Electrical stimulation mediated the neurite outgrowth of PC-12 cells on the conductive polylactic acid/reduced graphene oxide/polypyrrole composite nanofibers

[Display omitted] •The incorporation of rGO induced PPy to be continuously and densely coated on the surface of PLA/rGO nanofibers.•The incorporation of rGO can increase and stabilize the conductivity, i.e., PLA/rGO3.5/PPy shows the highest conductivity.•The growth, proliferation, and neurite growth of PC-12 exhibit the highest level with 400 mV/cm.•The protein adsorption is affected by electrical stimulation, which in turn regulates cell behavior. The synergistic effect of endogenous electric field and electrical stimulation (ES) has promising application in the repair and regeneration of injured peripheral nerve. Conducting polymers-based (especially polypyrrole (PPy)) nanofibers have received more attention due to the promotive effects on cell behaviors under ES. However, the conductivity of PPy is unstable and the inferior hydrophilicity hinders its broad applications. Herein, the stable conductive polylactic acid/reduced graphene oxide/polypyrrole (PLA/rGO/PPy) composite nanofibers were prepared by incorporating rGO into PLA, by the following in-situ PPy polymerized on the surface of the PLA/rGO nanofibers. The results show that PPy on the surface of composite nanofibers are dense and continuous, the wettability is significantly improved. With the presence of PPy and rGO, the conductivity and stability of PLA/rGO/PPy composite nanofibers increase, and the conductivity of PLA/rGO 3.5/PPy composite nanofibers was the highest conductivity (1.46 × 10−1 S/cm). The proliferation and differentiation of PC-12 cells seeded on the surface of PLA/rGO3.5/PPy composite nanofibers reach the highest level under 400 mV/cm. These results are beneficial for improving biomaterial properties and provide guidance to ES application in peripheral nerve repair.