This dissertation proposed the idea of “plasma-enhanced chemical vapor deposition on living substrates (PECVD on living substrates)” to bridge the gap between the thin film deposition technology and the biological and living substrates. This study focuses on the establishment of the knowledge and techniques necessary to perform “PECVD on living substrates” and contains three main aspects: development, characterization, and biological applications. First, a PECVD tool which can operate in ambient air and at low temperature was developed using a helium dielectric barrier discharge jet (DBD jet). It was demonstrated that various materials, such as polymeric, metallic, and composite films, can be readily synthesized through this technique. Second, the PMMA and copper films deposited using DBD jets were characterized. High-rate (22 nm/s), low-temperature (39 ºC) PMMA deposition was achieved and the film surface morphology can be tailored by altering the discharge power. Conductive copper films with an electrical resistivity lower than 1×10-7 ohm-m were obtained through hydrogen reduction. Both PMMA and copper films can be grown on temperature-sensitive substrates, such as plastics, pork skin, and even fingernail. The electrical, optical, and imaging characterization of the DBD jets was also conducted and several new findings were reported. Multiple short-duration current pulses instead of only one broad pulse per half voltage cycle were observed when a dielectric substrate was employed. Each short-duration current pulse is induced by a leading ionization wave followed by the formation of a plasma channel. Precursor addition further changed the temporal sequence of the pulses. An increase in the power led to a mode change from a diffuse DBD jet to a concentrated one. This mode change showed significant dependence on the precursor type, tube size, and electrode configuration. These findings regarding the discharge characteristics can thus facilitate the development of DBD-jet operation strategies to improve the deposition efficacy. Finally, this technique was used to grow PMMA films onto agar to demonstrate one of its potential biological applications: sterile bandage deposition. The DBD jet with the film depositing ability enabled the surface to be not only efficiently sanitized but also protected by a coating from being reached by bacteria.

Non-thermal plasma has a lot of ways for using in nowadays medicine. It presents many useful actions like charged particles, UV light, electric field, radicals, excited atoms and molecules. That complicated chemistry directs to uncountable synergistic interaction between cold plasma and biological systems, involve cells and tissues. This thesis is about effects of cold plasma to wound healing. Two different microwave plasma systems were used for the presented study. The first one was argon plasma torch generated by surface wave using the quartz capillary, the second one was plasma torch with reverse vortex argon flow. Diagnostics of plasma jet by optical emission spectroscopy shown the presence of active particles, which are responsible for a lot of impact of plasma treatment. Concentrations of active particles generated by plasma are dependent on conditions of plasma generation like power of generator and gas flow. For visual evidence of effects on skin caused by active particles was created simulation of skin tissue. Interaction between plasma jet and artificial skin tissue shown that UV light and temperature are not responsible for all observed effects which are noticed after plasma treatment. Some part of experiments was realized in collaboration with Medical University of Sofia in Bulgaria. The theory of positive effect to wound healing was supported by experiments based on treating artificially created wounds on laboratory mice by cold plasma. It was proved, that process of wound healing is significantly shorter after using plasma treatment in comparison with normal wound healing. Plasma treating of wound for 10 seconds in two consequent days seems like more effectively than application of plasma only one day. This Thesis was carried out as a part of international project PLASMABORDER that was supported by European commission under cohesion funds; programme INTEREG SK-CZ under contract No. 304011P709.

Growing interest in biomedical applications of nonthermal plasmas inspires the development of new plasmas sources. Dielectric barrier (DBD) and corona discharges produced in ambient air or in noble gas flow are typically applied. Direct production of plasma in liquids has a great potential for sterilization of liquid substances and extracorporeal blood treatment. The physical mechanisms of discharge formation in liquid medium are not fully understood.The first part of this thesis deals with the initiation and development of the nanosecond discharge in liquid dielectrics (deionized water, ethanol and n-pentane). Time-resolved shadowgraph visualization, optical emission spectroscopy and electrical diagnostics are applied to investigate the discharge formation on point anode.We have shown that depending on the applied voltage amplitude three different scenario can occur in the polar dielectric, namely, cavitation of a bubble, discharge development in the gaseous cavity (bush-like mode) and initiation of the filamentary discharge (tree-like mode) propagating in bulk liquid. Formation of the bush-like and the tree-like discharges is governed by distinct physical mechanisms, resulting in strongly different plasma parameters.In the second part of this work we address the question of how cold atmospheric plasma interacts with living cells in-vitro and in-vivo, and what is the mechanism of plasma induced cell death. Flowcytometry based cell viability assay with two markers AnnexinV (AV) and Propidium iodide (PI), demonstrates a dose dependent induction of the apoptosis for human T lymphocyte (Jurkat) and epithelial (HMEC) cells treated with DBD plasma. In nude mice model, induction of apoptosis and necrosis in dose dependant manner is observed by electron microscopy in thin epidermis sections. Histological analysis shows significant lesions appeared in epidermis, dermis, hypodermis and muscle as a function of treatment duration. Production of hydrogen peroxide in culture medium (PBS) exposed to DBD plasma is measured using selective fluorescent probe (Amplex® Red). Cell viability of human thyroid epithelial (HTori-3) and melanoma (1205Lu) cells demonstrates nonmonotonous dependence on H2O2 concentration. The major role of plasma produced hydrogen peroxide and DBD electric field is suggested.

Ces dernières années un nouveau type de décharges hors équilibre thermodynamique, aptes à générer des micro jets de plasma se propageant en atmosphère libre, a suscité beaucoup d’intérêt dans la communauté scientifique. Ces micro jets, produits dans des structures type décharge à barrière diélectrique, ont des propriétés particulièrement intéressantes, tant sur le plan de la physique des plasmas que sur celui des applications, en particulier pour des applications biomédicales ou de traitement de surface.Dans ce travail de thèse il est démontré que ces jets de plasma correspondent à la propagation à grande vitesse d'un front d'ionisation sans déplacement de matière. Une caractérisation des propriétés des jets (vitesse et distance de propagation) a été effectuée en fonction de la tension appliquée, du débit, de la composition du gaz, et de la géométrie de la décharge. La distribution spatio-temporelle des espèces réactives produites par le jet a été mesurée, et en particulier celle de l'état métastable He (2³S) mesuré par absorption laser. Des densités comprises entre 1.10¹² et 5.10¹³ cm-³ ont été obtenues pour l’état He (2³S). Sa distribution est annulaire à la sortie de la structure de la décharge et se referme le long du jet. La densité maximale est obtenue à une distance correspondant à la moitié de la zone où les atomes métastables sont présents, ce qui est en contradiction avec les modèles actuels. De plus, afin de mieux comprendre la physique des jets de plasma, nous avons fait interagir deux jets placés l’un en face de l’autre. L'étude de la contre propagation de deux jets révèle qu’il existe une distance minimale d'approche laissant entre eux une zone exempte de plasma. Après l’extinction des deux plasmas, une seconde décharge s’amorce exactement dans cette zone. Une étude détaillée couplant diagnostics électrique, imagerie ultra-rapide et spectroscopie d'émission nous a permis de montrer que cette décharge secondaire est due à une inversion de polarité conduisant à la création transitoire d'un piège à électrons.Dans le but d'aborder l'étude des applications des jets de plasma au domaine biologique, nous avons également étudié la dégradation de l’ADN plasmidique par un jet de plasma. Nous avons mis en évidence que ce type de plasma induit majoritairement des cassures simples et doubles brins, alors que très peu d’oxydations de base ou de sites abasiques sont observés, ceci même avec l’ajout de quelques pourcents d’oxygène dans le gaz. / Micro plasma jets operating at atmospheric pressure in free atmosphere have recently attracted great attention because of their numerous advantages. In fact, micro plasma jets can be operated stably at atmospheric pressure and propagated over some centimeters in a free atmosphere. Moreover, these jets are non-thermal plasmas and create numerous reactive species. These properties allow to use this kind of plasma in many applications, such as surface treatment, decontamination, and plasma medicine.In this work it is shown that these micro plasma jets correspond to the fast propagation of an ionization front with no displacement of matter. A characterization of the plasma proprieties (e.g. distance and velocity of propagation) has been done as a function of the applied voltage, gas flow, gas composition and discharge geometry. The spatiotemporal distribution of the reactive species created by the plasma has been measured, with a special focus on the helium metastable atoms which have been measured by absorption laser spectroscopy. The helium metastable atom densities obtained are in the range of 1.10¹² to 5.10¹³ cm-³. Thanks to a very good spatiotemporal resolution, we have done a time-resolved full cartography of the plasma. This allowed us to show that the helium metastable atom distribution is annular near the nozzle and becomes circular as the plasma propagates. The maximum helium metastable atoms density has been measured at about half of the distance where the helium metastable atoms are present. This observation is in contradiction with results reported by numerical models. To gain further insight into the physical processes of the plasma, we have placed two micro plasma jets face to face. This study showed that both plasmas interact in such a way that they never come into contact, letting a space free of plasma between them. Moreover, we revealed that after the extinction of the plasmas, a second discharge is ignited in the previously free space. Fast imaging, spectroscopy diagnostics and electrical measurements showed that this second discharge is due to a polarity reversal, which creates an electron trap. Aiming the study of the application of micro plasma jets in the plasma medicine field, we have studied the degradation of plasmid DNA by our plasma jet. We observed that the plasma treatment leads mostly to single and double strands breaks, and to very little base oxidation and abasite site, even when oxygen is added into the gas mixture.

L'intérêt croissant susciter par les applications biomédicales des plasmas non thermiques, inspire le développement de nouvelles sources plasmas. Les décharges à barrière diélectrique (DBD) ou les décharges couronne générées dans l'air ambiant ou dans le flux de gaz rare sont généralement utilisées. Production des plasmas directement dans un liquide a un grand potentiel pour les processus de stérilisation des substances liquides et pour le traitement extracorporel du sang. Les mécanismes physiques de formation d’une décharge électrique dans un milieu liquide ne sont toujours pas entièrement compris .La première partie de cette thèse examine le sujet de l'initiation et le développement de décharge nanoseconde dans les diélectriques liquides (eau déminéralisée, éthanol et n-pentane). La visualisation ombroscopique résolue en temps, la spectroscopie optique d'émission et les mesures électrique sont appliqués à l’étude d’une décharge électrique initiée sur une électrode à pointe positive.Nous avons montré que, selon l'amplitude de tension trois scénarios différents peuvent se produire dans des diélectriques polaires, notamment, la cavitation d'une bulle, le développement de décharge dans une cavité gazeuse (le mode ‘buisson’) et l'initiation de la décharge filamentaire (le mode ‘arborescent’) se propageant directement dans le liquide. La différence dans la formation et la propagation de deux modes de la décharge (‘buisson’ et ‘arbre’) révèle les mécanismes physiques étant très distincts.Dans la deuxième partie de ce travail, nous abordons la question d’interaction entre les plasmas froids atmosphériques avec les cellules vivantes in vitro et in vivo. L’étude porte sur le mécanisme de la mort cellulaire induite par le plasma. Cytométrie de flux avec deux marqueurs AnnexinV (AV) et de l'iodure de propidium (PI) a été appliquée pour l’analyse de la viabilité cellulaire. On montre l’induction de l' apoptose dans les cellules de T lymphocyte humain (Jurkat) et dans les cellules épithéliales (HMEC) traités par le plasma de DBD nanoseconde. Dans les souris nudes l'induction de l'apoptose et de la nécrose en fonction de la dose est observé par la microscopie électronique dans les coupes de l'épiderme. L'analyse histologique montre l’apparition des lésions importantes dans l'épiderme , derme, hypoderme et les muscles en fonction de la durée du traitement. Production de peroxyde d'hydrogène dans le milieu de culture (PBS) exposé au plasma de DBD est mesurée à l’aide d’une sonde fluorescente sélective (Amplex® Red). La viabilité des cellules de la thyroïde humaines ( HTori -3) et des cellules de mélanome (1205Lu) cellules démontre la dépendance nonmonotone de la concentration de H2O2. Le rôle majeur du peroxyde d'hydrogène produit par plasma et du champ électrique de la DBD est suggéré. / Growing interest in biomedical applications of nonthermal plasmas inspires the development of new plasmas sources. Dielectric barrier (DBD) and corona discharges produced in ambient air or in noble gas flow are typically applied. Direct production of plasma in liquids has a great potential for sterilization of liquid substances and extracorporeal blood treatment. The physical mechanisms of discharge formation in liquid medium are not fully understood.The first part of this thesis deals with the initiation and development of the nanosecond discharge in liquid dielectrics (deionized water, ethanol and n-pentane). Time-resolved shadowgraph visualization, optical emission spectroscopy and electrical diagnostics are applied to investigate the discharge formation on point anode.We have shown that depending on the applied voltage amplitude three different scenario can occur in the polar dielectric, namely, cavitation of a bubble, discharge development in the gaseous cavity (bush-like mode) and initiation of the filamentary discharge (tree-like mode) propagating in bulk liquid. Formation of the bush-like and the tree-like discharges is governed by distinct physical mechanisms, resulting in strongly different plasma parameters.In the second part of this work we address the question of how cold atmospheric plasma interacts with living cells in-vitro and in-vivo, and what is the mechanism of plasma induced cell death. Flowcytometry based cell viability assay with two markers AnnexinV (AV) and Propidium iodide (PI), demonstrates a dose dependent induction of the apoptosis for human T lymphocyte (Jurkat) and epithelial (HMEC) cells treated with DBD plasma. In nude mice model, induction of apoptosis and necrosis in dose dependant manner is observed by electron microscopy in thin epidermis sections. Histological analysis shows significant lesions appeared in epidermis, dermis, hypodermis and muscle as a function of treatment duration. Production of hydrogen peroxide in culture medium (PBS) exposed to DBD plasma is measured using selective fluorescent probe (Amplex® Red). Cell viability of human thyroid epithelial (HTori-3) and melanoma (1205Lu) cells demonstrates nonmonotonous dependence on H2O2 concentration. The major role of plasma produced hydrogen peroxide and DBD electric field is suggested.

Les plasmas froids produits par les décharges électriques sont des gaz faiblement ionisés, ce qui maintient la température du gaz à une température proche de la température ambiante, contrairement à la température de l'électron qui peut atteindre plusieurs électron-volts. Les applications des plasmas froids en médecine et en agriculture sont des nouveaux domaines de recherche multidisciplinaires basés sur les interactions de ces plasmas avec des organismes vivants. Le champ électrique ainsi que les espèces réactives de l’oxygène et de l'azote peuvent inactiver les bactéries, stimuler la régénération de la peau (dermatologie), la réduction tumorale (oncologie) et la germination des graines (agriculture). Ces nouveaux domaines de recherche, basé sur la chimie produite par l’interaction plasma-liquide est très prometteur et se développe rapidement. L’objectif de ce travail est d’étudier les interactions entre les plasmas froids et l’eau pour les applications biologiques, d’une part la promotion de la germination des graines au moyen d’une décharge à barrière diélectrique (DBD) et, d’autre part, l’effet ex vivo d’un traitement par jet de plasma froid sur la peau.Ce manuscrit est divisé en cinq chapitres: i) On présente tout d'abord une revue de la littérature présentant l'état de l’art concernant l'interaction plasma-liquide et les principales avancées en matière d'applications des plasmas froids à la germination des semences. Ii) Deuxièmement, les dispisitifs expérimentaux sont décrits, en particulier la fabrication de réacteurs à plasma utilisant l’impression 3D. Iii) Ensuite, la production d'espèces réactives gazeuses et aqueuses formées par des plasmas de type DBD a été mesurée quantitativement et l'interaction plasma-liquide a été analysée. Iv) Puis, plusieurs variétés de graines ont été sélectionnées pour évaluer l’effet un traitement par plasma DBD ; l'étude des mécanismes de promotion de la germination du plasma a été spécifiquement étudiée en traitant les graines de soja vert dans différentes conditions de décharge, dans différents milieux, avec un champ électrique seul et dans différentes conditions de cultures ou de niveau d'hydratation des graines.v) Enfin, l'imagerie paramétrique de Muller (MPI) a été appliquée pour la modification de la peau de souris ex vivo traitées par un plasma à jet d'hélium. / Non-Thermal-Plasmas (NTP) produced by electric discharges are weakly ionized gases, which keeps the gas temperature at near room temperature contrary to the electron temperature which can reach several electron-Volts. Applications of NTP to medicine and agriculture are new multidisciplinary research fields based on interactions of the Non-Thermal-Plasmas with living organisms. Electric field as well as Reactive Oxygen and Nitrogen Species produced by NTP may inactivate bacteria, stimulate skin regeneration (dermatology), tumor reduction (oncology) and seeds germination (agriculture). These new fields of research are based on the plasma-liquid chemistry. The objective of this work is to study the NTP interacting with water for biological applications including on one hand, the promotion of the germination of seeds using a Dielectric Barrier Discharge (DBD) and on the other hand, the effect of a plasma jet treatment ex vivo on skinThis manuscript is divided in five chapters: i) First a literature review is presented showing the state of the art of the plasma-liquid interaction, and the main advances of the application of non thermal plasmas to seed germination. Ii) Second, experimental set ups are described, in particular the manufacturing of plasma reactors using 3D printing. Iii) then , the production of gaseous and aqueous reactive species formed by DBD plasmas was measured quantitatively and plasma-liquid interaction was analyzed. Iv) Next, different varieties of seeds were selected to evaluate the effect of a DBD plasma treatment and the study of the mechanisms of plasma germination promotion was specifically investigated by treating mung bean seeds in different discharge conditions, in different mediums, in electric field alone and in different hydration levels of seeds.v) Finally, Muller parametric imaging (MPI) was applied to study the modification of ex vivo mice skin treated by a helium jet plasma.