自製介電質阻擋放電大氣低溫電漿之微生物滅菌研究

Bacterial sterilization by the homemade DBD plasma at atmospheric pressure

鄭書豪(Shu-Hao Cheng)

指導教授 ： 王明誠

中原大學/工學院/生物醫學工程研究所/碩士(2013年)

https://doi.org/10.6840/CYCU.2013.00378

摘要

目前介電質阻擋放電形式的大氣電漿技術已廣泛的應用在醫療、食品和生物技術等滅菌上。在一大氣壓下以介電質阻擋放電形式產生的電漿具有高電壓與低電流的特性，因此對生物組織的處理上不會造成危害。而本研究利用自行設計的高壓脈衝產生器結合自製的介電質阻擋放電電漿反應器做為滅菌研究。利用電感耦合效應使高壓線圈產生一連續性的高壓脈衝訊號，並進行113 cm2與235 cm2二種面積之反應器的激發測試，在2.6 kHz下113 cm2面積之反應器激發電漿時能夠產生8.8 kV的電壓與69 mA的電流，消耗功率為20 W，而在2.3 kHz下235 cm2面積之反應器激發電漿時能夠產生8.8 kV的電壓與88 mA的電流，消耗功率為33 W。利用OES光譜儀檢測電漿反應器激發時的光譜，由光譜所顯示出確實有文獻提及具有滅菌效果的OH基與777 nm的O原子。本實驗使用大腸桿菌與糞腸球菌做為滅菌效能的檢測，並進行SEM表面形貌的觀察、蛋白質的洩漏檢測與丙二醛含量的檢測來評估滅菌的效能與機制的探討。將107 CFU/ml濃度之菌液取10 µl均勻塗抹至18 mm × 18 mm基材上，並使用自製的電漿滅菌系統進行處理，結果發現大腸桿菌與糞腸球菌分別在45秒與1.8分鐘時可達到90 %的滅菌，並且在3分鐘與10分鐘後可以達到完全的滅菌。從SEM觀察電漿滅菌系統對大腸桿菌與糞腸球菌表面的破壞結果可以發現微生物表面產生出蝕刻與空洞的現象，蛋白質洩漏檢測則無明顯變化，但從TBARS法檢測丙二醛的含量可發現到大腸桿菌與糞腸球菌隨著電漿處理的時間增加丙二醛的含量也會隨之增加。證明了本研究所自製的介電質阻擋放電大氣低溫電漿設備對微生物確實有滅菌之效果。

關鍵字

大氣低溫電漿 ； 介電質阻擋放電 ； 電漿滅菌

並列摘要

Dielectric barrier discharge (DBD) plasma has been widely investigated into some emerging applications as alternative sterilization and disinfection method in the fields of biology and medicine. Despite the high breakdown voltage in air at atmospheric pressure, the average current of DBD plasma is low. Therefore, a DBD can be applied in direct contact with biological objects without causing any damage. In this study, we design high voltage pulse generator, combine the homemade atmospheric pressure DBD plasma device for sterilization. This study is inductively coupled effect of the high voltage coil to produce a continuous high voltage pulse signal, and then proceed to the plasma reactor excitation test in area of 113 cm2 and 235 cm2. The 113 cm2 plasma reactor discharge voltage and current is 8.8 kV and 68 mA respectively, the frequency is 2.6 kHz, and the mean power is 20W. The 235 cm2 plasma reactor discharge voltage and current is 8.8 kV and 88 mA respectively, the frequency is 2.3 kHz, and the mean power is 33W. Diagnose the active species in the plasma by optical emission spectroscopy (OES), and the OES spectrum shows indeed has been mentioned has caused microbial inactivation effect of OH radicals with O atoms of 777 nm. Samples of Escherichia coli and Enterococcus faecalis are selected for this study, and plasma induced structural damages of bacteria are investigated by SEM, Bradford assay and TBARS assay. The 10µl bacterial (107 CFU/ml) are transferred and spread on cover glass and stainless steel, and samples with a size of 18 mm × 18 mm, then are exposed to the homemade atmospheric pressure DBD plasma and respective treatment time. To find that E. coli and E. faecalis at 45 sec and 1.8 min can reach 90% of the sterilization respectively, and after 3 min and 10 min to achieve complete sterilization. The plasma treats cells have clear slits/ruptures on the surface by SEM, which evidences damage to the structure of the cell wall and membrane. The Bradford assay observation of the bacteria after plasma treatment does not find any significant changes. The TBARS assay can find that the MDA concentration increases gradually with increasing the plasma treatment time. This study proves the homemade atmospheric pressure DBD plasma system does have the efficacy of sterilization.

並列關鍵字

Plasma Sterilization ； Low Temperature Atmospheric Pressure Plasma ； Dielectric Barrier Discharge (DBD)

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