Australia - Handheld Plasma Flashlight Zaps Away Bacteria Instantly, Study

Chinese and Australian scientists have developed a handheld, battery-powered plasma-producing device that can rid skin of bacteria in an instant.

Chinese and Australian scientists have developed a handheld, battery-powered plasma-producing device that can rid skin of bacteria in an instant.

The handheld plasma flashlight, which costs under US$100 to make and uses battery power, could be used in ambulance emergency calls, natural disaster sites, military combat operations and many other instances where treatment is required in remote locations.

The study, the result of a collaboration between Huazhong University of Science and Technology, CSIRO, The University of Sydney, and the City University of Hong Kong, was published in the latest issue of the Journal of Physics D: Applied Physics.

In the study, the plasma flashlight effectively inactivated a thick biofilm of one of the most antibiotic and heat-resistant bacteria, Enterococcus faecalis – a bacterium which often infects the root canals during dental treatments.

The temperature of the plume of plasma in the experiments was between 20-23˚C, which is very close to room temperature and therefore prevents any damage to the skin.

The biofilms were created by incubating the bacteria for seven days. The biofilms were around 25 micrometres thick and consisted of 17 different layers of bacteria. Each one was treated for five minutes with the plasma flashlight and then analyzed to see how much of the bacteria survived.

Results showed that the plasma not only inactivated the top layer of cells, but penetrated deep into the very bottom of the layers to kill the bacteria.

“The bacteria form thick biofilms, which makes them enormously resistant against inactivation which is extremely difficult to implement. High temperatures are commonly used but they would obviously burn our skin,” said study co-author CSIRO Professor Kostya (Ken) Ostrikov.

“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 ran an analysis to see what species were present in the plasma and found that highly-reactive nitrogen and oxygen-related species dominated the results, similar to the ones found in our own immune system.

Ultraviolet radiation has also been theorized as a reason behind plasma’s success; however, this was shown to be low in the jet created by the plasma flashlight, adding to the safety aspect of the device.

The article can be found at: Pei X et al. (2012) Inactivation of a 25.5 µm Enterococcus faecalis biofilm by a room-temperature, battery-operated, handheld air plasma jet.

Samantha Chan

AsianScientist

Source: CSIRO;