In vitro and in vivo investigation on biodegradable Mg-Li-Ca alloys for bone implant application

Abstract

Magnesium alloys show promise for application in orthopedic implants, owing to their biodegradability and biocompatibility. In the present study, ternary Mg-(3.5, 6.5 wt%) Li-(0.2, 0.5, 1.0 wt%) Ca alloys were developed. Their mechanical strength, corrosion behavior and cytocompatibility were studied. These alloys showed improved mechanical strength than pure Mg and exhibited suitable corrosion resistance. Furthermore, Mg-3.5Li-0.5Ca alloys with the best in vitro performance were implanted intramedullary into the femurs of mice for 2 and 8 weeks. In vivo results revealed a significant increase in cortical bone thickness around the Mg-3.5Li-0.5Ca alloy rods, without causing any adverse effects. Western blotting and immunofluorescence staining of β-catenin illustrated that Mg-3.5Li-0.5Ca alloy extracts induced osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (hBMMSCs) through the canonical Wnt/β-catenin pathway. Our studies demonstrate that Mg-3.5Li-0.5Ca alloys hold much promise as candidates for the facilitation of bone implant application.