Osteogenic Effects of Ion Released from Biodegradable Metallic Magnesium and Calcium Coating

This study investigates the effects of ion release and pH elevation from a biodegradable metallic magnesium (Mg) -30 calcium (Ca) coating on osteogenesis using osteoblast-like cells. The coating, formed on titanium (Ti) via magnetron sputtering, has previously been shown to enhance osteogenesis by promoting calcite formation on the Ti surface upon degradation in vitro study. However, the individual and combined roles of released Mg²⁺, Ca²⁺, and pH elevation remain unclear. To clarify these effects, culture media supplemented with Mg²⁺ and Ca²⁺ salts are prepared. Mg²⁺ at 4-5 mm promotes early alkaline phosphatase (ALP) activity compared to the 0.9 mm control, without affecting proliferation but suppressing mineralization. Ca²⁺ at 2.3-3 mm enhances ALP activity without affecting proliferation or mineralization compared to the 1.3-2.2 mm control. When both ions coexist, proliferation, ALP activity, and mineralization are enhanced compared to Mg²⁺ alone, suggesting a synergistic effect. Furthermore, the elevated pH resulting from the Mg-30Ca extract more effectively promotes proliferation, accelerates the peak of ALP activity, and supports mineralization than ions co-supplementation. These findings indicate that Mg-30Ca coatings enhance osteogenesis through both ion release and pH elevation, providing new insight into the osteogenic potential of biodegradable metallic coatings.