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Innovation

The portable, germ-killing plasma flashlight

Handheld and battery-operated, the new plasma flashlight kills layers and layers of bacteria without burning your skin. Just 5 minutes, and a thick layer of the most antibiotic bacteria were killed.
Written by Janet Fang, Contributor

Handheld and battery-operated, the new plasma-producing device destroys bacteria on the skin almost instantly.

It’s powered by a 12 V battery, and it doesn’t require any external generator, wall power, or gas supply – making the plasma flashlight (pictured) handy for use in hospitals, ambulances, at natural disaster sites, and for combat operations.

Biofilms are thick, communal groups of bacteria. Normally, we encounter biofilms as plaque on our teeth, but they can also grow and thrive in wounds, holding up the healing process. Blasting the biofilm would make infections much easier for doctors and dentists to deal with.

So a team of Chinese and Australian researchers led by Xinpei Lu at the Huazhong University of Science and Technology designed a handheld plasma jet. Plasma is essentially ionized gas; if you pass electricity through a gas by applying a high voltage, you get plasma.

  1. To test the device, they experimented on one of the most antibiotic- and heat-resistant bacteria, Enterococcus faecalis.
  2. They incubated the bacteria for a week, until they grew into 17 different layers and about 25 micrometers thick. (Biofilms this thick are enormously resistant, and high temps are often used to inactivate them, but that would burn our skin.)
  3. The temperature of this plasma plume is between 20-23 degrees C, which is just a bit cooler than room temperature. The device itself is fitted with resistors to stop it heating up and making it safe to touch.
  4. After flashing the biofilm for 5 minutes from 5 millimeters away, the device had penetrated deep into the very bottom of the layers. For an individual bacterium, the inactivation time could be just tens of seconds.

The exact mechanism behind the antibacterial effect of plasma is largely unknown, although it’s thought that reactions between the plasma and the air surrounding it create a cocktail of reactive gases that are similar to the ones found in our own immune system, according to a news release.

The plasma flashlight could cost less than $100.

The device was presented in the Journal of Physics D: Applied Physics this week.

[Via Popular Mechanics, ScienceNOW]

Image from X Pei et al.

This post was originally published on Smartplanet.com

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