Photons and particles emitted from cold atmospheric-pressure plasma inactivate bacteria and biomolecules independently and synergistically

Abstract

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.

A Comparison of Floating-Electrode DBD and kINPen Jet: Plasma Parameters to Achieve Similar Growth Reduction in Colon Cancer Cells Under Standardized Conditions

“…Also, short wavelength UV radiation is efficiently scavenged by a few hundred nanometers of liquid layer [80]. A combination of different plasma properties is also possible as seen with bacteria [81][82][83]. Corroborating results of the jet plasma in the present work, presence and concentration of H 2 O 2 strongly correlated with cytotoxic effects of the kINPen [84][85][86] and other jet and DBD plasma sources [87][88][89][90], especially plasma-treated liquids [91][92][93].…”

Unraveling the interactions between cold atmospheric plasma and skin-components with vibrational microspectroscopy

“…In previous papers, Raman and mass spectrometry experiments of CAP treated amino acids 32 as well as proteins 17,18 showed evidences for an oxidation of amino acids like cysteine residues by ROS from cold atmospheric plasmas. Our work supports these results and verifies the possible oxidation of skin components like keratin by CAPs.…”

“…16 Raman spectroscopic and mass spectrometry investigations of dried glyceraldehyde 3-phosphate dehydrogenase treated with a microscale atmospheric-pressure plasma jet provide evidence for oxidation of the catalytic cysteines, leading to an inactivation of the protein. 17 In contrary, Raman spectroscopic results of the treatment of bovine serum albumin with the same particle jet show no oxidations at the cysteine groups of this protein, but indicate modifications at tyrosine residues. 18 In this study, we dissect the functional changes of the SC model components lanolin, which resembles human sebum, and keratin, the most abundant protein of the SC and epidermis, after treatment with a dielectric barrier discharge (DBD).…”

Synergistic effects of atmospheric pressure plasma‐emitted components on DNA oligomers: a Raman spectroscopic study

“…Despite an ongoing clinical evaluation of CAPs, little is known so far about the mechanisms that lead to macromolecule modification. In order to understand how CAPs achieve bacterial inactivation and how they might impact eukaryotic cells, we aim to gain insight into the molecular effects of plasmas in vitro and in vivo . The present paper will focus on the impact of separate components of a specified plasma source on the structure of the bio‐macromolecule DNA in vitro .…”