This work is a contribution to the development and implementation of non-thermal plasma technology for decontamination in the perspective of nosocomial and chronic wound innovative therapies. Multi jets devices based on Plasma Gun^® technology in static and scanning operation modes and bacterial lawns inoculated with resistant and non-resistant bacterial strains were designed and used. A pilot toxicity study exploring plasma treatment of wound bearing patients, performed with a low voltage plasma applicator, is documented as a first step for the translation of in vitro experiments to clinical care. Bacterial inactivation was demonstrated for Staphylococcus aureus, Pseudomonas aeruginosa and drug resistant S. aureus, P. aeruginosa and Escherichia Coli strains collected from patient wounds at Orleans (France) hospital. A few square centimeter large contaminated samples were inactivated following a single plasma exposure as short as one minute. Samples inoculated with a single but also a mix of three resistant pathogens were successfully inactivated not only right after their contamination but for mature lawns as well. Similar bactericidal action was demonstrated for antibiotic-resistant and non-resistant P. aeruginosa. The time exposure dependent increase of the inhibition spots, following multi jets exposure, is discussed as either the accumulation of reactive species or the likely combinatory action of both the reactive species and transient electric field delivery on inoculated samples.

Bacterial resistance to antibiotics has become a major public health problem in recent years. The occurrence of antibiotics in the environment, especially in wastewater treatment plants, has contributed to the development of antibiotic-resistant bacteria (ARB) and the spread of antibiotic resistance genes (ARGs). Despite the potential of some conventional processes used in wastewater treatment plants, the removal of ARB and ARGs remains a challenge that requires further research and development of new technologies to avoid the release of emerging contaminants into aquatic environments. Non-thermal atmospheric pressure plasmas (NTAPPs) have gained a significant amount of interest for wastewater treatment due to their oxidizing potential. They have shown their effectiveness in the inactivation of a wide range of bacteria in several fields. In this review, we discuss the application of NTAPPs for the degradation of antibiotic resistance genes in wastewater treatment.

Dans le domaine médical, l’évolution des techniques et des technologies ainsi que l’apparition de nouveaux matériaux ont favorisé le développement de dispositifs médicaux (DM) toujours plus performants et légers. Certains de ces matériaux sont difficilement stérilisables de par leur fragilité aux agents stérilisants (physiques ou chimiques). De nombreuses études ont montré l’efficacité des plasmas froids sur des souches bactériennes pathogènes mais le maintien à l’état stérile des DM fragiles et sensibles à la température reste un verrou technique à lever. Cette thèse CIFRE s’inscrit dans le cadre du projet ANR PLAS’STER. Il vise à développer un procédé industriel pouvant répondre à une certification comme stérilisateur par plasmas froids basse pression. Le caractère innovant réside en la création et au confinement d’un plasma à l’intérieur d’un sac de stérilisation assurant la préservation de l’état stérile du DM stérilisé. Une première partie a été consacrée à la caractérisation physique des décharges plasmas confinées dans le sac de stérilisation. Cette étude a permis d’identifier les espèces potentiellement bactéricides et de définir des conditions favorables à leur production. Dans un second temps, l’efficacité bactéricide du procédé a été démontrée sur des bactéries à Gram négatif et à Gram positif selon la norme EN556. En parallèle, l’étude paramétrique réalisée sur E. coli a apporté des éléments de réponse sur les mécanismes de stérilisation et a ouvert des pistes sur l’optimisation du procédé. Enfin, l’analyse post-traitement des propriétés de biomatériaux a démontré l’absence de modifications macromoléculaires et a validé la potentialité du procédé PLAS’STER comme alternative aux méthodes usuelles de stérilisation.

Surface dielectric barrier discharges (SDBDs) operating in atmospheric air are efficient sources of reactive oxygen and nitrogen species (RONS), making them promising candidates for food decontamination applications. However, their chemical output strongly depends on operating conditions and environmental humidity that can affect treatment efficacy and reproducibility. In this work, we characterize the transition between ozone-dominant (O3 mode) and nitrogen-oxidesdominant (NOX mode) operating regimes by combining ICCD imaging, optical emission spectroscopy, and time-resolved absorption measurements of O3 and NO2 . We demonstrate that an increase of the applied voltage and the dielectric temperature accelerates the shift from net ozone production to rapid O₃ destruction driven by NOx catalytic cycles, while water vapor further suppresses ozone formation through enhanced OH-and H-driven reactions. Spatiotemporal ICCD measurements reveal that humidity simultaneously modifies streamer morphology and enhances overall plasma intensity. These findings establish quantitative operating windows to control RONS production for applications requiring either oxidative (O3 -rich) or nitrosative (NOx -rich) biocidal environments, providing essential knowledge for optimizing plasma-based food safety technologies.

Microbiological contamination of surfaces is a significant issue across various sectors, posing a serious risk of pathogen transmission between individuals and impacting public health. Among the available decontamination methods, ultraviolet-C (UVC) radiation has seen a surge in popularity in recent years, particularly following the COVID-19 pandemic. However, concerns have been raised regarding the environmental impact and the risk for users of mercury-containing UVC devices. Despite their well-documented biocidal efficacy against a broad spectrum of microorganisms, UVC radiation can be significantly hindered by the presence of organic matter, biofilms, or surface irregularities that create shadowed areas. In this study, we present an innovative approach that combines a krypton-chlorine (KrCl) excimer lamp with a UVC phosphor. Optical characterization techniques − including optical emission spectroscopy, camera imaging, and irradiance measurements − were used to analyze the KrCl lamp and two lamp-phosphor combinations, revealing the complementary nature of these two UVC sources. This synergy was further investigated and validated against two bacterial species (Escherichia coli and Staphylococcus aureus) and the HAdV5 adenovirus. The promising results highlight new opportunities for enhancing UVC-based surface decontamination strategies by combining UVC radiation sources.

Hospital and urban wastewaters constitute major reservoirs of multidrug-resistant bacteria (MRB), antibiotic resistance genes (ARGs), and persistent pharmaceutical contaminants, which are only partially removed by conventional treatment plants. As a result, these pollutants are frequently detected in treated effluents destined for environmental discharge or reuse, raising serious public health concerns-especially for agricultural irrigation. This study explores a novel immersed dielectric barrier discharge (DBD) plasma source engineered for point-of-use decontamination of wastewater at emission sites. The plasma device was thoroughly characterized by electrical, optical, and chemical diagnostics to elucidate its operating regimes and capacity to generate reactive oxygen and nitrogen species (RONS) at the plasma-liquid interface. Findings demonstrate that the composition of the carrier gas critically shapes the production and transfer of short-and long-lived oxidants into the liquid phase. These results provide quantitative insights that support the ongoing optimization of plasma-based advanced oxidation systems for decentralized water treatment. They further illustrate how the careful control of plasma and gas composition can enhance the formation and transfer of oxidants, contributing to the broader field of plasma-liquid applications for the mitigation of emerging contaminants.