Aligned SF/P(LLA-CL)-blended nanofibers encapsulating nerve growth factor for peripheral nerve regeneration

Artificial nerve guidance conduits (NGCs) containing bioactive neurotrophic factors and topographical structure to biomimic native tissues are essential for efficient regeneration of nerve gaps. In this study, aligned SF/P(LLA-CL) nanofibers encapsulating nerve growth factor (NGF), which was stabilized by SF in core, were fabricated via a coaxial electrospinning technique. The controlled release of NGF from the nanofibers was evaluated using enzyme-linked immune sorbent assay (ELISA) and PC12 cell-based bioassay over a 60-day time period. The results demonstrated that NGF presented a sustained release and remained biological activity over 60 days. Nerve guidance conduits (NGCs) were fabricated by reeling the aligned SF/P(LLA-CL) nanofibrous scaffolds encapsulating NGF and then used as a bridge implanted across a 15-mm defect in the sciatic nerve of rats to promote nerve regeneration. The outcome in terms of regenerated nerve at 12 weeks was evaluated by a combination of electrophysiological assessment, histochemistry, and electron microscopy. All results clarified that the NGF-encapsulated-aligned SF/P(LLA-CL) NGCs promoted peripheral nerve regeneration significantly better than the aligned SF/P(LLA-CL) NGCs, suggesting that the released NGF from nanofibers could effectively promote the regeneration of peripheral nerve.