Characteristics and biocompatibility of a biodegradable genipin-cross-linked gelatin/β-tricalcium phosphate reinforced nerve guide conduit.

To modulate the mechanical properties of nerve guide conduit for surgical manipulation, this study develops a biodegradable composite containing genipin cross-linked gelatin annexed with β-tricalcium phosphate ceramic particles as a nerve guide material. The conduit was dark bluish and round with a rough and compact outer surface compared to the genipin cross-linked gelatin conduit (without β-tricalcium phosphate). Water uptake and swelling tests indicate that the conduit noticeably increases the stability in water, and the hydrated conduit does not collapse and stenose. The conduit has a sufficiently high level of mechanical properties to serve as a nerve guide. After subcutaneous implantation on the dorsal side of a rat, the degraded conduit only evokes a mild tissue response, and the formation of a very thin fibrous capsule surrounds the conduit. This paper assesses the effectiveness of the conduit as a guidance channel when we use it to repair a 10 mm gap in the rat's sciatic nerve. The experimental results show no gross inflammatory reactions of the peripheral nerve tissues at the implantation site in either group. In overall gross examination, the diameter of the intratubular and newly formed nerve fibers in the conduits exceeds that of the silicone tubes during the implantation period. The quantitative results indicate the superiority of the conduits over the silicone tubes. This study microscopically observes the nerve regeneration in the tissue section at the middle region of all implanted conduits. Therefore, the histomorphometric assessment demonstrates that the conduit could be a candidate for peripheral nerve repair.