In vitro osteogenic potential of magnesium alloy without and with calcium phosphate coating

Magnesium-based biomaterials have emerged as promising candidates for bone regeneration due to their biodegradability and favorable mechanical properties. This study investigated the effects of Magnesium alloys without (Mg1) and with (Mg2) calcium phosphate coating on osteoblast viability and activation. The physical structure of the alloys was analyzed by surface characterization, mechanical testing, and biodegradation assays. Biological performance was evaluated through MTT and MTS assays for cell viability and proliferation, quantification of alkaline phosphatase activity at 24 h, 7, and 15 days, and mineralization by Von Kossa staining, after 21 days. Cell morphology and apoptosis were assessed using fluorescence microscopy and immunostaining for caspase 3 and 9, while protein expression of BMP-2, OPG, and RANK-L was also investigated by immunostaining. The results demonstrated a significant increase in viable cells in both Mg1 and Mg2 groups after 24 and 48 h. Enhanced mineralization and a significant increase in alkaline phosphatase activity were observed in the Mg2 group. Both Mg1 and Mg2 groups exhibited a similar reduction in caspases 3 and 9 expression, indicating cell survival despite morphological changes. Furthermore, osteoblasts cultured on both alloys showed greater expression of BMP-2 and OPG, compared to the DMEM group. Taken together, these findings highlight the potential of calcium phosphate-coated magnesium alloy as a novel approach for bone restoration in the future.