By Lucas Laursen
Something funny happens to water when you spray it through an electrical field: The water can now fight microbes. (Or something in the water can.) Plasma-activated water (PAW) is a fascinating substance that scientists around the world are looking at, in a fast-developing field that’s testing a broad range of uses. Dutch environmental chemist Paul Leenders (TEDxArnhem talk: Plasma-activated water: Nature’s answer to chemical pesticides) hopes to harness PAW to fight microbes in hospitals and on farms. Here’s how it works.
Plasma-activated water: less exotic than it sounds. After solid, liquid and gas comes plasma, the fourth state of matter. Lightning is one of Nature’s ways of making plasma, and scientists can replicate it in the lab by running electricity through a pair of electrodes; the strong electrical field ionizes air molecules and turns them into plasma. Scientists have been experimenting with creating plasmas since the late 19th century; sometime in the mid-20th century they discovered that when they exposed water to a plasma, the water picked up molecules such as nitrogen oxide and hydrogen peroxide from the air that made it more acidic and capable of fending off microbes. “Spray the water through the lightning,” Leenders says, and then stir. Voilà: PAW.
Because science is never done. The science around PAW is still developing, but researchers are busy dreaming up potential applications for it. A Chinese team recently reported that soaking button mushrooms in plasma-activated water reduced counts of bacteria and fungus and helped keep the mushrooms fresher. A German team has been designing tests that would establish PAW’s suitability for sterilization in medical settings. And a Russian team published apaper in 2011 showing that PAW promoted germination and root growth in zinnia flowers. Meanwhile, an American team found that, oddly, a 15-minute exposure to PAW killed more E. coli bacteria suspended in the water than did a three-hour exposure. Read More>>