Fabrication and characterization of graphene foams and using it for electrical stimulation of human neural stem cells

Aim: In this study biocompatible 3D graphene oxide foams have been used for Human neural stem cells (hNSCs) culturing.
Material and For the first time, graphene oxide foam were fabricated by precipitation of chemically exfoliated graphene oxide sheets in an aqueous suspension onto the PET substrate at ~80 oC under UV irradiation.
By using scanning electron microscopy, the thickness of these foams (with linear density of ~10 GO sheets/µm) was measured around 10-50 µm. X-Ray photoelectron spectroscopy confirmed that the UV irradiation resulted in partial reduction of the layers during fabrication process. Also Raman spectroscopy demonstrated the presence of multilayer graphene oxide sheets (≥3 layers) in the foam structure. The Young’s modulus of the foams was obtained about 1.7 GPa. Furthermore, Four probe method found that the electrical sheet resistance of the GOFs was low enough (17-24 Ω/sq).
To produce the electrical simulation currents (~20 mA) used in differentiation of the neural stem cells into the neurons (rather than glial cells). Contact angle test also showed that rolling the GOFs resulted in formation of cross-section with superhydrophilic characteristic, inducing effective proliferation and differentiation of the hNSCs throughout the pores and interfaces of the scaffold. Moreover, Fluorescence imaging revealed that stimulating the hNSCs resulted in coaxial-like growth of the neural fibers and inducing differentiation of the neural stem cells in to the neurons.