【作者】 金英；

【导师】 任春生；

【作者基本信息】 大连理工大学 ， 等离子体物理， 2006， 硕士

【摘要】 本文介绍了具有快捷、低温、简单、高效及安全无污染等优点的消毒灭菌的方法——介质阻挡放电等离子体和大气压冷等离子体射流消毒灭菌。实验中,将等离子体和微生物相互作用发生的物理和生物化学反应的研究结合起来,有助于更好的研究探讨氦气、空气和氮气介质阻挡放电和氦气等离子体射流致死酵母菌的机制。 利用MTT比色法探讨了经过介质阻挡放电处理后酵母菌后的细胞的活性,并运用平板菌落计数法做出了经介质阻挡放电等离子体处理后的酵母菌存活数与处理时间的关系;通过存活曲线比较氦气、氮气和空气介质阻挡放电的灭菌效果发现氮气等离子体处理5分钟后可使存活数下降约5个数量级,空气下降了约6个数量级,而氦气处理5分钟后可使其减少约7个数量级。利用电子扫描电镜观察经介质阻挡放电产生的等离子体处理后的菌体形貌,发现氦气等离子体处理后的菌体细胞形态已难以辨认,空气和氮气处理后的菌体细胞壁有不同程度的破裂,同时,空气和氮气等离子体处理的菌液pH值并无大的波动,而氦气处理后的菌液pH随时间不断下降,酸度增加,有可能使细胞壁中的脂类物质被溶解,过低的pH值可能在活性物质和静电力的共同作用下加剧了破裂程度,因此破裂程度加深,提高了灭活效率。 同样利用MTT比色法探讨了经过氦气等离子体射流处理酵母菌后菌体的活性,并利用平板菌落计数法测得了氦气等离子体射流处理酵母菌的存活曲线,结果得到处理5分钟后存活数下降了约8个数量级,电子扫描电镜的照片显示菌体也严重受损,灭菌效率高于介质阻挡放电等离子体。然而等离子体处理的菌液远离放电腔,不直接与带电粒子直接作用,这很可能是氦气等离子体射流产生了更多的活性物质,同时pH随时间也大幅度下降,并且较氦气介质阻挡放电下降的快,这从一定程度上也能够证明氦气等离子体射流灭菌效率高于氦气介质阻挡放电等离子体。更多还原

【Abstract】 The dielectric barrier discharge (DBD) plasma and atmospheric pressure plasma jet (APPJ) sterilization is presented in this paper. They have been thought as a potential technology due to many advantages, such as a high efficiency, a quick speed, a nonthermal, and simple operation as well as non-toxicity process, which shows a great promise. In this paper, the mechanism of yeast inactivation in low temperature atmospheric pressure helium, nitrogen and air plasmas generated by DBD and helium plasma by APPJ is analyzed and compared.The results show that the three gas plasmas generated by DBD all have a high germicidal efficiency. The reduction of seven orders of magnitude of yeast suspension treated by helium DBD is presented, and the reduction of five orders of magnitude by nitrogen plasma and six orders of magnitude by air plasma is presented. The morphology of the yeast is observed by scanning electron microscopy, which reveals the yeast treated in helium DBD plasma is ruptured completely but there are only some flaws on the cell walls in nitrogen and air DBD plasma treatment samples, even the flaws on the cell walls treated by air DBD plasma are more significant than that by nitrogen DBD treatment. Simultaneously, pH values of the samples after 5 min nitrogen and air DBD plasma treatments have no remarkable change, while that the sample treated with helium DBD plasma descends with the treatment time extended, the value is beyond the optimum one for the yeast living environment. It is the combined action of electrostatic tension, reactive species that kill the yeast. While the different pH values are maybe the causes for a treatment effect and the cell rapture degree when different gas discharge plasma treatments are applied.The reduction of eight orders of magnitude by helium APPJ is presented. The morphology of the yeast is also observed by scanning electron microscopy, which reveals the yeast treated by APPJ plasma is also ruptured completely. It can be seen that the efficiency of APPJ plasma sterilization is higher than DBD plasma. Simultaneity the pH value of the samples after 5 min APPJ plasma treatment also descends quickly with the treatment time extended. While the sample is far away from the discharge room, there are long odds on the action of electrostatic tension. It maybe the combined action of more reactive species generated by helium APPJ and pH value that cause the higher efficiency.更多还原