Impact of Low-Temperature Plasmas on Deinococcus radiodurans and Biomolecules

Abstract

The effects of cold plasma on Deinococcus radiodurans, plasmid DNA, and model proteins were assessed using microbiological, spectrometric, and biochemical techniques. In low power O(2) plasma (approximately 25 W, approximately 45 mTorr, 90 min), D. radiodurans, a radiation-resistant bacterium, showed a 99.999% reduction in bioburden. In higher power O(2) plasma (100 W and 500 mTorr), the reduction rate increased about 10-fold and observation by atomic force microscopy showed significant damage to the cell. Damage to cellular lipids, proteins, and chromosome was indicated by losses of infrared spectroscopic peaks at 2930, 1651, 1538, and 1245 cm(-1), respectively. In vitro experiments show that O(2) plasmas induce DNA strand scissions and cross-linking as well as reduction of enzyme activity. The observed degradation and removal of biomolecules was power-dependent. Exposures to 200 W at 500 mTorr removed biomolecules to below detection limits in 60 s. Emission spectroscopy indicated that D. radiodurans cells were volatilized into CO(2), CO, N(2), and H(2)O, confirming that these plasmas were removing complex biological matter from surfaces. A CO(2) plasma was not as effective as the O(2) plasma, indicating the importance of plasma composition and the dominant role of chemical degradation. Together, these findings have implications for NASA planetary protection schemes and for the contamination of Mars.

DNA strand scission induced by a non-thermal atmospheric pressure plasma jet

“…[4][5][6] In contrast, our results show only a weak (below 10%) multifragmentation of DNA, which is observed as smeared bands in the gel image.…”

Nonthermal Plasma Inactivation of Food-Borne Pathogens

“…Low-pressure oxygen plasma has been shown to degrade lipids, proteins and DNA of cells (Mogul et al 2003). The reactive species in plasma have been widely associated to the direct oxidative effects on the outer surface of microbial cells.…”

Elimination of Biological Contaminations from Surfaces by Plasma Discharges: Chemical Sputtering

“…Many groups already demonstrated that plasma treatment can lead, under appropriate operational conditions, to fast sterilisation of different strains of bacteria or bacterial spores, [10][11][12][13][14] depyrogenation of bacterial endotoxins, [14][15][16][17][18] or to efficient elimination of protein residuals from surfaces. [14,[19][20][21][22][23][24][25] Plasma treatment of surfaces as a sterilisation or decontamination method is a promising approach to overcome limitations of conventional techniques. The precise characterisation of the employed plasma discharges, the application of sensitive surface diagnostic methods and targeted experiments to separate the effects of different agents, have led to rapid progress in the understanding of different relevant elementary processes.…”