Poly(caprolactone-co-oxo-crown ether)-based poly(urethane)urea for soft tissue engineering applications

Random copolymers of e-caprolactone and 2-oxo-12-crown-4 ether, poly(CL-co-OC), were used as soft segments in the synthesis of a set of poly(urethane)urea thermoplastic elastomers. With increasing OC content, the soft segment crystallinity decreased, which influenced the mech. properties: strain induced crystn. disappeared upon the introduction of OC into poly(CL). The material therefore became weaker, however, without a redn. in strain at break. All polymers showed mech. properties that are suitable for soft tissue engineering. Degrdn. studies of poly(CL-co-OC) copolymers revealed a higher intrinsic rate of hydrolysis as compared to poly(CL). When at least two neighboring OC units were present in the soft segment, a jump in the intrinsic hydrolysis rate was obsd. From this study we deduced an ideal OC:CL ratio for the thermoplastic elastomer soft segments for soft tissue engineering applications. An in vitro degrdn. study of these poly(urethane)urea showed an increased wt. loss. Combined with the enhanced hydrophilicity and reduced crystallinity, we are confident that this will indeed lead to an increased degrdn. rate in vivo.