Colonization of ion-modified polyethylene with vascular smooth muscle cells in vitro.

Polyethylene (PE) foils were implanted with 40 and 150 keV Ar+ ions to the fluences from 1 x 10(13) to 1 x 10(15) cm(-2). Production of conjugated double bonds, characterizing degradation of the PE surface layer, was studied using UV-VIS spectroscopy. Wettability of the PE surface, determined by conventional goniometric techniques, was shown to be an increasing function of both ion energy and fluence. It was also increased after exposure of PE to serum-supplemented cell culture media. Cell culture experiments showed that the ion irradiation significantly increased the adherence of vascular smooth muscle cells (VSMC) and their subsequent growth on the PE surface. On day 1 after seeding, the number of initially adhered VSMC exhibited two maxima. On day 3 after seeding. these maxima disappeared, which was partially due to a significantly shorter doubling time of VSMC. On the other ion-modified samples. the doubling time did not differ significantly from that on the unmodified PE. Enzyme-linked immunosorbent assay revealed increased concentration of talin, a protein of focal adhesion plaques, and alpha-actin, a marker of VSMC differentiation, in cells on ion-implanted surfaces. It can be concluded that the ion irradiation supports the adhesion and differentiation of VSMC without excessive proliferation of these cells.