I pursued my PhD
in the Electrical and Computer Engineering Department at Drexel
University. I worked in the A. J. Drexel Plasma Institute on atmospheric pressure cold plasma technology and its biomedical applications
with specific emphasis on dielectric barrier discharges and their interaction
with living tissue. My primary area of
research involved investigating and understanding the interaction of non-thermal
atmospheric pressure dielectric barrier discharge plasma with living tissue.
I worked in the following areas of research
Interaction of Non-Thermal DBD Plasma with Mammalian cells in vitro
Non-Thermal DBD Plasma for Tissue Engineering
Non-Thermal DBD Plasma for Cancer Treatment
Toxicity of Non-Thermal DBD Plasma Treatment of tissue using animal models
For my PhD I have been working on developing non-thermal atmospheric
pressure plasma as a novel tool for various clinical applications
ranging from skin sterilization, wound healing, angiogenesis to inducing
apoptosis in melanoma cancer cells. Specifically, I have been
investigating physical and biochemical mechanisms of interaction of
non-thermal plasma with cells and living tissue using in-vitro and
in-vivo (non-survival and survival porcine models) experimental
This was the first time anyone was studying the mechanisms of interaction of non-thermal plasma with cells. We discovered that plasma treatment of mammalian cells (MCF10A) leads to dose dependent DNA damage one hour after treatment using western blots and indirect immunofluorescence. We also determined that DNA damage is induced by organic peroxides formed as a result of long living neutral active organic reactive oxygen species (ROS) produced by non-thermal plasma in cell culture medium (read more).
Additionally we also showed that low dose non-thermal plasma enhances proliferation of endothelial cells via release of fibroblast growth factor (FGF-2)(read more), while high doses of non-thermal plasma leads to selective induction of apoptosis in melanoma cancer cells as confirmed by annexin-V/PI (flow cytometry), caspase-3 cleavage and TUNEL (fluorescence microscopy) assays (read more). Both these results were also mediated by ROS produced by plasma.
Current studies involve determining the type of DNA damage induced due to plasma treatment of cells by using viral transfection to knockdown DNA repair kinases like ATM/ATR and DNA-PK. We hypothesize that low-doses of non-thermal plasma lead to repairable DNA damage, while at higher doses plasma induces significant DNA damage which cannot be repaired by cells leading to cell death via apoptosis.
Thermal plasma and lasers are used in medicine to cut, ablate and cauterize tissues through heating, the effects of which are difficult to control. In contrast non-thermal plasma does not induce thermal damage and its effects can be selective and controlled; however, non-thermal plasma application directly to living tissues or cells has not been studied in detail. In order to exploit the potential for clinical applications, including wound sterilization, blood coagulation, and even cancer treatment, a mechanistic understanding of the interaction of non-thermal plasma with living tissues is required. We show here using mammalian cells in culture that dielectric barrier discharge (DBD) plasma has dose-dependent effects from increasing cell proliferation to inducing apoptosis and that these effects may be due to the formation of reactive oxygen species (ROS). We have specifically examined the induction of DNA damage by DBD plasma and determined that DNA damage may be induced by organic hydroperoxides formed as a result of ROS produced by neutral active species, which are generated by DBD plasma in cell culture medium.Relevant Publications
Effects of Non-Thermal Plasma on Mammalian Cells, S. Kalghatgi, C. Kelly, E. Cerchar, B. Torabi, O. Alekseev, A. Fridman, G. Friedman, J. Azizkhan-Clifford, PLoS ONE, 2010. 6(1): e16270. doi:10.1371/journal.pone.0016270. FULL TEXT (PDF)
Non-Thermal Plasma Induces DNA Damage Through the Generation of Long-lived Reactive Oxygen Species, C Kelly, E Cerchar, R Sensing, K Priya-Arjunan, G Fridman, A Fridman, G Friedman, J Clifford-Azizkhan, Drexel University College of Medicine Discovery Day, October 15th 2008, Philadelphia, PA.
Non-thermal dielectric barrier discharge plasma is now being widely developed for various medical applications such as skin sterilization, blood coagulation, induction of apoptosis in malignant tissues, and wound healing among others. This research explores the effect of non-thermal plasma on the vasculature, which is affected during plasma treatment of many tissues and may be an important potential target for clinical plasma therapy. Endothelial cells play a guiding role in angiogenesis, the growth of new blood vessels from existing vessels. In varied disease conditions, healing may result from promoting or inhibiting angiogenesis. Our specific hypothesis is that plasma treatment properties can be varied to grow or regress blood vessels. In this paper we investigate the potential enhancement of proliferation by non-thermal plasma treatment of endothelial cells, which line all blood contacting surfaces in the body. Porcine aortic endothelial cells were treated using non-thermal dielectric barrier discharge plasma for varying exposure times. Non-thermal plasma treatment at short exposures is relatively non-toxic to endothelial cells while treatment at longer exposures leads to induction of apoptosis. Fold growth was determined by counting attached cells seven days after plasma treatment. Cells treated with plasma demonstrated twice as much proliferation as untreated cells. Low levels of non-thermal plasma treatment induce endothelial cell proliferation. One potential mechanism for this proliferative effect could be plasma induced release of growth factors such as fibroblast growth factor-2 (FGF2), a potent angiogenic factor. (Manuscript in preparation)
Endothelial Cell Proliferation is Enhanced by Low Dose Non-Thermal Plasma Through Release of Fibroblast Growth Factor - 2, S. Kalghatgi, Gary Friedman, Alexander Fridman, Alisa Morss Clyne. Annals of Biomedical Engineering, Mar 2010, 38 (3): p 748 -757. FULL TEXT (PDF)
Non-Thermal Dielectric Barrier Discharge Plasma Treatment of Endothelial Cells, Sameer U. Kalghatgi, Gregory Fridman, Alexander Fridman, Gary Friedman, Alisa Morss Clyne, 30th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (IEEE EMBS), August 20-24, 2008, Vancouver, British Columbia, Canada. Full text
Treatment of Endothelial Cells by Non-Thermal Atmospheric Pressure Dielectric Barrier Discharge Plasma, Sameer Kalghatgi, Gregory Fridman, Alexander Fridman, Gary Friedman, Alisa Morss Clyne, Tenth Annual Research Day at Drexel University, April 22, 2008, Philadelphia, PA, USA
Non-thermal atmospheric plasma discharge (Plasma) may provide a novel approach to induction of apoptosis. The purpose of this study is to evaluate the apoptotic effects of non-thermal plasma on melanoma cells. Melanoma cells were treated with increasing levels of plasma by altering dose rate and evaluated by Trypan blue exclusion test, TUNEL® analysis, and Annexin-PI staining to determine viability and apoptotic activity. Trypan blue testing revealed that plasma treatment at low power 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 with high power plasma demonstrated an increase in apoptosis post-treatment. Annexin staining revealed a significant increase in apoptosis in plasma-treated cells post-treatment. Caspase-3 cleavage was also observed post plasma treatment. 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 (ROS) by plasma in fluid. Plasma may be a useful tool to induce directed cell death without inducing necrosis and inflammation. (Manuscript in preparation)
Non-Thermal Plasma Induces Apoptosis in Melanoma Cells via Production of Intracellular Reactive Oxygen Species, R. Sensenig*, S. Kalghatgi*, E. Cerchar, B. Torabi, G. Fridman, A. Shereshevsky, K. Arjunan, E. Podolsky, A. Fridman, G. Friedman, J. Azizkhan-Clifford, A. Brooks, Annals of Biomedical Engineering, Feb 2011, 39 (2): p 674 - 687 *Both authors contributed equally to the work. FULL TEXT (PDF)
Floating Electrode Dielectric Barrier Discharge Plasma in Air Promoting Apoptotic Behavior in Melanoma Skin Cancer Cell Lines, G. Fridman, A. Shereshevsky, M.M. Jost, A.D. Brooks, A. Fridman, A. Gutsol, V. Vasilets, G. Friedman,
Induction of Apoptosis by Non-Thermal Plasma Treatment of Melanoma Cells, R Sensenig, S Kalghatgi, E Cerchar, B Torabi, E Podolsky, K Priya-Arjunan, G Fridman, A Fridman, G Friedman, A Brooks, J Clifford-Azizkhan, Drexel University College of Medicine Discovery Day, October 15th 2008, Philadelphia, PA.
Non-thermal dielectric barrier discharge plasma produced at normal atmospheric pressure and applied directly to living tissues is now being widely considered for various applications in medicine, viz; skin sterilization, wound treatment, treatment in malignant tissues and many others. One of the key questions that arises in this type of topical treatment is if the skin remains undamaged after non-thermal plasma treatment. In this paper we study the possible short term and long term toxic effects of the non-thermal plasma treatment on intact living tissue. Non-thermal plasma has been shown to sterilize intact tissue without visible or microscopic damage, and our goal was to identify the boundaries of skin toxicity after treatment.
The results from the previous rodent model provided strong evidence for the ability of non-thermal plasma to sterilize the surface of the tissue without any visible or microscopic damage to the tissue. It is well established that porcine (pig) skin closely resembles human skin; hence we evaluated the potential toxic effects of non-thermal plasma treatment on underlying skin cells and tissue on intact porcine skin. We evaluated the potential toxic effects on intact porcine skin in two Yorkshire pigs whose dorsal surfaces were divided into 36 treatment areas, 3 untreated and 1 treated with an electrocautery burn (positive control). The remaining 32 areas were treated with 1 of 4 power settings: Highest power 1.0 Watt/cm^2 (n=2), 0.75 Watt/cm^2 (n=2), 0.50 Watt/cm^2 (n=2), and lowest power 0.25 Watt/cm^2 (n=26). Treatment at low power was either for 30 seconds, 2, 5, or 15 minutes. All other powers were treated for 3 minutes and observed at 1 minute intervals. We assessed skin and wound damage grossly and harvested each specimen for histological analysis immediately and 24 hours post treatment.
Low power treatment up to 15 minutes caused no gross, microscopic, or histological tissue damage, while 3 minutes at highest power damaged the epidermis and dermis. The first sign of gross change (erythema) occurred after 1 minute treatment at 0.50 Watt/cm^2. Damage through to the dermis was first seen after 3 minutes at 0.75 Watt/cm^2. Of note is that sterilization is achieved in about 5 sec at a low power treatment of 0.2 Watt/cm^2.
Low power plasma treatment is non-toxic to intact pig skin. The earliest signs of tissue damage occur at 0.50 Watt/cm2. Detailed analysis of any biochemical changes and inflammatory response initiation in the treated tissue will be carried out. Low power plasma treatment is now being evaluated as a safe method for sterilization of living tissue.
Live Pig Tissue and Wound Toxicity of Cold Plasma Treatment, D. Dobrynin, A. Wu, S. Kalghatgi, S. Park, N. Shainsky, K. Wasko, G. Fridman, A. Brooks, G. Friedman, A. Fridman. Plasma Medicine, 2011, 1(1): p 93 – 108. FULL TEXT (PDF)
Toxicity Analysis of Dielectric Non-Thermal Plasma Treatment of Living Tissue , D Dobrynin, A Wu, R Sensenig, G Fridman, M Balasubramanian, A Brooks, K Barbee, A Fridman, G Friedman, 35th IEEE International Conference on Plasma Science (ICOPS), June 15-19 2008, Karlsruhe, Germany. Poster (PDF)
Blood coagulation by non-thermal atmospheric pressure Dielectric Barrier Discharge plasma in vitro has been reported previously. We hypothesize that non-thermal plasma promotes rapid blood coagulation by enhancing natural coagulation processes. Further in depth understanding of the mechanism of blood coagulation by non thermal plasma is needed. Non-thermal plasma could coagulate blood through various pathways, viz.; direct effect on platelets which initiate coagulation process in-vivo, significantly influencing the concentration of major coagulation proteins in blood, direct effect of non thermal plasma on coagulation factors like fibrinogen etc or influence of non-thermal plasma on concentration of ions in blood. It has been demonstrated that non-thermal dielectric barrier discharge plasma significantly influences blood plasma protein and enzyme behavior. It has also been reported previously that non thermal plasma significantly increases concentrations of coagulations factors (like thrombin) and ion concentrations (like Calcium) in blood. It was hypothesized that the mechanism of rapid blood coagulation was due to the influence of non thermal plasma on concentration of ions in blood, specifically on calcium ions. However, recent studies have shown that change in calcium ion concentration might not be the major mechanism and selective effect of plasma on major blood proteins like albumin and fibrinogen is being studied. The direct effect of non-thermal plasma on various major coagulation proteins needs to be investigated. Results of in-vitro investigation of the effect of e-plasma on various major proteins and enzymes present in blood plasma, e.g. Albumin, Fibrinogen, Globulins, etc are presented. Initial results show that effect of non-thermal plasma is selective to particular proteins in blood plasma. Activity and structure of these proteins after non-thermal plasma treatment is analyzed via standard tests (SDS-PAGE) and linked to coagulation kinetics. Selectivity of non-equilibrium dielectric barrier discharge plasma and mechanism of non thermal plasma initiated blood coagulation is presented in the paper. (This work has been published in the IEEE Transactions on Plasma Science).
Mechanism of Blood Coagulation by Non-Thermal Atmospheric Pressure Dielectric Barrier Discharge Plasma, S.U. Kalghatgi, G. Fridman, M. Cooper, G. Nagaraj, M. Peddinghaus, M. Balasubramanian, V.N. Vasilets, A. Gutsol, A. Fridman, G. Friedman,
Blood Coagulation and Living Tissue Sterilization by Floating-Electrode Dielectric Barrier Discharge in Air, G. Fridman, M. Peddinghaus, H. Ayan, A. Fridman, M. Balasubramanian, A. Gutsol, A. Brooks, G. Friedman,
Mechanism of Blood Coagulation by Non-Equilibrium Atmospheric Pressure Dielectric Barrier Discharge Plasma, S. Kalghatgi, G. Fridman, M. Balasubramanian, M. Peddinghaus, A. Brooks, A. Gutsol, V. Vasilets, A. Fridman, G. Friedman, 18th International Symposium on Plasma Chemistry, August 26 - 31, 2007, Kyoto, Japan.
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Areas of Research
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