Ternary blends of PCL, SAN15 and SMA14: miscibility, crystallization and melting behaviour, and semicrystalline morphology

Electrospun membranes of carboxylated poly(ester urethane)urea/gelatin encapsulating pterostilbene for adaptive and antioxidative purposes

Oxidative stress caused by the harsh microenvironment after implantation of an artificial graft with mismatching mechanical properties usually triggers inflammation responses, which have adverse impacts on tissue regeneration. For coping with these problems, in this work, bioactive fibrous scaffolds were developed from specially synthesized carboxylated poly(ester urethane)urea (PEUU) and gelatin (Gel) by encapsulating pterostilbene (Pte) for the first time. The prepared electrospun membranes exhibited self-adaptable mechanical properties with high elasticity owing to the bonded electrospun fibers, cross-linking network between PEUU and Gel, and the inherent flexibility of the PEUU polymer in the fibrous matrix. The PEUU/Gel/Pte electrospun membrane containing 7% Pte could promote in vitro proliferation of human umbilical vein endothelial cells, and regulate vascular smooth muscle cells with excellent antioxidant properties via free radical scavenging. In vivo results in a rat subcutaneous implantation model further demonstrated the positive effect of the specially prepared PEUU/Gel/Pte scaffold on both normal cell growth and anti-inflammatory by promoting cellularization and polarizing macrophages toward the M2 phenotype. These PEUU/Gel/Pte electrospun membranes with adaptability benefit to tissue regeneration by modulating inflammation responses, especially applications in vascular regeneration.

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.