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12-04-2012 | Article

High-tech ‘flashlight’ kills dangerous bugs


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MedWire News: Scientists in China and Australia have developed a handheld, battery-operated device that can kill dangerous bacteria in an instant.

The device could be used in ambulance emergency calls, natural disaster sites, military combat operations, and other situations where treatment is required in remote locations.

The "plasma flashlight" was developed by an international team of researchers from Huazhong University of Science and Technology in Wuhan, China, The University of Sydney in New South Wales, Australia, and the City University of Hong Kong.

Similar in size to a conventional flashlight or torch, the device is powered by a 12 V battery and produces a jet of "plasma" - a form of gas containing ionized particles.

Plasma has long been known to have antimicrobial properties, say the researchers, and is already used to kill bacteria and viruses on the surface of the skin and in water.

The precise mechanism underlying these effects is unknown, but it is thought that reactions between the plasma and the air surrounding it create a cocktail of "free radicals," which are similar to the ones found in our own immune system.

Dr Luxin Pei and team tested the new device by firing the plasma at a thick layer of Enterococcus faecalis. This bacterium often infects the root canals during dental treatment and is considered extremely difficult to treat or eradicate.

After just 5 minutes of plasma treatment, all of the bacteria had been killed, including those at the very bottom of the thick film layer.

Dr Pei and colleagues comment: "In this study we chose an extreme example to demonstrate that the plasma flashlight can be very effective even at room temperature. For individual bacteria, the inactivation time could be just tens of seconds."

The researchers hope that their flashlight will soon be available for use by medical professionals. "The device can be easily made and costs less than US$ 100 [€ 77] to produce," noted Dr Kostya Ostrikov, another of the researchers. "Of course, some miniaturization and engineering design may be needed to make it more appealing and ready for commercialization."

The research is published in The Journal of Physics D: Applied Physics.

MedWire ( is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2012

By Joanna Lyford