Handheld plasma torch is like a lightsaber against bacteria

Plasma has many remarkable properties. In addition to being the fourth state of matter –along with solid, liquid and gas – it has been shown to kill bacteria, making it a potentially useful tool in medical environments.

Now the power of plasma can be in the palm of your hand with a new handheld plasma torch that can kill bacteria on the skin and other surfaces.

The device was developed by Australian and Chinese scientists and is being proposed as a tool for use in health care and the military.

Results from a study published in the Journal of Physics D: Applied Physics show 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.

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 temperature of the plume of plasma in the experiments was between 20-23 degrees C, which is easily tolerable by the skin.

“Bacteria form thick biofilms, which makes them enormously resistant against inactivation,” said CSRIO's Professor Kostya (Ken) Ostrikov, who is one of the co-authors of the study. “High temperatures are commonly used but they would obviously burn our skin.

“In this study we chose an extreme example to demonstrate that the plasma flashlight can be very effective even at room temperature.

“The device can be easily made and costs less than 100 US dollars to produce,” Ostrikov said.

Although the exact mechanism behind the anti-bacterial effect of plasma is unknown, it is thought that reactions between the plasma and the air surrounding it create a cocktail of reactive species that are similar to the ones found in our own immune system.

The device could be developed into a handheld device used by doctors and paramedics to treat bacterial infections in the field or in the hospital.