The effect of Ag dopants on the bioactivity and antibacterial properties of one-step synthesized Ag-containing mesoporous bioactive glasses

Mesoporous bioactive glass (MBG) is one of the potential biomaterials for bone reconstruction due to its superior bioactive property. One critical drawback of the MBG is that it has no inhibition ability for bacterial growth, and it can cause high risk of infection during an orthopedic surgery. Silver (Ag) has been reported to have a high inhibitory effect on bacterial growth, and therefore Ag-containing MBG has attracted much attention. However, there has been conflicting reports on whether Ag enhances or deteriorates the bioactivity of MBG. In order to clarify the role of Ag on the bioactivity of MBG, pure and Ag-containing MBG particles were synthesized using spray pyrolysis, and the bioactive and antibacterial properties have been investigated as a function of Ag concentration. The observation suggests that the influence of Ag on bioactivity of MBG depends on the location of Ag. When Ag locates within the MBG particle, Ag replaces Ca to reduce the number of non-bridging oxygen groups giving a lower bioactivity. When Ag locates on MBG surfaces, the releasing Ag ions act as nucleui of hydroxyapatite (HA) and therefore accelerate the HA formation rate resulting in a higher bioactivity.