Electrical Stimulation Increases Axonal Growth from Dorsal Root Ganglia Co-Cultured with Schwann Cells in Highly Aligned PLA-PPy-Au Microfiber Substrates

Nerve regeneration is a slow process that needs to be guided for distances greater than
5 mm. For this reason, different strategies are being studied to guide axonal growth and accelerate
the axonal growth rate. In this study, we employ an electroconductive fibrillar substrate that is able
to topographically guide axonal growth while accelerating the axonal growth rate when subjected
to an exogenous electric field. Dorsal root ganglia were seeded in co-culture with Schwann cells on
a substrate of polylactic acid microfibers coated with the electroconductive polymer polypyrrole,
adding gold microfibers to increase its electrical conductivity. The substrate is capable of guiding
axonal growth in a highly aligned manner and, when subjected to an electrical stimulation, an
improvement in axonal growth is observed. As a result, an increase in the maximum length of the
axons of 19.2% and an increase in the area occupied by the axons of 40% were obtained. In addition,
an upregulation of the genes related to axon guidance, axogenesis, Schwann cells, proliferation and
neurotrophins was observed for the electrically stimulated group. Therefore, our device is a good
candidate for nerve regeneration therapies.