Polylactic acid/chitosan-IKVAV Janus film serving as a dual functional platform for spinal cord injury repair.

The repair of traumatic spinal cord injury (SCI) remains a challenge due to the non-regenerative nature of functional neurons in adults. Neural stem cell (NSC)-based therapy has emerged as a promising approach for the treatment of SCI by replacing the damaged neurons with differentiated stem cells. However, directing the neuronal differentiation of implanted stem cells in the injury microenvironment is of great difficulty, especially considering that SCI is generally associated with severe fibrotic tissue infiltration, neuron inflammation, and tissue adhesion. Here, we propose a dual functional Janus film capable of preventing tissue adhesion and promoting the neuronal differentiation of stem cells for the treatment of SCI. The Janus film is composed of a layer of polylactic acid (PLA) and a layer of chitosan (CS) grafted with IKVAV peptides. The PLA layer prevents the invasion of the fibrotic tissue, while the IKVAV peptide-grafted CS layer offers support for NSC implantation and thus the neuronal differentiation of the NSCs. When serving as the dura patch, the Janus films seeded with NSCs promote the recovery of motor function and the regeneration of the injured spinal cord tissue of SCI rats. This dual functional Janus film holds great promise for treating SCI in combination with stem cell therapy.