Krishna Priya Arjunan

Non-thermal dielectric barrier discharge plasma induces angiogenesis through reactive oxygen species.

Vascularization plays a key role in processes such as wound healing and tissue engineering. Non-thermal plasma, which primarily produces reactive oxygen species (ROS), has recently emerged as an efficient tool in medical applications including blood coagulation, sterilization and malignant cell apoptosis. Liquids and porcine aortic endothelial cells were treated with a non-thermal dielectric barrier discharge plasma in vitro. Plasma treatment of phosphate-buffered saline (PBS) and serum-free medium increased ROS concentration in a dose-dependent manner, with a higher concentration observed in serum-free medium compared with PBS. Species concentration inside cells peaked 1 h after treatment, followed by a decrease 3 h post treatment. Endothelial cells treated with a plasma dose of 4.2 J cm–2 had 1.7 times more cells than untreated samples 5 days after plasma treatment. The 4.2 J cm–2 plasma dose increased two-dimensional migration distance by 40 per cent compared with untreated control, while the number of cells that migrated through a three-dimensional collagen gel increased by 15 per cent. Tube formation was also enhanced by plasma treatment, with tube lengths in plasma-treated samples measuring 2.6 times longer than control samples. A fibroblast growth factor-2 (FGF-2) neutralizing antibody and ROS scavengers abrogated these angiogenic effects. These data indicate that plasma enhanced proliferation, migration and tube formation is due to FGF-2 release induced by plasma-produced ROS. Non-thermal plasma may be used as a potential tool for applying ROS in precise doses to enhance vascularization.

Direct and controllable nitric oxide delivery into biological media and living cells by a pin-to-hole spark discharge (PHD) plasma

Nitric oxide has great potential for improving wound healing through both inflammatory and vascularization processes. Nitric oxide can be produced in high concentrations by atmospheric pressure thermal plasmas. We measured the physical characteristics and nitric oxide production of a pin-to-hole spark discharge (PHD) plasma, as well as plasma-produced nitric oxide delivery into liquid and endothelial cells. The plasma temperature was calculated as 9030 ± 320 K by the Boltzmann method, which was adequate to produce nitric oxide, although the average gas temperature was near room temperature. The plasma produced significant UV radiation and hydrogen peroxide, but these were prevented from reaching the cells by adding a straight or curved tube extension to the plasma device. Plasma-produced nitric oxide in gas reached 2000 ppm and rapidly diffused into liquid and cells. Cells remained viable following plasma treatment and showed a linear increase in cGMP concentration with plasma treatment, indicating an intracellular functional response to PHD plasma NO. These data suggest that this plasma may provide a novel method for delivering NO locally and directly for enhanced wound healing.

Plasma for Air and Water Sterilization

This chapter describes the research efforts of Drexel Plasma Institute (DPI) in the area of plasma-based air and water sterilization. Motivation of this research is presented as well as the methods for selection of parameters for the experimental systems. Experimentally obtained results for air sterilization demonstrate that the direct influence of plasma charged particles on airborne bacteria in combination with active chemical substances generated by plasma is the probable reason for high sterilization efficiency of the Dielectric Barrier Grating Discharge (DBGD). Energy input on the level of 13 kJ/m3 is enough to reach a 5-log reduction of viable E. coli bacteria. Experimentally reached D-value (the dosage required for a 90% reduction of the number of viable microorganisms) for E. coli bacteria deactivation in water using spark discharge is very low, about 125 kJ/m3, and UV-radiation is the most plausible sterilization factor in this case. A new semi-numerical model is proposed for initial phase of electrical breakdown in water.

Non-thermal dielectric barrier discharge plasma induces angiogenesis through reactive oxygen species

Vascularization plays a key role in processes such as wound healing and tissue engineering. Non-thermal plasma, which primarily produces reactive oxygen species (ROS), recently emerged as an efficient tool in medical applications. Liquids and endothelial cells were treated with a non-thermal dielectric barrier discharge plasma. Plasma treatment of phosphate buffered saline (PBS) and serum-free medium increased ROS concentration in a dose-dependent manner, with a higher concentration in serum-free medium. ROS concentration in cells peaked 1 hour after treatment. 4.2 J/cm2 increased cell proliferation, 2D and 3D migration, as well as tube formation. A fibroblast growth factor-2 (FGF-2) neutralizing antibody and ROS scavengers for hydrogen peroxide and hydroxyl radicals abrogated these angiogenic effects. Non-thermal plasma may be a potential tool for applying ROS in precise doses to enhance vascularization.

Retraction Note to: Non-thermal Plasma Induces Apoptosis in Melanoma Cells via Production of Intracellular Reactive Oxygen Species

Non-thermal atmospheric pressure dielectric barrier discharge (DBD) plasma may provide a novel approach to treat malignancies via induction of apoptosis. The purpose of this study was to evaluate the potential of DBD plasma to induce apoptosis in melanoma cells. Melanoma cells were exposed to plasma at doses that did not induce necrosis, and cell viability and apoptotic activity were evaluated by Trypan blue exclusion test, Annexin-V/PI staining, caspase-3 cleavage, and TUNEL® analysis. Trypan blue staining revealed that non-thermal plasma treatment significantly decreased the viability of cells in a dose-dependent manner 3 and 24 h after plasma treatment. Annexin-V/PI staining revealed a significant increase in apoptosis in plasma-treated cells at 24, 48, and 72 h post-treatment (p < 0.001). Caspase-3 cleavage was observed 48 h post-plasma treatment at a dose of 15 J/cm2. TUNEL® analysis of plasma-treated cells demonstrated an increase in apoptosis at 48 and 72 h post-treatment (p < 0.001) at a dose of 15 J/cm2. Pre-treatment with N-acetyl-l-cysteine (NAC), an intracellular reactive oxygen species (ROS) scavenger, significantly decreased apoptosis in plasma-treated cells at 5 and 15 J/cm2. Plasma treatment induces apoptosis in melanoma cells through a pathway that appears to be dependent on production of intracellular ROS. DBD plasma production of intracellular ROS leads to dose-dependent DNA damage in melanoma cells, detected by γ-H2AX, which was completely abrogated by pre-treating cells with ROS scavenger, NAC. Plasma-induced DNA damage in turn may lead to the observed plasma-induced apoptosis. Since plasma is non-thermal, it may be used to selectively treat malignancies.

Air and Water Sterilization using Non-Thermal Plasma

The sterilization effect of plasma on air and water were investigated in this study*. For air sterilization, a small scale model of HVAC was designed and Dielectric Barrier Discharge plasma source was used for treatment of air. This PDRF (Pathogen Detection and Remediation Facility) consisted of a circulatory airflow system, a plasma chamber and a sampling system. Air sterilization experiments were performed and the inactivation of Escherichia coli was studied. Conventional water sterilization methods such as chlorination, ozonation, filtration, UV irradiation etc have several drawbacks. Pulsed plasma discharge for the destruction of microorganisms in waste water and potable water is a cost effective technique developed recently. The energy efficiency of different types of plasma discharges in water contaminated with Escherichia coli has been studied. The effect of initial concentration of bacterial solution on the inactivation efficiency has also been studied

Mechanism of induction of apoptosis in melanoma cancer cells by non-thermal plasma

Induction of apoptosis, or programmed cell death, is an important factor in cancer therapy as cancer cells frequently have acquired the ability to avoid apoptosis and continue to multiply in an unregulated manner; thereby becoming resistant to traditional chemotherapeutic drugs. Nonthermal atmospheric plasma discharge may provide a novel approach to induction of apoptosis in cancer cells. The purpose of this study was to evaluate the apoptotic effects of non-thermal plasma on melanoma cells and understand the mechanism of initiation of apoptosis in melanoma cancer cells by non-thermal plasma. Melanoma cancer cell line (ATCC A2058) was cultured in Dulbeccos modified Eagles medium with 4 mM L-glutamine adjusted to contain 1.5 g/L sodium bicarbonate and 4.5 g/L glucose, and 10% fetal bovine serum. Cells were incubated at 37 C with 95% humidified air and 5% carbon dioxide. Melanoma cells were treated with increasing levels of non-thermal plasma by altering dose rate and were evaluated by Trypan blue exclusion test, TUNEL analysis, Caspase 3 cleavage and Annexin-PI staining to determine viability and apoptotic activity at various time points after plasma treatment. Trypan blue testing revealed that plasma treatment at low power for up to 15 seconds (1.5 J/cm2) did not significantly increase the number of dead cells immediately following treatment (time zero); however, at higher doses, the percent dead cells increased linearly with dose of plasma. TUNEL analysis of cells treated for 15 seconds at high power (15 J/cm2) demonstrated an increase in apoptosis at 24 and 48 hours post-treatment (p < 0.05). Annexin-V staining revealed a significant increase in apoptosis in plasma-treated cells at 24, 48, and 72 hours post-treatment (p < 0.05). Caspase-3 cleavage was observed at 48 hours post plasma treatment at a dose of 15 seconds (15 J/cm2). Pretreatment with N-acetyl cysteine (NAC), a free radical scavenger, significantly decreased apoptosis in plasma-treated cells. Plasma treatment induces apoptosis in melanoma cells through a pathway that appears to be dependent on production of reactive oxygen species by plasma in fluid. ROS penetrate the cells and may induce high levels of DNA damage resulting in the induction of apoptosis. Plasma may be a useful tool to induce directed cell death without inducing necrosis and inflammation.

A novel pin-to-hole spark discharge plasma produces nitric oxide for medical applications

Nitric oxide, an important signaling molecule in endothelial cells, mediates many processes at the cellular as well as tissue levels. Several diseases such as diabetes, coronary artery diseases and hypertension are characterized by a reduction in the bioavailability of NO, which leads to endothelial dysfunction1. The use of NO donors has several drawbacks which includes inducing systemic side effects, due to their non-localized action. We have developed a novel pinto-hole spark discharge (PHSD) plasma device which generates nitric oxide (NO), which can be applied safely and locally to endothelial cells at low concentrations.

Decontamination of drinking water using a pulsed spark plasma discharge

This paper presents experiments conducted using a high voltage pulsed spark plasma discharge having the following parameters: peak-to-peak voltage 25 kV, peak-to-peak current 400 A, pulse duration 1.8 mus, frequency 1-50 Hz and energy per pulse 2 J. This study demonstrates that a rather low energy input of 75 J/L of water is required to obtain a one-log reduction in Escherichia coli concentration. It was also found that water treated with plasma has a prolonged resistance to E. coli even hours after treatment. Similar work has been done by other researchers and attempts were made to understand the underlying mechanism.

Non-Thermal Dielectric Barrier Discharge Plasma Promotes Vascularization Through Reactive Oxygen Species

Angiogenesis, the growth of new blood vessels from existing vessels, plays a key role in growth, and wound healing. Insufficient vascularization contributes to impaired wound healing in diabetic patients and the elderly. Tissue engineering is limited by the inability to adequately vascularize constructs to provide nutrients to the tissue core, thus limiting the size of engineered organs.Copyright