Investigating Schwann Cell Response On Polypyrrole Substrates Upon Electrical Stimulation

In peripheral nervous system regeneration, current injury models suggest that Schwann cell migration and guidance are necessary for successful regeneration and synaptic reconnection after injury. Conducting polymers such as polypyrrole (PPy) are attractive candidates for neural conduits because they can be fabricated to exhibit chemical, contact, and electrical stimuli. Despite this interest in conducting polymers, very little work has been performed to assess the effect that electrical stimulation via polypyrrole has on Schwann cell behavior. Here we investigate the mechanism by which Schwann cells (SC) interact with polypyrrole in the presence of an electric field. SCs were stimulated on polypyrrole at different electric field strengths in the presence of different known biomarkers (i.e., laminin, fibronectin, and nerve growth factor) that had been previously adsorbed onto the material. The cell behavior was determined by monitoring its migration and secretion and by characterizing protein adsorption on the PPy upon electrical stimulation. To determine the effect electrical stimulation through the PPy substrate has on the adsorption of stimulatory proteins, different oxidation states of polypyrrole were used in combination with different soluble protein concentrations to determine an adsorption profile. These results will prove invaluable in optimizing conducting polymers for neural engineering and other biomedical applications.