Micropatterned polymer substrates control alignment of proliferating Schwann cells to direct neuronal regeneration

In this study we have examined the use of microcontact printed polymeric substrates for their ability to control Schwann cell attachment and direct proliferation. Schwann cell guidance is a crucial factor in directing peripheral nerve regeneration. Elastomeric stamps of poly(dimethyl siloxane) were created from lithographic masters. The stamp pattern consisted of stripes and spaces 10-50 μm wide. The substrates including poly(methyl methacrylate), poly(hydroxybutyrate), and poly(ε-caprolactone) were plasma treated along with the stamps. The stamps were "inked" with laminin, a permissive protein for Schwann cell adhesion, and stamped onto the substrates. Schwann cells were seeded onto the substrates in serum free media. After 24 hrs media was replaced with serum-containing growth media and changed daily thereafter. Phase contrast images were taken at 24 hr intervals after seeding. After monolayer formation, the samples were fixed and fluorescently labeled. We found that the laminin micropatterns directed Schwann cell adhesion to the patterned areas when seeded in serum free media. The addition of a growth media to stimulate proliferation caused some loss in orientation control initially, but when monolayer formation was complete a high degree of orientation could be observed. Our results indicate that patterned polymeric substrates may enhance peripheral nerve regeneration by creating a highly ordered Schwann cell matrix for guidance of neurons.