Oriented Schwann cell monolayers for directed neurite outgrowth

Schwann cells are an important component of the peripheral nervous system and participate in peripheral nerve regeneration. They create a supportive environment for neurite outgrowth by releasing trophic factors and up-regulating permissive molecules on their surface. In addition, Schwann cells are able to self-organize into linear arrays in vitro and in vivo, suggesting a possible role in neurite guidance. Previously, we showed that Schwann cell placement and orientation in subconfluent cultures can be controlled using microlithographically patterned laminin substrates (Thompson, D. M., and H. M. Buettner. Tissue Eng. 7(3):247-266, 2001). In the current study, these substrates were used to create oriented Schwann cell monolayers. Both Schwann cell orientation and coverage were quantified in response to seeding density, culture medium, and micropattern dimensions. In serum-free medium, increasing the seeding density yielded a linear increase in coverage of the substrate area but decreased cell alignment. In an alternate approach, Schwann cells were first seeded in serum-free medium at moderate seeding density, allowed to align, then expanded in serum-containing growth medium. This produced complete coverage without large seeding densities while preserving alignment to the micropattern. Alignment and coverage were unaffected by micropattern dimensions. This work provides a useful methodology for investigating Schwann cell guidance effects on growing neurites.