Design and optimization of a biodegradable porous zein conduit using microtubes as a guide for rat sciatic nerve defect repair.

Various degradable biomaterials have been used to bridge injured peripheral nerve defect; however, drawbacks such as poor mechanical properties, inappropriate degradation rate, and toxic degradation products continue to limit the application of them in nerve repair. Considering the unique properties of zein, such as its biocompatibility, biodegradability and ease of fabrication, we report the use of zein conduits to repair injured rat sciatic nerves with a 10-mm defect. Three-dimensional zein conduits were designed with/without pores, and with/without microtubes including in the lumen of conduits. Zein conduit with microtubes yielded satisfactory results in sciatic function index (SFI), proximal compound muscle action potentials, density of myelinated nerve fibres and myelin thickness, which were not inferior to autograft but slightly superior to the hollow conduit at the 4th month post-implantation. The conduits degraded almost completely within two months, which was shorter than the suggested period of four months. Thus, the use of a porous conduit with microtubes inside as the guidance may play important roles in successful repair. Notably, the regulatory body will more likely approve designs employing a single component, such as the natural polymer zein.