Abstract

Biocompatible reduced graphene oxide (rGO) could deliver drugs for synergistically stimulating stem cells directed differentiation with influences on specific cellular activities. Here, we prepared a biodegradable gelatin reduced graphene oxide ([email protected]) to evaluate its functions in promoting rat adipose derived mesenchymal stem cells (ADSCs) chondrogenic differentiation through delivering kartogenin (KGN) into the stem cell efficiently. The optimum KGN concentration (approximately 1 μM) that promoted the proliferation and chondrogenic differentiation of ADSCs was clarified by a series of experiments, including immunofluorescent (IF) staining (Sox-9, Col II), alcian blue (Ab) staining, toluidine blue (Tb) staining and real-time quantitative PCR analysis of the chondrogenic markers. Meanwhile, the biocompatibility of[email protected]was evaluated to clearly define the nonhazardous concentration range, and the drug loading and releasing properties of[email protected]were tested with KGN for its further application in inducing ADSCs chondrogenic differentiation. Furthermore, the mechanism of[email protected]entering ADSCs was investigated by the different inhibitors that are involved in the endocytosis of the nanocarrier, and the degradation of the[email protected]in ADSCs was observed by transmission electron microscopy (TEM). The synergistic promoting effect of[email protected]nanocarrier on ADSCs chondrogenesis with KGN was also studied by the IF, Ab, Tb stainings and PCR analysis of the chondrogenic markers. Finally, the intracellular Reactive Oxygen Species (ROS) and autophagy induced by KGN/[email protected]complex composites were tested in details for clarification on the correlation between the autophagy and chondrogenesis in ADSCs induced by[email protected]All the results show that[email protected]as a biocompatible nanocarrier can deliver KGN into AD