Sterilization Mechanism by Functional Radical Transportation of BiocompatiblePlasma Flow

本课题研究了非平衡等离子体流中自由基的传输及其杀菌机理，旨在开发新型等离子体杀菌系统，以保护人类环境免受病原微生物的侵害。本课题的研究结果如下：低温氩等离子体能在常压下对大肠杆菌进行灭菌，并能灭活大肠杆菌。大肠杆菌是由于暴露于等离子体下细胞质膜和外膜的破坏以及暴露于来自等离子体源的紫外线辐射下核酸的破坏而产生的。通过使用ICP-MS分析存活细胞和细胞质材料的钾渗漏，并通过SEM观察形态学方面来澄清这些。这一结果发表在《应用物理快报》上，并被选入《生物物理研究虚拟杂志》。研制成功了极微弱辐射的光学分析系统，其测量强度可达<-8>放电区的10倍。利用该系统对放电区下游自由基流场进行了光学研究，并开发了一种新型的非平衡等离子体导管消毒系统。该系统能够在低于70摄氏度的低温条件下，在5分钟内对抗紫外线和耐热细菌进行灭菌。通过流场和自由基辐射分析系统的研究，证实了等离子体在管内产生自由基流，从而实现了杀菌，并在5篇学术论文和7项专利（其中1项国际专利）中进行了总结。

The radical transportation and its sterilization mechanisms in the nonequilibrium plasma flow were studied in this research project for development of innovative plasma sterilization system to protect human environment from infection by pathogenic microorganism. The results of this research project are summarized as follows.Escherichia coli can be sterilized by a low-temperature argon plasma flow at atmospheric pressure and the inactivation of E. coli results from the destructions of the cytoplasmic membrane and the outer membrane under plasma exposure and the destruction of nucleic acids by exposure to ultraviolet radiation from the plasma source. These were clarified by analyzing the surviving cells and the potassium leakage of cytoplasmic material using ICP-MS, and by observing the morphological aspect by SEM. This result was published in the "Applied Physics Letters" and it was selected for the "Virtual Journal of Biological Physics Research". Optical analysis system for very weak emission was successfully developed, which is capable of measuring intensity of 10^<-8> of that in the discharge region. Using this system, the radical flow fields downstream the discharge region was optically investigated.An innovative catheter sterilization system using a nonequilibrium plasma flow was developed. This system is capable of sterilizing anti-UV and anti-heat bacteria within 5 minutes under the condition of low temperature less than 70 degrees Celsius. The sterilization was caused by a radical flow induced by plasma in the tube, which were clarified by analysis systems for the flow fields and radical emissions.Those results were summarized in the 5 academic papers and 7 patents which includes 1 international patent.