Dissolution behavior of CaO-MgO-SiO 2 -based multiphase bioceramic powders and effects of the released ions on osteogenesis.

In the present study, the dissolution behavior of the CaO-MgO-SiO2 -based multiphase bioceramic powders as well as the effects of released ions on osteogenesis was investigated. In the dissolution process, Ca, Mg, and Si ions could be dissolved out from the powders. The incorporation of Mg could slow down the degradation rate of the powders so that to reduce the local concentration of Ca and Si ions. In return, the dissolution of Ca and Si ions leading to the formation of a porous SiO2 -rich layer could enhance the readsorption of free Mg ions in solution and thus down-regulate the concentration of Mg ions. In addition, the released ions exhibited both positive and negative synergistic effects on osteogenesis with a concentration-dependent manner. Trace amount of released Si ions could stimulate cell proliferation and osteogenic differentiation in the presence of Ca and Mg ions. The optimal concentration of Ca-Mg-Si ion combination to promote osteogenesis was existed in the 1/4 diluted extract, whereas a slightly inhibitory effect on cell proliferation and ALP activity was observed in the 1/2 diluted extract with higher concentration of Ca and Si ions . All above results suggested that the ion dissolution behavior of the CaO-MgO-SiO2 -based multiphase bioceramic could be regulated via adjustment of the composition so that released ions could be maintained at an appropriate composite concentration to cooperatively regulate the osteogenesis. This research provided an experimental basis for further optimization and application of CaO-MgO-SiO2 -based multiphase bioceramics with controlled ion dissolution and excellent physicochemical and biological properties. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3159-3168, 2017.