Abstract: Magnesium-calcium (Mg-Ca) alloys have emerged as promising candidates for temporary bioimplant applications as they possess the required biodegradability, biocompatibility, and mechanical properties. However, the corrosion behavior of Mg-Ca alloys, especially in protein-containing physiological environments, remains insufficiently understood. This study investigates the effect of bovine serum albumin (BSA) addition to Hanks' balanced salt solution (HBSS) on the corrosion of a Mg-Ca alloy having low Ca content, which minimizes secondary precipitates and thus mitigates localized corrosion. Investigation of corrosion resistance employing potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) infers that BSA adsorption on the alloy surface inhibits dissolution, retarding corrosion during the initial exposures, but is followed by corrosion acceleration due to a destabilization of the Mg-Ca surface after extended immersion. Surface characterization using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) provides mechanistic insights into the dual role of BSA addition to HBSS. This study illustrates the complex interaction between proteins and Mg-alloy substrate, and may further facilitate the reliable design of temporary bioimplants.

Key words: Lean magnesium alloy, Temporary bioimplants, Biodegradable implants, Surface characterization