Preparation of insulin-immobilized polyurethanes and their interaction with human fibroblasts

Insulin-immobilized polyurethanes (PU) were prepared by the graft polymerization of acrylic acid on oxygen plasma-treated PU, followed by a coupling reaction with polyethylene oxide (PEO) and subsequently with insulin. Modified PUs were characterized by measuring the water contact angle, the electron spectroscopy for chemical analysis and the attenuated total reflection Fourier-transform infrared spectroscopy. The wettabilities of the PU surfaces were increased by the introduction of acrylic acid, PEO and insulin. The amount of insulin immobilized was controlled by changing the concentrations of grafted acrylic acid and PEO. The interactions of human fibroblasts with surface-modified PUs were investigated using [3H]-thymidine incorporation and optical microscopy. Compared to the PU control, the proliferation of cells on the insulin-immobilized PUs was accelerated irrespective of the presence of serum while it was not influenced by PEO grafting. It seemed to be certain, from the experiments with high performance liquid chromatography, that A chain of insulin mainly reacted with the amine-end group of PEO grafted during the immobilization reaction.