远程氧等离子体对大肠杆菌的灭菌效果与机理研究

采用Langmuir双电子探针和电子自旋共振诊断技术分别定量测定了远程氧等离子体场中各活性物种的分布.考察了远程氧等离子体对医用聚四氟乙烯表面大肠杆菌的灭活作用,并通过对灭菌后菌悬液蛋白质泄漏量、脂质过氧化物生成量及细菌DNA电泳图的测定分析了其灭菌机理.结果表明:远程氧等离子体中的电子、离子浓度随远程距离的增大迅速降低,30 cm后接近于0,而自由基浓度则相对降低缓慢,40 cm处仍为初始浓度的70%;远程氧等离子体60 s内的灭菌效果值在放电区可高达3.42,在远程距离40 cm以内也均在3.32以上,符合消毒灭菌的要求;电子、离子对细菌细胞膜的快速刻蚀及自由基对胞膜中多价不饱和脂肪酸的攻击分别是放电区及远程30cm后灭菌的主要原因.氧等离子体中紫外光的灭菌效果微弱.

Germicidal Efficiency and Mechanisms of Escherichia Coli by Remote Oxygen Plasma

Double Langmuir electron probes and electron spin resonance(ESR) were used to measure the distribution of electrons,ions and free radicals in remote oxygen plasma.The germicidal effect(GE) of Escherichia coli on the surface of medical polytetrafluoroethylene(PTFE) film by remote oxygen plasma was investigated,and then,the quantity of protein leakage and the production of lipid peroxide in bacterial suspension as well as DNA agarose electrophoresis were measured after sterilization to analyse the inactivation mechanisms.The results show that in remote oxygen plasma,the concentrations of electrons and ions decrease rapidly with the increasing distance from the center of induction coil,which approach to zero at 30 cm,whereas the concentration of free radicals reduces slowly,namely,decrease 30% within 40 cm.GE reaches 3.42 in discharge zone(0 cm) and exceeds 3.32 within 40 cm when plasma treatment parameters are set as plasma RF power at 100 W,treatment time at 60 s and oxygen flux at 40 cm3/min.Fast etching action on cell membrane by electrons,ions and attacking polyunsaturation fatty acid(PUFA) in cell membrane by free radicals are the primary reasons of oxygen plasma sterilization in discharge and remote zone,respectively.The GE of UV radiation in remote oxygen plasma gets feeble.