The effect of chitosan molecular weight and its content on the mechanical, microstructural and biological parameters of biomaterial intended for cartilage tissue regeneration

Chitosan is widely used in the synthesis of modern artificial constructs, but its varying molecular weight (Mw) and deacetylation degree make selection challenging. This study examines how chitosan's Mw and concentration affect the mechanical, microstructural, and biological properties of potential cartilage scaffolds. The results revealed that samples with higher amounts of chitosan content (2 and 3 %) exhibited mechanical parameters similar to human cartilage tissue. The obtained results also suggested that using a higher chitosan concentration (2 %) was appropriate for enhancing the compressive strength and stiffness of the potential cartilage scaffold. Raman microspectroscopy showed chemical interactions between chitosan, curdlan, and hydroxyapatite in the scaffolds, confirming the formation of hybrid structures. Additionally, produced biomaterials were characterized by a porous microstructure with the wide range of pore diameters (7-500 μm). An increase in both chitosan concentration and Mw was found to reduce pore diameters, with the average pore size ranging from 37 to 200 μm. All scaffolds were non-toxic to human bone marrow derived mesenchymal stem cells (hMSCs) and human adipose tissue-derived mesenchymal stem cells (ADSCs). Among all tested scaffolds, the most promising biomaterial, with the highest biomedical potential, was synthesized using 2 % of medium Mw (153.9 kDa) chitosan.