Enhancement of neural stem cell survival, proliferation and differentiation by IGF-1 delivery in graphene oxide-incorporated PLGA electrospun nanofibrous mats

The mammalian central nervous system has a limited ability for self-repair under injury conditions. The treatment of nerve injuries has been revolutionised with the development of tissue engineering techniques. However, the lack of bioactivity has severely restricted the application of biodegradable implants for neurogenesis. Therefore, surface modification of biomaterials is crucial to improve their bioactivity and promote endogenous repair mechanisms for nerve regeneration. Insulin-like growth factor 1 (IGF-1) is a growth factor for neuroprotection and neurogenesis. In this study, IGF-1 was successfully immobilised on graphene oxide (GO)-incorporated poly(lactic-co-glycolic acid) (PLGA) biodegradable electrospun nanofibres. For the in vitro investigation, neural stem cells (NSCs) were cultured on different nanofibres to observe various cellular activities. GO enhanced NSC survival under H2O2 pre-treatment and neuronal differentiation to some extent. More importantly, the immobilisation of IGF-1 onto the PLGA/GO nanofibres resulted in significantly increased NSC survival, proliferation, and differentiation. Findings from this study revealed that using PLGA/GO electrospun nanofibres to immobilise IGF-1 has excellent potential for the enhancement of the neuroprotective and neurogenic effects of nerve implants.