Spinal cord injury affects nearly twenty five thousand Americans, with an additional ten thousand new injuries per year. This project proposes the use of a non-biodegradable hydrogel as a mechanical support to fill the injury site and provide a protected environment for the regenerating neurons. The hydrogel can be designed to match the mechanical stiffness of the local tissue to reduce the amount of stress shearing around the implant. The use of a thermally responsive, injectable polymer, PNIPAAm-PEG branched copolymer, is proposed as a minimally invasive surgical technique. Below its LCST, typically around 29-32C, the polymer forms a miscible solution with water, but above its LCST, it becomes hydrophobic, separating from water and forming a semi porous gel. The aqueous polymer solution can be created with cell culture media and seeded with bone marrow stromal cells in order to physically entrap cells into the scaffold when it is injected into the defect. This would allow the cells to proliferate creating an environment more attractive to growing neurons. This environment can be enhanced with the addition of biodegradable polymer microparticles loaded with trophic factors to promote both nerve growth as well as angiogenesis.