Understanding the influence of HEPES buffer concentration on the biodegradation of pure magnesium: an electrochemical study

Kannan, M. Bobby, Khakbaz, Hadis, and Yamamoto, A. (2017) Understanding the influence of HEPES buffer concentration on the biodegradation of pure magnesium: an electrochemical study. Materials Chemistry and Physics, 197. pp. 47-56.

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Abstract

A systematic electrochemical study was performed to understand the influence of HEPES buffer concentration on the biodegradation behaviour of pure magnesium in a pseudo-physiological solution (Earle's balanced salt solution (EBSS)). Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarisation experiments suggest that HEPES accelerates the degradation of magnesium. While 5% CO2 in EBSS reduced the polarisation resistance (R-p) of magnesium by similar to 79%, addition of HEPES (25 mM) to EBSS decreased the R-p of magnesium by similar to 98% and escalated the corrosion current (i(corr)) by over an order of magnitude as compared to that in EBSS. Increase in HEPES concentration (50 mM and 100 mM) further increased the degradation of magnesium. Interestingly, the bulk pH difference between EBSS + HEPES and EBSS + CO2, before and after the electrochemical testing, was only marginal. However, the polarisation curves and Fourier transform infrared (FTIR) spectroscopy analysis suggest that HEPES affected the formation of insoluble salt layer (phosphate and carbonate) on the surface of magnesium. This effect can be attributed to the increase in the ionic strength of the solution due to HEPES addition.

Item ID: 50638
Item Type: Article (Research - C1)
ISSN: 1879-3312
Keywords: magnesium, biomaterials, degradation, HEPES, EBSS
Funders: National Institute for Materials Science (NIMS), Japan Society for Promotion of Science (JSPS)
Projects and Grants: JSPS KAKENHI Grant number 26282151
Date Deposited: 20 Sep 2017 10:45
FoR Codes: 09 ENGINEERING > 0903 Biomedical Engineering > 090301 Biomaterials @ 100%
SEO Codes: 86 MANUFACTURING > 8612 Fabricated Metal Products > 861299 Fabricated Metal Products not elsewhere classified @ 100%
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