Reduced graphene oxide functionalized nanofibrous silk fibroin matrices for engineering excitable tissues

Tissue engineering has provided an alternative strategy for the regeneration of functional tissues for drug screening and disease intervention. The central challenge in the development of mature and functional excitable tissues is to design and construct advanced conductive biomaterials that can guide cells to form electrically interconnected networks. The objective of this study was to develop reduced graphene oxide modified silk nanofibrous biomaterials with controllable surface deposition on the nanoscale. A vacuum filtration system was applied to attain reduced graphene oxide nanolayer deposition. The results demonstrate that with this method, a uniform and compact reduced graphene oxide nanolayer was formed, and the conductivity and nanofibrous morphology of the materials was well controlled. The composite nanofibrous scaffolds were applied for the engineering of cardiac tissues and demonstrated a great ability to promote tissue formation and functions, including the expression of cardiac-specific proteins, the formation of sarcomeric structures and gap junctions, and tissue contraction. External electrical stimulation further enhanced the maturation level of cardiac tissues cultured on these conductive scaffolds. All these results demonstrated the great potential of reduced graphene oxide functionalized silk biomaterials fabricated using our method for recapitulating electrical microenvironments for the regeneration of functional excitable tissues.