Microarray Analysis of Transcriptomic Response of Escherichia coli to Nonthermal Plasma-Treated PBS Solution

We developed a technique of generating nonthermal atmospheric plasma-activated solution that had broad-spectrum antibacterial properties. Plasma-activated phosphate-buffered saline (PBS) causes rapid inactivation of bacteria following generation of oxidative stress. However, dose optimization requires understanding of cellular mechanisms. The objective of this study was to explore genome-wise response to develop gene expression profile of Escherichia coli using DNA microarray following exposure to plasma-activated PBS solution. Upon exposure to plasma-treated PBS solution, E. coli cells had differentially expressed genes involved in oxidative stress, and cell envelope and membrane associated porin and transporters. The genes involved in house-keeping and metabolism, energy generation, motility and virulence were conversely downregulated. This is the first report which demonstrates a severe oxidative stress induced in E. coli cells in response to an exposure to nonequilibrium nonthermal dielectric-barrier discharge plasma-activated PBS solution, and the genes that are responsive to reactive oxygen species appeared to play a role in cellular stress. Such studies are important to identify targets of inactivation, and to understand plasma-treated solution and bacterial cell interactions.