Preparation of body-temperature-triggered shape-memory polyurethane with biocompatibility using isosorbide and castor oil

Shape memory polyurethanes (SMPUs) have attracted much attention in the biomedical field because they can easily control the transition temperature (T-trans) to shape memory and are biocompatible. In this study, a shape memory polyurethane with both biocompatibility and a T-trans close to the body temperature was synthesized by using natural derivatives of isosorbide and castor oil in place of petroleum-based materials. Isosorbide and castor oil were used to form net points, and polycaprolactone diol (PCL diol) acted as the switching segment. The synthesized four polyurethane (PCL diol/isosorbide/castor oil, PICU-1, 2, 3, 4) with different isosorbide contents exhibited desired thermal and mechanical properties. In the thermo-cyclic shape memory testing experiment, the PICU series demonstrated good shape memory property, with more than 95% shape recovery ratio (R-r) and more than 90% shape fixity ratio (R-f), and PICU-3 recovered its shape within 20 s in a 37 degrees C water bath. In addition, the PICU series proved to be safe materials with excellent biocompatibility, as indicated by the observed C2Cl2 cells viability and proliferation. The stent made with the PICU-3 film showed near complete magnetization at 37 degrees C within 18 s and proved to be a suitable self-expanding stent.