The application of biopolymers in tissue engineering is of a great interest due to of their inherent properties such as cell adhesion, biodegradation, bioavailability, and viscoelasticity. In this study, we synthesized cryogels based on biopolymers of gelatin, chitosan, and chondroitin sulfate by cryopolymerization and studied the effect of chondroitin sulfate on changing the physicochemical properties of cryogels such as pore size, pore volume, density, gel fraction, and biodegradation. A macroporous surface of the synthesized polymers has been investigated by SEM. The glass transition temperatures of the crosslinked cryogels, determined by the DSC method, were higher compared to that of the non-crosslinked cryogel used as a reference. The results of the MTT test showed that aqueous extracts of the prepared cryogels had no toxic effect on rat adipose-derived mesenchymal stem cells. The research in this area is of great importance and provides new insights into novel, effective methods for obtaining biopolymers that can be used as carriers of cells.

Cryogels are a unique macroporous material for tissue engineering. In this work, we study the effect of hyaluronic acid on the physicochemical properties of cryogel as well as on the proliferation of a 3D model of mesenchymal stem cells. The functional groups of the synthesized cryogels were identified using Fourier transform infrared spectroscopy. With an increase in the content of hyaluronic acid in the composition of the cryogel, an increase in porosity, gel content and swelling behavior was observed. As the hyaluronic acid content increased, the average pore size increased and more open pores were formed. Degradation studies have shown that all cryogels were resistant to PBS solution for 8 weeks. Cytotoxicity assays demonstrated no toxic effect on viability of rat adipose-derived mesenchymal stem cells (ADMSCs) cultured on cryogels. ADMSC spheroids were proliferated on scaffolds and showed the ability of the cryogels to orient cell differentiation into chondrogenic lineage even in the absence of inductive agents. Thus, our results demonstrate an effective resemblance to extracellular matrix structures specific to cartilage-like microenvironments by cryogels and their further perspective application as potential biomaterials.

Cryopolymers are a class of 3D structural polymers, which are widely used in tissue engineering. Using cryopolymerization technology, physical cross-linked macroporous cryogels based on gelatin and chitosan were synthesized at –12 ºC, –30 ºC and –70 ºC for application as carriers for cell cultures. The presence of functional groups was investigated by IR spectroscopy. The effect of temperature on physicochemical properties such as pore volume, density, gel fraction and biodegradation of cryogels was studied. The results obtained showed that the pore volume (up to 87.6 %) and the gel fraction (up to 80 %) increased, and the density (0.078 %) and pore sizes of cryogels decreased as the temperature decreased from –12 ºC to –70 ºC. The study of biodegradation showed that, polymers had a more degradable property in relation to saline solution with an increase in the cryopolymerization temperature. The results of electron microscopy showed the porous morphology of the surfaces of the synthesized cryogels. The average pore size varied from 150 to 300 μm. The toxicity test showed that aqueous extracts from cryogels did not have a highly toxic effect on MSCs in the adipose rats tissue, since the cell viability was 55–75 %

Using autologous mesenchymal stem cells, 12 patients with pathology of the knee joint cartilage were successfully treated. At the first stage, all patients underwent traditional arthroscopic knee debridement, during which a sample of the synovium was taken, after which the sample was transferred to the National Center for Biotechnology for the cultivation of mesenchymal stem cells. After culturing a therapeutically effective number of cells, the material was punctured into the cavity of the affected joint. Evaluation of the results demonstrated a positive effect of the method on the course of the disease.