Induction of Osteogenic Differentiation of Human Adipose-Derived Stem Cells by a Novel Self-Supporting Graphene Hydrogel Film and the Possible Underlying Mechanism

Graphene and its derivatives have received increasing attention from scientists in the field of biomedical sciences because of their unique physical properties, which are responsible for their interesting biological functions. With a range of extraordinary properties such as high surface area, high mechanical strength, and ease of functionalization, graphene is considered highly promising for application in bone tissue engineering. Here, we examined the effect of using a self-supporting graphene hydrogel (SGH) film to induce the osteogenic differentiation of human adipose-derived stem cells (hADSCs). In comparison to conventional graphene and carbon fiber films, the SGH film had higher mechanical strength and flexibility. Moreover, we found that the SGH film was nontoxic and biocompatible. Of particular interest is the fact that the film alone could stimulate the osteogenic differentiation of hADSCs, independent of additional chemical inducers. Such effects are stronger for the SGH film than for graphene or carbon fiber films, although the induction capacity of the SGH film is not as high as that of the osteogenic-induced medium. The excellent osteoinductivity of the SGH film is closely related to its remarkable physical properties that include specific nanostructures, surface morphology, strong cell adherence, reasonable surface hydrophilicity, and high protein absorption.