Pharmaceutica Analytica Acta

Abstract

Study of Sterilization and Disinfection in Room Air by Using Atmospheric Microplasma

Kazuo Shimizu, Yuki Komuro, Shigeki Tatematsu and Marius Blajan

An effective and economical sterilization method is required due to the increase of the health consciousness in living spaces in the recent years, especially in the hospital, the airborne bacteria, and the surface colonized bacteria are the serious problem known as the hospital-acquired infection. Non-thermal plasma sterilization received a lot of attention as a replacement of traditional sterilization methods. Microplasma, which is atmospheric pressure nonthermal plasma, has been studied for application in various fields. It is a dielectric barrier discharge and has many advantages over other types of non-thermal plasmas, and is generated at atmospheric pressure thus does not require costly vacuum enclosures; the discharge voltage is about 600 V to 1.5 kV and discharge gap is only 10 to 100 μm. Microplasma is suitable for applications not only indoor air cleaning, odor control, but also surface treatment or medical field because of the above mentioned advantages. We investigated the remote sterilization effect and sterilization process for airborne bacteria by using atmospheric microplasma. Gram-negative bacteria Escherichia coli and Gram-positive bacteria Alicyclobatillus were the target to be sterilized in this study. The experiment was performed with air and Ar as the process gases, to confirm the influence of different radical species in the microplasma, on the bacteria cultures. The process gas flows through the parallel plate electrodes with holes which were covered with dielectric material, and energized at about 600 V~1.5 kV. Sterilization and disinfection was by microplasma carried out for both Gram-negative bacteria and Gram-positive bacteria, and resulted successfully.