Graphene Derivatives Functionalized Polycaprolactone/Gelatin Electrospun Nanofibrous Membrane Through Mussel-Inspired Polydopamine: Multifunctional Scaffold with High Potential for Nerve Tissue Engineering

Injuries to the nervous system continue to be a problem on a global scale due to the limited capacity of the nervous system to self-repair. Today, electrospun nanofibrous membranes (NFMs) are widely used in nerve tissue engineering due to their advanced properties such as low-cost, being uncomplicated, the potential to give direction to neurite outgrowth, and their highly manageable properties. Recently, the fabrication of functionalized NFMs has been proposed as a viable strategy to help restore the function of the nervous system. This would be accomplished by creating the ideal microenvironment that could mimic the features of the extracellular matrix of neural cells such as conductivity. The main objective of this project was to construct a biocompatible and electro-conductive NFM with the potential to promote proliferation and induce differentiation into neuron-like cells in PC12 cells. Basic PCL and gelatin based scaffolds seem to lack the highly desired properties of cellular implants for neural tissue engineering such as high biocompatibility, tailored biodegradability, high antibacterial, and ROS scavenging properties. For this purpose, Poly(ε-caprolactone)/gelatin (PG) electrospun nanofibrous scaffolds were coated with GO and GQD through Mussel-inspired polydopamine (DOPA) (PG-DOPA-GO and PG-DOPA-GQD). There is a dearth of research on the application of GQD in neural tissue engineering, and there is no comparative assessment of GO and GQD’s effectiveness when coated through DOPA on the surface of PG NFM, in PC12 differentiation. For the first time, the outcomes of these NFMs, as neural tissue engineering scaffolds are assessed and contrasted from the standpoints of surface, structure, mechanical, and biological aspects. Apart from that, as far as we know, this is the first work using graphene-based nanomaterials via polydopamine mediated coatings in PG NFMs for nerve tissue engineering. The NFMs structural analysis through SEM, FTIR, and EDAX determined that the nanofibrous membranes are porous and truly coated by DOPA, GO, and GQD. It was also demonstrated that PG-DOPA-GO and PG-DOPA-GQD NFMs are highly conductive, hemo-compatible, antibacterial, possessing good hydrophilicity. At the same time, they are displayed to be biodegradable with adjustable structural integrity and stiffness. The NFMs potential to induce the expression of neuron-like differentiation factors in the PC12 cells cultured on the scaffold was determined by introducing neurofilament-200 (NF200) and Nestin antibodies after 7 days’ cell ceding. Simultaneously, qRT-PCR analysis confirmed that the NF-200 and Nestin genes, both among the important genes regulating neural differentiation, are highly expressed when the conductivity and biocompatibility of the scaffold are increased through GO coating. Overall, the PG-DOPA-GO NFM was determined to outperform the other scaffolds regarding increased proliferation, viability, and neuron-like differentiation-related factors in PC12 cells, both assessed by ICC and qRT-PCR, in vitro.

Graphical Abstract