Assessing Cytocompabitility of Novel High Ductility Magnesium Alloys

Magnesium-based alloys have attracted considerable attention in the last decade due to its biocompatibility, ability to degrade in vivo, and suitable mechanical properties. New application possibilities, such as orthopedic implant, sutures and vascular stents, have the potential to reduce the number of second surgeries as well as significant long-term adverse effects due to perennial existence of the device. Magnesium alloys do not produce any toxic corrosion product during degradation; however, its rapid, uncontrolled degradation rates raise concerns, as the surrounding tissues get affected. Currently, there are no studies to date reported to evaluate the cytotoxicity of magnesium-based alloys on airway epithelium cells. The aim of this study is to assess the in vitro cytotoxicity of our proprietary patent pending ultra-high ductility (UHD) magnesium alloys specifically aimed at tracheal stent application. In this study, pure Mg, AZ31, and three alloys of different compositions containing lithium, aluminum, and zinc are tested. MTT testing and DAPI & F-action staining were performed to determine the effects of the degradation products of these novel alloys with different dilution ratios on the human bronchial epithelial cell line (BEAS-2B). These results demonstrated comparable cytotoxicity of our proprietary magnesium alloys to commercial pure magnesium and AZ31 alloys. ICP-OES and the MTT analyses show a potential impact of lithium ion concentration on the cell viability. Through DAPI & F-Actin staining, it can be seen that the alloys do not have an adverse impact on the morphology of the cells. The effect of magnesium ions on the aggregation of BEAS-2B cells can also be seen in the DAPI & F-Actin staining. The in vitro studies, combined with the in vivo experiments that are currently proceeding, will elucidate the biocompatibility of each alloy, and will also help ascertain the suitability of these novel ultra-high ductility (UHD) alloys for tracheal stent applications.