Polyurethane/polycaprolactane blend with shape memory effect as a proposed material for cardiovascular implants.

Shape memory materials have been proposed for cardiovascular stents due to their self-expansion ability. The most ideal way to anchor a stent is using self-expansion in the range of body temperature. This work, for the first time, reports the use of polyurethane/polycaprolactone (PU/PCL) blend as a proposed material for shape memory stents. Polyurethane copolymer based on poly(epsilon-caprolactone) diol was melt blended with PCL in four different ratios of 20, 30, 40 and 50 wt.% and their shape memory behaviors were examined. All blends except for PU/PCL(80/20) showed shape memory effects with recovery temperatures of around the melting temperature of PCL in the blends. The melting behavior of the PCL in the blends is strongly influenced by composition. Changing the composition of the blend system and crystallization conditions adjusted shape recovery to the range of body temperature for PU/PCL(70/30) blend. The in vitro biocompatibility of PU/PCL(70/30) blend was evaluated in this study using human bone marrow mesenchymal stem cells (hBMSCs). The adhesion, morphology and mitochondrial function were analyzed in order to investigate the cell viability during cell culture on PU/PCL(70/30) blend surface. The results showed that the blend supported cell adhesion and proliferation, which indicated good biocompatibility. Our results suggested that this blend might be a potential material as a stent implant.