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Carbon nanomaterials have shown promise as biocompatible, conductive scaffolds that direct neural tissue regeneration. The goal is to influence stem cell fate by engineering a controlled micro- and macro- environment that imitates living tissue, while simultaneously monitoring cell metabolites. To approach this goal, we synthesized a highly porous, pyrolitic nanofiber carbon material through a stress-induced graphitization process [1]. The carbon macrostructure was synthesized to have either a random or aligned orientation by controlling nanofiber deposition using an electrospinning technique. The resulting carbon has ideal conductive properties for electrical stimulation, a microstructure allowing for mechanical stimulation, and a controlled, porous 3D geometry mimicking the extracellular matrix (ECM) of mature cells. The unique graphitic structure is abundant in nitrogen heteroatoms and edge planes, which not only improves its electrochemical kinetics (with heterogeneous electron transfer rate of koapp = 0.2 cm/s in dopamine) but also promotes cellular adhesion by increasing nucleation sites for stem cells to attach and form neural networks. The compatibility of the carbon material as a stem cell scaffold was assessed by successfully growing and differentiating mouse neural stem cells (NSCs) on the untreated material without the addition of any ECM proteins or adhesion factors. The influence of fiber alignment on stem cell fate was also studied by growing NSCs on the carbon material with both aligned and randomly oriented nanofibers. Finally, the ability of the material to act as a simultaneous scaffold and sensor was assessed by measuring extremely low concentrations (<1μM) of dopamine in cell media.
[1] Ghazinejad, Maziar, et al. "Graphitizing non-graphitizable carbons by stress-induced routes." Scientific reports 7.1 (2017): 16551.
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