Chitosan nanofibers for peripheral nerve applications

The clinical gold standard for bridging peripheral nerve gaps of critical length is the transplantation of autologous nerve tissue, which is harvested from sensory nerves of the same patient¹. In general, autologous nerve grafts provide optimal guidance cues for regenerating nerve fibers, such as peripheral glia cells and Schwann cells (SCs). They do not only produce regeneration-promoting factors but also line their basal laminae up to the so-called bands of Bungner, the guiding tubes within the distal nerve segments². Undoubtedly, the use of autologous nerve tissue leads to loss of sensation at the site of harvest and the functional outcome after its utilization is described to range from extremely poor to satisfying. As an alternative to this, tubulisation strategies, using biomaterials, have been performed^3-5. However, so far the results have been quite disappointing. To tackle this, new biomaterials have been developed that can easily be modified to provide an optimized environment for peripheral nerve regeneration and qualify as substitutes for autologous nerve grafts. Chitosan is among the biodegradable polymers that demonstrate good properties for neural tissue engineering⁶. It is an attractive material to produce as an inner guidance of nerve conduits, because it can easily be blended with other materials or be processed in different ways provide guiding and structural cues supporting axonal regrowth⁷.