Proliferation and differentiation of mesenchymal stem cell on collagen sponge reinforced with polypropylene/polyethylene terephthalate blend fibers.

Although tissue-engineered scaffolds made from collagen sponge are suitable for cell infiltrating, easily supplying oxygen and nutrients to cells, and removing the waste products, their mechanical properties are not satisfactory to be used as scaffold materials for tissue engineering applications. To improve mechanical properties of collagen, a novel porous scaffold for bone tissue engineering was prepared with collagen sponge reinforced by polypropylene/polyethylene terephthalate (PP/PET) fibers. Collagen solution (6.33 mg/mL) with PP/PET fibers (collagen/fiber ratio [w/w]: 1.27, 0.63, 0.42, 0.25) was freeze-dried, followed by cross-linking of combined dehydrothermal and glutaraldehyde. A scanning electron microscopy-based analysis of surface of the sponges demonstrated that the sponge with collagen/fiber <0.25 exhibited homogenous and interconnected pore structure with an average pore size of 200 µm. Incorporation of PP/PET fibers significantly enhanced the compressive strength of the collagen sponge. Proliferation and osteogenic differentiation of mesenchymal stem cell in collagen sponges reinforced with PP/PET fibers incorporation were significantly enhanced compared with collagen sponge without PP/PET incorporation. We conclude that incorporation of PP/PET fibers not only improves the mechanical properties of collagen sponge, but also enables mesenchymal stem cells to positively improve their proliferation and differentiation.

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.