Chemical characterization of degradation products in bio-degradable coronary magnesium stents.

Bioresorbable magnesium stents are a promising future treatment for coronary artery stenosis. However, even after decades of development, the degradation process, ideal degradation time and biological response in vivo are still not fully understood. The degradation products, such as hydroxides, phosphates, and carbonates, delay the corrosion through the formation of corrosion fronts. We will study the chemistry of these fronts using Ca K-edge µ XANES spectroscopy. Furthermore, Mg is alloyed with rare earth elements to improve the mechanical and corrosion properties. These elements accumulate as so-called intermetallic particles, due to their slower degradation compared to the matrix material, with unknown systemic toxicological effects. Thus, we will investigate a common and promising Mg alloy and determine the particle composition and if they completely corrode before exiting the corrosion layer, or if they are incorporated into the surrounding tissue through µXRF.