Methods of Enhancing the Anti-Cancer Effect during the Simultaneous Processing of Cells by a Cold Atmospheric Plasma Jet and Gold Nanoparticles

The present study compares the operation of two cold atmospheric plasma jet (CAPJ) configurations: needle‐to‐cylinder electrode configuration (CAPJ I) and single high‐voltage cylinder electrode around the quartz tube (CAPJ II). The CAPJs were operated in argon flowing through a quartz capillary with 0.5‐mm inner diameter into the ambient air, and the plasma was generated by sinusoidal kHz frequency AC power supplies. The main emphasis of the study was on the mechanism of the initiation of ionization waves for these two configurations. For both CAPJs, there appeared several ionization waves during one half‐period of the applied voltage waveform, and the number of ionization waves increased at higher voltage amplitudes. However, we discovered marked differences in the initiation of the ionization waves for two different CAPJ configuration. The applied voltage controlled the initiation of consecutive ionization waves, which propagated from the grounded electrode towards the tube orifice in CAPJ I. In the case of CAPJ II, certain time had to pass for the initiation of a new ionization wave, and subsequent ionization waves within the same half‐period started at the tube orifice. In addition to the differences in the initiation of the ionization waves, we observed that the CAPJ I was ignited and sustained at lower voltages, while CAPJ II produced a longer plasma jet. The observed advantages and deficiencies of investigated CAPJ configurations point out their potential in different applications.

Cold plasma-liquid interaction becomes a growing interdisciplinary area of research involving plasma physics, fluid science, and chemistry. Plasma-liquid interaction has gained more interest over the last many years due to its potential applications in different fields. Cold atmospheric plasma jet is an emerging technology for surface drinking water treatment to improve quality and surface modification that is chemical-free and eco-friendly. Cold plasma treatment of water samples results in changes in turbidity, pH, and conductivity and in the formation of reactive oxygen and nitrogen species (RONS). As a result, plasma-activated water has a different chemical composition than water and can serve as an alternative technique for microbial disinfection. CAPJ has been generated by a high voltage 5 kV and a high frequency 19.56 kHz power supply. The discharge has been characterized by an optical method. To characterize the cold atmospheric pressure argon plasma jet, discharge plume temperature, and electron rotational and vibrational temperature have been determined. Cold atmospheric argon plasma jet produced at atmospheric condition contains high energetic electrons, ions, UV radiation, reactive oxygen, and nitrogen species named as cold plasma which has a wide range of applications in the biomedical industry, as well as in water treatment. Nowadays, researches have been carried out on ozonation through plasma jet interaction with surface drinking water. In this paper, we compare the change in physical and chemical parameters of surface water used for drinking purposes. The significant change in the physical parameters such as pH, turbidity, and electrical conductivity was studied. In addition, the significant changes in the concentration and absorbance of nitrate, ferrous, and chromium ions with respect to treatment time were studied. Our results showed that plasma jet interaction with surface drinking water samples can be useful for the improvement of water quality and an indicator for which reactive species play an important role in plasma sterilization.

As the ‘heart’ of high-current vacuum electronic devices, explosive emission cathodes play an important role in their applications. In this work, a titanium dioxide (TiO2)/carbon fibre cathode prepared by a cold atmospheric plasma jet is reported. TiO2 on the carbon fibre surface prepared by an atmospheric plasma jet is at the mixture of anatase and rutile phases. The field enhancement factor of the TiO2/carbon fibre cathode is 6681, which is over ten times higher than that of the carbon fibre cathode. Furthermore, the TiO2 coating slows the diode impedance collapse and decreases the cathode plasma expansion velocity from 1.5–2.0 to 1.0–1.5 cm µs−1, which is explained by a cathode plasma model. The surface of the TiO2/carbon fibre cathode is covered by 1.6 cm2 plasma, far exceeding that of the carbon fibre cathode (1.1 cm2), which enables uniform explosive electron emission. The obtained results show that TiO2/carbon fibre cathodes prepared by cold atmospheric plasma jets will be potential candidates as high-current explosive electron emitters.

Background: The common microorganism in caries process are Streptococcus mutans and Lactobacilli. Candida albicans have correlation with Streptococcus mutans for enhanced dental caries. Cold Atmospheric Plasma (CAP) is called as non-thermal as result of electrons are more heated than heavy particles which are at room climate. CAP jets are ionized native gas outflow, produced underneath typical pressure through microwaves, high frequency or pulsed direct current employing noble gases. There are many application of CAP in dentistry: in periodontology, implantology, prosthodontic, operative dentistry and in cariology. This study aimed to measure the sensitivity of the S. mutans and C. albicans to CAP jet. Material and methods: In this experiment, newly developed Cold atmospheric plasma jet (Iraqi made) using argon gas at a Gas flow rate 10 l/min, 175volt and Frequency 2.45 GHz At room temperature such that the nozzle tip had a maximum distance of 2mm from the agar plate. Cold atmospheric plasma effect was tested at different times on the viable numbers of Streptococci mutans and Candida albicans. Result: Through the irradiation of CAP jet on agar plates the antimicrobial efficacy for S. mutans and C. albicans was measured at different time the 3, 6, 9 minutes. Multiple pairwise comparisons using Tukey HSD showed there is significant reduction of colony
 
 forming unit (CFU) for Streptococci mutans by plasma at all time compared to control. multiple pairwise comparisons using Tukey HSD showed there is highly significance differences for C. albicans was observed for all times in comparison to control (p<0.01). The data of the current study was analyzed using statistical package for social science (SPSS version 22). Thus, it can be concluded that Cold Atmospheric plasma (argon gas) jet have anti-microbial efficacy against Streptococci mutans and Candida albicans. but it effects on Candida albicans more than on Streptococci mutans.

To investigate the potential role of the hydroxyl radical (•OH) in cold atmospheric plasma (CAP) jet treatment, two fluorescence-based methodologies are utilised to measure DNA strand breaks. The first comprises a model system of a double-stranded DNA oligomer, where the respective strand ends are tagged with fluorophore and quencher molecules; and the second, a cell culture system reporting DNA strand breaks using the γ-H2AX assay. During the various CAP jet treatments, optical emission spectroscopy is used to detect the •OH in the gas phase and electron spin resonance is used to detect the •OH in solution. The CAP jet production of the •OH is shown to correlate to CAP jet induced DNA damage both with the DNA model and in biological cells. Results indicate that the CAP jet induces a higher degree of DNA damage when the CAP plume is in contact with the target solution. The potential of a ‘plasma screen’ based upon a hydrogel film, as a method to remove the DNA-damaging •OH species from reaching skin cells, is shown to significantly reduce DNA damage whilst facilitating the delivery of hydrogen peroxide. These findings could aid in the development of CAP jet-based applications where DNA damage is the objective (e.g. in cancer treatment) and others where it is to be avoided, e.g. in open-wound treatment and dermatology.

This study aimed to evaluate the effects of cold atmospheric pressure plasma (CAPP)jet on Trichophyton rubrum growth, germination and adherence to nail. The effects of plasma jet on T. rubrum conidia germination and on mycelial growth were evaluated by in vitro assays. An ex vivo nail infection model was used to evaluate the effects on conidia adherence and infection. Biochemical analyses of nail fragments exposed or not to CAPP were performed by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. Plasma jet exposure for 10 and 15min completely inhibited mycelial growth after only one exposure. Fifteen minutes of exposure could reduce conidia germination in suspension. Fungal suspensions exposed to plasma jet for 10 and 15min were not able to infect nail specimens. These results were corroborated by ATR-FTIR analyses of nail fragments. In conclusion, single exposure to CAPP for 15min was able to inhibit fungal growth, adherence and infection capacity. The results suggest that cold atmospheric plasma jet can be a promising alternative for the treatment of onychomycoses caused by T. rubrum.

Cold atmospheric plasma (CAP) jet exhibits remarkable properties that trigger cell death in cancer cells. The effect of CAP on cancer cells is influenced by several factors including plasma jet discharge voltages, gas composition and cancer cell type. Consequently in clinics it becomes challenging to plan plasma cancer treatments for a particular cancer types. To address this, we present preliminary results for an in vitro model which includes an optimal feedback control scheme that can adjust treatment conditions based on the actual cancer cell response. Translation to an in vivo model will be the next objective of the presented project. First, a mathematical model is presented for the dynamic response of cancer cells to CAP jets based on experimental data that provide temporal measurements of cancer cell viability after CAP treatments. A differential equation is developed to model the influence of CAP on the viability of two cancer cell lines, U-87 MG and MDA-MB-231, under varying treatment duration and plasma discharge voltages. Subsequently, a control scheme is presented to determine CAP treatment conditions in an optimal fashion by reducing cancer cell viability less than a prescribed goal while minimizing a weighted sum of the treatment duration and the discharge voltage. This is further extended to a model predictive control framework such that a pre-planned CAP treatment schedule is revised according to the actual cancer cell response. The efficacy of the proposed approach is illustrated by numerical simulations based on experimental data.

In this paper, a cold atmospheric plasma (CAP) jet array is generated by a 2-D array device of seven CAP jets arranged in a honeycomb configuration and designed with single-electrode configuration as the elemental plasma jet. The work is motivated by the challenge of using inherently small atmospheric plasmas to address many large-scale processing applications. The discharge characteristics of the plasma jet array are investigated based on detailed electrical, spectroscopic, and imaging characterizations. The CAP jet array is shown to achieve good temporal jet-jet uniformity. Furthermore, the dynamic behavior of the jet discharges is studied particularly through two series of intensified-charge-coupled-device images taken at the end views. It has been found that the seven jets show a good temporal synchronization and jet-jet uniformity, as well as rich dynamics of jet-jet interactions such as a slight repulsion at surrounding jet heads, particularly for a small gas flow rate of helium. These dynamic features offer possible insights with which to better control the jet-jet interactions and further optimize the design of large-scale CAP sources.

The Effect of Plasma Activated Verbascoside on HIF-1A Expression as Valuable Metastasis and Angiogenesis factor in HT-29 Colon Cancer Cells

Tussah pebrine disease resulting from Nosema bombycis (NB) spores causes massive production and economic losses in the silk industry in China. This paper reports on highly effective inactivation of NB spores for the control of pebrine disease by using an atmospheric pressure cold plasma jet. Both Giemsa dyeing measurement and tussah breeding experiment show that the atmospheric pressure He plasma jet containing 1% <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">${\rm O}_{2}$</tex></formula> kills almost all the NB spores with a <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$10^{7}$</tex></formula> population within an exposure time of 5 min. Scanning electron microscopy measurements and UV absorbance spectra show that plasma inactivation has withered up the NB spores and resulted in the spores inactivated. Both energy dispersive spectroscopy and optical emission spectroscopy measurements showed that plasma-created reactive particles, such as O and accompanied charged species can play an important role in the inactivation processing.

Cold atmospheric plasma jet (CAPJ) can be an effective approach for treating tumors. We have previously shown that selectivity in tumor cell killing can be achieved with certain parameters of CAPJ generation and exposure duration. This selectivity was attributed to differences in the ability of tumor and healthy cells to overcome oxidative stress and was associated with CAPJ-dependent reactive oxygen and nitrogen species. We also showed that gold nanoparticles (GNPs) enhanced the cytotoxic effect of CAPJ against various cancer cells. To enhance the antitumor effect of CAPJ &lt;i&gt;in vivo&lt;/i&gt;, we proposed to apply gold nanoparticles carrying molecule targeting to tumor cells. In this study, mouse melanoma B16 cells expressing tyrosinase-related protein (Tyrp1) were used as a tumor model. We defined plasma jet parameters for the efficient growth inhibition of subcutaneously transplanted B16 tumor. The use of CAPJ-activated Ringer's solution or the autophagy inhibitor chloroquine (CQ) did not enhance the antitumor effect of CAPJ. Conjugates of GNPs with Tyrp1 antibodies (GNP-Tyrp1) were synthesized and their activity was tested against B16 cells &lt;i&gt;in vitro&lt;/i&gt;. We showed that both free Tyrp1 antibodies and conjugates GNP-Tyrp1 had no cytotoxic effect on cells without CAPJ exposure. B16-bearing mice were intratumorally injected with GNP-Tyrp1 (35 &amp;mu;g/mouse) and free GNPs, followed by a single exposure to CAPJ. We demonstrated that only the application of GNPs with the targeted molecule followed by CAPJ treatment caused tumor growth inhibition. Thus, targeting of GNPs to tumor cells with cancer cell-specific antibodies enhances the antitumor effect of cold plasma jet.

Cold atmospheric plasma (CAP) jet is currently intensively investigated as a tool for new and potentially transformative cancer treatment modality. However, there are still many unknowns about the jet behavior that requires attention. In this paper, a helium CAP jet is tested in an electrostatic field generated by a copper ring. Using Rayleigh microwave scattering method, some delays of the electron density peaks for different ring potentials are observed. Meanwhile, a similar phenomenon associated with the bullet velocity is found. Chemical species distribution along the jet is analyzed based on the jet optical emission spectra. The spectra indicate that a lower ring potential, i.e., lower DC background electric field, can increase the amount of excited N2, N2+, He, and O in the region before the ring, but can decrease the amount of excited NO and HO almost along the entire jet. Combining all the results above, we discovered that an extra DC potential mainly affects the temporal plasma jet properties. Also, it is possible to manipulate the chemical compositions of the jet using a ring with certain electric potentials.

In this work, the direct and indirect removal of Acid Blue 25 (AB25) from water by using cold atmospheric pressure plasma jet (APPJ) has been demonstrated. APPJ with a pin electrode type configuration operating with argon as a working gas was used as a plasma source for treatments. In this configuration, argon plasma was formed in the contact with surrounding air over the liquid surface. The plasma was driven by using a high voltage radio frequency (RF) power supply. The system was characterized by the measurement of electrical characteristics and by employing optical emission spectroscopy (OES). The electrical characterization gave information about the voltages and currents, i.e., working points of the discharge, as well as power deposition to the sample. OES recorded the emission spectra and confirmed several existing reactive species in the gas phase of the plasma system. During the direct treatment, AB25-containing solution was directly exposed to APPJ. The direct treatment was performed by modifying various experimental parameters, such as initial AB25 concentrations, treatment times, and input powers. In the indirect treatment, AB25 was treated by using plasma activated water (PAW). The characterization of PAW was performed and various plasma-induced long-lived species, such as nitrate (NO3−), nitrite (NO2−) and hydrogen peroxide (H2O2) have been quantified using colorimetric techniques. Besides, blank experiments have been conducted with main constituents in PAW, where AB25 was treated individually by NO3−, NO2−, and H2O2 and with a mixture of these three species. As expected, with the direct treatment almost complete removal of AB25 was achieved. The measurements also provided an insight into the kinetics of the degradation of AB25. In the indirect treatment, PAW removed a significant amount of AB25 within 17 days. In the blank experiments, H2O2 containing solutions created a favourable influence on removal of AB25 from liquid.

A novel approach combining experimental and numerical methods for the study of reaction mechanisms in a cold atmospheric plasma jet is introduced. The jet is operated with a shielding gas device that produces a gas curtain of defined composition around the plasma plume. The shielding gas composition is varied from pure to pure .The density of metastable argon in the plasma plume was quantified using laser atom absorption spectroscopy. The density of long-living reactive oxygen and nitrogen species (RONS), namely , , , , and , was quantified in the downstream region of the jet in a multipass cell using Fourier-transform infrared spectroscopy (FTIR).The jet produces a turbulent flow field and features guided streamers propagating at several that follow the chaotic argon flow pattern, yielding a plasma plume with steep spatial gradients and a time dependence on the scale while the downstream chemistry unfolds within several seconds. The fast and highly localized electron impact reactions in the guided streamer head and the slower gas phase reactions of neutrals occurring in the plasma plume and experimental apparatus are therefore represented in two separate kinetic models. The first electron impact reaction kinetics model is correlated to the LAAS measurements and shows that in the guided streamer head primary reactive oxygen and nitrogen species are dominantly generated from . The second neutral species plug-flow model hence uses an source term as sole energy input and yields good agreement with the RONS measured by FTIR spectroscopy.

Evaluation of RAC1 Gene Expression Under Exposure Of Plasma Activated Verbascoside in HT-29 Colorectal Cancer Cells