Anti-Bacterial Action of Plasma Multi-Jets in the Context of Chronic Wound Healing

Thomas Maho,Claire Douat,Sébastien Dozias,Maryvonne Demasure,Thierry Prazuck,Jean-Michel Pouvesle,Isabelle Goard,Augusto Stancampiano,Raphaelle Binois,Pablo Escot Bocanegra,Inna Orel,Clément Tocaben,Eric Robert,Laurent Hocqueloux,Claire Le Helloco,Fabienne Brulé-Morabito

doi:10.3390/app11209598

Abstract

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.

Highlights

As introducing new people to “plasma” as “ionized gas”, one mentions that plasma is the fourth state of matter and represents more than 99% of the baryonic matter of the universe
This work reports on the design and operation of multi jets devices based on the plasma gun technology [42,43]
The first device developed as a “multi spot plasma applicator” and a slightly modified derived version labeled as “diffuse mode plasma applicator” allows to deliver 52 millimeter-sized helium jets in ambient air at a pulse repetition rate of 2 kHz

Summary

Introduction

As introducing new people to “plasma” as “ionized gas”, one mentions that plasma is the fourth state of matter and represents more than 99% of the baryonic matter of the universe. Natural plasmas are fascinating (aurora), a unique source of energy on earth (sun power), at the origin of basic mater physics (stars, quark plasma, amino acid generation as the bricks of life), but they are somehow “hostile”, generating huge transient current and overvoltage in lightning, electromagnetic disturbance in the pole region, intense energetic radiation fluxes constraining microorganisms and life expansion. This was one the first historical development of plasma science and technology to try to benefit from the radiative (UV, X-rays) and chemical compounds (oxidants, metastable states, charged particles with high energy) of plasmas for decontamination or sterilization purposes. Plasma are known to be a potential and likely unique strategy for resistant microorganism’s reduction, mostly due to plasma’s multifaceted features, merging energetic radiation, energetic particles, and chemically active compound cocktail likely combining short and long-lived oxidants

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