Biocompatibility of Fe–O films synthesized by plasma immersion ion implantation and deposition

Pure iron is a potential material for coronary artery stents based on its biocorrodible and nontoxic properties. However, the iron stents could lose their mechanical stability prematurely due to their corrodible degradation. In this study, Fe–O thin films were prepared on the pure iron by plasma immersion ion implantation and deposition (PIII&D) to improve its corrosion resistance and biocompatibility. The X-ray photoelectron spectroscopy (XPS) and glancing angle X-ray diffraction (GAXRD) results showed the phase structure of the films transformed from FeO to Fe3O4 with the increase of the oxygen flux. The Fe–O film fabricated under the low oxygen flux (3.4 sccm) effectively improved the corrosion resistance of pure iron and had much better adhesion than under the high oxygen flux. The systematic evaluation of hemocompatibility, including in vitro platelets adhesion, prothrombin time (PT), thrombin time (TT), indicated that the number of platelet adhesion, platelet activation on the surface of FeO film were remarkably decreased compared with pure iron, the PT and TT were almost the same as the original plasma. The results of human umbilical vein endothelial cells (HUVECs) culture showed HUVECs had good adhesion and proliferation behavior on the FeO film. It was indicated that, after depositing FeO thin film by PIII&D under the low oxygen flux, the corrosion resistance and biocompatibility of pure iron were effectively improved.