Scheme 1.

Schematic illustration of SPION-mediated magnetic actuation promoting nerve regeneration by inducing and maintaining repair-supportive phenotypes in Schwann cells. SPIONs were injected under the epineurium at the distal end of the sciatic nerve crush site, then the sciatic nerve was exposed at the gradient magnetic field (MF). Through interacting with magnetic field, SPIONs produce a magnetic stimulation on Schwann cells, initiating the mechanotransduction process, activating intracellular biochemical signals, inducing and maintaining the repair phenotypes of Schwann cells by regulating the expression of regeneration-related genes, and ultimately promoting sciatic nerve regeneration