Peripheral nerve injury still remains a major clinical surgical challenge, since the current clinical solutions lead to an often-unsatisfactory nerve regeneration. Despite autologous nerve grafts being considered the gold standard, tissue engineered nerve guidance grafts are candidate alternatives to overcome this unmet medical need. Neurotrophic factors can stimulate and control neurogenesis at the nerve injury site. Nerve growth factor (NGF) is the most prominent neurotrophic factor, being recognized to facilitate the survival and the innervation of autonomic nerves and sensory neurons. Therefore, the local delivery of NGF from nerve stimulation grafts might enhance nerve regeneration.

In this work, we demonstrate the selective retrieval of autologous NGF, derived from rat blood plasma, bound at the surface of an electrospun nanofibrous substrate (NFM). For that, anti-NGF antibody was immobilized at the surface of NFMs, at the maximum concentration of 10 mg/mL, capable to selectively bind autologous NGF. The neurogenesis potential of the NFM functionalized with autologous NGF was further evaluated by culturing rat pheochromocytoma (PC12) cells during 7 days, without further induction. The biological results indicate that NGF delivery system promotes neuronal differentiation of PC12 cells, being more effective than the control condition. In summary, autologous NGF bound at the surface of NFM might be able to promote functional peripheral nerve regeneration.  

Acknowledgements

The authors would like to acknowledge the Portuguese FCT for the PhD grant of M.R.C. (PD/BD/113797/2015) financed by the PATH (FSE/POCH/PD/169/2013), the IF grant of A.M. (IF/00376/2014), and the projects SPARTAN (PTDC/CTM-BIO/4388/2014) and FRONthera (NORTE-01-0145-FEDER-0000232).