ADHESION AND PROLIFERATION OF CULTURED HUMAN AORTIC SMOOTH-MUSCLE CELLS ON POLYSTYRENE IMPLANTED WITH N- CORRELATION WITH POLYMER SURFACE POLARITY AND CARBONIZATION(, F+ AND AR+ IONS )

Physicochemical surface properties and biocompatibility were studied i n polystyrene (PS) implanted with 150 keV N+, F+ and Ar+ at doses rang ing from 1 x 10(12) to 1 x 10(15) cm(-2). Adhesion and proliferation o f cultured human aortic smooth muscle cells (SMCs) on ion implanted PS were thoroughly examined for dependence on implanted dose and ion spe cies and in close relation to polymer surface oxidation, surface polar ity, concentration of conjugated double bonds and sheet resistivity. T he surface polarity of PS was a smooth, increasing function of the imp lanted dose. However, the dependence of SMC population density on the implanted dose was found to be more complicated. After 18 h cultivatio n time (i.e. when only cell attachment and spreading took place), the number of adhered SMCs and their degree of spreading first increased w ith increasing ion dose, and after reaching a maximum at the dose of 5 x 10(12) cm(-2), they decreased to original values. For doses above 5 x 10(14) cm(-2), an increase in SMC population density and spreading was again observed. The first maximum in cell adhesion can be explaine d by slight increases in the surface polarity and wettability, optimal for cell adhesion, and the second maximum by progressive carbonizatio n of the PS surface. After 96 h cultivation time (i.e. when the cells proliferated intensively), the dramatic dependence of the SMC populati on density on implanted dose is mostly smeared out. This observed depe ndence of SMC attachment, spreading and subsequent proliferation on th e implanted dose was similar in all three ion species, but highest cel l densities were achieved on PS implanted with Ft ions. (C) 1996 Elsev ier Science Limited