October 2012

Controlling Plasmas for a Cleaner World

New findings indicate that ionized plasmas like those in neon lights and plasma TVs can be used to sterilize water, making it antimicrobial for as long as a week after treatment.

Click to enlarge photo. Enlarge Photo

Image courtesy of Steve Graves

Low temperature plasma in air creates a variety of ionized and chemically reactive oxygen and nitrogen species that can diffuse into nearby liquids or skin, where they can kill microbes similar to the way some drugs and immune cells kill microbes by generating similar or identical reactive chemicals.

The Science

Researchers at the University of California, Berkeley have revealed conditions under which Plasma-Activated Water created via indirect air dielectric barrier discharge can maintain antibacterial effectiveness for a period of up to 7 days.

The Impact

Plasmas interacting with water can be controlled to create antibacterial compounds, creating a useful disinfectant for up to seven days, and a potential improvement over traditional heat and chemical methods for sterilization of medical equipment and wounds.

Summary

When water is exposed to air adjacent to dielectric-barrier-discharge generated plasma, various chemical compounds including hydrogen peroxides and nitrites arise in the water that have the ability to kill bacteria.  This water is known as Plasma-Activated Water (PAW). Work at the University of California at Berkeley partially funded by the Office of Science Fusion Energy Sciences program through its Center for Predictive Control of Plasma Kinetics has shown that the PAW can stay antibacterial for up to seven days. Suspensions of E. coli were exposed to PAW for various durations over a 7-day period; samples exposed for longer times showed a significant decrease in the E. coli population.  Because of its anti-bacterial capacity, PAW has the potential for a multitude of applications such as sterilization of medical equipment and the treatment of wounds. While further research remains before PAW can be used in clinical settings, these early results are promising.

Contact

Douglas S. Clark
clark@berkeley.edu

David B. Graves
graves@berkeley.edu

Funding

Office of Science Fusion Energy Sciences (FES) program, UC Berkeley, and Department of Homeland Security (DHS) Scholarship and Fellowship Program administered by ORISE.

Publications

Matthew J Traylor et al.“Long-term antibacterial efficacy of air plasma-activated water,”  J. Phys. D: Appl. Phys. 44 472001 (2011).  [doi:10.1088/0022-3727/44/47/472001External link]

Matthew J Pavlovich et al. “Effects of discharge parameters and surface characteristics on ambient gas plasma disinfection,” Plasma Processes and Polymers. 9, in press (2012).

Related Links

http://graves-lab.cchem.berkeley.eduExternal link

http://iopscience.iop.org/0022-3727/44/47/472001External link

Highlight Categories

Program: FES

Performer/Facility: University

Additional: Technology Impact

Last modified: 3/18/2013 10:29:28 AM