A self-powered microsphere-electret/conductive bacterial cellulose composite for sciatic nerve repair

Physiologically related electrical microenvironments play an indispensable role in nerve regeneration and repair. Simulating the electrophysiological characteristics of nerves through bionic construction of bioelectric fields has attracted wide attention, as it can regulate the behavior of nerve cells and promote the repair of nerve injuries. Electret is a kind of material that can maintain permanent polarization state without external electric field, and can be used as a new self-powered electrical stimulation method for nerve regeneration and repair. In this work, a novel self-powered conductive nerve conduit with both electret electrical effects and conduction activity was constructed to promote peripheral bioelectret nerve regeneration and repair. The microsphere electret is embedded on the bacterial cellulose structure through the self-polymerization reaction of dopamine, wherein the microsphere electret can provide micro-power and release electrical signals through the conducting layer of polydopamine. The maximum conductivity of the composite bioelectret can reach 6.2 × 10 −3  S/cm, and the output charge can reach 264 pC at a bending strain of 50 %. In vitro, composite bioelectret provided a good electrophysiological microenvironment for cells and enhance their adhesion, proliferation and migration capabilities. In the repair of sciatic nerve in rats, the electret effect and conductivity of composite bioelectret provide continuous electrical stimulation for repairing microenvironment, strengthen the communication among cells, and promote axon growth and myelin regeneration. Conductive composite bioelectret provides a new non-contact electrical stimulation strategy for nerve repair by combining the dual synergistic effects of conductivity and electret self-powered.