Effects of magnesium ion supplement on physicochemical properties and bioactivities of medical bone materials converted from oyster shell

Oyster is a very important cultured shellfish in Taiwan. About 10 % of oyster shells are discarded as waste every year without proper utilization. Therefore, the waste oyster shells were converted into bone materials included β-tricalcium phosphate [β-Ca3(PO4)2, β-TCP] and 4 kinds of β-tricalcium magnesium phosphate [(Ca,Mg)3(PO4)2, β-TCMP], which were supplemented with 1–4 folds of original amount of magnesium ion (Mg2+) in the oyster shell. The crystal structures of these five converted materials were analyzed by X-ray diffraction. The peak of Mg2+ was elevated with increasing level of Mg2+ in β-TCP. The particle size and surface pore were smaller and more by using scanning electron microscopy observations. The bioactivity of these materials was studied by using osteoblasts (MG-63 cells). All five materials were non-toxic. It had the best cell viability when Mg2+ was added with 3 folds of original amount. It was also found that supplement of Mg2+ has the effect on promoting the differentiation of osteoblasts. Among them, adding 3 folds of Mg2+ in β-TCMP has the best effect on cell differentiation. In addition, Mg2+ has the effect on promoting the mineralization of cells. Among them, adding 3 folds of Mg2+ in β-TCMP has the best effect. Hence, β-TCP and/or β-TCMP prepared from oyster shells have the effect on increasing bioactivity of osteoblasts. Among of them, β-TCP with 3 folds of original amount of Mg2+ in TCP shows the best effect.