用于脉冲电场灭菌的微系统的研究

发布时间：2018-09-19 20:26

【摘要】：近年来，用水环境不断恶化，而人们对水质的要求越来越高，饮用水中微生物的杀灭也变得越来越重要。传统的灭菌方法，如化学灭菌法，会产生有毒副产物，难以满足人们的健康要求，进而出现了多种物理灭菌技术。其中电灭菌方法中的脉冲电场灭菌技术由于处理时间短、能效高、温升小、无化学毒副产物等优点，成为一种具有巨大发展潜力的非热灭菌技术。然而，传统的脉冲电场灭菌系统需要能提供几千伏甚至几十千伏高压的脉冲发生器，使得设备成本高，限制了其推广应用。为了解决这一问题，本文开展了用于脉冲电场灭菌的微系统的研究，通过电极间距的缩小可以大大降低所需脉冲电压。在装置研究的基础上，以大肠杆菌为实验对象，利用几百伏的脉冲，实现了高效灭菌。为了清楚了解脉冲电场杀菌操作的过程和为电脉冲杀菌微系统的研制做对照，本文先利用传统的脉冲电场灭菌系统进行实验研究。研究结果表明，无论是模拟循环水处理的脉冲灭菌系统，还是方波脉冲的静态处理系统，都需要几千伏电压才能获得较好的灭菌效果。随后，本文研制了一种适于脉冲电场灭菌的柔性微芯片。通过COMSOL软件仿真分析了平板-齿状（PCT）电极、交叉梳状（ICT）电极和对称齿状电极（SCT）三种电极结构，并加工了两种电极结构的芯片用于实验研究。利用聚酰亚胺基底加工制作了柔性芯片，并在此基础上制作了微处理室，搭建脉冲电场灭菌微系统实验平台，并对多种影响灭菌的参数进行了研究。实验结果证明，，电极结构会对灭菌效果造成影响，其中PCT结构比ICT结构更优，这与仿真结果相符合。在基于PCT结构的微系统中，200V方波脉冲作用于大肠杆菌悬液，就能获得很好的灭菌效果。同时，高场强、宽脉宽、长的处理时间、成分简单的缓冲液、处在早期生长状态的细菌都对灭菌效果有增强作用。此外，基于微芯片的处理室利用介电电泳力，可将细菌富集到高场强区域，进而获得更好的灭菌效果。最后，本文研制了静态和连续的微间隙平板电极处理室，并分别搭建脉冲电场灭菌微系统，进行相关的灭菌实验。实验表明：对于铜电极的静态灭菌系统，电压360V（电场20kV/cm），脉宽50μs，脉冲间隔200ms，50～100个脉冲的处理条件下，杀菌效果好；而对于铜电极的连续灭菌系统，电参数不变，流量控制在200μL/min左右，也获得了很好的灭菌效果。
[Abstract]:In recent years, with the deterioration of the water environment and the increasing demand for water quality, the sterilization of microorganisms in drinking water has become more and more important. Pulsed electric field sterilization (PEF) has become a promising non-thermal sterilization technology due to its advantages of short processing time, high energy efficiency, low temperature rise and no chemical toxic by-products. However, the traditional PEF sterilization system needs to provide pulse generators with thousands or even tens of kilovolts of high voltage, which makes the equipment cost high and limits its push. In order to solve this problem, a micro-system for pulsed electric field sterilization has been developed in this paper. The required pulse voltage can be greatly reduced by reducing the electrode spacing.
In order to understand the sterilization process of pulsed electric field and compare with the development of ELECTROPULSED sterilization micro-system, the traditional pulsed electric field sterilization system was used to carry out experimental research. Pressure can achieve better sterilization effect.
Then, a flexible microchip suitable for pulsed electric field sterilization was developed. Three kinds of electrode structures, flat-tooth (PCT), cross-comb (ICT) and symmetrical toothed (SCT), were simulated and analyzed by COMSOL software, and two kinds of electrode structures were fabricated for experimental research. The experimental results show that the electrode structure will affect the sterilization effect, and the PCT structure is better than the ICT structure, which is consistent with the simulation results. At the same time, high field strength, wide pulse width, long treatment time, simple composition buffer, bacteria in the early growth state can enhance the sterilization effect. In addition, the processing chamber based on microchip can enrich bacteria to the bacteria by dielectric electrophoresis force. High field strength area and better sterilization effect.
Finally, the static and continuous micro-gap plate electrode processing chamber was developed, and the pulsed electric field sterilization micro-system was set up to carry out the relevant sterilization experiments. The experimental results showed that the sterilization effect of static sterilization system of copper electrode under the conditions of voltage 360V (electric field 20kV/cm), pulse width 50us, pulse interval 200ms, 50-100 pulses. Good; for the continuous sterilization system with copper electrode, the electrical parameters remain unchanged, and the flow rate is controlled at about 200 mu L/min, which also achieves good sterilization effect.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R123.1

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