Oriented artificial nanofibers and laser induced periodic surface structures as substrates for Schwann cells alignment

People with injuries to the peripheral nervous system suffer from paralysis of the facial muscles, fingers and hands or toes and feet, often for the rest of their lives, due to its poor functional regeneration. Therefore, to improve patients' quality of life, there is an urgent need for conduits that effectively support the healing of large defects in nerve pathways through specific guidance of nerve cells. This paper describes two specific methods for achieving directed growth of Schwann cells, a type of glial cells that can support the regeneration of the nerve pathway by guiding the neuronal axons in the direction of their alignment. One method uses aligned polyamide-6 (PA-6) nanofibers produced via electrospinning on a very fast rotating structured collector, which enables easy nanofiber detachment, without additional effort. The other method implies the exposure of a poly(ethylene terephthalate) (PET) foil to a KrF* laser beam, that renders a nanorippled surface topography. Schwann cell growth on these substrates was inspected after one week of cultivation by means of scanning electron microscopy (SEM). For both methods we show that Schwann cells grow in a certain direction, predetermined by nanofiber and nanoripple orientation. In contrast, cells cultivated on randomly oriented nanofibers or unstructured surfaces, show an omnidirectional growth behavior. These two methods can be used to produce nerve conduits for the treatment of injuries to the peripheral nervous system.