Spectroscopic study of excited molecular nitrogen generation due to interactions of metastable noble gas atoms

Scally, Laurence; Lalor, James; Gulan, Miroslav; Cullen, Patrick J.; Milosavljević, Vladimir

doi:10.1002/ppap.201800018

Cited by 7 publications

(6 citation statements)

References 49 publications

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“…From the OES data obtained, a line ratio method was used to determine the distribution of electron energies within the discharge. [ 10 ] Given that the spectrometer used gives the intensity results in arbitrary units, the method employed only gives an indication as to whether there is a higher density of low‐ or high‐energy electrons. From this, the most probable reaction mechanisms and how certain species are formed can be asserted.…”

Section: Methodsmentioning

confidence: 99%

Diagnostics of a large volume pin‐to‐plate atmospheric plasma source for the study of plasma species interactions with cancer cell cultures

Scally

Behan

Carvalho

et al. 2021

Plasma Processes & Polymers

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A large gap pin‐to‐plate, atmospheric‐pressure plasma reactor is demonstrated as means of in vitro study of plasma species interactions with cell cultures. By employing optical emission and optical absorption spectroscopy, we report that the pin‐to‐pate plasma array had an optimal discharge frequency for cell death of 1000 Hz in ambient air for the target cancer cell line, human glioblastoma multiform (U‐251MG). The detected plasma chemistry contained reactive oxygen and nitrogen species including OH, N2, N2+ and O3. We show that by varying the plasma discharge frequency, the plasma chemistry can be tailored to contain up to 8.85 times higher levels of reactive oxygen species (ROS) as well as a factor increase of up to 2.86 for levels of reactive nitrogen species (RNS). At higher frequencies, ROS are more dominant than RNS, which allows for a more dynamic and controlled environment for sample study without modifying the inducer gas conditions. When used for treatment of culture media and cell cultures, variation of the plasma discharge frequency over the range 1000–2500 Hz demonstrated a clear dependence of the responses, with the highest cytotoxic responses observed for 1000 Hz. We propose that the reactor offers a means of studying plasma–cell interactions and possible cofactors such as pro‐drugs and nanoparticles for a large volume of samples and conditions due to the use of well plates.

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Section: Methodsmentioning

confidence: 99%

Diagnostics of a large volume pin‐to‐plate atmospheric plasma source for the study of plasma species interactions with cancer cell cultures

Scally

Behan

Carvalho

et al. 2021

Plasma Processes & Polymers

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“…By taking the line intensity ratio of N2(337nm)/N2 + (391nm), the ratio of low energy electrons to high energy electrons can be found. This gives a better understanding of what reaction mechanisms may occur and which excitation routes are most likely for the generation of reactive species within the plasma discharge (Scally et al, 2018)…”

Section: Optical Measurementmentioning

confidence: 99%

Pin Electrode Reactor: A novel cold atmospheric plasma device and its potential in glioblastoma treatment

Carvalho

Behan

Scally³

et al. 2021

Preprint

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Glioblastoma multiforme (GBM) is the most common and biologically aggressive brain tumour. The current standard therapy for GBM consists in surgical resection, followed by radiotherapy and chemotherapy. Yet, the treatment is limited due to the area for the surgical resection and for the inability of some drugs to cross the brain blood barrier, leading to a general prognostic of no more than a year. Cold atmospheric plasma (CAP) is a new approach in the treatment of this challenging disease. CAP interaction with cells is dependent on physical and chemical factors, with different plasma discharges, cell type, and culture conditions leading to different CAP activity. Considering the plasma self-adaptation that different plasma discharge modes can undergo, which leads to different interaction plasma/cells, the characterization of a new device is essential. In this study we analysed the effect of a novel large pin-to-plate non-thermal atmospheric plasma on U-251 MG cells under different conditions. The analysis of reactive oxygen and nitrogen species (RONS) on plasma, media and cells were also assessed. We were able to demonstrate that the pin-to-plate device is cytotoxic to GBM cells in a dose, time and ROS dependent manner. The measurements of RONS on plasma/media also give us an insight on the chemical effect of this novelty device, and the possibility to better understand the use of this device as a promising GBM therapy.

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“…However, the use of just ambient air led to the formation of excited atomic nitrogen (N I), and with CO 2 as an admixture with ambient air, the generation of C 2 was detected. The formation of these reactive species, and the others detected in this work, could be inferred through the use of the electron energy distribution function (EEDF) obtained from the line ratio of (N 2 -337/N 2 + -391) [ 38 ]. From this, the most likely paths for reaction mechanisms could be highlighted and the energetics that occur at the sample’s surface during treatment give rise to a better understanding of possible surface modifications.…”

Section: Resultsmentioning

confidence: 99%

“…This was due to species such as O 2 , OH, and H 2 O having longer residence times within the applied electrical field, which allowed them to aid in more reaction mechanisms that create O 3 as the energetics were larger here due to their residence time in the direct electrical field. The possible reaction mechanisms can be seen below in Equations (1)–(3), where M is a third body atom or molecule such as O, N 2 *, or OH [ 38 , 39 , 40 ].

…”

Section: Resultsmentioning

confidence: 99%

Significance of a Non-Thermal Plasma Treatment on LDPE Biodegradation with Pseudomonas Aeruginosa

Scally,

Gulan,

Weigang

et al. 2018

Materials

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The use of plastics has spanned across almost all aspects of day to day life. Although their uses are invaluable, they contribute to the generation of a lot of waste products that end up in the environment and end up polluting natural habitats such as forests and the ocean. By treating low-density polyethylene (LDPE) samples with non-thermal plasma in ambient air and with an addition of ≈4% CO2, the biodegradation of the samples can be increased due to an increase in oxidative species causing better cell adhesion and acceptance on the polymer sample surface. It was, however, found that the use of this slight addition of CO2 aided in the biodegradation of the LDPE samples more than with solely ambient air as the carbon bonds measured from Raman spectroscopy were seen to decrease even more with this change in gas composition and chemistry. The results show that the largest increase of polymer degradation occurs when a voltage of 32 kV is applied over 300 s and with a mixture of ambient air and CO2 in the ratio 25:1.

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Spectroscopic study of excited molecular nitrogen generation due to interactions of metastable noble gas atoms

Cited by 7 publications

References 49 publications

Diagnostics of a large volume pin‐to‐plate atmospheric plasma source for the study of plasma species interactions with cancer cell cultures

Diagnostics of a large volume pin‐to‐plate atmospheric plasma source for the study of plasma species interactions with cancer cell cultures

Pin Electrode Reactor: A novel cold atmospheric plasma device and its potential in glioblastoma treatment

Significance of a Non-Thermal Plasma Treatment on LDPE Biodegradation with Pseudomonas Aeruginosa

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