Tissue-Adaptive BSA Hydrogel with Dual Release of PTX and bFGF Promotes Spinal Cord Injury Repair via Glial Scar Inhibition and Axon Regeneration.

Spinal cord injury (SCI) is a severe clinical disease usually accompanied by activated glial scar, neuronal axon rupture, and disabled motor function. To mimic the microenvironment of the SCI injury site, a hydrogel system with a comparable mechanical property to the spinal cord is desirable. Therefore, a novel elastic bovine serum albumin (BSA) hydrogel is fabricated with excellent adhesive, injectable, and biocompatible properties. The hydrogel is used to deliver paclitaxel (PTX) together with basic fibroblast growth factor (bFGF) to inhibit glial scar formation as well as promote axon regeneration and motor function for SCI repair. Due to the specific interaction of BSA with both drugs, bFGF, and PTX can be controllably released from the hydrogel system to achieve an effective concentration at the wound site during the SCI regeneration process. Moreover, benefiting from the combination of PTX and bFGF, this bFGF/PTX@BSA system significantly aided axon repair by promoting the elongation of axons across the glial scar with reduced reactive astrocyte secretion. In addition, remarkable anti-apoptosis of nerve cells is evident with the bFGF/PTX@BSA system. Subsequently, this multi-functionalized drug system significantly improved the motor function of the rats after SCI. These results reveal that bFGF/PTX@BSA is an ideal functionalized material for nerve repair in SCI.