低温氧等离子体杀灭铜绿假单胞菌的效果及机理

Low temperature oxygen plasma sterilization effect on Pseudomonas aeruginosa

摘要:

【目的】本文采用低温氧等离子体，在自行设计的远程等离子体反应装置中，对位于不同放电区域（放电区，余辉区，远程区）的模拟染菌载体聚对苯二甲酸乙二醇酯（PET）表面的铜绿假单胞菌(Pseudomonas aeruginosa)的杀灭效果和机理进行了研究。【方法】采用扫描电子显微镜观察了等离子体处理前后细菌细胞的形貌变化，采用考马斯亮蓝法测定了等离子体处理后细菌蛋白质泄漏量，采用双悬浮探针对氧等子体的电子温度和离子浓度以及电子自旋共振波谱对自由基浓度进行了测定。【结果】强放电区、余辉区和远程区处理30s后的灭菌效果分别为4.2 ，3.8和2.6；扫描电镜观察结果和蛋白泄漏量测定结果证明细菌细胞被损毁，在强放电区是电子、离子、自由基和紫外光子的协同作用，而在余辉区和远程区的灭杀作用主要因自由基所为。【结论】证明该反应装置可有效实现活性粒子的分离，在远程等离子体场中揭示了等离子体灭菌的规律和机理。

Abstract:

[Objective] Low temperature oxygen plasma was used to sterilize the Pseudomonas aeruginosa samples on the polyethylene terephthalate (PET) sheets in a self-designed reactor that included the discharge area, afterglow area and remote area. [Methods] Before and after plasma treatment, the cell morphology was studied by scanning electron microscopy (SEM). The cell wall or cell membrane cracking was testified to determine the content of protein by using coomassie light blue technique. Besides, double Langmuir probe and electron spin resonance spectroscopy were used to determine the temperature of electrons (ions) and the concentration of free radicals, respectively. [Results] Under the treatment time of 30 s, the germicidal effects were 4.2, 3.8 and 2.6 respectively in the three areas. SEM observations showed that the plasma activity cracks the cell wall and cell membrane, resulting in cellular content leakage. In addition, the results from electron spin resonance spectroscopy and double Langmuir electron probe showed that electrons, ions and oxygen free radicals played important roles in sterilization in the discharge area, but only oxygen free radicals acted to sterilize the bacteria in the afterglow area and the remote area. [Conclusion] The active species can be separated effectively in this reaction equipment, and we further elucidated the mechanisms of plasma sterilization in the remote plasma field.