#PLASMA PARTICLES FULL#

To tackle the problem, on the plasma side, we chose to take a multi-step approach working our way up from a single well-characterized plasma source with constant operating conditions (step one), to the same well-characterized source operated with different gas mixtures (step two), finally to sources that are more complex in terms of their range of interactions with biological systems (step three).

In addition, both come in large varieties. The main challenge is that individually plasmas and bacteria are highly complex with regard to their composition and properties. It is our long-term goal to gain an in-depth understanding of the antibacterial mechanisms of different plasmas on a molecular level. Previous in vitro experiments showed that particles emitted from plasma cause DNA strand breaks, whereas photons emitted from plasma cross-link DNA strands. further demonstrated mutagenic properties of plasma using bacterial spores. Published evidence supports a number of mechanisms: etching (the removal of matter) by accelerated ions disruption of the cell membrane by electroporation and formation of membrane ruptures and breakage of DNA or protein backbones. Thus, if the molecular mechanisms of interaction with biological samples were fully understood, then plasmas could be tuned for specific applications. Plasmas can be modulated to preferentially produce radicals, metastables, ions or photons simply by adjusting the gas composition and treatment conditions. Several studies have assessed inactivation efficiencies for bacteria, fungi, bacterial and fungal spores, and viruses however, the underlying molecular mechanisms of inactivation and the contributions of the different plasma components are poorly understood. ).Ĭold atmospheric-pressure plasmas inactivate microorganisms on time-scales ranging from seconds to minutes. These have found applications in the emerging field of plasma medicine (reviewed in Kong et al. Over the past decade, there has been growing interest in the artificial ‘cold’ plasmas, particularly in atmospheric-pressure plasmas with gas temperatures below 40☌. Naturally occurring plasmas are typically hot (the sun being a good example), but ‘cold’ plasmas can be found in nature as well, as for instance the aurora borealis. Plasmas, referred to as the fourth state of matter, are generated through the ionization of gas molecules by electric fields. 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. The plasma effluent, and particularly the plasma-generated particles, also rapidly inactivate proteins in the cellular milieu.

The particles also induce breaks in the DNA backbone. We demonstrate that both plasma-generated particles and (V)UV photons modify DNA nucleobases. The lethal effects of the plasma effluent exceed the zone of physical damage. Using scanning electron microscopy, we show that plasma-emitted particles cause physical damage to the cell envelope, whereas UV radiation does not. 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.

#PLASMA PARTICLES FULL#

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. The disinfecting properties of plasmas are of particular interest, given the threat of antibiotic resistance to modern medicine. 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.

Plasma particles