Congratulations to Korentin Géraud on successfully defending his PhD thesis in plasma medicine

Congratulations to Korentin Géraud on successfully defending his PhD thesis entitled “Cold plasma endotherapy applied to oncology: from the physics of guided streamers to feasibility and therapeutic efficacy in preclinical models” on March 24, 2026.

• Abstract
  • This research is part of the emerging field of cold atmospheric plasma (ACP) applications in medicine, and more specifically in oncology. For over a decade, the electrical, chemical, thermal and radiative properties of these partially ionized gases have been studied owing to their ability to induce oxidative stress in tumor cells. Among cancers with poor prognosis, cholangiocarcinoma (a rare, aggressive and anatomically hard-to-reach biliary tumor) represents a clinical indication with a significant unmet medical need.
    The main challenge lies in the still incomplete understanding of the physical and chemical mechanisms governing plasma discharges in confined and miniaturized geometries, such as catheters. Furthermore, the technical feasibility and safety of such devices have not yet been demonstrated in endoscopic or biliary environments. These fundamental and technological limitations hinder the clinical translation of CAPs and justify an integrated approach combining fundamental physics, biomedical engineering and preclinical validation.
  • The overall goal of this thesis is to establish the scientific, technological and preclinical foundations of a biliary endotherapy using cold plasma, with cholangiocarcinoma as a model. Four objectives were pursued: (i) to characterize the physics of guided streamers in miniaturized catheters; (ii) to design a platform integrating physical and biological diagnostics; (iii) to define a safe electro-thermal operating window compatible with biliary tissues; (iv) to validate the feasibility and tolerance of the procedure in preclinical models.
  • The methodological approach first focused on the innovation of a side-orifice plasma catheter, currently protected by a patent application, whose plasma properties were characterized using ultrafast ICCD imaging, as well as electrical, thermal and chemical analyses. This made it possible to link the dynamics of guided streamers to the generation of reactive oxygen and nitrogen species (RONS). The catheter was successively tested on artificial biliary models, ex vivo porcine digestive systems, and in vivo animal models.
  • The results show that streamer propagation follows reproducible kinetic sequences, governed by the catheter geometry, gas flow rate and applied voltage. A stable operating window (5-10 kHz, 5-7 kV) maintains the temperature below 40 °C while producing H₂O₂ concentrations above 40 µM and NO₂⁻ levels around 10 µM in aqueous environments. These conditions ensure a strictly non-thermal regime, guaranteeing tissue safety. Endoscopic introduction of the plasma catheter was validated in both ex vivo and in vivo models. In pigs, the procedure proved technically feasible, with no macroscopic lesions or histological abnormalities observed after 40 days.
  • The implications of this work are twofold: it establishes a rigorous continuum between the physics of confined discharges and their biological validation, and it demonstrates the feasibility of a safe, minimally invasive plasma endotherapy. These results lay the groundwork for a future clinical application of cold plasma in the treatment of endoluminal tumors.
     
• Location
  • Sorbonne Université, Campus Pierre & Marie Curie, room 24-34-509
• Jury composition
  • Andrea CIARDI - Professor - Jury Chair
  • Philippe GUILLOT - Professor - Reviewer
  • Claire DOUAT - Lecturer - Reviewer
  • Nofel MERBAHI - Professor - Reviewer
  • Azadeh VALINATTAJ OMRAN - Lecturer - Examinatrice
  • Marine CAMUS - Professor - Examiner
  • Laura FOUASSIER - Researcher - Guest
  • Thierry DUFOUR - Lecturer - PhD supervisor