Abstract:The deactivation effect and antimicrobial mechanism of Staphylococcus aureus biofilm by the plasma activated water (PAW) induced by atmospheric pressure air plasma were studied. The colony forming units (CFU) method was used to estimate the deactivation effect of biofilm, and the resazurin fluorescence staining method was used to study the metabolic rate of cells. The intracellular reactive oxygen and concentration of representative long-life active components in plasma activated water were detected by H2-DCFDA fluorescence staining and spectrophotometry, respectively. The results showed that after 30 minutes immersion in activated water generated in 60 minutes, the number of CFU decreased from 107.4 to 102.6, about 70% bacteria in the biofilm lose their metabolism. The concentration of intracellular reactive oxygen species (ROS) in biofilm significantly increased after plasma activated water treatment. With the extension of plasma treating time, the concentrations of H2O2, NO2- and O3 in plasma activated water increased in varying degrees. Based on the above analysis, the plasma activated water has a good sterilization performance, and the synergistic effect of a large number of active groups accumulated in activated water and intracellular ROS may be the main reason for biofilm inactivation. Key words:plasma activated water (PAW)/ biofilm inactivation/ Staphylococcus aureus biofilm.
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1.School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China 2.Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China Received Date: 2019-01-24 Accepted Date: 2019-03-15 Available Online: 2019-09-30 Keywords:plasma activated water (PAW)/ biofilm inactivation/ Staphylococcus aureus biofilm Abstract:The deactivation effect and antimicrobial mechanism of Staphylococcus aureus biofilm by the plasma activated water (PAW) induced by atmospheric pressure air plasma were studied. The colony forming units (CFU) method was used to estimate the deactivation effect of biofilm, and the resazurin fluorescence staining method was used to study the metabolic rate of cells. The intracellular reactive oxygen and concentration of representative long-life active components in plasma activated water were detected by H2-DCFDA fluorescence staining and spectrophotometry, respectively. The results showed that after 30 minutes immersion in activated water generated in 60 minutes, the number of CFU decreased from 107.4 to 102.6, about 70% bacteria in the biofilm lose their metabolism. The concentration of intracellular reactive oxygen species (ROS) in biofilm significantly increased after plasma activated water treatment. With the extension of plasma treating time, the concentrations of H2O2, NO2- and O3 in plasma activated water increased in varying degrees. Based on the above analysis, the plasma activated water has a good sterilization performance, and the synergistic effect of a large number of active groups accumulated in activated water and intracellular ROS may be the main reason for biofilm inactivation.