Biocompatibility study of Fe-doped zirconia-toughened alumina ceramic for artificial joints

Fe-doped zirconia toughened alumina (Fe: ZTA) ceramic is a promising material for artificial joint implants because of high density, good mechanical properties and excellent wear resistance. To evaluate its use in biological implants, Fe: ZTA ceramics with different Fe contents (0–5 wt.%) were fabricated using the fast hot pressed sintering method, and the biocompatibility of Fe: ZTA ceramics and the biotoxicity of wear debris from Fe: ZTA were systematically studied. The additive Fe element mainly exists in the form of FeAl2O4. The addition of Fe results in the increase of surface hydrophobicity and the decrease of surface energy and polar component, improving the protein absorption on Fe: ZTA surface. According to the culture results with osteoblasts and macrophages, Fe doping can increase the osteoblast activity and does not cause significant macrophage activation on the surface of Fe: ZTA ceramics. Particularly, the 1.5 wt% Fe: ZTA ceramic can significantly improve the cytocompatibility of osteoblasts and reduce the inflammatory reaction. On this basis, 1.5 wt% Fe: ZTA ceramic with the best biocompatibility was used to prepare the wear debris, and the biotoxicity of wear debris was further studied. The result confirms that wear debris of Fe: ZTA ceramic (50–1000 μ g/ml) does not cause the significant decrease in osteoblast activity and has no significant effect on the osteoblast morphology, without distinct cytotoxicity. The wear debris of Fe: ZTA (≤ 200 μ g/ml) will not cause significant inflammatory response. This study can provide guidance for the application of Fe: ZTA ceramic in biological implants.