Investigation of Schwann cell behaviour on RGD-functionalised bioabsorbable nanocomposite for peripheral nerve regeneration

Abstract

Current commercially available nerve conduits fail to support nerve regeneration gaps larger than 30 mm in length due to the simple intra-luminal design of these conduits which are unable to biomimic the native neural environment. There is, therefore, a major clinical demand for new smart biomaterials, which can stimulate neuronal cell proliferation and migration, and facilitate nerve regeneration across these critical sized defects. In this study, we aimed to investigate Schwann cell (SC) behaviour seeded on the bioabsorbable version of the nanocomposite material, POSS modified poly (caprolactone) urea urethane (PCL), functionalised with arginine-glycine-aspartic acid (RGD) peptide. Successful synthesis of RGD peptide as well as the chemical structure of POSS-PCL nanocomposite film was investigated by Fourier transform infrared spectroscopy. Cell viability assay and morphological assessment were performed to investigate the cytocompatibility of the fabricated constructs. Successful immobilisation of RGD peptide onto the nanocomposite surface was confirmed by water contact angle, Brilliant Blue (BB) staining and thin layer chromatography. Both POSS-PCL and RGD-POSS-PCL nanocomposite scaffolds supported SC attachment, proliferation and morphological differentiation, important aspects for peripheral nerve regeneration. However, a significant increase in SC process length and morphological differentiation towards maturation was observed on the cells grown on RGD-POSS-PCL film. RGD-POSS-PCL nanocomposite demonstrated a significant improvement in SCs spreading and its integrin-dependent process outgrowth (P<0.05). Conduits made by POSS-nanocomposite may be suitable for the next generation of commercially available conduit required to meet current clinical demand in peripheral nerve regeneration and repair as they are currently undergoing in vivo preclinical study.