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The Shull Group |
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73. "Neurotrophin releasing single and multiple lumen nerve conduits" Yang, Y.; Laporte, L.D.; Rives, C.B.; Jang, J.-H.; Lin, W.-C.; Shull, K.; Shea, L.D., J. Controlled Release, 104, 433 (2005).
Abstract: Tissue engineering strategies for nerve repair employ polymer conduits termed guidance channels and bridges to promote regeneration for peripheral nerve injury and spinal cord injury, respectively. We present an approach for fabrication of nerve conduits with single and multiple lumens capable of controlled release of neurotrophic factors. These conduits were fabricated from a mixture of poly(lactide-co-glycolide) (PLG) microspheres and porogen that were loaded into a mold and processed by gas foaming. A wet granulation process was implemented to enhance homogeneity of the mixture for loading into molds. The porosity and mechanical properties of the constructs were regulated by the porogen to polymer microsphere ratio. The neurotrophin, nerve growth factor (NGF), was incorporated into the conduit by either mixing lyophilized protein with the polymer or encapsulating the protein within the microspheres prior to gas foaming. A sustained release was observed for at least 42 days, with the release rate controlled by the method of incorporation and the polymer molecular weight. Released NGF retained its bioactivity, as demonstrated by the ability to stimulate neurite outgrowth from primary dorsal root ganglion (DRG). Polymer conduits with controllable lumen diameters and rate of protein release may enhance nerve regeneration by guiding and stimulating neurite outgrowth.