Surface modification of polyhydroxyalkanoate films and their interaction with human fibroblasts

A poly(3-hydroxybutylate-co-hydroxyvalerate) (PHA) film containing 34 mol.% 3-hydroxyvalerate (Biopol D600P) was prepared by the solvent cast method u sing a 10 wt.% chloroform solution of PHA. The PHA film was exposed to an o xygen plasma glow discharge to produce peroxides on its surfaces. These per oxides were then used as catalysts for the polymerization of acrylic acid ( AA) in order to prepare carboxyl group-introduced PHA (PHA-C). Insulin-immo bilized PHA was prepared using the coupling reaction of PU-C with insulin. The surface-modified PHAs were then characterized by attenuated total refle ction Fourier transform infrared spectroscopy, electron spectroscopy for ch emical analysis, and a contact angle goniometer. The amounts of insulin dir ectly coupled to the carboxyl groups on PHA-C and coupled to the terminus a mino groups of the grafted polyethylene oxide were 2.9 and 0.8 mug cm(-2), respectively. The PHA water contact angle (75 degrees) decreased with AA gr afting (33 degrees) and insulin immobilization (31 degrees), thereby exhibi ting the increased hydrophilicity of the modified PHAs. When compared with PHA and PHA-C, the proliferation of human fibroblasts in the presence of se rum was significantly accelerated on the insulin-immobilized PHAs. (C) 2001 Elsevier Science B.V. All rights reserved.