Vertically Aligned Peptide Nanotube Arrays as a Substrate for Neural Cell Differentiation

There is an increasing need for biocompatible neuronal cell proliferation and regeneration scaffolds as regeneration of the neurite structures is slow and complex, which results in permanent nerve cell damage. Non-invasive electrical stimulation could potentially enhance neural cell proliferation and differentiation. Interfacing cells with biocompatible materials with electrical properties could be harnessed to introduce potential gradients across the cell membrane for neurological activation and repairs. The ability to stimulate individual neurons can impact the development of neural networks, and enhanced motor rehabilitation. The influence of voltage stimulation on human neural progenitor cells will be studied in-vitro using a high-density array of peptide-based nanotubes deposited via plasma-enhanced chemical vapor deposition (PECVD). Peptide-based building blocks containing aromatic amino acids that can self-assemble to form highly organized nanoscale structures with key functional properties such as biocompatibility, high aspect ratios, semi-conductivity, and stiffness will be used as the scaffold in this study. Tryptophan and tyrosine are aromatic amino acids known for their redox properties and roles in neurotransmitter synthesis. These structures have the ability to “carry” cells, which should result in functional modifications and an altercation in protein behavior, which can lead to highly polarized cells. Following the analysis of physicochemical properties of these peptide nanostructures, we studied the biological interactions and influence these scaffolds on human bone marrow neuroblasts and neural progenitor cells and subjected to an electrical stimulation. Prior studies have used carbon nanotubes scaffolds for subsequent electrical stimulation protocols, but their cytotoxicity makes their use in many biological systems undesirable. Electrical stimulation can induce the depolarization of the plasma membrane, as well as affect the function of membrane proteins, including enzyme activity and ion-transporting channels. These processes are most likely generated via the increased presence of reactive oxygen species (ROS), which are highly reactive molecules that have also been found to potentially act as an intermediate signal transducer between neural cells for the purpose of cell differentiation. To test the same, MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) cytotoxicity studies, morphological cellular interaction imaging through SEM and confocal imaging, dopamine-enzyme linked immunosorbent assay, immunostaining for neuronal markers, and real-time polymerase chain reaction (q-PCR) for gene expression were carried out on the neuronal cells cultured on the synthesized peptide bioscaffolds.