For the first time, anisotropic hydrogel material with a highly oriented structure was obtained by the chemical reaction of polymer-analogous transformation of chitosan glycolate—chitosan base using triethanolamine (TEA) as a neutralizing reagent. Tangential bands or concentric rings, depending on the reaction conditions, represent the structural anisotropy of the hydrogel. The formation kinetics and the ratio of the positions of these periodic structures are described by the Liesegang regularities. Detailed information about the bands is given (formation time, coordinate, width, height, and formation rate). The supramolecular ordering anisotropy of the resulting material was evaluated both by the number of Liesegang bands (up to 16) and by the average values of the TEA diffusion coefficient ((15–153) × 10⁻¹⁰ and (4–33) × 10⁻¹⁰ m²/s), corresponding to the initial and final phase of the experiment, respectively. The minimum chitosan concentration required to form a spatial gel network and, accordingly, a layered anisotropic structure was estimated as 1.5 g/dL. Morphological features of the structural anisotropic ordering of chitosan Liesegang structures are visualized by scanning electron microscopy. The hemocompatibility of the material obtained was tested, and its high sorption–desorption properties were evaluated using the example of loading–release of cholecalciferol (loading degree ~35–45%, 100% desorption within 25–28 h), which was observed for a hydrophobic substance inside a chitosan-based material for the first time.

The paper considers the formative processes of chiral nano- and microparticles in solutions of D-aminoglucan chitosan (CS) in L- and D-aspartic acid (AspA) by means of the counterionic condensation of components and the stabilization of particles by a polysiloxane shell. The effect of the L- and D-enantiomers of AspA on the structure, size, shape, and zeta potential of nano(micro)particles was studied using IR spectroscopy, dynamic light scattering, and electron and optical microscopy. It was found that chiral particles of CS·L-AspA and CS·D-AspA are non-toxic, hemo- and biocompatible, and exhibit high growth-stimulating activity in the test plants, with the best effect observed for homochiral D-glucan–D-AspA particles.

The majority of studies of fungal utilization of chitosan are associated with the production of a specific enzyme, chitosanase, which catalyzes the hydrolytic cleavage of the macrochain. In our opinion, the development of approaches to obtaining materials with new functional properties based on non-destructive chitosan transformation by living organisms and their enzyme systems is promising. This study was conducted using a wide range of classical and modern methods of microbiology, biochemistry, and physical chemistry. The ability of the ascomycete Fusarium oxysporum Schltdl. to modify films of chitosan with average-viscosity molecular weights of 200, 450, and 530 kDa was discovered. F. oxysporum was shown to use chitosan as the sole source of carbon/energy and actively overgrew films without deformations and signs of integrity loss. Scanning electron microscopy (SEM) recorded an increase in the porosity of film substrates. An analysis of the FTIR spectra revealed the occurrence of oxidation processes and crosslinking of macrochains without breaking β-(1,4)-glycosidic bonds. After F. oxysporum growth, the resistance of the films to mechanical dispersion and the degree of ordering of the polymer structure increased, while their solubility in the acetate buffer with pH 4.4 and sorption capacity for Fe²⁺ and Cu²⁺ decreased. Elemental analysis revealed a decrease in the nitrogen content in chitosan, which may indicate its inclusion into the fungal metabolism. The film transformation was accompanied by the production of extracellular hydrolase (different from chitosanase) and peroxidase, as well as biosurfactants. The results obtained indicate a specific mechanism of aminopolysaccharide transformation by F. oxysporum. Although the biochemical mechanisms of action remain to be analyzed in detail, the results obtained create new ways of using fungi and show the potential for the use of Fusarium and/or its extracellular enzymes for the formation of chitosan-containing materials with the required range of functional properties and qualities for biotechnological applications.