载银珊瑚羟基磷灰石的抑菌活性与细胞毒性研究

Antibacterial activity and in vitro cytotoxicity of silver-coated coral hydroxyapatite

目的 评价负载不同浓度银离子后的珊瑚羟基磷灰石（CHA）对大肠杆菌和金黄色葡萄球菌的抑菌效果与细胞毒性.方法 采用真空冷冻干燥法制备1×10^-2～1×10^-5 mol/L Ag＋浓度的载银CHA（Ag-CHA）,然后采用琼脂平板抑菌法评价Ag-CHA对大肠杆菌和金黄色葡萄球菌的抑菌效果,并测量24 h后的抑菌圈直径.采用甲基噻唑基四唑（MTT）法评价8×10^-5mol/L的Ag-CHA在2、4、7d对L929小鼠成纤维细胞的毒性作用. 结果 载银浓度为1×10^-2～8×10^-5mol/L的Ag-CHA对大肠杆菌和金黄色葡萄球菌的抑菌圈直径均大于12 mm,有明显的抑菌作用;而载银浓度低于8×10^-5mol/L的Ag-CHA无抑菌作用.载银浓度低于8×10^-5mol/L的Ag-CHA对L929细胞无毒性作用;8×10^-5mol/LAg-CHA浸提液作用细胞2、4、7 d后,细胞生长状态良好,相对增殖率均大于90%,毒性等级为0或1级.结论 最佳载银浓度为8×10^-5mol/L,该条件下的Ag-CHA有良好的抑菌作用,且无细胞毒性.

Objective To evaluate the antibacterial activity against Escherichia coli and Staphylococcus aureus and cytotoxicity of silver-coated coral hydroxyapatite （Ag-CHA） at different Ag＋ concentrations. Methods Vacuum freeze-drying technique was applied to obtain the silver-coated Ag-CHA at from 1 × 10^-2 to 1 × 10^-5 mol/L Ag^＋ concentrations. Antibacterial tests against Escherichia coli and Staphylococcus aureus were carried out by flat plate diffusion method. The inhibition zones were measured after culture for 24 hours to evaluate the antibacterial activity of Ag-CHA. The leaching solution of 8 × 10^-5 mol/LAg-CHA was prepared and mouse fibroblast L929 was cultured at 2, 4, 7 days with the leaching solution.Finally MTT method was used to evaluate the cytotoxicity of Ag-CHA. Results Ag-CHA at a concentration from 1 × 10^-2 to 8 × 10 ^-5 mol/L Ag^＋ had obvious inhibition zones of over 12 mm against E. coli and S. aureus, whereas Ag-CHA at a concentration less than 8 × 10^-5 mol/L had no antibacterial effect. Ag-CHA from 0 to 8 × 10^-5 mol/L Ag＋ had no cytotoxicity on L929. Cell relative growth rates（RGR） for 8 × 10 ^-5mol/L Ag-CHA were all larger than 90% and the cytotoxicity grades were 0 or 1 after culture for 2, 4, 7days. Conclusion Ag-CHA at a concentration of 8 × 10^-5 mol/L Ag^＋ may have the most effective antibacterial activity but no cytotoxicity.