Degradation of Magnesium Alloys in Artificial Urine Solution for Urological Device Applications

Abstract

Magnesium-based alloys are promising for various biomedical applications due to their advantageous mechanical and biological properties. In this study, we investigated the potential use of magnesium-based alloys for urological device applications, e.g. a biodegradable and antibacterial ureteral stent. Previous studies showed that magnesium-based samples significantly inhibited bacterial growth and colony formation in artificial urine (AU) solution as compared with the polyurethane-based stent. This current study focuses on long-term magnesium-based sample degradation in AU solution and deionized water. We studied the effects of alloy composition (magnesium alloyed with yttrium or aluminum and zinc) and surface condition (oxide versus metallic surface) on the rate of degradation. Sample degradation was measured by the change in sample mass, pH of immersion solution, and magnesium ion concentration in the solution. Results showed that both alloy composition and surface condition affected the rate of degradation in the AU solution. For instance, magnesium-yttrium alloy degraded the fastest and the presence of the oxide layer increased its degradation rate in the AU solution. The overall degradation rate in the AU solution was in this order (fastest to slowest degrading): MgY_O > MgY > Mg_O > AZ31. Further investigation is necessary to determine the efficacy and safety of magnesium-based biodegradable stents for urological applications.