A nested-lumen nerve graft design for neuroengineering

A biomimetic nerve graft design was developed for use in peripheral nerve regeneration. Nerve endings are difficult to suture or enjoin without support and autograft techniques also lead to added morbidity. Most clinically available synthetic nerve grafts are only capable of facilitating neuroregeneration across small lesions (<5 mm). Review of electroconductive epolymers, hydrogel and composite systems confirmed carbon nano-tube (CNT) and polycaprolactone biomaterials as being suitable candidates for reparative nerve conduits or scaffolds. An electrospun microfiber fMWCNTPCL composite conduit design was developed to re-connect large nerve gaps (>5 mm). Nested single-lumen and multilumen configurations with an insulating outer-portion were developed to mimic the fascicular architecture observed in peripheral nerves. Polymer solutions and composite suspensions were electrospun into microfiber membranes under the influence of 5 kV electric field. 80mm length conduit graft specimens were fabricated. Specimens were tension tested and found to have a Young’s Modulus of 15.7 ± 2.9 MPa and a tensile strength of 1.17 ± 0.16 MPa and 1.37 ± 0.08 MPa for the single and multi-channel grafts respectively. Graft specimens were verified for spinal cord (kangaroo tail) attachment by suturing and did not result in tearing under 1.2 N tensile load. A preliminary neurotoxicity study using N2A cell-line confirmed cell-scaffold adhesion and viability.