Development of chitosan/hyaluronic acid hydrogel scaffolds via enzymatic reaction for cartilage tissue engineering

Biomimetic hydrogels have been developed in the fabrication of multifunctional microenvironments for cell culture and tissue fabrication. In the current study, different compositions of hyaluronic acid (HA) and chitosan (CH) derivatives with opposite charges were fabricated. To increase the interaction between these components phenol moieties were substituted on the backbone of HA (HAPH) and CH (CHPH) via carbodiimide-mediated condensation reaction, and then subjected to enzymatic cross-linking in the presence of horseradish peroxidase to create a stable hybrid microenvironment for cell encapsulation and tissue engineering. The gelation time, enzymatic degradation, and water contact angle of hydrogels reduced with increasing HAPH content. The rheological and mechanical properties of the hydrogels showed that a moderate concentration of HAPH can have the best results in the hydrogel structure. Hydrogel morphology altered depending on the amount of incorporated HA in CH precursor hydrogel solution and their pore size distribution decreased with increasing HAPH. The cellular studies showed proper cell viability and proliferation on optimum blend hydrogel surface compared with the neat hydrogels. Furthermore, the hybrid hydrogels demonstrated good characteristics for the expression of cartilage tissue markers and a higher propensity of MSCs to differentiate into cartilage-like cells compared to the control samples. Overall, the results suggest the optimum hybrid hydrogel can provide a superior biological microenvironment for chondrocytes in three-dimensional cartilage tissue engineering.