A method to deliver patterned electrical impulses to Schwann cells cultured on an artificial axon

Information from the brain travels back and forth along peripheral nerves in the form of electrical impulses generated by neurons and these impulses have repetitive patterns. Schwann cells in peripheral nerves receive molecular signals from axons to coordinate the process of myelination. There is evidence, however, that non-molecular signals play an important role in myelination in the form of patterned electrical impulses generated by neuronal activity. The role of patterned electrical impulses has been investigated in the literature using co-cultures of neurons and myelinating cells. The co-culturing method, however, prevents the uncoupling of the direct effect of patterned electrical impulses on myelinating cells from the indirect effect mediated by neurons. To uncouple these effects and focus on the direct response of Schwann cells, we developed an in vitro model where an electroconductive carbon fiber acts as an artificial axon. The fiber provides only the biophysical characteristics of an axon but does not contribute any molecular signaling. In our 'suspended wire model', the carbon fiber is suspended in a liquid media supported by a 3D printed scaffold. Patterned electrical impulses are generated by an Arduino 101 microcontroller. In this study, we describe the technology needed to set-up and eventually replicate this model. We also report on our initial in vitro tests where we were able to document the adherence and ensheath of human Schwann cells to the carbon fiber in the presence of patterned electrical impulses (hSCs were purchased from ScienCell Research Laboratories, Carlsbad, CA, USA; ScienCell fulfills the ethic requirements, including donor's consent). This technology will likely make feasible to investigate the response of Schwann cells to patterned electrical impulses in the future.