In the past grant period, our objective was to develop new approaches for transdermal photopolymerization to introduce cells in vivo. We were able to employ UVA and visible light that penetrate through the skin to photopolymerize liquid materials injected subcutaneously. We implemented this strategy to grow tissue engineered cartilages that resemble native neocartilages by injecting a mixture of poly(ethylene oxide) dimethacrylate and chondrocytes followed by transdermal photopolymerization. We believe the field of tissue engineering can still benefit from the development of new biomaterials, thus the purpose of this renewal grant is to develop new biodegradable and biocompatible elastomers for applications, such as tissue engineering of blood vessels of the craniofacial complex. For many tissue engineering approaches, it is often critical that the mechanical properties of the scaffold match that of the native tissue. Most of the currently available biodegradable polymers are not mechanically compliant with soft tissues. In preliminary studies, we have attempted to address this shortage by developing a tough biodegradable elastomer, poly (glycerol sebacate), or PGS. Our specific aims for this renewal grant are: 1. Modify PGS to promote cell adhesion, proliferation, and migration. 2. Develop methodologies to fabricate PGS into open porous foams. 3. Develop technologies to fabricate PGS into fibers for fibrous mesh. 4. Evaluate biocompatibility of modified PGS with vascular cells (as a model cell line) and the performance of PGS scaffold in the tissue engineered construct of blood vessels. 5. Implantation and testing of tissue engineered vascular tissues in animal models.