Gas and heat dynamics of a micro-scaled atmospheric pressure plasma reference jet

Kelly, Scott David; Golda, Judith; Turner, M. M.; Gathen, Volker Schulz-von der

doi:10.1088/0022-3727/48/44/444002

Cited by 40 publications

(45 citation statements)

References 40 publications

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“…The half-life of the enzyme was estimated to be 75.3 and 82.3 s for synthetic air and nitrogen, respectively. Plasma ignited in argon turned out to inactivate rAaeUPO significantly faster than in synthetic air or nitrogen with an enzyme half-life of 28.1 s. This may be because argon is an atomic gas so that rotational or vibrational excitation does not occur and electron impact leads to ionization with a higher probability [33,34]. With the same setup, the H 2 O 2 production rates in the treated liquid were significantly higher for argon, indicating a higher influx of reactive species from the plasma [35].…”

Section: Resultsmentioning

confidence: 99%

Protection strategies for biocatalytic proteins under plasma treatment

Yayci¹,

Dirks²,

Kogelheide³

et al. 2020

J. Phys. D: Appl. Phys.

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In plasma-driven biocatalysis, enzymes are employed to carry out reactions using species generated by non-thermal plasmas as the precursors. We have previously demonstrated that this is feasible in principle, but that the approach suffers from the short lifetime of the biocatalyst under operating conditions. In this work, protection strategies were investigated to prevent the dielectric barrier discharge plasma-induced inactivation of biocatalysts, using recombinant unspecific peroxygenase from Agrocybe aegerita (rAaeUPO), one of the most promising enzymes for plasma-driven biocatalysis. Treatment in oxygen-free atmospheres did not provide any advantage over treatment in synthetic air, indicating that the detrimental reactive species did not originate from oxygen in the plasma phase. Chemical scavengers were employed to eliminate undesired reactive species, without any long-term effect on enzyme lifetime. Similarly, chaperones, including the known stress response proteins Hsp33, CnoX, and RidA did not increase the lifetime of rAaeUPO. Immobilization of the biocatalyst proved effective in preserving enzyme activity. The residual activity of rAaeUPO after plasma treatment strongly depended on the specific immobilization support. Essentially complete protection for at least 15 min of plasma exposure was achieved with an epoxy-butyl-functionalized carrier. This study presents new insights into plasma-protein interactions and plots a path forward for protecting biocatalytic proteins from plasma-mediated inactivation.

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Section: Resultsmentioning

confidence: 99%

Protection strategies for biocatalytic proteins under plasma treatment

Yayci¹,

Dirks²,

Kogelheide³

et al. 2020

J. Phys. D: Appl. Phys.

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“…To meet reference conditions, the COST-jet was operated at 4 mm electrode-liquid distance, compared to 9 mm for the kINPen., which might result in higher • O densities near the gas-liquid interface for the COST-jet. However, • O densities can also be affected by the mean gas velocity, which is higher for kINPen, as well as the gas flux dynamics (turbulent in kINPen, laminar in COST-jet) [49, 55]. The COST-jet is well known to produce relevant amounts of • O in the gas and liquid phase [56, 57].…”

Section: Resultsmentioning

confidence: 99%

Nitrosylation vs. oxidation – How to modulate cold physical plasmas for biological applications

et al. 2019

Self Cite

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Thiol moieties are major targets for cold plasma-derived nitrogen and oxygen species, making CAPs convenient tools to modulate redox-signaling pathways in cells and tissues. The underlying biochemical pathways are currently under investigation but especially the role of CAP derived RNS is barely understood. Their potential role in protein thiol nitrosylation would be relevant in inflammatory processes such as wound healing and improving their specific production by CAP would allow for enhanced treatment options beyond the current application. The impact of a modified kINPen 09 argon plasma jet with nitrogen shielding on cysteine as a thiol-carrying model substance was investigated by FTIR spectroscopy and high-resolution mass spectrometry. The deposition of short-lived radical species was measured by electron paramagnetic resonance spectroscopy, long-lived species were quantified by ion chromatography (NO 2 - , NO 3 - ) and xylenol orange assay (H 2 O 2 ). Product profiles were compared to samples treated with the so-called COST jet, being introduced by a European COST initiative as a reference device, using both reference conditions as well as conditions adjusted to kINPen gas mixtures. While thiol oxidation was dominant under all tested conditions, an Ar + N 2 /O 2 gas compositions combined with a nitrogen curtain fostered nitric oxide deposition and the desired generation of S-nitrosocysteine. Interestingly, the COST-jet revealed significant differences in its chemical properties in comparison to the kINPen by showing a more stable production of RNS with different gas admixtures, indicating a different • NO production pathway. Taken together, results indicate various chemical properties of kINPen and COST-jet as well as highlight the potential of plasma tuning not only by gas admixtures alone but by adjusting the surrounding atmosphere as well.

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“…In a differently designed RF-driven plasma jet gas temperatures are observed of several hundreds of degrees 39 , while temperature measurements in the plasma plume of an AC kHz-driven plasma jet show only a gas temperature of 35 °C 28 . Numerical and experimental work done by Kelly et al on the micro scaled reference jet show a great variance of gas temperature depending on the working mode of that jet 40 . The temperature increase due to the heat exchange between the heated helium core and the cooled surrounding air has not been observed and reported in literature before to the best of our knowledge.…”

Section: Discussionmentioning

confidence: 99%

Revealing Plasma-Surface Interaction at Atmospheric Pressure: Imaging of Electric Field and Temperature inside the Targeted Material

Slikboer

Acharya

Sobota

et al. 2020

Sci Rep

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The plasma-surface interaction is studied for a low temperature helium plasma jet generated at atmospheric pressure using Mueller polarimetry on an electro-optic target. The influence of the AC kHz operating frequency is examined by simultaneously obtaining images of the induced electric field and temperature of the target. The technique offers high sensitivity in the determination of the temperature variation on the level of single degrees. Simultaneously, the evolution of the electric field in the target caused by plasma-driven charge accumulation can be measured with the threshold of the order of 105 V/m. Even though a specific electro-optic crystal is used to obtain the results, they are generally applicable to dielectric targets under exposure of a plasma jet when they are of 0.5 mm thickness, have a dielectric constant greater than 4 and are at floating potential. Other techniques to examine the induced electric field in a target do not exist to the best of our knowledge, making this technique unique and necessary. The influence of the AC kHz operating frequency is important because many plasma jet designs used throughout the world operate at different frequency which changes the time between the ionization waves and hence the leftover species densities and stability of the plasma. Results for our jet show a linear operating regime between 20 and 50 kHz where the ionization waves are stable and the temperature increases linearly by 25 K. The charge deposition and induced electric fields do not increase significantly but the surface area does increase due to an extended surface propagation. Additionally, temperature mapping using a 100 μm GaAs probe of the plasma plume area has revealed a mild heat exchange causing a heating of several degrees of the helium core while the surrounding air slightly cools. This peculiarity is also observed without plasma in the gas plume.

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Gas and heat dynamics of a micro-scaled atmospheric pressure plasma reference jet

Cited by 40 publications

References 40 publications

Protection strategies for biocatalytic proteins under plasma treatment

Protection strategies for biocatalytic proteins under plasma treatment

Nitrosylation vs. oxidation – How to modulate cold physical plasmas for biological applications

Revealing Plasma-Surface Interaction at Atmospheric Pressure: Imaging of Electric Field and Temperature inside the Targeted Material

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