The scientists of the RUB create cold armospheric-pressure plasmas. They test the effect of UV radiation and reactive particles at bacterial cells and molecules; © RUB/Jan-Wilm Lackmann
As they destroy bacteria very efficiently, plasmas constitute an alternative to chemical disinfectants and potentially to antibiotics, as well. How they achieve this effect has been investigated by scientists at the Ruhr-Universität (RUB).
Cold atmospheric-pressure plasmas attack the prokaryote's cell envelope, proteins and DNA. "This is too great a challenge for the repair mechanisms and the stress response systems of bacteria," says Dr Julia Bandow, Head of the Junior Research Group Microbial Antibiotic Research at the RUB. "In order to develop plasmas for specific applications, for example for treating chronic wounds or for root canal disinfection, it is important to understand how they affect cells. Thus, undesirable side effects may be avoided right from the start."
Depending on their specific composition, plasmas may contain different components, for example ions, radicals or light in the ultraviolet spectrum, so-called UV photons. Until now, scientists have not understood which components of the complex mixture contribute to which extent to the antibacterial effect. Bandow's team has analyzed the effect of UV photons and reactive particles, namely radicals and ozone, on both the cellular level and on the level of single biomolecules, namely DNA and proteins. On the cellular level, the reactive particles alone were most effective: they destroyed the cell envelope. On the molecular level, both plasma components were effective. Both UV radiation and reactive particles damaged the DNA; in addition, the reactive particles inactivated proteins.
Atmospheric-pressure plasmas are already being used as surgical tools, for example in nasal and intestinal polyp extraction. Their properties as disinfectants may also be of interest with regard to medical applications. "In ten years, bacteria might have developed resistance against all antibiotics that are available to us today," says Bandow. Without antibiotics, surgery would become impossible due to high infection rates.
COMPAMED.de; Quelle: Ruhr-Universität Bochum