents, with even >99% overall separation efficiency.

Elevated concentrations of lead and copper in the natural environment, primarily due to polymetallic ore processing, underscore the urgent need for advanced remediation strategies. The chemical similarity between these metals complicates their selective separation during water treatment. Chitosan-based adsorbents, which are both biodegradable and environmentally benign, offer a promising approach. In this study, a derivative of the 4-(2-pyridylazo)resorcinol (PAR) was synthesised and used in a sustainable mechanochemical process to modify chitosan. The modified material was characterised by ¹³C NMR and FTIR spectroscopy, and its adsorption properties were evaluated using ICP-AES. The PAR-derivative-modified chitosan exhibited high adsorption efficiency for lead ions (95.4%) and lower efficiency for copper ions (38.3%). These findings indicate that chitosan-based materials can be effective for heavy metal adsorption removal and possess significant potential for the selective separation of Pb(II) from Cu(II).