Thiol-ene click-functionalized polybutadiene elastomers achieve durable and biocompatible polyurethanes for long-term implantable systems

Conventional polyurethanes for implants suffer from hydrolytic/oxidative degradation due to ester/ether bonds. To overcome this, in this research, we have developed aging-resistant implantable medical polyurethanes to address the issue of their limited durability. The synthesis involves ethanethiol for the click reaction-mediated elimination of the C C in terminal hydroxy polybutadiene (HTPB), resulting in the creation of HTPB-SH. Subsequently, an aging-resistant implantable polyurethane, HTPB-SH-PU, is synthesized. This material demonstrates not only remarkable thermal stability (T d5% >290°C) but also superior mechanical performance, evidenced by a tensile strength of 35.1 MPa and an elongation at break of 196.74%. Moreover, HTPB-SH-PU is exhibiting outstanding aging resistance. In a hydrolysis aging test, it retains 71% of its tensile strength after 35 days, with negligible yellowing. To enhance biocompatibility, gastrodin is incorporated at various concentrations (0%, 0.5%, 1.0%, 2.0%), and the modified polyurethanes display excellent cytocompatibility, haemocompatibility, and histocompatibility. Therefore, the HTPB-SH-PU series represents a promising candidate for implantable medical devices such as pacemakers and artificial blood vessels, offering a solid theoretical foundation and material options for future research and development in medical polymers.