Reduction-sensitive rapid degradable poly(urethane-urea)s based on cystine

Two kinds of novel reduction-sensitive rapid degradable poly(urethane-urea)s were synthesized and characterized based on a cystine derivative chain extender which provided active sites for reductive degradation. In vitro degradation study was carried out under physiological conditions mediated by glutathione and dithiothreitol respectively, and was assessed by 1H NMR, GPC and SEM. The results indicated that the disulfide bonds in poly(urethane-urea)s were effectively cleaved while the structures of urethane groups and soft segments remained almost unaffected. Still, the rate and degree of reductive degradation could be controlled by the structures of the polymers. The influence of the poly(urethane-urea)s on human umbilical vein endothelial cells was investigated by WST-1 assay. The results indicated that the polymers sustained much higher cell viability than the controls. It is possible that the poly(urethane-urea)s can be potentially applied for temporary biomaterials such as wound closure devices, cell scaffolds and sophisticated drug delivery systems.