Controllable Construction of Biomimetic Chitosan-based Hydrogels and Their Effects on Biological Behavior of Pluripotent Stem Cells

Biomimetic chitosan hydrogels (CS-GNPs)with controllable physical and chemical properties for inducing periodontal tissue regeneration were prepared by performing a nucleophilic substitution reaction on the ester group of the natural protein crosslinker genipine (GNP)with polyglucine (1-4)-2-amino-beta-D glucose (chitosan,CS)as the matrix under acidic conditions. The structure and morphology of the materials were characterized,and the mechanical properties,porosity,swelling rate,and degradation rate of the material were detected. The cytotoxicities of the materials were evaluated by the viability detection of mice fibroblasts (L-929)in vitro. The effects of the materials on the biological behavior of pluripotent stem cells were analyzed by observing the proliferation rate of periodontal ligament stem cells (hPDLSCs)and detecting mRNA expression levels of periodontal ligament-related genes PLAP-1,COL1,SCX and POSTN by qPCR. The experimental results showed that CS-GNP with different physicochemical characteristics could be obtained by changing the ratio of GNP. The mechanical signals of the materials affected the biological behaviors of pluripotent stem cells and changing the elastic modulus of the materials could regulate the extension area and proliferation rates of stem cells. When the material ' s modulus of elasticity was (46. 02 +/- 15. 7)kPa,which was close to the normal periodontal ligament extracellular matrix,the differentiation of hPDLSCs could be induced to the direction of the periodontal ligament. The results verified that the physical signals of the stem cell microenvironment could regulate the fate and differentiation of cells,and the simulation of natural extracellular matrix hardness could greatly regulate the directional differentiation of pluripotent stem cells, providing feasible model materials and systems for analyzing and characterizing the influence of the cell microenvironment on stem cell behavior.