The “Star Trek” Method of Hand Washing

February 15, 2010 in Medicine by RangelMD

Plasma is a form of matter – the most common form of matter in the universe – whereby atoms and molecules essentially lose their electrons. When energy – thermal or electromagnetic – is applied to a gas, which is matter that is already in a highly energetic state, the electrons and molecules become separated from each other and exist in a gas-like state or “soup” of separate electrons and molecules.  This state makes it very easy for plasma to conduct electricity. In addition to replacing the Lava Lamp, it turns out that plasmas are great sanitizers as well.

Sol (i.e the big sustained fusion reaction at the center of our solar system) is one big ball of plasma by virtue of massively high temperatures. Neon signs work because of the electrical current applied directly to an inert gas to energize ions in the gas and cause them to emit light. Sticking your hand or other body part in either a high thermal plasma field or an electrical current is going to ruin your day (and destroy tissue).  However, physicists have found that far lower temperatures and electrical fields that generate much less ionization (one part in a billion) are all that is needed to sufficiently sanitize human skin without causing tissue damage.

Gregor Morfill and colleagues at the Max-Planck Institute for Extraterrestrial Physics in Garching have shown how low-temperature plasmas can be used to clean hands conveniently in seconds. Their device contains a slab of dielectric material sandwiched between a solid electrode and a sheet of wire mesh. When they put a large voltage of 18 kV across the solid electrode and mesh, the resultant strong electric field generates numerous nano- and microsecond discharges that partially ionize the air. This ionization leaves ultraviolet radiation and a cocktail of chemical products – including ozone, nitrogen oxide, hydrogen peroxide and free radicals – which together kill bacteria.

The ultraviolet radiation instantly kills microbes while the chemical byproducts have both short term and longer lasting effects to prevent regrowth. This dual attack works on bacteria, viruses, and even fungi and has been shown to effectively treat tinea pedis (athletes foot) infections.

Because this method takes only 4 seconds and does not use soap and water that requires drying or lotions or creams that need to be spread around and rubbed into the skin, plasma skin sanitizers could dramatically increase the compliance rate of “hand washing” for medical personnel thus reducing the spread of deadly microbes from patient to patient.

Welcome to the 21st century! Next up, flying cars.

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