a method of making a new type of biomaterials , biodegrable crosslinked urethane - containing polyester elastomers and a scaffold - sheet engineering method for tissue engineering applications is provided . cupes can be synthesized by forming a linear pre - polymer , which is a polyester , introducing the urethane bonds into polyester using a diisocyanate as a linker , and crosslinking the resulting urethane containing linear polymers to form cupes via post - polymerization . this family of polymers , cupes , exhibit excellent biocompatibility with desired degradation . tissue engineering scaffolds made of cupes are soft and elastic , and have good mechanical strength . complex tissue grafts can be constructed by a novel layer - by - layer scaffold - sheet engineering design using cupe sheets . cupe scaffolds can provide openings for cell to cell communication across scaffold layers and angiogenesis into the depth of the construct . biomolecules , such as anticoagulants , can be incorporated into the cupe polymers , increasing their viability as vascular graft scaffolds .