title: Dominant role of molybdenum in the electrochemical deposition of biological macromolecules on metallic surfaces.
abstract: The corrosion of CoCrMo, an alloy frequently used in orthopedic implants, was studied with an electrochemical quartz crystal microbalance (QCM) in three physiologically relevant solutions. Mass changes were measured during potentiodynamic tests, showing material deposition in protein solutions at potential levels that caused mass loss when the proteins were not present. X-ray photoelectron spectroscopy (XPS) data indicated that the deposited material was primarily organic and therefore was most likely derived from proteins in the electrolyte. Material deposition consistently occurred at a critical potential and was not dependent on the current density or total charge released into solution. Corrosion studies on pure Co, Cr, and Mo in protein solutions found material deposition only on Mo. We hypothesize that organic deposition results from the interaction of Mo(VI) with proteins in the surrounding solution. The organic layer is reminiscent of tribochemical reaction layers that form on the surface of CoCrMo hip bearings, suggesting that these types of layers can be formed by purely electrochemical means.
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Martin
authors.forename: Robin
authors.initials: R
authors.lastname: Pourzal
authors.forename: Mathew T
authors.initials: MT
authors.lastname: Mathew
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Shull
mesh_terms: D000497:Alloys / Q000737:chemistry*; D055664:Electrochemical Techniques; D046911:Macromolecular Substances / Q000737:chemistry; D008982:Molybdenum / Q000737:chemistry*; D058525:Quartz Crystal Microbalance Techniques; D013499:Surface Properties
chemical_list: D000497:Alloys; D046911:Macromolecular Substances; D008982:Molybdenum
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