Insight into synergetic effects of serum albumin and glucose on the biodegradation behavior of WE43 alloy in simulated body fluid

Abstract

The biodegradation rate of Mg alloy medical devices, such as screws and plates for temporary bone fracture fixation or coronary angioplasty stents, is an increasingly important area of study. In vitro models of the corrosion behavior of these devices use revised simulated body fluid (m-SBF) based on a healthy individual’s blood chemistry. Therefore, model outputs have limited application to patients with altered blood plasma glucose or protein concentrations. This work studies the biodegradation behavior of Mg alloy WE43 in m-SBF modified with varying concentrations of glucose and bovine serum albumin (BSA) to (1) mimic a range of disease states and (2) determine the contributions of each biomolecule to corrosion. Measurements include the Mg ion release rate, electrolyte pH, the extent of hydrogen evolution (as a proxy for corrosion rate), surface morphology, and corrosion product composition and effects. BSA (0.1 g l–1) suppresses the rate of hydrogen evolution (about 30%) after 24 h and—to a lesser degree—Mg2+ release in both the presence and absence of glucose. This effect gets more pronounced with time, possibly due to BSA adsorption on the Mg surface. Electrochemical studies confirm that adding glucose (2 g l–1) to the solution containing BSA (0.1 g l–1) caused a decrease in corrosion resistance (by around 40%), and concomitant increase in the hydrogen evolution rate (from 10.32 to 11.04 mg cm–2 d–1) to levels far beyond the tolerance limits of live tissues.