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Corrosion study of iron‐cobalt alloys for MRI‐based propulsion embedded in untethered microdevices operating in the vascular network
Author(s) -
Pouponneau Pierre,
Savadogo Oumarou,
Napporn Teko,
Yahia L'hocine,
Martel Sylvain
Publication year - 2010
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.31575
Subject(s) - corrosion , materials science , cobalt , metallurgy , magnetization , alloy , electrolyte , biomedical engineering , chemistry , magnetic field , electrode , medicine , physics , quantum mechanics
Our group have shown in an experiment performed in the carotid artery of a living swine that magnetic gradients generated by a clinical magnetic resonance imaging (MRI) system could propel and navigate untethered medical microdevices and micro‐nanorobots in the human vasculature. The main problem with these devices is that the metal necessary for magnetic propulsion may corrode and induce cytotoxic effects. The challenge, then, is to find an alloy with low corrosion yet providing an adequate magnetization level for propulsion in often stringent physiological conditions. Because of their high magnetization, we studied the corrosion behavior of two iron‐cobalt alloys, Permendur (49% Fe, 49% Co, 2% V) and Vacoflux 17 (81% Fe, 17% Co, 2% Cr), in physiological solution by potentiodynamic polarization assay, surface analysis, and corrosion electrolyte analysis. Both alloys exhibited low corrosion parameters such as a corrosion potential ( E corr ) of −0.57 V/SCE and E corr of −0.42 V/SCE for Vacoflux 17. The surface of Permendur samples was homogenously degraded. Vacoflux 17 surface was impaired by cracks and crevices. Both alloys had a stoichiometric dissolution in the electrolyte, and they released enough cobalt to induce cytotoxic effects. This study concluded that Fe‐Co alloys could be used preferably in medical microdevices if they were coated so as not to come in contact with physiological solutions. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010