Electrochemical property and surface composition of metallic biomaterials under the in vivo and in vitro environments
National Institute of Material Science (NIMS), Tsukuba, Japan
Biocompatibility and corrosion of metallic biomaterials is dominated by interaction between the material surface and tissue (cells). In this study, the interaction of metallic biomaterials with cells was examined by electrochemical measurement and surface analysis of the materials retrieved from the patients or immersed in medium with and without cells.
Polarisation test of pure Ti and 316L stainless steel was performed in medium with and without fibroblast cells. Influence of the cells on cathodic reaction depended on cell density and cathodic current density corresponding to the reduction of dissolved oxygen decreased with the increase of cell density. Protectiveness of passive film on pure Ti was not significantly influenced with the cells whereas that on 316L steel decreased with the cells.
On the surface of Ti alloy orthopaedic devices retrieved from the patients, calcium and phosphor always precipitated. In the case on 316L steel devices, these elements precipitated on the surface formed in hard tissue more frequently than that in soft tissue. Similar results were obtained on the surfaces formed in the medium with and without the cells. The amount of precipitated calcium and phosphor on pure Ti was larger than that on 316L steel. Moreover, the presence of cells caused the decrease of these elements. Characteristic influence of the cells appeared on the chemical state of sulphur precipitated. The binding energy of S2p XPS spectra on the surfaces formed in the human body and with the cells was rather lower than that on the surface formed without the cells.
Consequently, interaction between metallic biomaterials and cells forms a different interface environment from that in the absence of cells. In order to accurately evaluate the biocompatibility and corrosion of the materials, the dominant factor derived from cells should be elucidated.
Presentation: Invited at E-MRS Fall Meeting 2007, Symposium D, by Sachiko Hiromoto
See On-line Journal of E-MRS Fall Meeting 2007
Submitted: 2007-04-26 08:57 Revised: 2009-06-07 00:44