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International audience; Advances in plasma medicine, and particularly those concerning dermatology and microbial decontamination of biological surfaces, have recently led several laboratories to take an interest in the applications of atmospheric pressure cold plasmas to cosmetics (e.g. [1][2][3]), a field in which the use of "physical" principles (e.g. weak current, light, ultrasound, lasers) is more widespread. At the same time, there are already plasma-based systems for skin treatments on the market, many of which use thermal effect mediated by plasmas whose action, linked to local energy delivery and increase in temperature [4], is fundamentally different from that of non-equilibrium cold plasmas. In addition, the treatment using thermal plasmas, usually involve damages to healthy skin (mostly erythema and micro-burns) which should not be sought in the case of daily cosmetic treatments.Considering the above, it appeared important to discuss what could be transferred from achievements in cold plasma medicine to cosmetics, to clarify the contours of what "plasma cosmetics" can be and to appreciate what are the market needs in this sector. That also extends to decontamination and to packaging for cosmetic products as used plasma medicine sources can also serve to induce surface modifications of interest in this domain. To this end, the first meeting on Plasma Cosmetic Science (IMPCS1) was organized in Orléans, France, in November 2019. In this presentation, after recalling the general context, we will address the main themes dealt with during this meeting and we will set out the main lessons learned from the presentations and discussions concerning the future opportunities for Plasma Cosmetics.IMPCS1 was supported by Le Studium and Région Centre-Val de Loire. The authors belongs to the Plasma Cosmetic Consortium financed by the Le Studium Loire Valley Institute for Advanced StudiesReferences[1] E. Robert, G. Busco, C. Grillon and J-M Pouvesle, “Potential of low temperature atmospheric pressure plasma sources in cosmetic”, COSMINNOV 2016, Orléans, France, May 25 2016[2] K.Y. Baik “Application of atmospheric pressure plasma treated water for hair loss therapy” ISPB 2017, Jeju, Korea, June 27 2017[3] Th von Woedtke, H-S. Metelmann and K-D Weltmann, “Plasma in cosmetic applications: possibilities and boundary conditions”, ISPB 2018, Incheon, Korea, July 25 2018[4] Foster, K. W et al, “Advances in plasma skin regeneration. Journal of Cosmetic Dermatology, 7: 169-179 (2008)

Recently, Iseni (arXiv:1709.03109v1) reported measurements and analysis of electric field (EF) strengths adjacent to propagating ionization waves (IWs) in non-thermal atmospheric pressure He plasma jets. We demonstrate that these measurements are in error due to an improperly aligned electric field probe., Comment: 3 pages, 2 figures, comment on arXiv:1709.03109v1

International audience; The potential beneficial impact of plasma is being investigated for many biotechnological and medical applications. However, translating promising in vitro results to in vivo (bio)medical outcomes remains a challenging task. One of the major challenges in the translation of plasma technologies to in vivo, and ultimately clinical use, is the lack in the fine control necessary for an efficient and safe use of plasma sources in medical applications; this we attribute to the mutual interaction between plasma and target [1]. Many key fundamental questions on the mechanisms taking place at the interface between plasma and (bio) targets still need to be addressed. While there is an abundance of literature on the biological effects of plasma treatment, there are only a few reports on the physico-chemical characterization of the plasma during the treatment process. Even considering a very simple scenario using a plasma jet to treat a 2D culture of cells in a plastic multi-well plate, it is not known in detail how the physical environment of the micro-well may influence the biological effects of the plasma. Recent research has reported how the geometry of the multi-well plate, as well as the electrical characteristics of the support on which it stands, can have a significant impact on the experiment and its reproducibility [1, 2]. Furthermore, the presence or absence of a liquid and small variations in its depth/volume can completely change the nature and the distribution of the bioactive plasma-generated RONS reaching the bottom of the well [3].As it will be presented, surprisingly, even in small liquid volumes (e.g. 0.2–2 ml) typical of biomedical in vitro experiments, the impinging plasma jet on the biological liquid can induce the formation of fast and complex electro fluid dynamic (EFD) flows. These flows are affected by plasma parameters and can lead to vortex recirculation. Whereas biological effects will always be the focus of plasma medicine, it is important for the advancement of this field to achieve a deeper understanding and a greater awareness of the physico-chemical processes taking place during our plasma biomedical experiments.Acknowledgements: PLASCANCER (INCa-PlanCancer N°17CP087-00), GdR 2025 HAPPYBIO and and ERC APACHE Nº714793).References[1] A. Stancampiano, T.-H. Chung, S. Dozias, J.-M. Pouvesle, L. M. Mir, and E. Robert, IEEE Trans. Radiat. Plasma Med. Sci., Early Acess, 10.1109/TRPMS.2019.2936667 (2019)[2] S. Mohades, A. Lietz, J. Kruszelnicki and M. Kushner, Plasma Process. Polym, e1900179 (2019)[3] S. Sasaki, R. Honda, Y. Hokari, K. Takashima, M. Kanzaki and T. Kaneko, J. Phys. D: Appl. Phys, 49, 334002 (2016)

International audience; Following in vitro assessment of cancer cells and the benefit of a combined treatment based on incubation with plasma treated solution and application of Pulsed Electric Field in the context of reversible cell membrane permeabilization, this work reports on the in vivo evaluation of such combined innovative antitumor approach. Three independent studies, dealing with immunocompetent mice bearing fibrosarcoma tumors and involving control groups, PEF treated group (Bleomycine Electro Chemo Therapy (ECT) and combined plasma treated PBS (p-PBS) and PEF treatments, were performed. A single-shot treatment was applied 12 days after tumor cell injection, and follow up of tumor volume was performed for more than two months. The main conclusions of these studies indicate that (i) p-PBS production and storage was highly reproducible and allow for in vivo studies requiring large volume of such solutions; (ii) Bleomycin, p-PBS, and their combined injection has no antitumor action; (iii) ECT as a reference therapy is efficient, especially for fast growing tumors; (iv) combined p-PBS and ECT treatment allow for a slower tumor growthrate, for fast growing tumors, and lead to a significant increase of the number of tumor regressions; and (v) composition of p-PBS solution for different plasma exposures might be a unique parameter for a fine tuning of the efficiency of the combined antitumor treatment.

International audience; Plasma jets are being intensively researched for cancer therapy with encouraging initial clinical outcomes already realised. However, the fine control of plasma jets remains challenging due to the mutual interaction between plasma and target [1]. Even considering perhaps one of the simplest scenarios in a research laboratory, using a plasma jet to treat a 2D culture of cells in a plastic multi-well plate, it is not known in detail how the physical environment of the micro-well may influence the nature of the plasma jet treatment. This study aims to shed light into this topic by investigating how electro fluid dynamic (EFD) flows influence the delivery of the bioactive plasma-generated RONS when a plasma jet is used to treat a conductive biologically-relevant liquid (i.e. PBS) in a standard tissue culture grade 24-well plate [2]. The results show how the formation of complex EFD flows in the liquid induce a non-uniform distribution of the RONS, especially within the first few seconds of treatment (Fig. 1a). Shortly after the ignition of the plasma jet an initial rapid liquid stream can reach the bottom of the well, whereas a stable vortex mixing is observed few seconds later (Fig. 1b). Experimental results indicate that electric charge accumulation on the liquid surface and plasma induced gas swirling could be the causes of the liquid motions. Furthermore, the liquid depth and the voltage polarity were found to be critical parameters in controlling the delivery of the RONS to the bottom of the well. A multijet plasma source was, then, used for the treatment of PBS (pPBS), which was combined with a pulsed electric field (PEF) to permeabilise B16-F10 murine melanoma cells. Compared to PEF alone, the combined treatment with pPBS (applied before and after PEF exposure) can greatly increase the number of permeabilised cells and the uptake of a model non-permeant molecule (Yo-Pro®-1) to confirm the permeability of the cell membrane (Fig. 1c). This synergistic effect of plasma treated PBS and PEF could open new opportunities for the application of plasma jets in electrochemotherapy

National audience; Plasma jets are intensively studied for biomedicine applications but their fine control remains challenging due to the mutual interactions between plasma and target. Even considering the simplest scenario in a research laboratory, a plasma jet treating a 2D culture of cells, it is not known in detail how the physical environment of the micro-well may influence the treatment. This study aims to shed light on this topic by investigating how electro fluid dynamic (EFD) flows influence the delivery of the bioactive plasmagenerated reactive species when a plasma jet is used to treat a biologicallyrelevant liquid (i.e. PBS) in a standard tissue culture grade 24-well plate. The results show how the formation of complex EFD flows in the liquid induce a non-uniform distribution species. Shortly after the ignition of the plasma jet a fast stream can reach the bottom of the well, whereas a stable toroidal vortex mixing is observed few seconds later. Electric charge accumulation on the liquid surface and plasma induced gas swirling could be the causes of the liquid motions. Furthermore, the liquid depth/volume and the voltage polarity are found to be critical parameters in controlling the delivery of the RONS to the bottom of the well.

International audience; We target and report on the use of either single or multi so-called cold atmospheric pressure plasma jets, based on Plasma Gun technology [1], to expose liquid solutions eventually containing seeds or immerged seedlings for agricultural applications. Besides, the upscaling capability of multi jet setups in comparison with single jet devices for the generation of attractive chemicals in solutions, the consideration of the diffusion of plasma produced reactive species in liquid samples is the focus of our investigations. With the single jet configuration, two mode of exposures of liquid samples are considered: a “conventional” protocol where plasma jet plume impinges on the top of the solution and a more rarely investigated and documented method where the plasma jet is “transferred” into gas bubbles exiting from an immerged nozzle [2]. The talk will report on in-bubble plasma generation, water solution treatment using bubble plasma gun device, and the diffusion of reactive species in the liquid container. Using KI coloration as a broad range oxidation reporter, it is measured that while conventional plasma jet exposure leads to very slow and very inhomogeneous reactive species diffusion in the solution, generation of plasma in bubbles induces a sudden, very homogeneous and surprising oxidation of the whole volume of a few mL. Work is in progress to try and simulate the plasma generation in bubble and the consecutive reactive species delivery in the solution. With the conventional protocol, Schlieren visualization indicates that air and helium mixing and flow properties above the liquid surface correlates with the oxidation patterns revealed in the solution. Air entrainment along and inside the plasma plume with plasma jet in free jet mode or impinging over various targets was recently reported with a dielectric barrier discharge based helium plasma jet [3]. Dealing with plasma solution generation using plasma jet and/or treatment of solution containing either attached or suspended cells or samples of interest for agriculture, it is suspected that neither slow diffusion using conventional plasma jet exposure nor opportunity with bubble arrangement were so far considered with sufficient care.References [1] JM Pouvesle, C Cachoncinlle, R Viladrosa, A Khacef, E Robert, S Dozias, Transient plasma ball generation system at long distance, US Patent 8,482,206 [2] A. Hamon, C. Douat, S. Dozias, J.M. Pouvesle, E. Characterization of plasma generation in bubbles with a plasma gun. 22nd International Conference on Gas Discharges and Their Applications GD2018, Inst. Phys. Belgrade; SASA; Univ. Belgrade, Sep 2018, Novi Sad, Serbia. hal-01943383 [3] Y Morabit, RD Whalley, E Robert, MI Hasan, JL Walsh, Turbulence and entrainment in an atmospheric pressure dielectric barrier plasma jet, Plasma Processes and Polymers, e1900217

International audience; This work reports on the interaction of so-called plasma jet with or within liquid solutions. The use ofthe Plasma Gun as an archetypical setup for processing liquid samples or humid tissues in thecontext on plasma biomedical applications but also in a more innovative configuration where plasmajet is immersed in solution to generate plasma in gas bubbles will be discussed. In the "abovesolution" setup, recent experiments have shown that reactive species generation and delivery in theliquid could be very non intuitive, revealing the existence of steady state vortexes, surfaceaccumulation zones, needle-like transient patterns, ... depending on various operating conditionssuch as gas flow, pulse repetition rate, distance to the sample, while being quite universal for variousliquid containers typically used for biomedical applications. Conversely, the in-bubble plasmageneration while being very dependent on the operating conditions as well and on the liquid electricalconductivity, is shown to allow for a, at a first glance surprising, very fast and very homogenousdelivery of reactive species in liquid samples. Plasma generation is gas bubbles will be documented,together with the reactive species generation efficiency versus gas flow rate, number of plasma pulsedelivery in a single bubble. It is shown that plasma generation in gas bubble has drastic impact on thebubble expansion dynamics and that synchronization of plasma pulse generation during the bubblelifetime could be a key parameter to optimize the reactive species generation and balance.Perspectives for multi bubble plasma reactors delivered in large liquid volume processing will bediscussed.

International audience; The last decade has seen an impressive increase of the research dedicated to the biological applications of low temperature atmospheric pressure plasmas. Medical appli-cations are tacking an increasing place underlined by many clinical trials. They now concern numerous domains, including blood coagulation, dental care, skin decontamination and hygiene, wound and ulcer treatment, dermatology, cancer treatment. Biological applications are also now extended to agriculture and, more recently, to cosmetic. Despite the huge number of in vitro and in vivo experiments, there are still numerous challenges to overcome linked to the nature of the encountered target (biological tissues and materials, organs and their direct environment, liquids) that have a direct effect on the produced plasma itself and on the generated species. That must therefore be taken into account in the applied treatments and complicates the definition of a "plasma dose" expected by many.

International audience; Non-thermal plasmas, produced from dielectric barrier discharges in air or from rare gas plasma jet devices, generate at room temperature, long and short lifetime reactive species (RS) in gaseous phase or in the liquid solution on which they impinge, ionic species, UV photons and intense transient electric fields (EF). In the last decade, the main focus was drawn on the RS to understand and optimize their action in the frame of the broad topic of “Plasma medicine”. More recently, the characterization and implication of EF in biomedical applications is studied, considering the generation of ns to μs duration, kV/cm amplitude features of plasma EF. Plasma have been shown to be a potential alternative to more “conventional technologies” for gene transfer, cell permeabilization, drug delivery in various applications including for cancer therapy. Quite recently, the concepts of reversible electroporation, especially the models of so called pore formation in cell membranes were broaden and detailed involving not only the key role of EF but also the oxidation of cell membrane associated with RS. Thus it appears we attend to a unique opportunity to reach more insights and achieve cell manipulation process optimization with considering the potential complementary or synergistic delivery of pulsed electric fields and plasma for in vitro and in vivo protocols.Besides a quick overview of some significant works focused on the use of non-thermal plasmas in interaction with cell membranes, the lecture will document the results obtained so far with the Plasma Gun developed at GREMI for first, cancer cell permeabilization with various plasma delivery protocols, and second on the first demonstrations of the positive combined action of pulsed electric fields (PEF) and plasma for antitumor action. Cell permeabilization has been performed in vitro for different adherent cell lines, exposed to plasma jet delivered at various pulse repetition rates for short duration and followed with cell incubation in plasma treated solution. The combination of plasma and PEF is studied in vitro and with murine models considering the delivery of pulsed voltage and current pulses (electroporation) together with plasma treated solutions in contact with biological targets (suspended cancer cells in electroporation cuvettes or tumors) at different delays with respect to the electroporation step.AcknowledgmentsWork supported by PLASCANCER project INCa-PlanCancer-n°17CP087-00 and GDR CNRS 2025 HAPPYBIO

International audience; The last decade has seen an impressive increase of the research dedicated to the biomedical applications of low temperature plasmas, especially with plasma sources working at atmospheric pressure. In this new trend, beside decontamination/sterilization and surface treatment that have already a quite long story through low-pressure plasma research and developments, medical applications are tacking an increasing place underlined by the actual numerous clinical trials. Medical applications of low temperature plasmas now concern a very wide range of domains, including primary haemostasis and blood coagulation, dental care, skin decontamination and hygiene, wound and ulcer treatment, dermatology, cancer treatment. Biological applications are also now extended to agriculture and, more recently, to cosmetic. Despite the huge number of in vitro and in vivo experiments there are still numerous challenges to overcome linked to the nature of the encountered target (biological tissues and materials, organs and their direct environment, liquids) that have a direct effect on the produced plasma itself and on the generated species. It is clear that the extremely strong coupling between the characteristics of the plasma and those of the target, as already shown, will play a very important role in the results observed during the treatments. A variation in the chemical or physical characteristics of the target will involve significant differences in the gas flow, the local temperature, or the induced electric field, resulting de facto in variations in the production of the reactive species. It also concerns the transposition of the results between the in vitro and the in vivo experiments that are carried out under extremely different conditions, especially concerning the equivalent electric circuit of the reactor / plasma / biological target assembly. These problems directly affect the identification of the processes involved and currently limit the possibility of a definition of a "dose" in plasma treatments. Recently, study reported led to reflections on non-sustainable tumor response. The loss of effectiveness under long-term plasma treatment of cancer tissue opens questions about plasma application and protocol. It must be considered that the treated area is morphologically and chemically changing over the time, from activated surrounding to more normal tissues that are less humid and bacteriologically cleaner. This aspect is particularly important for the development of efficient systems and protocols in plasma cancer treatment but also for any other plasma therapeutically approaches. It induce a in real-time in situ control of plasma production and at longer term a protocol adaptation taking into account the biological target evolution. Some progress are already done in that domain

International audience; Molecular delivery in cells combining low cytotoxicity and high efficiency using physical techniques remains to be optimized In this work, we report on the use of a cold atmospheric pressure plasma jet device called Plasma Gun as an innovative strategy for cell membrane permeabilization In our previous study[ 1 we focused on evaluating key parameters needed to achieve an efficient molecular delivery We showed that a low number of pulses (between 1 000 and 100 000 and a 30 minute incubation at 37 C of the treated cells were enhancing molecular uptake in a ring shape pattern with no significant toxicity In this report, we investigated cell permeabilization kinetics and surprisingly, best permeabilization levels were reached when molecular injections in the cell medium and plasma treatments were not simultaneous Indeed, best efficiency was measured when the injection was performed a few minutes after plasma This transient permeabilization was also measured for longer delays of molecular injection which confirms the non toxic nature of our plasma treatment conditions

International audience; Drug delivery in cancer cells combining low cytotoxicity and high efficiency remains to be optimized with physical techniques. Several studies have shown that cold atmospheric plasmas (CAPs) have demonstrated their relevance in biomedical applications and are prone to be quite useful tools in medicine. Plasma could be used to deliver chemotherapy [1] or nucleic acids [2] via enhancement of cell permeabilization. Parameters needed for helium plasma to induce cell membrane permeabilization on cancer cells were investigated (Fig.1). A frequency of 100 Hz for 100 s, corresponding to 10,000 pulses, with an applied voltage of 14 kV was used. Both plasma electric field and endocytosis involvement in molecular uptake were studied [3]. Kinetics of plasma-induced permeabilization were also studied. Highest permeabilization efficiency was observed when propidium iodide was added after treatment (up to 40% of propidium iodide positive cells in both HeLa and 4T1). No significant toxicity was observed in these conditions as the viability in HeLa cells was measured to be of 80%. A treatment combining doxorubicin and plasma also showed improvement of cell membrane permeabilization. Figure 1: Round-shaped permeabilization spot of propidium iodide in 4T1 cells after plasma jet treatmentReferences [1] W. Zhu, S.-J. Lee, N. J. Castro, D. Yan, M. Keidar, and L. G. Zhang, Scientific Report, 6, (2016).[2] M. Jinno, Y. Ikeda, H. Motomura, Y. Kido and S. Satoh. Archives Biochemistry Biophysics, 605, 59-66 (2016) [3] V. Vijayarangan, A. Delalande, S. Dozias, J.-M. Pouvesle, C. Pichon, and E. Robert, IEEE Transactions on Radiation and Plasma Medical Sciences, 2, 1-7 (2017).

International audience; Plasma jets are being intensively studied for biomedicine applications but their fine control remains challenging due to the mutual interactions between plasma and target. Even considering perhaps one of the simplest scenario in a research laboratory, using a plasma jet to treat a 2D culture of cells in a plastic multi-well plate, it is not known in detail how the physical environment of the micro-well may influence the nature of the plasma jet treatment. [see Mohades 2020 and Stancampiano 2019] This study aims to shed light on this topic by investigating how electro fluid dynamic (EFD) flows influence the delivery of the bioactive plasma-generated RONS when a plasma jet is used to treat a biologically-relevant liquid (i.e. PBS) in a standard tissue culture grade 24-well plate. The results show how the formation of complex EFD flows in the liquid induce a non-uniform distribution of the RONS, especially within the first few seconds of treatment. Shortly after the ignition of the plasma jet an initial rapid liquid stream can reach the bottom of the well, whereas a stable vortex mixing is observed few seconds later (Fig.1). Electric charge accumulation on the liquid surface and plasma induced gas swirling could be the causes of the liquid motions. Furthermore, the liquid depth/volume and the voltage polarity are found to be critical parameters in controlling the delivery of the RONS to the bottom of the well. Mohades, S., Lietz A., Kruszelnicki, J., Kushner, M. J. : 2020, Plasma Processes and Polymers, 17, 3Stancampiano, A., Chung, T.-H., Dozias, S., Pouvesle, J.-M., Mir, L. M., Robert, E. : 2019, IEEE Trans. Radiat. Plasma Med. Sci., 4, 3

International audience; Cold atmospheric plasmas (CAPs) have demonstrated to be quite useful tools in biomedicalapplications and their relevance in medicine is getting more and more recognized. Drug deliveryin cancer cells combining low cytotoxicity and high efficiency remains to be optimized withphysical techniques. Several studies have shown that plasma could be used to deliverchemotherapy [1] or nucleic acids [2] via enhancement of cell permeabilization. We investigatedthe parameters needed for helium plasma to induce cell membrane permeabilization on cancercells for drug delivery purposes. 10,000 plasma pulses were used at a frequency of 100 Hz for100 s with an applied voltage of 14 kV. Both plasma electric field and endocytosis involvementin molecular uptake were also studied [3]. Kinetics of plasma-induced permeabilization werestudied. Highest permeabilization efficiency was observed when propidium iodide was addedafter treatment (up to 40% of propidium iodide positive cells in both HeLa and 4T1). Nosignificant toxicity was observed in these conditions as the viability in HeLa cells was measuredto be of 80%. Doxorubicin was used as an anticancer drug. A treatment combining doxorubicinand plasma decreased the concentration of doxorubicin needed to achieve 50% of cytotoxicity byenhancing doxorubicin uptake in cancer cells.References[1] W. Zhu, S.-J. Lee, N. J. Castro, D. Yan, M. Keidar, and L. G. Zhang, Scientific Report, 6,(2016).[2] M. Jinno, Y. Ikeda, H. Motomura, Y. Kido and S. Satoh. Archives BiochemistryBiophysics, 605, 59-66 (2016)[3] V. Vijayarangan, A. Delalande, S. Dozias, J.-M. Pouvesle, C. Pichon, and E.

International audience; Since a few decades atmospheric pressure plasma jets have been used for surface modification ofpolymers, deposition of different inorganic coatings as well as organic plasma polymer films [1].However, for biomedical applications, very often surface modification of complex shapes may berequired such as, for example, inner walls of vascular grafts or catheters. In this work, the potentialof surface modification of films and tubes inner wall with a helium transported discharge and aplasma gun has been investigated [2-4]. This type of discharges allow both admixture of monomer,upstream and downstream of the reactor. The development of nano thick polyethylene glycol(PEG) coatings by using Diethylene Glycol Methyl Ether (DEGME), via plasma polymerizationis presented. UHMWPE films and HDPE tubes were used as the substrate. Different experimentalconditions were used to induce modification in the inner surface of the tubes as well as thesubstrates placed outside the jet. Surface characterization was performed with the aim ofunderstanding the surface modification effects by means of FTIR, AFM, XPS and contact anglemeasurements. The results have shown that PEG coatings have been successfully deposited insidethe tubes. The spectral analysis of PEG coatings deposited at different locations of downstreamtubes show substantial changes in the chemical composition of the coatings with an increase of thedistance from the powered electrode. Also, cell adhesion or non-adhesion of PEG like coatingswith respect to cells were studied. Better cell non adhesive properties with respect to cancer cellswere observed for coatings which were deposited near the high voltage electrode. The possibilityto deposit such coatings inside tubes is quite an interesting result for inside catheter tubes, used forevacuation of pathogen biological liquids but also for food applications. A transporting dischargeand also plasma gun at atmospheric pressure were used for the treatment of UHMWPE films andHDPE tube. The results show that in different configurations, the two competitive processes, i.e.,crosslinking and functionalization, can be optimized in order to limit the ageing inside the tube.Our results indicate that the helium transporting plasma has a potential to modify the surfaceproperties the films and inner wall of long tubes especially relevant for biomedical applications.References[1] S. Bhatt, J. Pulpytel, and F. Arefi-Khonsari, Surface Innovations, 3, 63 (2015).[2] A.V.Omran, F. Sohbatzadeh, S.N. Siadati, A. H.Colagar, Y. Akishev, F and Arefi-Khonsari,Journal of Physics D: Applied Physics, 50, 315202 (2017).[3] E. Robert, E. Barbosa, S. Dozias, M. Vandamme, C. Cachoncinlle, R. Viladrosa, and J.M.Pouvesle, Plasma processes and polymers, 6, 795 (2009).[4] A. Valinataj Omran, A. Baitukha, J. Pulpytel, F. Sohbatzadeh, and F. Arefi‐Khonsari, PlasmaProcesses and Polymers, 15 (2018).

International audience; Plasma discharges have been known for quite a long time as a method to allow for cell permeabilization and likely to involve electric fields, UV photons and charged or excited particles, e.g.[1]. Comparison of different plasma devices, including so called “cold atmospheric pressure plasma” based on dielectric barrier discharge, but also combined role of electrical and chemical factors was more recently investigated with its potential interest as a new method for cell transfection [2]. In a very recent paper [3] not only radical produced by the plasma source but also intense electric field, as high as 150 kV/cm delivered on adherent cells are reported to induce transient increase in intracellular calcium concentrations, thereby playing a key role in dell response to plasma stimulus [3].In this work, we report on the use of plasma jet, so called Plasma Gun developed at GREMI, as an innovative drug delivery technique for adherent, HeLa and 4T1 cells. The role of different plasma source operation parameters but also plasma delivery protocols has been studied. Propidium iodide and FITC-Dextran were used as permeabilization markers. Cellular uptake was assessed by fluorescence microscopy and flow cytometry. Cell viability and reactive oxygen and nitrogen species produced were measured. Percentage of propidium iodide positive cells was the highest for 1,000, 10,000,and 100,000 pulses corresponding to 100 s-long treatments [4]. We found that cellular uptake was more efficient after a 30-minute incubation time at 37°C. Drug uptake kinetics was also investigated showing that surprisingly best permeabilization levels were achieved when plasma treatment is processed a few minutes before and not simultaneously with the drug injection in the culture medium. Transient permeabilization following plasma treatment was measured for longer delays for drug injection also confirming the non-toxic nature of plasmas when a limited number of pulses are delivered. The specific role of plasma induced transient electric fields is under investigation to try to elucidate not only the plasma mode of action but the ring shape permeabilization patterns, already previously reported by other groups [5], as well

National audience

National audience

International audience; The majority of atmospheric pressure plasma jet (APPJ) applications involves the interaction between the plasma and a target. The understanding of the mechanisms underlining this interaction is a key step for the future development of APPJ technology. Nevertheless, many widely adopted target configuration, such as those encountered in in vitro biomedical studies have barely been investigated from a physical point of view. The present study shows how APPJ can induce vortex formation and lead to strongly non-uniform distribution of plasma-generated long-lived reactive species in a vessel with the characteristic length scale of the wells commonly adopted for in vitro biomedical studies

The invention relates to a method ( S ) for generating a plurality of cold - plasma jets at atmospheric pressure in orderto treat a target ( 2 ) , wherein said method includes the following steps : producing ( S1 ) a primary cold - plasma jet( 3 ) at atmospheric pressure using a plasma source ( 10 ) ; placing ( S2 ) a substrate ( 20 , 21 , 30 , 32 , 34 ) near the target( 2 ) to be treated , said substrate ( 20 , 21 , 30 , 32 , 34 ) includingat least two through - holes ; and passing ( S3 ) the plasmathrough the through - holes ( 22 ) of the substrate ( 20 ) such as to generate at least two secondary cold - plasma jets ( 4 ) atatmospheric pressure

International audience; Low temperature plasma treated solutions are under intense study with respect to their key importance for plasma biomedical, plasma environmental and plasma agriculture technologies applications [1,2]. In this work, we report on the use of various plasma jet based delivery protocols likely to generate reactive species enriched solutions for such applications. The baseline setup consists in the use of the Plasma Gun (PG) device [3] delivering a so called plasma plume a few mm away from the liquid to be treated. Such single jet configuration is easily turned into a multi jets setup [4], using a branching capillary assembly, while keeping the same power supply operated with the same voltage amplitude and microsecond pulse repetition rate together with the same range of buffer gas flow rates flushed inside the primary capillary plasma generation reactor. As a second kind of protocol, we report on the liquid solution treatment when plasma reactor capillary is immersed inside liquid solutions, thus resulting in the generation of plasma inside buffer gas bubbles. Reactive species generation in liquid solutions is reported using either plasma plumes or in-bubble plasmas based on the Plasma Gun devices. In-bubble plasma generation with triggering of plasma ignition at different stages of the bubble dynamics, offers opportunities for reactive species balance modulation. Our experiments show that plasma can be delivered in small volume bubbles which then allow for efficient diffusion in the bulk liquid solution, thus opening opportunities for efficient high repetition rate multi bubbles plasma delivery.

International audience; This presentation will review different diagnostics used to study atmospheric pressure plasma jets in the presence or not of a target (conductive target, dielectric target, liquid target of various conductivities). Among all, these diagnostics include Optical Emission Spectroscopy, Fast Imaging, Laser Absorption, Laser Induced fluorescence, Schlieren measurements, Current and Electrical Field measurements. It will be shown how the complementary obtained data can be used to access precise description of the evolving generated plasma over time and space and the related induced plasma chemistry. The role of the target and its nature on the plasma characteristics will be underlined.

International audience; The last decade has seen an impressive increase of the research dedicated to the biological applications of low temperature atmospheric pressure plasmas. Medical applications are tacking an increasing place underlined by many clinical trials. Biological applications extended to agriculture and, more recently, to cosmetic. Despite the huge number of experiments, there are still numerous challenges to overcome linked to the nature of the encountered target (biological tissues and materials, organs and their direct environment, liquids) that have a direct effect on the produced plasma itself and on the generated species.The extremely strong coupling between the plasma characteristics and those of the target (e.g. ref. [1, 2]), plays a very important role in the results observed during treatments. A variation in the chemical or physical characteristics of the target will involve significant differences in the gas flow, the local temperature, or the induced electric field, resulting de facto in variations in the production of the reactive species. It also concerns the transposition of the results between the in vitro and the in vivo experiments that are carried out under extremely different conditions, especially concerning the equivalent electric circuit of the reactor / plasma / biological target assembly. These problems directly affect the identification of the processes involved and currently limit the possibility of a definition of a "dose" in plasma treatments. In addition, a study recently reported in [3] led to think over non-sustainable tumor response. The loss of effectiveness under long-term plasma treatment of cancer tissue opens questions about plasma application and protocol. It must be considered that the treated area is morphologically and chemically changing over the time, from activated surrounding to more normal tissues that are less humid and bacteriologically cleaner. This aspect is of particular importance for the development of efficient systems and protocols for any plasma therapeutic approaches. It induce a in real-time in situ control of plasma production and at longer term a protocol adaptation taking into account the biological target evolution.We will discuss the induced changes in gas flow and plasma characteristics, as well as changes induced in microenvironment of living targets. We will emphasize on the fact that plasma diagnostics must be performed in real treatment conditions. We will also tackle the main issues and challenges linked to the control of the multimodal action of non-equilibrium cold plasmas on living organisms.[1] T. Darny, J.M. Pouvesle, J. Fontane et al, PSST, 26 105 001 (2017)[2] T. Darny, J.M. Pouvesle, V. Puech et al, PSST, 26 045 008 (2017)[3] H.R. Metelmann, C. Seebauer, V. Miller et al, Clinical Plasma Medicine 9, 6 (2018)

International audience; In this work we developed a plasma source based on a Plasma Gun reactor able to generate small quantities of CO. The production fraction of CO molecules has been measured ex-situ by means of gas chromatography. We showed that the density is in the 100-10000 ppm range. The CO concentration can be controlled by varying the gas mixture and by tuning the applied voltage. In CO clinical application, the typical dose used is in the range of 100-1000 ppm. It means that this plasma reactor is suitable as CO source for biological applications.

International audience; The transport and distribution phenomena of reactive oxygen and nitrogen species (RONS) into biological tissue following non-thermal plasma treatment have received much attention. The aim of this study is to test the efficacy of Plasma Gun (PG) on transporting the reactive species in an agar composed tissue phantom. RONS are generated on the agar gel by the plasma treatment and they continue to spread in the depth after plasma exposure. The amount of RONS after passing through the tissue phantom are strongly depending on discharge parameters such as distance to the target and capillary shape.