Biphasic Electrical Stimulation of Schwann Cells on Conducting Polymer-Coated Carbon Microfibers

Electroactive biomaterials are a key emerging technology for the treatment of neural damage. Conducting polymer-coated carbon microfibers are particularly useful for this application because they provide directional support for cell growth and tissue repair and simultaneously allow for ultrasensitive recording and stimulation of neural activity. Here, we report in vitro experiments investigating the biology of Schwann cells (SCs), a major player in peripheral nerve regeneration, on electroconducting microfibers. The optimal molecular composition of the cell substrate and cell culture medium was studied for SCs dissociated from rat and pig peripheral nerves. The substrate molecules were then attached to carbon microfibers coated with poly (3,4-ethylenedioxythiophene) doped with poly [(4-styrenesulfonic acid)-co-(maleic acid)] (PCMFs), which served as an electroactive scaffold for culturing nerve explants. Biphasic electrical stimulation (ES) was applied through the microfibers, and its effects on cell proliferation and migration were assessed in different cell culture media. Rodent and porcine SCs avidly migrated on PCMFs functionalized with a complex of poly-L-lysine, heparin, basic fibroblast growth factor, and fibronectin. Serum and forskolin/heregulin increased, by two-fold and four-fold, the number of SCs on PCMFs, respectively, and ES further doubled cell numbers without favoring fibroblast proliferation. ES additionally increased SC migration. These results provide a baseline for using biofunctionalized PCMFs in peripheral nerve repair.