Engineering PCL/lignin nanofibers as an antioxidant scaffold for the growth of neuron and Schwann cell.

Antioxidant is critical for the successful of nerve tissue regeneration, and biomaterials with antioxidant activity might be favorable for peripheral nerve repair. Lignin, a biopolymer from wood with excellent antioxidant properties, is still "unexplored" as biomaterials. To design an antioxidative bioscaffold for nerve regeneration, here we synthesized lignin-polycaprolactone (PCL) copolymers via solvent free ring-opening polymerization (ROP). Then such lignin-PCL copolymers were incorporated with PCL and engineered into nanofibrous scaffolds for supporting the growth of neuron and Schwann cell. Our results showed that the addition of lignin-PCL enhanced the mechanical properties of PCL nanofibers and endowed them with good antioxidant properties (up to 98.3 ± 1.9% free radical inhibition within 4 h). Cell proliferation assay showed that PCL/lignin-PCL nanofibers increased cell viability compared to PCL fibers, especially after an oxidative challenge. Moreover, Schwann cells and dorsal root ganglion (DRG) neurons cultured on the nanofibers to assess their potential for nerve regeneration. These results suggested that nanofibers with lignin copolymers promoted cell proliferation of both BMSCs and Schwann cells, enhanced myelin basic protein expressions of Schwann cells and stimulated neurite outgrowth of DRG neurons. In all, these sustainable, intrinsically antioxidant nanofibers may be a potential candidate for nerve TE applications.