Structure and biocompatibility of ion beam modified polyethylene.

Structural changes of polyethylene (PE), induced by irradiation with 40 keV Ar+ ions at a fluence of 1x10(12)-1x10(15) cm(-2), are characterized by different experimental methods and physical parameters of the modified PE are related to its biocompatibility. Production of oxidized structures and conjugated double bonds in the PE surface layer modified by the ion irradiation was proved using IR, UV-VIS spectroscopies and a Rutherford backscattering technique. The fusion of macrophages onto implants made of as-irradiated and chemically doped PE was studied in vivo. It was found that the free surface energy is not a decisive factor affecting the non-self-recognition of the modified PE by macrophages. The fusion of macrophages, however, was found to be different on the as-irradiated specimens and the specimens additionally doped with acrylic acid.