Atmospheric Pressure Multijet Plasma Sources For Cancer Treatments

Abstract

Single plasma jets have allowed significant advances in in vivo or directly on human experiments (e.g. [1],[2]). The results are particularly promising, but ultimately likely to be limited in the future due to the fact that the treatment times are rather long due to the very small treated surface area resulting from the produced plasma. There is a real challenge to develop sources that allow treatment over larger areas while remaining practical and at a reasonable cost. There are already flexible or rigid surface DBDs but that require an extremely small distance between the reactor and the treated tissues, which limits their use in many situations, particularly when the treated surfaces exhibit large variations in the surface morphology leading to points of attachment of streamers and therefore very inhomogeneous treatment. The jets are very useful in this type of situation because they adapt to all types of surfaces whether they are smooth or highly structured, or even if they have holes or cavities difficult to reach in the case of a surface plasma. On the other hand, floating DBDs are very sensitive to the nature of the treated substrate and the presence of seeps can prevent their operation. "Ideal" sources are therefore sources with the flexibility of a jet and surfaces comparable to large DBDs.

It is in this spirit that we have developed a new generation of applicators based on a single Plasma Gun system to generate a multitude of jets (from tens up to few hundreds) from a primary plasma jet, as shown in the photos below.

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Before proceeding to in vivo treatments, we qualified the sources through in vitro experiments of decontamination on both colonies grown on agar plates in traditional Petri dishes, to check the equivalence of each of the jets generated, and colonies grown on very large agars scanned with our systems to treat very large surfaces in an easy way. The results are extremely encouraging and demonstrated the effectiveness of the multijet system, which allows both large-scale targets to be processed, as well as reducing processing times that can quickly become prohibitive with single-jet systems. At the same time as experimental results obtained on generation of different types of multijets, we will present results obtained with those on the decontamination of multi-resistant bacterial colonies grown from inpatient samples.