Emulsion templated composites: Porous nerve guidance conduits for peripheral nerve regeneration

Peripheral nerve regeneration fails following more severe injuries where the gap between nerve stumps is too large. Nerve guidance conduits (NGCs) can be implanted to connect the nerve stumps and provide a regenerative microenvironment. This study shows that poly(glycerol sebacate)-methacrylate (PGS-M), a photocurable and biodegradable elastomer, can be used to fabricate porous NGCs. Further, novel developments in emulsion templating techniques are used to generate composite structures and their mechanical properties are investigated. The most appropriate composite for nerve tissue repair had a compressive and tensile Young's modulus of 0.168 MPa and 0.694 MPa respectively, much closer to that of native nerve tissue than previously used polymers. SEM images revealed high porosity/interconnectivity of NGCs, important for the diffusion of nutrients to further aid nerve regeneration. FITC-Dextran (150 kDa) effectively diffused through conduit walls. Histological analysis demonstrated the small pore size successfully prevented infiltration of fibroblasts. In vitro studies indicated that the NGCs were cytocompatible. Ex vivo analysis showed that neurons of embryonic chick dorsal root ganglia grew on the surface of the conduits, and Schwann cells migrated effectively along the lumen. This study demonstrates a novel way of fabricating porous scaffolds and demonstrates their potential for the treatment of PNI.