Multi-channeled gelatin scaffold incorporated with neurotrophic gradient and nanotopography as nerve guidance conduit for peripheral nerve regeneration

摘要

Artificial nerve conduits can be used as nerve grafts to enhance the regeneration of large nerve defects. Many studies suggest that fibrous and multi-channeled scaffolds can potentially be used for nerve regeneration, as the aligned fibers can provide the guidance effect for axonal growth and the mulit-channeled structure mimics the fascicular architecture and decreases the nerve dispersion. A number of studies indicate that concentration gradients of guidance molecules influence axonal growth and cell migration. However, up to now, few studies have combined aligned fibers, mulit-channeled structure and neurotrophic concentration gradients in one integrated system to study their synergistic effect on peripheral nerve regeneration. In this study, aligned fibers were fabricated using an electrospinning technique. The multi-channeled scaffold incorporated with concentration gradient of neurotrophic growth factors was created by a gradient maker. We expect that (ⅰ) the aligned fibers can guide the axonal growth to particular direction; (ⅱ) mulit-channeled structure can provide necessary support and decrease the nerve dispersion; (ⅲ) the guidance of molecules gradient can promote axon outgrowth from the proximal stump to distal end. Conclusions: In this study, we have successfully developed a nerve guidance conduit containing aligned electrospun nanofibers in the multi-channeled gelatin scaffold with the incorporation of neurotrophic gradient. The results show that Rhod-GNs scaffold display a long-term controlled release of encapsulated biomolecules. This pattern suggests the possibility to provide and maintain effective constant concentration release of neurotrophic factors for nerve regeneration. The mechanical property of fabricated nerve conduit is significantly improved after dehydrothermal treatment (DHT) and enzymatic crosslinking (mTG). In in vitro study, differentiated neural stem cells (NSCs) can extend their neurites along the aligned nanofibrous structure. We are now combining theses three stimulating factors together to study their synergistic effect and evaluate the potential for the application in peripheral nerve regeneration.