Influences of mechanical properties and permeability on chitosan nano/microfiber mesh tubes as a scaffold for nerve regeneration.

We have developed chitosan nonwoven micro/nanofiber mesh tubes and examined the effects of their mechanical strength and permeability on nerve regeneration. Chitosan nano/microfibrous tubes with a deacetylation rate (DAc) of 78% or 93% were prepared by electrospinning. A chitosan film tube with a DAc of 93% was also fabricated and combined with the nano/microfibrous tubes to form bilayered tubes with a nano/microfiber mesh inner structure and a film outer layer. Nano/microfiber mesh tubes with a DAc of 78% or 93%, bilayered tubes with a nano/microfiber mesh inner structure with a DAc of 78% or 93% and a film outer layer with a DAc of 93%, and film tubes with a DAc of 93% were each tested as bridge grafts into injured rat sciatic nerve. Isografting was performed as a control. Although the functional recovery of motor activity was delayed in each group, sensory function reemerged first in the isograft group followed by the group receiving nano/microfiber mesh tubes with a DAc of 93%. Histological analysis was consistent with these results. The chitosan nano/microfiber mesh tubes with a DAc of 93% have sufficient mechanical properties to preserve tube space, provide a better scaffold for cell migration and attachment, and facilitate humoral permeation to enhance nerve regeneration.