Bioinspired mineral-polymeric hybrid hyaluronic acid/poly (?-glutamic acid) hydrogels as tunable scaffolds for stem cells differentiation

Aiming at the difficulty of integrated repair of osteochondral tissue, we designed a hybrid hydrogel scaffold that mimicked the microenvironment of osteochondral niches. Besides, the nano-hydroxyapatite (nHAP) was specially introduced into the hydrogel for its natural ability to promote bone regeneration. The hydrogel also exhibited good toughness (7500 KJ/m3), strength (1000 kPa), viscoelasticity, and in vitro cell experiments showed that hydrogels had quite good cytocompatibility (near 100 % viability). The results of the threedimensional (3D) cell culture also proved that the survival rate of the cells in the hybrid hydrogels doped with nHAP and dispersion were the highest. In vitro RT-qPCR experiments proved that after being cultured in hydrogel scaffolds doped with nHAP, bone mesenchymal stem cells (BMSCs) could express genes related to osteoblasts and chondrocytes. As a result, this hydrogel provides a general for developing alternative materials applicable for stem cells differentiation and even osteochondral tissue engineering.