纳米和微米级二氧化硅对表皮葡萄球菌的影响

Effect of silica with different sizes on Staphylococcus epidermidis

目的探究可吸人纳米细颗粒物对人体表面正常菌群的生物活性效应。方法将表皮葡萄球菌悬液分别加入含终浓度为0（对照）-400μg／ml微米和纳米二氧化硅的培养基培养4、24和48h。测定表皮葡萄球菌的存活率、形态、膜通透性变化，同时对作用前、后的微米和纳米二氧化硅进行红外光谱分析。结果在50，400μg／ml二氧化硅暴露范围内，微米和纳米二氧化硅暴露表皮葡萄球菌的存活率均呈下降趋势，与对照组比较，纳米二氧化硅暴露组细菌存活率降低有统计学意义（P〈0．05）；微米二氧化硅对表皮葡萄球菌存活率的抑制无统计学意义；400μg／ml纳米二氧化硅暴露组细菌数目减少，菌体皱缩，400μg／ml微米二氧化硅暴露组菌体轻微凹陷。随着暴露剂量和时间的增加，微米和纳米二氧化硅暴露表皮葡萄球菌培养液中Ca2＋和K＋浓度均呈上升趋势。与微米二氧化硅暴露组比较，大于100μg／ml纳米二氧化硅组培养液中K＋浓度较高，差异具有统计学意义（P〈0．05），Ca2＋浓度的升高仅在400μg／ml组有统计学意义（P〈0．05）。红外光谱分析表明表皮葡萄球菌与微米和纳米二氧化硅作用后均有新峰出现，分别位于波数2961cm-1、2929cm-1、1545cm-1和1452cm-1、1401cm-1。结论纳米二氧化硅抑制表皮葡萄球菌的作用强于微米二氧化硅，纳米和微米二氧化硅暴露同表皮葡萄球菌均存在界面作用效应。

Objective To understand the biological effects of nanoparticles on human surface normal bacteria. Methods Staphylococcus epidermidis were treated with nano-silica and micro-silica at concentrations of 0 to 400 μg/ml silica suspensions for 4 h, 24 h and 48 h respectively, and the effects on cell viability,morphology,cell membrane damage and changes of silica surface group were studied. Results The cell viability decreased significantly in a dose-dependent manner in nano-silica group compared with the control. The exposure group of these two suspensions at dosage of 400 μg/ml both showed morphology changes. As increasing in dosage and time, the concentrations of Ca2＋ and K＋ in both group increased. Compared with micro-silica group, the change of K＋ was significantly different in nano-siliea group at dosage of 200 to 400 μg/ml, but the change of Ca2＋ was significantly different only at 400 μg/ml. Infrared spectroscopy showed that the surface group of the two samples changed after interaction with the bacteria. Conclusion The biological effects of nano-silica on Staphylococcus epidermidis was more obvious compared with micro-silica. Interface interaction of the silica-microorganism system on surface morphology and surface group was seen in the present study.