title: Metal release and speciation of released chromium from a biomedical CoCrMo alloy into simulated physiologically relevant solutions.
abstract: The objective of this study was to investigate the extent of released Co, Cr(III), Cr(VI), and Mo from a biomedical high-carbon CoCrMo alloy exposed in phosphate-buffered saline (PBS), without and with the addition of 10 µM H2 O2 (PBS + H2 O2 ), and 10 g L(-1) bovine serum albumin (PBS + BSA) for time periods up to 28 days. Comparative studies were made on AISI 316L for the longest time period. No Cr(VI) release was observed for any of the alloys in either PBS or PBS + H2 O2 at open-circuit potential (no applied potential). However, at applied potentials (0.7 V vs. Ag/AgCl), Cr was primarily released as Cr(VI). Co was preferentially released from the CoCrMo alloy at no applied potential. As a consequence, Cr was enriched in the utmost surface oxide reducing the extent of metal release over time. This passivation effect was accelerated in PBS + H2 O2 . As previously reported for 316L, BSA may also enhance metal release from CoCrMo. However, this was not possible to verify due to the precipitation of metal-protein complexes with reduced metal concentrations in solution as a consequence. This was particularly important for Co-BSA complexes after sufficient time and resulted in an underestimation of metals in solution.
authors.affiliation: KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Division of Surface and Corrosion Science, Stockholm, Sweden.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Hedberg
authors.forename: Inger
authors.initials: I
authors.lastname: Odnevall Wallinder
mesh_terms: D000818:Animals; D002244:Carbon; D002417:Cattle; D002857:Chromium / Q000032:analysis; D055664:Electrochemical Techniques; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008422:Materials Testing; D010084:Oxidation-Reduction; D056951:Photoelectron Spectroscopy; D012710:Serum Albumin, Bovine / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology; D012995:Solubility; D012996:Solutions; D013193:Stainless Steel; D014800:Vitallium / Q000737:chemistry*
chemical_list: D012996:Solutions; D002857:Chromium; D013193:Stainless Steel; D014800:Vitallium; D012710:Serum Albumin, Bovine; D012965:Sodium Chloride; D002244:Carbon; D006861:Hydrogen Peroxide
keywords: bovine serum albumin; chromium; hydrogen peroxide; metal release; speciation