Self-Powered Electrical Stimulation for Enhancing Neural Differentiation of Mesenchymal Stem Cells on Graphene-Poly(3,4-ethylenedioxythiophene) Hybrid Microfibers.

Engineered conductive scaffolds toward neural regeneration should have the ability to regulate mesenchymal stems cell (MSC) differentiation into neural lineage through an electrical stimulation-assisted culture process. In this work, a self-powered electrical stimulation-assisted neural differentiation system for MSCs was realized by combining a high effective triboelectric nanogenerator (TENG) to supply pulsed electric simulation signals and a poly(3,4-ethylenedioxythiophene) (PEDOT)-reduced graphene oxide (rGO) hybrid microfiber (80 μm in diameter) as a scaffold. The conductive PEDOT endows the rGO-PEDOT hybrid microfiber with an enhanced electrical conductivity and maintains a good cytocompatibility. MSCs cultured on this highly conductive rGO-PEDOT hybrid microfiber possess enhanced proliferation ability and good neural differentiation tendency. Importantly, by inducing electric pulses generated by the TENG as the electrical stimulation signal, which are triggered by human walking steps, neural differentiation of MSCs is dramatically improved. This study illustrates the customizability of the rGO-PEDOT hybrid microfiber for neural tissue engineering scaffolding applications, underlines the potential of a self-powered TENG electrical stimulation system for accelerating MSC differentiation into neural cells without bio/chemical cues, and suggests the TENG's practical use as a wearable stimulation system to assist nerve regeneration for a walking person.