Synthesis, characterizations, and biocompatibility of block poly(ester-urethane)s based on biodegradable poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3/4HB) and poly(ε-caprolactone)

A type of block poly(ester-urethane)s (abbreviated as PUBC) based on bacterial copolyester poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3/4HB) and biodegradable poly(epsilon-caprolactone) (PCL) was synthesized by melting polymerization using 1,6-hexamethylene diisocyanate (HDI) as the coupling agent, with different 3HB, 4HB and PCL contents and segment lengths. Stannous octanoate (Sn(Oct)2) was used as catalyst. The chemical structure, molecular weight and thermal property were characterized by H-1 NMR, FTIR GPC, DSC and TGA. DSC analysis revealed that the PUBC polyurethanes exhibit amorphous to semi-crystalline (20.9% crystallinity degree) with T-g range from -39.7 to -21.5 degrees C. The hydrophilicity was investigated by static contact angle of deionized water and CH2I2. The obtained PUBCs are hydrophobic (water contact angle 73.7-90.2 degrees). Platelet adhesion study and plasma recalcification time revealed that the block polyurethanes possess hemastasis ability. CCK-8 assay illuminated that the no cytotoxic polyurethanes maintain rat aortic smooth muscle cells (RaSMCs) good viability. It was found that the 4HB content in the materials is an important factor to affect the sustainable cell viability. (C) 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A:7586, 2013.