Loading, Sustained Releasing And Antibacterial Ability Of Silver Ions On Mesoporous Bioactive Glass

Since bioactive glass (BG) possesses excellent biological activities, the applications of tissue repair and replacement are increasingly clinically. But in recent years, many studies have found that when implanted in human tissue, it will form a layer of protein membrane in the surface of BG and bacteria are very easy to adhere to the protein membrane and then grow and reproduce, causing serious infection in the sites of implanting, leading to loosening and falling of the implant ahead of time, resulting in failure of treatment. Therefore, the research and development of antibacterial BG, which can combine treatment rehabilitation and prevention of infection, will have important medical values.On the basis of broad-spectrum bactericidal effect of silver ions and the applications of mesoporous bioactive glass(MBG) in the fields of loading and release of drug. This paper used tri-block copolymer P123 as a template agent and TEOS, TEP, four water-calcium nitrate as inorganic precursor to prepare ternary-assembled mesoporous bioactive glass M58S with sol-gel method and then the prepared M58S was amino-modified by KH550(SM58S).The vitro biological activity of M58S and SM58S were studied in the simulated body fluid (SBF). The modified M58S and SM58S(Ag-M58S,Ag-SM58S) were loaded silver ions with the method of ion exchange, using M58S and SM58S as carriers and AgNO₃ solution as the exchange solution. The relationship between initial concentration of silver nitrate, loading time, temperature and the amount of loaded silver was studied and the release of Ag-M58S and Ag-SM58S in both deionized water and SBF were also searched. Based on these studies, the composite porous membranes was made through M58S,Ag-M58S,Ag-SM58S mixing with the silk fibroin with freeze-drying method and the antibacterial activities of M58S, Ag-M58S, Ag-SM58S and the composite porous membranes were studied preliminarily. The main conclusions are as follows:1. The prepared M58S had the structure of three-dimensional pore with highly ordered hexagonal phase. The size distribution of mesoporous pore was very narrow and uniform, the vast majority concentrated 10nm.The specific surface area of M58S was 269.54 g/m², the pore volume of mesoporous pore was 0.61 g/cm³. Through the vitro bioactivity tests, it was found that M58S had excellent ability of deposition of petal-like hydroxyapatite.2. The surface of M58S was modified by KH550 successfully bonding with Si-O-Si and the rate of grafting was about 2.89%. Moreover, the surface organic modification didn't affect in-vitro biological activity .3. Both M58S and SM58S were ideal carriers with high saturated amount of loaded silver, but SM58S had larger capacity than that of M58S.The uniformity of silver ions loading was also good.4. Ag-M58S and Ag-SM58S had good ability of releasing silver ions in both de-ionized water and SBF medium. By comparison, the sustained release property was better in the SBF medium, laying a foundation of long-term and effective antibacterial achievement.5. M58S possessed certain antibacterial property itself.Ag-M58S and Ag-SM58S had strong and durable antibacterial property. Pure porous silk fibroin membrane (SF) was not antibacterial, M58S/SF had weak antibacterial property.Ag-M58S/SF and Ag-SM58S/SF had good anti-bacterial property and the anti-bacterial property of Ag-SM58S/SF was more stable, durable and efficient in particular.