Photons and particles emitted from cold atmospheric-pressure plasma inactivate bacteria and biomolecules independently and synergistically.
Cold atmospheric-pressure plasmas are currently in use in medicine as surgical tools and are being evaluated for new applications, including wound treatment and cosmetic care. The disinfecting properties of plasmas are of particular interest, given the threat of antibiotic resistance to modern medicine. Plasma effluents comprise (V)UV photons and various reactive particles, such as accelerated ions and radicals, that modify biomolecules; however, a full understanding of the molecular mechanisms that underlie plasma-based disinfection has been lacking. Here, we investigate the antibacterial mechanisms of plasma, including the separate, additive and synergistic effects of plasma-generated (V)UV photons and particles at the cellular and molecular levels. Using scanning electron microscopy, we show that plasma-emitted particles cause physical damage to the cell envelope, whereas UV radiation does not. The lethal effects of the plasma effluent exceed the zone of physical damage. We demonstrate that both plasma-generated particles and (V)UV photons modify DNA nucleobases. The particles also induce breaks in the DNA backbone. The plasma effluent, and particularly the plasma-generated particles, also rapidly inactivate proteins in the cellular milieu. Thus, in addition to physical damage to the cellular envelope, modifications to DNA and proteins contribute to the bactericidal properties of cold atmospheric-pressure plasma.
Biology of Microorganisms, Biology and Biotechnology, Ruhr University Bochum, , Universitätsstrasse 150, 44780 Bochum, Germany.
Jan-Wilm
JW
Lackmann
Simon
S
Schneider
Eugen
E
Edengeiser
Fabian
F
Jarzina
Steffen
S
Brinckmann
Elena
E
Steinborn
Martina
M
Havenith
Jan
J
Benedikt
Julia E
JE
Bandow
D001412:Bacillus subtilis / Q000187:drug effects* / Q000235:genetics / Q000528:radiation effects / Q000648:ultrastructure; D004249:DNA Damage; D004269:DNA, Bacterial / Q000187:drug effects / Q000528:radiation effects; D004203:Disinfection / Q000379:methods*; D017930:Genes, Reporter; D008855:Microscopy, Electron, Scanning; D017785:Photons; D058626:Plasma Gases / Q000494:pharmacology*; D014466:Ultraviolet Rays
D004269:DNA, Bacterial; D058626:Plasma Gases
UV; antibacterial mechanisms; atmospheric-pressure plasma; biomacromolecules; plasma medicine; reactive oxygen species