大气压等离子体射流对细菌芽孢灭活机理研究

Inaction Mechanism of Bacteria Spore with Atmospheric Pressure Plasma

为研究低温大气压等离子体灭菌机理,设计了一种单电极等离子射流装置。使用该装置对枯草杆菌芽孢进行了细菌灭活实验。利用扫描电镜(SEM)观察了氩等离子体处理前后细菌芽孢的形貌变化;测量了等离子体处理后枯草杆菌芽孢蛋白质泄漏量,并进行了光谱诊断。实验结果表明枯草杆菌芽孢经氩等离子体射流处理5 min后,芽孢杀灭率低于两个量级。温度和紫外光在细菌灭活中作用较小,羟基自由基不起主要作用。SEM结果显示氩等离子体处理5 min后枯草杆菌芽孢形态基本保持完整。根据SEM、蛋白质泄漏量和发射光谱分析结果,推断高能粒子在细菌灭活中起主要作用。高能粒子对细菌细胞壁和细胞膜造成一定的刻蚀作用,并最终导致了枯草杆菌芽孢的失活。

The possible mechanisms responsible for the inaction of Bacillus subtilis spore with the atmospheric pres- sure argon plasma, generated with a lab-built, single-electrode plasma jet, were experimentally studied. The impacts of the inaction conditions, including the plasma exposure time, temperature, ultraviolet （UV） irradiation, and electric field, on the inaction rate were evaluated.The morphologies and protein leakage of the spores,before and after the plasma exposure, were characterized with scanning electron microscopy, conventional emission spectroscopy, and optical spectroscopy. After the plasma exposure for 5 min, the killing-log-value of Bacillus subtilis spore was found to be less than 2.0, little depend- ing on the heat, UV irradiation, and hydroxyl radicals. We suggest that the energetic particles of the plasma may seriously damage cell walls or membranes, and eventually inactivate the spores.