A multi-layered nerve guidance conduit design adapted to facilitate surgical implantation

The gold standard procedure after a severe nerve injury is the nerve autograft, yet this technique has drawbacks. In recent years, progress has been made in the development of artificial nerve guides to replace the autograft, but no device has been able to demonstrate superiority. The present study introduces an adaptable foundation design for peripheral nerve regeneration.

Silk fibroin was electrospun, creating a tri-layered material with aligned fiber surfaces and a randomly deposited fiber interior. This material was rolled into a micro-channeled conduit, which was then enveloped by a jacket layer of the same tri-layered material.

The proposed implant design succeeds in incorporating various desirable aspects of synthetic nerve guides, while facilitating the surgical implantation process for medical application. The aligned fiber surfaces of the conduit support axon guidance, while the tri-layered architecture improves its structural integrity compared with a fully aligned fiber material. Moreover, the jacket layer creates a small niche on each end which facilitates surgical implantation. An in vivo study in rats showed that nerve regeneration using this device was comparable to results after direct suture.

This proof-of-principle study, therefore, advances the development of tissue engineered nerve grafts by creating an optimized guidance conduit design capable of successful nerve regeneration.