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ABSTRACT: The present study investigated the feasibility of applying pulsed corona discharges to blood plasma to reduce the viscosity of blood plasma and whole blood. Blood plasma was separated from blood cells, treated with corona discharges, and filtered before it was re-mixed with blood cells. Plasma viscosity (PV), whole blood viscosity (WBV), and low-density lipoprotein (LDL)-c concentration were measured before and after the corona treatment and filtration. Both PV and WBV increased in the case of the corona treatment only, whereas both of them decreased in the case of the corona treatment plus filtration. In particular, the LDL-c decreased in the case of the corona treatment plus filtration by 31.5% from the baseline value. The effect of the corona treatment on the reduction of the WBV was significant at low shear rates, but not at high shear rates, suggesting that the precipitation of the molecules in blood plasma by the corona treatment and subsequent removal may suppress the aggregation of erythrocytes and improve rheological properties of blood.
The Review of scientific instruments 03/2013; 84(3):034301. · 1.52 Impact Factor
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ABSTRACT: In this study we have studied the initial stage of the nanosecond-pulsed
discharge development in liquid phase. Modeling predicts that in the case of
fast rising strong nonhomogeneous electric fields in the vicinity of high
voltage pin electrode a region saturated with nanoscale non-uniformities may be
developed. This phenomenon is attributed to the electrostriction mechanisms and
may be used to explain development of breakdown in liquid phase. In this work,
schlieren method was used in order to demonstrate formation of negative
pressure region in liquids with different dielectric permittivity constants:
water, ethanol and ethanol-water mixture. It is shown that this density
perturbation, formed at the raising edge of the high voltage pulse, is followed
by a generation of a shock wave propagating with the speed of sound away from
the electrode, with negative pressure behind it.
02/2013;
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ABSTRACT: Direct pulsed spark discharge treatment was found to be able to induce the precipitation of calcium ions in supersaturated
hard water (Yang et al. in Water Res 44:3659, 2010). The present study investigated possible pathways for the plasma-induced
precipitation. Both UV and reactive species were found not the major factors that stimulate the precipitation in present setup.
A transient hot-wire method was used to investigate the effect of plasma-induced local micro-heating. Approximately 15% drop
in the calcium-ion concentration was observed, indicating that the local micro-heating effect could be the major contributing
factor. Additionally, a nanosecond pulsed corona discharge was used to investigate the non-thermal effect of plasma, and a
maximum 7% drop in the calcium hardness was observed. Calcite with rhombohedron morphology was observed in both cases, similar
to the structure observed in the spark discharge treatment case, indicating that calcium-ion precipitation process could be
attributed to both the thermal and non-thermal effects produced by the plasma.
KeywordsPhysical water treatment–Pulsed spark discharge–Hard water–Calcium carbonate precipitation
Plasma Chemistry and Plasma Processing 05/2012; 31(1):51-66. · 1.60 Impact Factor
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ABSTRACT: Non-thermal dielectric barrier discharge (DBD) plasma is now being widely developed for various clinical applications1,2 but the mechanisms of interaction of such plasmas with mammalian cells are still not well understood. It is known that DBD plasma produces ozone and it is possible that the effects of plasma may be mediated purely by ozone. Although typically requiring much higher treatment time than the typical plasma treatment times reported here, ozonation is, in fact, widely employed to kill microorganisms in water and is also used for wound healing. It has been shown earlier that plasma treatment of mammalian cells submerged in a shallow layer of culture medium can result in dose dependent DNA damage. We wanted to understand the role of ozone in mediating the interaction of non-thermal plasma DBD plasma with mammalian cells. Upon comparing plasma treatment of mammalian breast epithelial cells with ozone treatment we found that ozone treatment is qualitatively different from non-thermal DBD plasma and in fact does not play a role in mediating the observed effects of plasma on mammalian cells.
Plasma Processes and Polymers 04/2012; 9(7):2012. · 2.47 Impact Factor
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Andrew S Wu,
Sameer Kalghatgi,
Danil Dobrynin,
Rachel Sensenig,
Ekaternia Cerchar,
Erica Podolsky,
Essel Dulaimi,
Michelle Paff,
Kimberly Wasko,
Krishna Priya Arjunan,
Kristin Garcia,
Gregory Fridman,
Manjula Balasubramanian,
Robert Ownbey,
Kenneth A Barbee, Alexander Fridman,
Gary Friedman,
Suresh G Joshi,
Ari D Brooks
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ABSTRACT: Thermal plasma is a valued tool in surgery for its coagulative and ablative properties. We suggested through in vitro studies that nonthermal plasma can sterilize tissues, inactive pathogens, promote coagulation, and potentiate wound healing. The present research was undertaken to study acute toxicity in porcine skin tissues. We demonstrate that floating electrode-discharge barrier discharge (FE-DBD) nonthermal plasma is electrically safe to apply to living organisms for short periods. We investigated the effects of FE-DBD plasma on Yorkshire pigs on intact and wounded skin immediately after treatment or 24h posttreatment. Macroscopic or microscopic histological changes were identified using histological and immunohistochemical techniques. The changes were classified into four groups for intact skin: normal features, minimal changes or congestive changes, epidermal layer damage, and full burn and into three groups for wounded skin: normal, clot or scab, and full burn-like features. Immunohistochemical staining for laminin layer integrity showed compromise over time. A marker for double-stranded DNA breaks, γ-H2AX, increased over plasma-exposure time. These findings identified a threshold for plasma exposure of up to 900s at low power and <120s at high power. Nonthermal FE-DBD plasma can be considered safe for future studies of external use under these threshold conditions for evaluation of sterilization, coagulation, and wound healing.
Journal of Surgical Research 03/2012; · 2.25 Impact Factor
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ABSTRACT: Nonthermal plasma has been shown to be effective in reducing pathogens on the surface of a range of fresh produce products. The research presented here investigated the effectiveness of nonthermal dielectric barrier discharge plasma on Salmonella enterica and Campylobacter jejuni inoculated onto the surface of boneless skinless chicken breast and chicken thigh with skin. Chicken samples were inoculated with antibiotic-resistant strains of S. enterica and C. jejuni at levels of 10(1) to 10(4) CFU and exposed to plasma for a range of time points (0 to 180 s in 15-s intervals). Surviving antibiotic-resistant pathogens were recovered and counted on appropriate agar. In order to determine the effect of plasma on background microflora, noninoculated skinless chicken breast and thighs with skin were exposed to air plasma at ambient pressure. Treatment with plasma resulted in elimination of low levels (10(1) CFU) of both S. enterica and C. jejuni on chicken breasts and C. jejuni from chicken skin, but viable S. enterica cells remained on chicken skin even after 20 s of exposure to plasma. Inoculum levels of 10(2), 10(3), and 10(4) CFU of S. enterica on chicken breast and chicken skin resulted in maximum reduction levels of 1.85, 2.61, and 2.54 log, respectively, on chicken breast and 1.25, 1.08, and 1.31 log, respectively, on chicken skin following 3 min of plasma exposure. Inoculum levels of 10(2), 10(3), and 10(4) CFU of C. jejuni on chicken breast and chicken skin resulted in maximum reduction levels of 1.65, 2.45, and 2.45 log, respectively, on chicken breast and 1.42, 1.87, and 3.11 log, respectively, on chicken skin following 3 min of plasma exposure. Plasma exposure for 30 s reduced background microflora on breast and skin by an average of 0.85 and 0.21 log, respectively. This research demonstrates the feasibility of nonthermal dielectric barrier discharge plasma as an intervention to help reduce foodborne pathogens on the surface of raw poultry.
Journal of food protection 01/2012; 75(1):22-8. · 1.94 Impact Factor
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ABSTRACT: Here we present the results of an experimental study of the effect of ions produced in a dc corona discharge on inactivation of bacteria on the surface of agarose gel. Both positive and negative corona discharges in various gases at different humidities were studied. The measurements in air, O(2), N(2), Ar and He mixtures show that there is no inactivation in pure N(2), pure O(2) and an N(2)-H(2)O mixture. The best results were achieved in the case of direct treatment, when discharge was ignited in oxygen and water-containing mixtures. We show that neither UV radiation, ozone or H(2)O(2) nor other neutral active species alone produced by corona have an effect on bacteria viability. It is shown that the main role of charged particles may be related to the faster transport of active peroxide species-cluster ions OH(-)(H(2)O)(n) and H(3)O(+)(H(2)O)(n). The efficiency of these radicals is much higher than that of the oxygen radicals and ions (including [Formula: see text] and O(3)) and that of nitrogen and argon ions.
New Journal of Physics 10/2011; 13. · 4.18 Impact Factor
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ABSTRACT: 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.
Journal of The Royal Society Interface 06/2011; 9(66):147-57. · 4.40 Impact Factor
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ABSTRACT: Observations of atmospheric-pressure dielectric barrier discharge are conducted through a water-filled electrode in atmospheric-pressure argon gas flow. Quasi-symmetric self-organized discharge filaments were observed. The streamers moved with the gas flow, and the migration velocity increased with increasing gas velocity.
IEEE Transactions on Plasma Science 05/2011; 39(11):2060-2061. · 1.17 Impact Factor
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ABSTRACT: In most cases, the electric breakdown of liquids is initiated by the application of high electric field on the electrode, followed by rapid propagation and branching of plasma channels. Typically plasmas are only considered to exist through the ionization of gases and typical production of plasmas in liquids generates bubbles through heating or via cavitation and sustains the plasmas within those bubbles. The question arises: is it possible to ionize the liquid without cracking and void formation?To answer this question we used a pulsed power system with 32–220 kV pulse amplitude, 0.5–12 ns pulse duration, 150 ps rise time. The discharge cell had a point-to-plate geometry with a tip diameter of 100 µm. These parameters allowed us to observe non-equilibrium plasma generation. The measurements were performed with the help of a 4Picos ICCD camera. It was found that the discharge in liquid water forms on a picosecond time scale. The increase of emission intensity and plasma formation took 200–300 ps. The diameter of the excited region near the tip of the high-voltage electrode was ~1 mm. After this initial stage emission rapidly decreased and the plasma region became almost invisible after 500 ps. The absence of emission during the rest of the pulse is explained by a decrease of the electrical field on the boundary of the conductive zone.Thus we have demonstrated the possibility of formation of non-equilibrium plasma in the liquid phase and investigated the dynamics of excitation and quenching of non-equilibrium plasma in liquid water.
Plasma Sources Science and Technology 03/2011; 20(2):024003. · 2.52 Impact Factor
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ABSTRACT: Oxidative stress leads to membrane lipid peroxidation, which yields products causing variable degrees of detrimental oxidative modifications in cells. Reactive oxygen species (ROS) are the key regulators in this process and induce lipid peroxidation in Escherichia coli. Application of nonthermal (cold) plasma is increasingly used for inactivation of surface contaminants. Recently, we reported a successful application of nonthermal plasma, using a floating-electrode dielectric-barrier discharge (FE-DBD) technique for rapid inactivation of bacterial contaminants in normal atmospheric air (S. G. Joshi et al., Am. J. Infect. Control 38:293-301, 2010). In the present report, we demonstrate that FE-DBD plasma-mediated inactivation involves membrane lipid peroxidation in E. coli. Dose-dependent ROS, such as singlet oxygen and hydrogen peroxide-like species generated during plasma-induced oxidative stress, were responsible for membrane lipid peroxidation, and ROS scavengers, such as α-tocopherol (vitamin E), were able to significantly inhibit the extent of lipid peroxidation and oxidative DNA damage. These findings indicate that this is a major mechanism involved in FE-DBD plasma-mediated inactivation of bacteria.
Antimicrobial Agents and Chemotherapy 01/2011; 55(3):1053-62. · 4.84 Impact Factor
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ABSTRACT: Thermal plasmas and lasers have been widely used in medicine to cut, ablate and cauterize tissues through heating; in contrast, non-thermal plasma produces no heat, so its effects can be selective. In order to exploit the potential for clinical applications, including wound healing, sterilization, blood coagulation, and cancer treatment, a mechanistic understanding of the interaction of non-thermal plasma with living tissues is required. Using mammalian cells in culture, it is shown here that non-thermal plasma created by dielectric barrier discharge (DBD) has dose-dependent effects that range from increasing cell proliferation to inducing apoptosis. It is also shown that these effects are primarily due to formation of intracellular reactive oxygen species (ROS). We have utilized γ-H2AX to detect DNA damage induced by non-thermal plasma and found that it is initiated by production of active neutral species that most likely induce formation of organic peroxides in cell medium. Phosphorylation of H2AX following non-thermal plasma treatment is ATR dependent and ATM independent, suggesting that plasma treatment may lead to replication arrest or formation of single-stranded DNA breaks; however, plasma does not lead to formation of bulky adducts/thymine dimers.
PLoS ONE 01/2011; 6(1):e16270. · 4.09 Impact Factor
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Rachel Sensenig,
Sameer Kalghatgi,
Ekaterina Cerchar,
Gregory Fridman,
Alexey Shereshevsky,
Behzad Torabi,
Krishna Priya Arjunan,
Erica Podolsky, Alexander Fridman,
Gary Friedman,
Jane Azizkhan-Clifford,
Ari D Brooks
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ABSTRACT: 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/cm(2). 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/cm(2). 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/cm(2). 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.
Annals of biomedical engineering 10/2010; 39(2):674-87. · 2.41 Impact Factor
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ABSTRACT: The effect of underwater pulsed spark discharge on the precipitation of dissolved calcium ions was investigated in the present study. Water samples with different calcium hardness were prepared by continuous evaporation of tap water using a laboratory cooling tower. It was shown that the concentration of calcium ions dropped by 20–26% after 10-min plasma treatment, comparing with no drop for untreated cases. A laser particle counting method demonstrated that the total number of solid particles suspended in water increased by over 100% after the plasma treatment. The morphology and the crystal form of the particles were identified by both scanning electron microscopy and X-ray diffraction. Calcite with rhombohedron morphology was observed for plasma treated cases, comparing with the round structure observed for no-treatment cases. It was hypothesized that the main mechanisms for the plasma-assisted calcium carbonate precipitation might include electrolysis, local heating in the vicinity of plasma channel and a high electric field at the tip of plasma streamers, inducing structural changes in the electric double layer of hydrated ions.
Water Research 06/2010; · 4.86 Impact Factor
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ABSTRACT: Bacterial contamination of surfaces with methicillin-resistant Staphylococcus aureus (MRSA) is a serious problem in the hospital environment and is responsible for significant nosocomial infections. The pathogenic contaminants form biofilms, which are difficult to treat with routine biocides. Thus, a continuous search for novel disinfection methods is essential for effective infection control measures. This demonstration of a novel technique for the control of virulent pathogens in planktonic form as well as in established biofilms may provide a progressive alternative to standard methodology.
We evaluated a novel technique of normal atmospheric nonthermal plasma known as floating-electrode dielectric-barrier discharge (FE-DBD) plasma against a control of planktonic and biofilm forms of Escherichia coli, S aureus, multidrug-resistant methicillin-resistant S aureus (MRSA) -95 (clinical isolate), -USA300, and -USA400, using widely accepted techniques such as colony count assay, LIVE/DEAD BacLight Bacterial Viability assay, and XTT (2,3-Bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) assay.
Exposure of free living planktonic forms of E coli, S aureus, and MRSA were rapidly inactivated by DBD plasma. Approximately 10(7) bacterial cells were completely (100%) killed, whereas 10(8) and 10(9) were reduced by approximately 90% to 95% and 40% to 45%, respectively, in less than 60 seconds (7.8 J/cm(2)) and completely disinfected in < or =120 seconds. In established biofilms, the susceptibility of MRSA USA400 was comparable with USA300 but less susceptible than MRSA95 (clinical isolate), S aureus, and E coli (P < .05) to FE-DBD plasma, and plasma was able to kill MRSA more than 60% within 15 seconds (1.95 J/cm(2)). The killing responses were plasma exposure-time dependent, and cell density dependent. The plasma was able disinfect surfaces in a less than 120 seconds.
Application of DBD plasma can be a valuable decontamination technique for the removal of planktonic and biofilm-embedded bacteria such as MRSA -USA 300, -USA 400, methicillin-sensitive S aureus (MSSA), and E coli, the more common hospital contaminants. Of interest, E coli was more resistant than S aureus phenotypes.
American journal of infection control 05/2010; 38(4):293-301. · 3.01 Impact Factor
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ABSTRACT: Non-thermal dielectric barrier discharge plasma is being developed for a wide range of medical applications, including wound healing, blood coagulation, and malignant cell apoptosis. However, the effect of non-thermal plasma on the vasculature is unclear. Blood vessels are affected during plasma treatment of many tissues and may be an important potential target for clinical plasma therapy. Porcine aortic endothelial cells were treated in vitro with a custom non-thermal plasma device. Low dose plasma (up to 30 s or 4 J cm(-2)) was relatively non-toxic to endothelial cells while treatment at longer exposures (60 s and higher or 8 J cm(-2)) led to cell death. Endothelial cells treated with plasma for 30 s demonstrated twice as much proliferation as untreated cells five days after plasma treatment. Endothelial cell release of fibroblast growth factor-2 (FGF2) peaked 3 h after plasma treatment. The plasma proliferative effect was abrogated by an FGF2 neutralizing antibody, and FGF2 release was blocked by reactive oxygen species scavengers. These data suggest that low dose non-thermal plasma enhances endothelial cell proliferation due to reactive oxygen species mediated FGF2 release. Plasma may be a novel therapy for dose-dependent promotion or inhibition of endothelial cell mediated angiogenesis.
Annals of biomedical engineering 12/2009; 38(3):748-57. · 2.41 Impact Factor
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ABSTRACT: Mechanisms of plasma interaction with living tissues and cells can be quite complex, owing to the complexity of both the plasma and the tissue. Thus, unification of all the mechanisms under one umbrella might not be possible. However, the authors are attempting to make first steps in this direction. In this paper, analysis of interaction of floating electrode dielectric barrier discharge (FE-DBD) with living tissues and cells is presented and biological and physical mechanisms are discussed. In physical mechanisms, charged species are identified as the major contributors to the desired effect and a mechanism of this interaction is proposed. Biological mechanisms are also addressed and a hypothesis of plasma selectivity and its effects is offered.
New Journal of Physics 11/2009; 11(11):115020. · 4.18 Impact Factor
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ABSTRACT: The operating regimes and the structures of dc corona discharges in air, nitrogen, helium and hydrogen–methane mixtures are studied for a point to plate electrode configuration. The characteristics of the dc negative corona discharge are investigated. In addition to the bright glow at the cathode (pin) region, a uniform diffuse glow is observed near the anode (plate) surface for the negative corona. This diffuse glow is observed in air and hydrogen–methane discharges only and not in nitrogen discharges. The presence of a glow near the planar anode is perhaps due to the increased electric field caused by a negative ion sheath formed only in electronegative gases. Optical emission spectroscopy (OES) was used to obtain species, spatially resolved temperature measurements and electric field estimations for the corona discharges in air. For the negative corona, the presence of a weak glow indicates an active plasma region near the positive planar electrode which may be useful for processing techniques such as plasma enhanced chemical vapor deposition. The dc negative corona discharge was observed to deposit films on the anode surface for air and methane.
Plasma Sources Science and Technology 06/2009; 18(3):035016. · 2.52 Impact Factor
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Advanced Materials 06/2009; 21(40):4039 - 4044. · 13.88 Impact Factor
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ABSTRACT: Non-thermal dielectric barrier discharge plasma is currently being developed for a wide range of medical applications, including blood coagulation, malignant cell apoptosis, and wound healing. However, the effect of non-thermal plasma on the vasculature is unclear. Blood vessels are affected during plasma treatment of many tissues, and vessels themselves may be an important clinical plasma therapy target. We investigated the effect of non-thermal plasma treatment on endothelial cells, which line the inner surface of blood vessels. Non-thermal plasma treatment at short exposures (up to 30 seconds; 4 J/cm(2)) was relatively non-toxic to endothelial cells. Endothelial cells treated with plasma for 30 seconds demonstrated twice as much proliferation as untreated cells five days after plasma treatment. Proliferation was abrogated by a fibroblast growth factor-2 neutralizing antibody and reactive oxygen species inhibitors. This suggests that plasma-induced endothelial cell proliferation is caused by growth factor release following reactive oxygen species cell membrane damage. These data suggest that low power non-thermal plasma treatment is a potential novel therapy for promotion of endothelial cell mediated angiogenesis.
Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 01/2009; 2009:6030-3.
