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Gjika E.,George Washington University | Scott D.,George Washington University | Shashurin A.,Purdue University | Zhuang T.,US Medical Innovations | And 2 more authors.
Plasma Medicine | Year: 2016

The coagulation properties of the argon plasma coagulation (APC) technique present tremendous potential for a wide range of endoscopic applications. Although several studies have explored the endoscopic application of this technique, there has been no previous research about the relevant argon plasma properties during coagulation. We have investigated the role of power in the interactions between plasma and biological tissue, and have reported on the dielectric properties of the APC treated samples. The data revealed that at a resistance of 1 kΩ, the applied power was within 10% to 15% of the power setting, and the average resistance of the animal samples was between 0.8 and 3.7 kΩ. The data also suggested that the amount of power applied could be adjusted according to the expected tissue resistance range. Additionally, it was determined that the burned surface caused by the APC treatment was on average two to three times less conductive than the untreated surface. The data also revealed that 60%–80% of the power produced by the electrosurgical generator was delivered into the biological tissue, and the plasma channel consumed the remaining 20%–40%. This study establishes a guide for the investigation of optimal argon thermal plasma properties for biological tissue application. © 2016 by Begell House, Inc.

Ratovitski E.A.,George Washington University | Ratovitski E.A.,Johns Hopkins University | Cheng X.,George Washington University | Yan D.,George Washington University | And 5 more authors.
Plasma Processes and Polymers | Year: 2014

Cold atmospheric plasma (CAP) has just recently been showing promising anti-cancer activities supported by ability to induce cell death via apoptosis and cell cycle arrest leading to tumor cell destruction in vitro, and in vivo. Several studies showed the ability of CAP-activated media to modulate the tumor cell environment a link between the generation of reactive oxygen species/reactive nitrogen species and cancer cell death following CAP treatment. Targeting cancer cells through ROS-mediated mechanisms has become an attractive strategy for effective and selective cancer treatment by exploiting the aberrant redox characteristics of cancer cells. These effects support the potential direct (CAP) and indirect (CAP-activated media) applications for adjuvant anti-cancer therapeutics, in a combination with the chemo-, radio-, and nano-therapies. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Yan D.,George Washington University | Sherman J.H.,George Washington University | Cheng X.,George Washington University | Ratovitski E.,Johns Hopkins University | And 2 more authors.
Applied Physics Letters | Year: 2014

Cold atmospheric plasma (CAP) constitutes a "cocktail" of various reactive species. Accumulating evidence shows the effectiveness of CAP in killing cancer cells and decreasing the tumor size, which provides a solid basis for its potential use in cancer treatment. Currently, CAP is mainly used to directly treat cancer cells and trigger the death of cancer cells via apoptosis or necrosis. By altering the concentration of fetal bovine serum in Dulbecco's modified Eagle's medium and the temperature to store CAP stimulated media, we demonstrated controllable strategies to harness the stimulated media to kill glioblastoma cells in vitro. This study demonstrated the significant role of media in killing cancer cells via the CAP treatment. © 2014 AIP Publishing LLC.

Canady J.,Jerome Canady Research Institute for Advanced Biological and Technological science | Shashurin A.,George Washington University | Wiley K.,Jerome Canady Research Institute for Advanced Biological and Technological science | Fisch N.J.,Princeton University | Keidar M.,George Washington University
Plasma Medicine | Year: 2013

Plasma and injury properties produced by US Medical Innovations (USMI) elec­trosurgical systems were characterized using an explant pig’s liver samples. It was observed that plasma length, tissue temperature, and injury size increases with applied power increase. Transition from conventional to argon coagulation mode (<0.5 L/min) leads to redistribution of the discharge power over the larger tissue area causing abrupt decrease of injury depth and increase of eschar diameter. Flow rate is not a primary factor affecting the tissue temperature. The depth and diameter of injury was minimal for the case of hybrid argon plasma cut opera­tional mode. © 2013 by Begell House, Inc.

PubMed | George Washington University, Tel Aviv University and Jerome Canady Research Institute for Advanced Biological and Technological science
Type: | Journal: Scientific reports | Year: 2015

Electric discharge utilized for electrosurgery is studied by means of a recently developed method for the diagnostics of small-size atmospheric plasma objects based on Rayleigh scattering of microwaves on the plasma volume. Evolution of the plasma parameters in the near-electrode sheaths and in the positive column is measured and analyzed. It is found that the electrosurgical system produces a glow discharge of alternating current with strongly contracted positive column with current densities reaching 10(3) A/cm(2). The plasma electron density and electrical conductivities in the channel were found be 10(16) cm(-3) and (1-2) Ohm(-1) cm(-1), respectively. The discharge interrupts every instance when the discharge-driving AC voltage crosses zero and re-ignites again every next half-wave at the moment when the instant voltage exceeds the breakdown threshold.

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