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PHD STUDENT (M/F): Study on the potential of cold plasma jets for the treatment of (multi)resistant bacterial strains in terrestrial and space conditions (M/F)

This offer is available in the following languages:
Français - Anglais

Date Limite Candidature : lundi 30 mai 2022

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General information

Reference : UMR7344-CORDEL-007
Workplace : ORLEANS
Date of publication : Monday, May 9, 2022
Scientific Responsible name : Robert Eric
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 October 2022
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly

Description of the thesis topic

Cold plasmas (ionized gases at room temperature) make it possible to decontaminate not only equipment but also biological surfaces such as human skin. Plasma jets allow, for example, the treatment of patients with chronic wounds or bedsores by using, among other things, their bactericidal effect. The objective of this original project is to study the bactericidal performance of an atmospheric plasma jet ("Plasma Gun" developed by the GREMI laboratory) under terrestrial gravity and/or microgravity conditions.
The plasmas used on Earth are a source of free radical species for multiple applications ranging from decontamination to medicine passing through agriculture and combustion and could also be used during space travel in these same application fields.
The space exploration of the next decades will require the preparation of manned spaceflights of long duration. There are still many challenges to overcome before considering such expeditions in the near future. To anticipate these space trips, it is essential to test new technologies that will allow people to live in total autonomy in small isolated vessels with limited resources. The International Space Station (ISS) is the first microgravity research laboratory for scientific experiments. Each mission aboard the ISS increases our knowledge of life in microgravity and ultimately allows us to predict what problems may arise during long periods of exposure to these particular conditions. Biology and medicine occupy a special place in the experiments carried out during the various missions. The effect of bacteria or viruses under these specific conditions is particularly studied. This is why, in this project, we propose to address a terrestrial problem, and a fortiori spatial one, which is the inactivation of bacteria by plasma.
The main application targeted by this project is therefore the disinfection of surfaces, in particular biological ones, colonized by bacterial strains resistant to antibiotics and/or other conventional techniques and possibly to living beings, concerning for example the treatment of human or animal wounds.

Work Context

This multidisciplinary thesis project requires both plasma physics and biology skills for the use of model bacteria and pathogenic bacteria. It will take place within two laboratories that are complementary for the addressed theme, the GREMI (UMR 7344, INSIS) specialist in plasmas and the CBM (UPR 4301, INC and INSB) specialist in chemistry and biology and within the “Centre Hospitalier Régional d'Orléans (CHRO)” for its expertise in multi-resistant bacteria (Infectious Risk Prevention Service). Specific analysis devices from the two laboratories will be used, in particular the CBM imaging platform (confocal microscopy) and the GREMI's rapid imaging resources (intensified and rapid cameras). This thesis project will be directed by an HDR researcher and by three co-supervisors, an assistant professor and a researcher from GREMI and an assistant professor from CBM.
Studies were initiated in 2017 jointly by the GREMI, the CBM and the CHRO on the bactericidal effect of plasma. In addition, a Franco-German ANR project "Plasfect" was accepted in 2021, the final objective being to treat chronic or infected human wounds with plasma in order to accelerate or initiate patient healing. The GREMI is the French referent of this ANR and is in charge, among other things, of the design and development of the plasma device used by the various researchers involved in this project. The work carried out during this thesis will complement the knowledge provided by the different teams working on “Plasfect”.
On the other hand, various actions carried out at the GREMI laboratory have made it possible to prepare, in conjunction with Novespace (Company organizing the parabolic flight campaigns in microgravity), an experimental bench qualified for parabolic flights (microgravity condition). In this context, a project (S.A.F.E) already accepted by the CNES (Centre National d'Etudes Spatiales) makes it possible to participate in two parabolic flight campaigns in 2022. This project aims to validate the operation of the Plasma Gun in microgravity and to optimize its action on model bacteria.
This thesis project is based on the use of Plasma Gun technology. It makes it possible to generate cold plasma jets in ambient air by means of pulsed electrical discharges and a dedicated applicator/reactor. The generated plasma jet can be applied to targets of all kinds, dielectric or metallic, containing or not model bacteria. The specific physical and biological diagnostics of laboratories and department involved will make it possible to study the production of reactive species and their effects on bacteria.
This project can be broken down into six areas of research:
• Study of the physics of the plasma jet in the air: geometry and characterization of the composition of the plasma according to the discharge parameters.
• Study of plasma modifications induced during the interaction with an agar gel target in laboratory and in microgravity conditions.
• Study of the effect of reactive species generated by plasma on bacteria added on an agar gel or in a liquid.
• Comparison of results obtained on model bacteria in laboratory and in microgravity conditions during parabolic flight campaigns; optimization of the production of species according to the discharge parameters.
• Study of the effect of the Plasma Gun on strains of multi-resistant bacteria using the operating conditions defined on model bacteria.
• Microbiology analyzes on bacteria upstream and post plasma treatment:
• Use of advanced experimental devices of the CBM microscopy platform.
• Analysis of the integrity of the bacteria DNA by electrophoresis.

Constraints and risks

The Phd student will work with electrical installations delivering high voltage; will handle chemicals and bacteria, which will require working in compliance with safety conditions and health rules of microbiology.
The thesis will take place in two laboratories and at the CHRO less than five kilometers apart.
Regular travel between the three research entities and specific missions will take place as part of Phd subject and of the parabolic flight campaigns, respectively.

Additional Information

To apply, send your application file: detailed CV, one-page cover letter, Master transcripts, contact details for two references (persons likely to be contacted).
The candidate must hold a Master 2 Research or/and an engineering degree with a focus on Plasma and/or Energy and/or Fluid Mechanics.
A deep attraction for the experimental approach and skills in optical diagnostics and spectroscopy are necessary.
Knowledge of experimental data/video analysis software is particularly desired.
Synthesis and writing skills in French and English are expected.
Experience in project management related to plasma and/or microbiology is appreciated.
The candidate must be rigorous, autonomous and motivated.

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