A sandwich structured drug delivery composite membrane for improved recovery after spinal cord injury under longtime controlled release

A sandwich structured composite membrane for longtime controlled release of nerve growth factor (NGF) to repair spinal cord injury (SCI) is prepared through electrospray. In this system, PLA film is used as the sealing layer to prevent drug diffusion and provide mechanical support, PLGA microspheres as the sandwich layer to load and controlled release NGF, and chitosan (CS) film as the planting layer to seed bone marrow mesenchymal stem cells (BMSCs). The composite membrane has good biocompatibility and can effectively promote PC-12 cells to differentiate into neurons. In addition, the composite membrane can be directly applied to the injured areas without further damage. The longtime sustained release of NGF guaranteed enough requirement time for SCI repair, which will decrease the administration frequency and improve patient compliance. The administration of BMSCs coupled with the sandwich composite membrane effectively relieves SCI, decreases cavity formation, enhances neuronal regeneration and tissue repair, as well as improves the recovery of locomotor functions. Overall, this present work provides a future perspective for the treatment of SCI by the NGF-loaded sandwich composite membrane with prolonged drug release function.