The myelin sheath is an insulating system that wraps axons, long neuronal projections, enabling them to correctly propagate electrical impulses. Its production (myelination) occurs only around large axons via unknown mechanisms. Since myelinating proteins might be selectively present on big caliber axons, it is unclear whether myelination is driven by biological cues or axonal physical features, such as the axon’s size itself.

Seonok Lee, University of California, USA, and colleagues, demonstrated that nanofiber scaffolds are powerful tools to study how myelination occurs. The scientists created polystyrene nanofibers with a broad range diameter and used them as axon surrogates. By cultivating them together with myelinating cells, they mimicked myelination in vitro and specifically demonstrated the crucial role played by the axonal diameter during this process.

Thus, polystyrene nanofibers are novel tools to study myelination and to evaluate drugs promoting this event.

• A culture system to study oligodendrocyte myelination processes using engineered nanofibers,
  S. Lee, M. K. Leach, S. A. Redmond, S. Y. Chong, S. H. Mellon, S. J. Tuck, Z. Q. Feng, J. M. Corey, J. R. Chan,
  Nat. Methods. 2012, 9(9), 917–922.
  DOI: 10.1038/nmeth.2105