PLGA porous scaffolds by polydopamine-assisted immobilization of NGF for spinal cord injury repair

The degradable polymer biomaterials have great potential in the field of nerve regeneration, which have gradually been applied to spinal cord injury repair. In this study, a polylactic acid-glycolic acid copolymer (PLGA) porous scaffold was prepared by the process of phase inversion, then the surface of the scaffold was modified by polydopamine (PDA) as a substrate, followed by adsorption of nerve growth factor (NGF) to obtain a PDA-PLGA/NGF scaffold. The characterization and hydrophilicity of the scaffolds were evaluated by electron microscopy, EDX and contact angle measurement. The effect of PDA modification on the binding efficiency and release profile of NGF was observed by ELISA. The proliferation and differentiation of NSCs on the surface of biomaterials was evaluated by MTT, immunofluorescence staining and PCR. Subsequently, the rat T9 spinal cord transection model was established and the nerve scaffolds were implanted to injured site. Our results showed PDA modification could significantly improve the NGF adsorption capacity and provide sustained release of NGF. PDA-PLGA/NGF scaffolds could not only enhance NSCs proliferation and neuronal differentiation in vitro, but also promote recovery of spinal cord injury in vivo. Therefore, we believed that PDA-PLGA/NGF scaffolds could be a promising method to facilitate neurogenesis and repair spinal cord injury.