Fight the Lice: Researchers Develop Chemical-free Plasma Comb

Head lice are deft, hide from light and are hard to get rid of once they have attached themselves to hair follicles. Infestations with lice result in terrible itching and their most common victims are children between the ages of three and ten. Infestations of these bloodsucking parasites are commonly dealt with using chemicals such as special shampoos, lotions or gels and a specialized nit comb – often with multiple repeats until all nits (the eggs of these animals) are completely removed. For the children, the drawn-out procedure is unpleasant and painful. Also, many parents are especially hesitant to use chemical products, as some of their active ingredients are harmful to children and infants. This potential noxiousness is also relevant for patients with pre-existing ailments, such as asthma or allergies. Researchers at the Application Center for Plasma and Photonics of the Fraunhofer Institute for Surface Engineering and Thin Films IST in Göttingen, Germany, are therefore developing an alternative treatment method that could eliminate the use of biocides and chemicals. For this goal, cold atmospheric pressure plasma is used: it reliably kills the parasites without causing harm or discomfort to the host. The researchers have developed a special plasma lice comb for this application. The trick to this new technology lies in the high-voltage generator that sends electrical pulses to the metal teeth of the comb, which serve here as electrodes. The air between two electrodes, or teeth, is ionized in the presence of the high-voltage pulses; thus, plasma is generated out or air.

No Health Hazard

The high voltage is delivered only in very short bursts, using just enough energy to accelerate the tiny electrons without heating up the heavy gas particles pulses; thus, plasma is generated. In this manner, the temperature of the plasma can be set to room temperature. The cold plasmas kill both the lice and the nits without harming the hair or scalp. The process is completely harmless to humans. "After only one treatment, half of the wingless pests are already dead and the rest are gone within a day," says Prof. Dr. Wolfgang Viöl, director of the Application Center for Plasma and Photonics.  The researcher and his team confirmed this through extensive efficacy and safety testing, which was conducted in cooperation with a research institute. Also, the plasma comb has already been introduced in regional pediatric offices and can be used just like a normal comb. The researchers plan to initially bring it to market in small production batches as a cosmetic product. It could also be used as health care device in developing countries, where head lice transmit dangerous bacteria such as typhoid or five-day fever pathogens, Viöl explains. And by altering the shape of the comb and the distance between the teeth, it is also possible to use the comb for treating infestations on house pets. The Volkswagen Foundation supports Viöl with a Research Professorship within its

funding initiative "Niedersächsisches Vorab".