In Vitro Cytocompatibility and Osteogenic Potential of Biodegradable Mg–Sr Alloys

The cytocompatibility and osteogenic ability of novel as-extruded Mg–xSr (x = 0.25, 1.0, 1.5, 2.5 wt%) alloys are systematically investigated by in vitro cell adhesion and proliferation, alkaline phosphatase (ALP) activity, real-time RT-PCR evaluation, and mineralization tests. The results indicate that in addition to no cytotoxicity towards MC3T3-E1 cells, the Mg–Sr alloys, particularly Mg–1.5Sr, obviously promote the adhesion, proliferation, alkaline phosphatase activity, matrix mineralization and collagen secretion of MC3T3-E1 cells compared to pure Mg. Nearly all the osteogenesis-related genes, namely Runx2, Opn, Sp7, and Bmp2, are up-regulated for Mg–xSr, compared to pure Mg. In particular, Mg–1.5Sr reveals the best osteogenic ability. Our work suggest that novel as-extruded Mg–1.5Sr alloy, which exhibits excellent in vitro cytocompatibility and osteogenic ability, is promising in expediting clinical acceptance of biodegradable magnesium alloys.