對於醫院重覆使用或廢棄的器材，為避免造成交叉感染或群聚感染，使用後必須嚴格遵守器械消毒及滅菌之處理才能再用。目前醫院傳統的殺菌方法，如：EtO、H2O2-clod plasma，可能會有毒性殘留、需真空設備、效率低、成本高…等缺點。近年來，大氣微電漿系統已陸續被應用在消毒殺菌的處理方法。
本實驗以射頻供應器作為微電漿系統的激發源、氬氣為主要激發氣體，其中，添加少量氧氣當作活性氣體，直接對懸浮細菌作處理，如：大腸桿菌、金黃色葡萄球菌、嗜熱桿菌，菌液濃度控制於8*106 CFU/ml。其放置於挖空的聚二甲基矽氧烷(polydimethyl siloxane, PDMS)基板上，隨著氧氣添加量(0~0.2 %)、處理時間的不同，找出最好之殺菌效率。電漿激發過程中，以光學放射光譜儀即時監控其內部的激發物種變化，如：NO*、N2*、OH*、O*、Ar*，且在處理後，於掃描式電子顯微鏡下觀察其細菌形貌的改變。
實驗結果顯示，待測物於電漿噴口處6 mm，對於臨床常見細菌，如：大腸桿菌、金黃色葡萄球菌，不同氧氣添加量之微電漿系統，達滅菌時間需於90~120 sec；對於生物菌株，如：嗜熱桿菌，也可於180 sec達至抑菌效果。此外，由OES光譜分析中，距電漿噴口處越遠，如：9 mm，其電漿內的物種會明顯下降，故對大腸桿菌與金黃色葡萄球菌之滅菌確效中，達滅菌時間需延長至180 sec。經由電漿處理後之細菌，經由SEM觀測，此三種細菌，會有破裂、變形趨勢，此顯示，本實驗裝置並不是單純抑制細菌生長，而是可以有效破壞細菌。

In hospitals, many antimicrobial methods are used for medical devices. The disadvantages of traditional sterilization methods (eq., EtO, H2O2-clod plasma) in hospital include the presence of residual toxic compounds, vacuum system, low sterilizing efficiency and high cost. In recent years, micro-plasma systems are applied for sterilization.
In this study, radio frequency-induced argon plasma system added oxygen to generate plasma to treat bacteria in water including Escherichia coli, Staphylococcus aureus, Bacillus stearothermophilius (8×106 CFU/ml) at atmospheric pressure. The water containing bacteria was placed on a polydimethyl siloxane (PDMS) holder and exposed to micro-plasmas of various oxygen /argon ratios for different exposure times. After treatment, the sterilization efficiency was evaluated. In addition, we also used optical emission spectroscope (OES) to detect the excited species (ex, NO*, N2*, OH*, O*, and Ar*) during plasma excitation process. After treatment, the change of the bacterial morphology was observed by scanning electron microscopy (SEM).
The results showed that the clinical bacteria (E. coil and S. aureus ) were killed after micro-plasma treatment for 90~120 sec. However, B. stearothermophilius (usually used as biological indicator) was inactivated after 180 sec plasma treatment. In addition, as working distance between plasma nozzle and specimens increased, the concentration of excited species in micro-plasma decreased from OES spectra. For this reason, the sterilization time of E. coli and S. aureus was increased to 180 sec. Based on SEM images, the bacteria broke into debris or their morphology changed after micro-plasma treatment. In conclusion, micro-plasma can be used as an effective tool for inactivating bacteria on medical device.

[1] Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008
[2] R. E. J. Sladek and E. Stoffels, "Deactivation of Escherichia coli by the plasma needle", Journal of Physics D: Applied Physics, Vol. 38, 1716-1721, 2005.
[3] J. Raiser and M. Zenker, "Argon plasma coagulation for open surgical and endoscopic applications: state of the art", Journal of Physics D: Applied Physics, Vol. 39, 3520-3523, 2006.
[4] J. A. Perez-Martinez, R. Pena-Eguiluz, R. Lopez-Callejas, A. Mercado-Cabrera, R. A. Valencia, S. R. Barocio, J. S. Benitez-Read and J. O. Pacheco-Sotelo, "An RF microplasma facility development for medical applications", Surface & Coatings Technology, Vol. 201, 5684-5687, 2007.
[5] G. F. Gregory Fridman, Alexander Gutsol, Anatoly B. Shekhter, and A. F. Victor N. Vasilets, "Applied Plasma Medicine", Plasma Process. Polym., Vol. 5, 2008.
[6] M. Moreau, N. Orange and M. G. J. Feuilloley, "Non-thermal plasma technologies: new tools for bio-decontamination", Biotechnology Advances, Vol. 26, 610-617, 2008.
[7] K. D. Weltmann, R. Brandenburg, T. V. Woedtke, J. Ehlbeck, R. Foest, M. Stieber and E. Kindel, "Antimicrobial treatment of heat sensitive products by miniaturized atmospheric pressure plasma jets (APPJs)", Journal of Physics D: Applied Physics, Vol. 41, 194008, 2008.
[8] M. Laroussi, D. A. Mendis and M. Rosenberg, "Plasma interaction with microbes", New Journal of Physics, Vol. 5, 41-41, 2003.
[9] M. G. Kong, G. Kroesen, G. Morfill, T. Nosenko, T. Shimizu, J. v. Dijk and J. L. Zimmermann, "Plasma medicine: an introductory review", New Journal of Physics, Vol. 11, 115012, 2009.
[10] F. G. G. A. S. A. B. V. V. N. Fridman G and A. Fridman, "Applied plasma medicine", Plasma Process. Polym., Vol. 5, 503, 2008.
[11] 行政院衛生署, "醫療統計年報", 2008.
[12] 行政院環境保護署醫療廢棄物資料網
[13] W. P. Menashi, "Treatment of surfaces." US Patent, 3 383 163, 1968.
[14] L. E. Ashman and W. P. Menashi, "Treatment of surfaces with low pressure plasmas." US Patent, 3 701 628, 1972.
[15] R. M. Boucher (Gut), "State of the art in gas plasma sterilization." Med. Device Diagnost. Indust., Vol. 7, 51-56, 1985.
[16] M. Moisan, J. Barbeau, S. Moreau, J. Pelletier, M. Tabrizian and L. H. Yahia, "Low-temperature sterilization using gas plasmas: a review of the experiments and an analysis of the inactivation mechanisms", International Journal of Pharmaceutics, Vol. 226, 1-12, 2001.
[17] A. Schutze, J. Y. Jeong, S. E. Babayan, J. Park, G. S. Selwyn and R. F. Hicks, "The atmospheric-pressure plasma jet: a review and comparison to other plasma sources", IEEE Transactions on Plasma Science, Vol. 26, 1685-1694, 1998.
[18] H. Ohkawa, T. Akitsu, M. Tsuji, H. Kimura, M. Kogoma and K. Fukushima, "Pulse-modulated, high-frequency plasma sterilization at atmospheric-pressure", Surface and Coatings Technology, Vol. 200, 5829-5835, 2006.
[19] T. Akitsu, H. Ohkawa, M. Tsuji, H. Kimura and M. Kogoma, "Plasma sterilization using glow discharge at atmospheric pressure", Surface and Coatings Technology, Vol. 193, 29-34, 2005.
[20] C. Tendero, C. Tixier, P. Tristant, J. Desmaison and P. Leprince, "Atmospheric pressure plasmas: A review", Spectrochimica Acta Part B: Atomic Spectroscopy, Vol. 61, 2-30`, 2006.
[21] M. Korachi, Z. Turan, K. Senturk, F. Sahin and N. Aslan, "An investigation into the biocidal effect of high voltage AC/DC atmospheric corona discharges on bacteria, yeasts, fungi and algae", Journal of Electrostatics, Vol. 67, 678-685, 2009.
[22] J. H. Choi, I. Han, H. K. Baik, M. H. Lee, D.-W. Han, J.-C. Park, I.-S. Lee, K. M. Song and Y. S. Lim, "Analysis of sterilization effect by pulsed dielectric barrier discharge", Journal of Electrostatics, Vol. 64, 17-22, 2006.
[23] N. Ekem, T. Akan, Y. Akgun, A. Kiremitci, S. Pat and G. Musa, "Sterilization of Staphylococcus aureus by atmospheric pressure pulsed plasma", Surface and Coatings Technology, Vol. 201, 993-997, 2006.
[24] L. Xu, P. Liu, R. J. Zhan, X. H. Wen, L. L. Ding and M. Nagatsu, "Experimental study and sterilizing application of atmospheric pressure plasmas", Thin Solid Films, Vol. 506, 400-403, 2006.
[25] S. U. Han, P. L. Jin and Z. L. Shou, "Sterilization of bacterial endospores by an atmospheric-pressure argon plasma jet", Applied Physics Letters, Vol. 90, 261501, 2007.
[26] L. Jin-Pyo, S. U. Han and L. Shou-Zhe, "Influence of oxygen in atmospheric-pressure argon plasma jet on sterilization of Bacillus atrophaeous spores", Physics of Plasmas, Vol. 14, 093504, 2007.
[27] D. Yixiang, C. Huang and Q. S. Yu, "Cold plasma brush generated at atmospheric pressure", Review of Scientific Instruments, Vol. 78, 015104, 2007.
[28] Q. S. Yu, C. Huang, F. H. Hsieh, H. Huff and Y. Duan, "Bacterial inactivation using a low-temperature atmospheric plasma brush sustained with argon gas", Journal of biomedical materials research. Part B, Applied biomaterials, Vol. 80, 211-219, 2007.
[29] Q. S. Yu, C. Huang, F. H. Hsieh, H. Huff and D. Yixiang, "Sterilization effects of atmospheric cold plasma brush", Applied Physics Letters, Vol. 88, 013903, 2006.
[30] Z. Cao, J. L. Walsh and M. G. Kong, "Atmospheric plasma jet array in parallel electric and gas flow fields for three-dimensional surface treatment", Applied Physics Letters, Vol. 94, 021501, 2009.
[31] U. Cvelbar, D. Vujoaevi, Z. Vratnica and M. Mozeti, "The influence of substrate material on bacteria sterilization in an oxygen plasma glow discharge", Journal of Physics D: Applied Physics, Vol. 39, 3487-3493, 2006.
[32] B. Gweon, D. B. Kim, S. Y. Moon and W. Choe, "Escherichia coli deactivation study controlling the atmospheric pressure plasma discharge conditions", Current Applied Physics, Vol. 9, 625-628, 2009.
[33] M. G. L. F. Montealegre, M. Ristic and M. A. James, "Growth inhibition of bacteria bovis in culture by secretion from bovine mononuclear phagocytes", Infection and Immuntity, Vol. 50, 523-526, 1985.
[34] I. Langmuir, "Oscillations in ionized gases", Proceedings of the National Academy of Sciences of the United States of America, Vol. 14, 627-637, 1928.
[35] K. H. Becker, K. H. Schoenbach and J. G. Eden, "Microplasmas and applications", Journal of Physics D: Applied Physics, Vol. 39, R55-R70, 2006.
[36] K. H. Becker, "High-pressure microplasmas, a new world of low-temperature plasmas", 2005.
[37] U. Kogelschatz, "Applications of microplasmas and microreactor technology", Contributions to Plasma Physics, Vol. 47, 80-88, 2007.
[38] "Spacecraft sterilization using non-equilibrium atmospheric pressure plasma", 18th International Symposium on Plasma Chemistry, Kyoto, Japan, August 26-31, 2007.
[39] L. Xu, H. Nonaka, H. Y. Zhou, A. Ogino, T. Nagata, Y. Koide, S. Nanko, I. Kurawaki and M. Nagatsu, "Characteristics of surface-wave plasma with air-simulated N2 O2 gas mixture for low-temperature sterilization", Journal of Physics D: Applied Physics, Vol. 40, 803-808, 2007.
[40] Y. Jin, C. Ren, Z. Xiu, D. Wang, Y. Wang and H. Yu, "Comparison of Yeast Inactivation Treated in He, Air and N2 DBD Plasma", Plasma Science and Technology, Vol. 8, 720-723, 2006.
[41] T. Watanabe, S. Furukawa, J. Hirata, T. Koyama, H. Ogihara and M. Yamasaki, "Inactivation of Geobacillus stearothermophilus spores by high-pressure carbon dioxide treatment", Applied and environmental microbiology, Vol. 69, 7124-7129, 2003.
[42] H. Liu, J. Chen, L. Yang and Y. Zhou, "Long-distance oxygen plasma sterilization: Effects and mechanisms", Applied Surface Science, Vol. 254, 1815-1821, 2008.
[43] H. Miao and C. Jierong, "Inactivation of Escherichia coli and properties of medical poly(vinyl chloride) in remote-oxygen plasma", Applied Surface Science, Vol. 255, 5690-5697, 2009.
[44] K.P. Talaro and A. Talaro, "Foundations in Microbiology Basic Principles", 4th 2002.
[45] C. W. Chen, H. M. Lee and M. B. Chang, "Influence of pH on inactivation of aquatic microorganism with a gas-liquid pulsed electrical discharge", Journal of Electrostatics, Vol. 67, 703-708, 2009.
[46] Y. L. Han, S. U. Han, F. H. Yi and H. P. Yun, "Influence of water acidity on ozone decay time and its applications", Applied Physics Letters, Vol. 92, 174102, 2008.
[47] H. S. Uhm, Y. F. Hong, H. Y. Lee and Y. H. Park, "Increase in the ozone decay time in acidic ozone water and its effects on sterilization of biological warfare agents", Journal of hazardous materials, Vol. 168, 1595-1601, 2009.
[48] M. Se Youn, W. Choe and B. K. Kang, "A uniform glow discharge plasma source at atmospheric pressure", Applied Physics Letters, Vol. 84, 188-190, 2004.
[49] J. J. Shi and M. G. Kong, "Radio-frequency dielectric-barrier glow discharges in atmospheric argon", Applied Physics Letters, Vol. 2007.
[50] G. Chen, S. Chen, W. Feng, W. Chen and S. z. Yang, "Surface modification of the nanoparticles by an atmospheric room-temperature plasma fluidized bed", Applied Surface Science, Vol. 254, 3915-3920, 2008.
[51] A. Bogaerts, R. Gijbels and J. Vlcek, "Modeling of glow discharge optical emission spectrometry: Calculation of the argon atomic optical emission spectrum", Spectrochimica Acta Part B: Atomic Spectroscopy, Vol. 53, 1517-1526, 1998.
[52] U. Cvelbar, N. Krstulovic, S. Milosevic and M. Mozetic, "Inductively coupled RF oxygen plasma characterization by optical emission spectroscopy", Vacuum, Vol. 82, 224-227, 2007.
[53] L. Shou-Zhe, H. Wen-Tong, Z. Jialiang and W. Dezhen, "Optical diagnosis of an argon/oxygen needle plasma generated at atmospheric pressure", Applied Physics Letters, Vol. 94, 111501, 2009.
[54] M. R. Boscariol, A. J. Moreira, R. D. Mansano, I. S. Kikuchi and T. J. A. Pinto, "Sterilization by pure oxygen plasma and by oxygen-hydrogen peroxide plasma: an efficacy study", International journal of pharmaceutics, Vol. 353, 170-175, 2008.
[55] 蔡文城, "培養基滅菌的時間及溫度", 九州圖書公司, 1115, 1993.
[56] R. A. Venezia, M. Orrico, E. Houston, S.-M. Yin and Y. Y. Naumova, "Lethal activity of nonthermal plasma sterilization against microorganisms", Infection control and hospital epidemiology : the official journal of the Society of Hospital Epidemiologists of America, Vol. 29, 430-436, 2008.
[57] 中華民國行政院環境保護署環境檢驗所