This review considers articles on the formation of hydrogels based on chitosan as well as succinylated and quaternized chitosan derivatives. They are synthesized using low toxicity reagents, under ordinary conditions (low production costs). Chitosan derivatives are soluble in an extended range of pH values and characterized by mucoadhesiveness, bioavailability and biodegradability, which extends the potential of their medical applications. One of the most important properties of chitosan and its derivatives is the ability to form hydrogels. Depending on the nature of the bonds that occur during formation, hydrogels are divided into chemically or physically crosslinked, or a mixture of the two. Chemically crosslinked gels have covalent bonds, while physically crosslinked gels are formed by noncovalent interactions, for example, ionic. Mixed hydrogels have both types of crosslinking.

Despite continuous progress in the development of advanced dressing materials, there is a constant need for dressings used in an environment of infected and hard-to-heal wounds. Dressings that meet the above described requirements are products based on chitin and its derivatives. Chitosan and chitin derivative dressings are now becoming a very effective medical device in healing hard-to-heal wounds, as well as in the control of severely bleeding wounds. Chitosan and chitin are particularly valuable raw materials that accelerate wound healing processes, and they are also biocompatible and antibacterial. Dressings made of butyric-acetic chitin copolyester are intended for treating wounds of various aetiologies, including chronic wounds in which the healing process is disturbed by concomitant diseases. Materials based on chitosan are also widely used in the area of heavily bleeding and chronic wounds.

Three-dimensional (3D) biomaterial manufacturing strategies show an extraordinary driving force for the development of innovative solutions in the biomedical sector, including drug delivery systems, disease modelling and tissue and organ engineering. Due to its remarkable and promising biological and structural properties, chitosan has been widely studied for decades in several potential applications in the biomedical field. However, tools in the form of 3D printers have created new possibilities for the production of chitosan models, implants and scaffolds for cell cultures that are much more precise than existing ones. The article presents current achievements related to the possibility of using chitosan to create new materials for 3D printing in the form of chitosan bioinks, filaments, resins and powders dedicated for bioprinting, fused deposition modelling, stereolithography/digital light processing and selective laser sintering methods, respectively.

Polysaccharides are polymers of long chains of monosaccharide units linked via glycosidic bonds. Starch, cellulose, chitin and their derivatives, such as chitosan, are examples of polysaccharides. Chitin is the second most common natural polysaccharide in the world (after cellulose). Chitin and chitosan are amino polysaccharides. Chitosan is often obtained by chemical, or sometimes enzymatic, deacetylation of chitin. These compounds are increasingly being modified to the nanometric scale. New engineering nanomaterials show better chemical, biological, mechanical, thermal, electrical and sorption properties than the primary materials. In this paper, the methods of chitosan nanomaterials synthesis and their adsorption properties of metal cations are discussed. As it is shown, the selected chitosan nanomaterials have promising adsorption properties of metal cations.

Chitosan and its derivatives are renewable biopolymers characterized by high biocompatibility; therefore, they are harmless to humans and allow immune tolerance and improved hydrophilicity. Moreover, chitosan has been the most studied of all polysaccharides used in biomedical applications during the last decade. Combinations of chitosan and porphyrinoid compounds in hybrid materials have revealed many potential applications for biomedical sciences. The main advantage of such materials is an increase in the solubility of porphyrinoids in body fluids and therefore greater release of singlet oxygen to the treated tissue. Chitosan-based drug delivery systems can improve the targeting of porphyrinoids and their release at predetermined locations and finally achieve desired therapeutic effects with minimal side effects. Hence, porphyrinoid-chitosan materials can be applied in drug delivery systems, cancer theranostics and magnetic resonance imaging. The combination of chitosan and porphyrinoids also appears useful in the healing and repairing of damaged organs, tissue engineering, regenerative medicine, as well as dressing materials. Huge benefits are related to the treatment of wounds, which has been presented for self-healing hydrogels based on chitosan and porphyrinoids. Furthermore, the chitosan/porphyrinoid combinations have revealed enormous benefits for antimicrobial photodynamic therapy.

Membranes were prepared using three chitosans with different molecular weights and degrees of deacetylation. The influence of chitosan features on membrane physicochemical properties, i.e. degree of swelling, contact angle and tensile strength, as well as membrane separation properties in ethanol dehydration by the vapour permeation process are discussed. The conducted experiments showed that an increase in the chitosan molecular weight led to an increase in the membrane surface contact angle concomitant with a decrease in the material selectivity coefficient. On the other hand, an increase in the chitosan degree of deacetylation caused a reduction in ethanol and improved the water permeate flux. There was greater selectivity in the test process for membranes prepared from chitosan with the lowest molecular weight.

Textile products enriched with natural substances, e.g. hyaluronic acid, plant hydrolates, collagen and chitosan, may find wide application in cosmetics because of increasing consumer interest in natural products. Furthermore, in view of global environmental pollution, products that are produced through biochemical changes as a result of composting are sought. This makes it possible to enter such designed cosmetic products into the scheme of the currently desired circular economy. Compostable textiles are an ecological alternative to product backlogs and polluting the environment in the form of post-consumer waste. Therefore, this research work developed a technology for applying natural substances on a biodegradable polyester fibrous substrate. This study developed the optimal composition of a mixture consisting of natural substances with properties applicable to the cosmetic industry, for applications such as cosmetic masks to improve the appearance of the skin. The composition of active substances that have beneficial effects on the skin, e.g. moisturizing, regenerating, antibacterial and caring, was determined. The mixture was effectively applied on a spunbound nonwoven substrate of made from aliphatic-aromatic copolyester by impregnation. The employed polymer degraded in a compost environment and its modifiers additionally supported this process. The unique composition of the applied coating layer consisted of a mixture of sodium hyaluronate, collagen, bitter orange blossom hydrolate (Neroli) and chitosan lactate. The coated nonwoven fabric was subjected to physical, mechanical, microbiological as well as chemical purity and structural tests (Fourier transform infrared spectroscopy and scanning electron microscopy) and degree of degradation in a compost environment was assessed on the basis of its weight loss.

This article presents data on the effect of processing avocado fruit on the dynamics of physiological and biochemical processes during low-temperature storage. The aim was to explore the effect of processing Fuerte avocado fruit with ‘Agrokhit’, ‘KHAN-8’ and ‘Extrasol-90’ preparations on the dynamics of physiological and biochemical processes during storage. The effectiveness of the preparations on the change in physiological and biochemical processes during storage of avocado fruit was evaluated by the release of carbon dioxide during their respiration, by the activity of terminal oxidases and the hydrolysis of pectin substances. The respiration rate, the activity of terminal oxidases – catalase, peroxidase, phenol oxidase, tyrosinase – and the kinetics of the hydrolysis of protopectin and pectin depended on the type of preparation and the duration of storage. Processing avocado fruit with the examined preparations did not violate metabolism, which was regulated by change in the activity of terminal oxidases of the plant cells, a reduced respiration rate and the rate of hydrolysis of protopectin and pectin. As a result, there was an increase in the storage period and fruit ripening. To slow down the physiological and biochemical processes – to increase the duration of ripening and storage of avocado fruit – it is recommended that they be treated with chitin derivatives Agrokhit and KHAN-8.

Plastic is undoubtedly the most convenient type of packaging, but at the same time it is not ecologically friendly. The widespread use of packaging materials all over the world makes us think more and more about the harm of plastic to the environment and humans. It does not decompose in natural conditions and accumulates in huge quantities, because it is mostly used as a single-use packaging. Therefore, the development of environmentally friendly biodegradable edible films and coatings is relevant. Edible food packaging is an important step in food production and one of the innovative directions of food packaging development. This article presents materials on the development of the formulation and manufacturing technology of new composite materials based on sodium alginate and chitosan for the production of edible coatings and films. The results of the physical, chemical and bactericidal properties of these materials are presented.

Nanocrystalline hydroxyapatite (n-HAp), which has low crystallinity, has attracted great attention due to its similarity to the inorganic part of human bone. Therefore, many studies have focused on creating new formulations combining n-HAp with some biopolymers, such as chitosan, in order to imitate biological bone tissue. The importance of chitosan and its derivatives in biomedical applications has grown significantly in the last three decades due to its biodegradability and renewable source. Besides, chitosan and its derivatives present excellent biocompatibility and biofunctionality, which make them promising materials in bone tissue engineering. In the present study, the chitosan was, first, extracted from the shell of the freshwater crab species Potamon algeriense following demineralization, deproteinization, decolouration (raw chitin) and deacetylation (chitosan) steps. Then, a novel composite based on n-HAp and extracted chitosan (CTS) with varying chitosan contents, from 5% to 20% (w/w), was synthesized and characterized for potential application in tissue regeneration. The obtained composites were characterized using X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetric analysis. The precipitated n-HAp/CTS nanocomposites similar to natural bone are promising composites for bone tissue engineering applications.

Gynecological scientific journals report that traditional therapeutic regimens used to treat vaginal inflammation recommended by global treatment centers and health organizations are not producing satisfactory results. Insufficient duration of the drug’s contact with vaginal mucosa does not provide adequate pH conditioning the physiological biocenosis of the organ. The conducted research and obtained positive results encourage further research possibilities in the field of optimization of pharmaceutical properties of the examined gynecological preparations. Assuming the above assumptions tested impact of polyvinylpyrrolidone K-15, polyvinylpyrrolidone K-30 and polyvinylpyrrolidone K-90 in the properties of the globules. The study was prepared formulations with different pH and rheological properties. The device simulating the conditions in the vagina, studied the adhesion and movement of the gel on the mucosa of the organ. Globules after application of the apparatus simulates the natural conditions in the gel passes and cover the surface. A wide range of pH of the gels allows the selection of the optimum formulation.

A crucial technological task that must be solved in the production of sausage products is to stabilize the product’s red colour. In this paper, we propose a scheme to determine the most significant parameters of the quality of dry-cured sausages by their colour characteristics. For this purpose, colour digital images were obtained, which were further processed using two classical colour representation systems: RGB and xyY. We monitored changes in pH and the ratio of water to dry matter in meat products. These crucial sausage properties were changed by introducing chitin-containing supplements into their recipes, which allowed us to solve two tasks simultaneously. The first comprises, as already mentioned, changing the properties of sausages to obtain correlations with colour characteristics. The second is to enrich meat products with chitin complex for preventive purposes to improve people’s nutrition. The construction of correlation dependencies using each coordinate separately in two colour systems showed that each system (RGB and xyY) has one colour channel with a maximum correlation coefficient. This is due to the colour features of sausages, which can be represented to the greatest extent with the help of only one colour coordinate in the considered colour representation systems (RGB and xyY). Using these colour coordinates will allow one to achieve maximum measurement accuracy. Thus, two tasks are being solved: the enrichment of food with dietary supplement and the development of a method to control their content.

Termites are insects that can damage buildings, paper and plants. Termites are controlled by using termiticides (chemicals). Besides polluting the environment, termiticides may have harmful effects to organisms, including humans, and destroy metal. The use of chemicals will be environmentally and economically profitless. A joint effort to utilize biodegradable material will help to reduce the negative impacts of termiticides. One of the materials that can use to control termites is chitosan. The purpose of this study was to determine the termiticidal activity of chitosan on paper against termites. The termiticidal activity test followed method JIS K 1571 2004. The resistance of paper to termite damage was determined by calculating the percentage of weight loss and termite mortality rate. The following concentrations of chitosan in acetic acid were used: 0.5%, 1%, 1.5% and 2%. The test result showed that weight loss percentages were 20.49%, 16.37%, 15.77% and 10.80%, respectively. On the other hand, the weight loss percentage of paper without chitosan was 32.69%, which shows that termites do not favour chitosan used in the paper. The activity of termites was successfully inhibited when the concentration of chitosan was increased, and the percentage of paper weight loss decreased from 10.80% to 20.49%. Paper without chitosan had a termite mortality rate of 18.3%; The addition of chitosan increased termite mortality to 28.2%–30.4%. The percentage of weight loss decreased with increasing termite mortality. The termite mortality rate show that chitosan is nontoxic and potential as biotermiticide for paper.

In this work, we report a stepwise formation method of a chitosan/sodium alginate polyelectrolyte complex (CS/SA PEC) membrane. The proposed method aiming at the utilization of the ultrasonic treatment of chitosan and sodium alginate solution allowed us to obtain a highly homogeneous hybrid membrane for electrochemical usage. The CS/SA PEC membrane saturated in a 2 M Li₂SO₄ aqueous solution was used in electrochemical double layer capacitor (EDLC) cell to study its applicability as quasi-solid electrolyte. Electrochemical characteristic of EDLC cells was determined by electrochemical impedance spectroscopy, cyclic voltammetry and galvanostatic charge/discharge methods. The results show that the EDLC cell with CS/SA PEC quasi-solid electrolyte exhibit a comparable specific capacitance (102 F g⁻¹ for 0–0.8 V) to CS reference (100 F g⁻¹ for 0–0.8 V) and commercial separator (99 F g⁻¹ for 0–0.8 V) cells. Thus, the CS/SA PEC membrane can be considered as an alternative modification for chitosan-based materials of electrochemical purpose.

Damage to the nervous system, in particular spinal cord injuries, is a burden for the patient and is usually the cause of irreversible disability. The progress observed in the last decade in the fields of biology, biomaterial engineering and neurosurgery has created new treatment solutions while preventing further neurodegenerative processes. The most important research is focused on the implementation of polymer structures in clinical practice, especially chitosan hydrogels, which are the scaffolds for regenerating axons. This article presents a new generation of biomaterials that have the ability to gel in response to temperature changes; they are intended for injectable scaffolds for nerve cell cultures. Two types of hydrogels were prepared based on chitosan lactate and chitosan chloride using uridine 5’-monophosphate disodium salt. The structure of the systems was observed under a scanning electron microscope and examined using Fourier transform infrared spectroscopy. In addition, thermal properties were tested using differential scanning calorimetry.

The aim of this paper was to conduct preliminary instrumental tests to determine the possibility of injection applications for thermosensitive chitosan systems, including injection needles and application conditions. Among the many biomedical and pharmaceutical applications of chitosan, the minimally invasive thermosensitive scaffolds that form in vivo are an interesting solution. Despite many studies on colloidal chitosan systems undergoing sol-gel phase transition, almost no studies have examined their injectability. It has been stated that the use of acetic acid as a solvent reduces the forces needed for injection. Moreover, the key impact of injection temperature was determined. Storing the medium at room temperature before the injectability test led to a decrease in the value of forces needed for injection. The obtained results are discussed based on the change of the rheological properties of the chitosan hydrogels.

Hydrogel films composed of chitosan and agar or chitosan, agar and honey/bee pollen were prepared; they could be used as active wound dressings. During this study, various types of gel films were prepared using chitosan with different molecular weights and ratios of the two biopolymers. In addition, compositions with different amounts of honey or bee pollen were obtained. The selected samples were characterized by determining typical properties that are important for wound dressings. The best two-component films had a chitosan to agar weight ratio of 2:1. From among the examined tri-component films, the 2:1:0.5 weight ratio of chitosan, agar and 50 wt% honey solution was the best composition.

The properties of one-component and mixed monolayers of phospholipid 1,2–dipalmitoyl–sn–glycero–3–phosphocholine (DPPC) and polypeptide cyclosporine A (CsA) on the chitosan subphase were studied. DPPC is the main component that builds biological membranes, and CsA is an immunosuppressive drug typically used in medicine to prevent transplant rejections. The stability and reversibility of compression of these insoluble monolayers in the presence of chitosan (Ch) were examined by the Langmuir technique. The stability of the monolayers depended on the monolayer composition as well as the initial pressure (π₀) of the relaxation process. The smallest changes in the relative pressure as a function of time were obtained at π₀ = 10 mN/m. During compression–decompression cycles, the effect of chitosan was noticeable and caused isotherm shifts.