Investigation of the antimicrobial activity at safe levels for eukaryotic cells of a low power atmospheric pressure inductively coupled plasma source

Abstract

Low power atmospheric pressure inductively coupled thermal plasma sources integrated with a quenching device (cold ICP) for the efficient production of biologically active agents have been recently developed for potential biomedical applications. In the present work, in vitro experiments aimed at assessing the decontamination potential of a cold ICP source were carried out on bacteria typically associated with chronic wounds and designed to represent a realistic wound environment; further in vitro experiments were performed to investigate the effects of plasma-irradiated physiological saline solution on eukaryotic cells viability. A thorough characterization of the plasma source and process, for what concerns ultraviolet (UV) radiation and nitric oxide production as well as the variation of pH and the generation of nitrates and nitrites in the treated liquid media, was carried out to garner fundamental insights that could help the interpretation of biological experiments. Direct plasma treatment of bacterial cells, performed at safe level of UV radiation, induces a relevant decontamination, both on agar plate and in physiological saline solution, after just 2 min of treatment. Furthermore, the indirect treatment of eukaryotic cells, carried out by covering them with physiological saline solution irradiated by plasma, in the same conditions selected for the direct treatment of bacterial cells does not show any noticeable adverse effect to their viability. Some considerations regarding the role of the UV radiation on the decontamination potential of bacterial cells and the viability of the eukaryotic ones will be presented. Moreover, the effects of pH variation, nitrate and nitrite concentrations of the plasma-irradiated physiological saline solution on the decontamination of bacterial suspension and on the viability of eukaryotic cells subjected to the indirect treatment will be discussed. The obtained results will be used to optimize the design of the ICP source for an effective production of reactive species, while keeping effluent temperature and UV radiation at values compatible with biomedical treatments.

Effects and safety of atmospheric low‐temperature plasma on bacterial reduction in chronic wounds and wound size reduction: A systematic review and meta‐analysis

“…1 Low-temperature atmospheric plasmas (APs) are generated under atmospheric pres-sure at ambient temperatures ranging from 20 C to 50 C. With the development of low-temperature APs, at temperature ranges of approximately 38 C at the point of application, 2 new therapeutic options directed against prokaryotic cells (eg, microorganisms) living on eukaryotic cells (eg, human tissue) are available. 3 Interest in the medical application of APs is rapidly increasing. The first study on the use of argon plasma for tumour removal were reported in 1989.…”

Cold Atmospheric Pressure Plasma Treatment Modulates Human Monocytes/Macrophages Responsiveness

“…Besides presenting a negligible heat component, CAPs are characterized by several biological active components, such as ions, electrons, reactive oxygen (ROS) and nitrogen (RNS) species, UV radiation, playing a synergic action in the interaction of CAP with biological substrates [11]. Therefore, CAPs may be used for the treatment of cells and biological tissues by properly selecting the most suitable source and operating conditions for plasma generation to avoid any thermal damage [12,13]. Indeed, the Authors have previously shown an effect of CAP in a number of different eukaryotic cell types [14][15][16][17].…”

Unraveling the permeation of reactive species across nitrated membranes by computer simulations

“…For the hydrophilic RONS, the ΔG values were calculated as the difference between the free energy maximum and the free energy minimum, while for the hydrophobic RONS, as the free energy maximum at the headgroup region. 3 ref. [36] Overall, the hydrophobic RONS present clearly lower permeation barriers than the hydrophilic RONS, see Figure 2 and Table 1.…”

“…Likewise, many bacteria have become resistant to the antibiotics available in medicine. Non-thermal plasma, also called cold atmospheric plasma (CAP), has emerged as a therapeutic modality against bacteria [3,4] and against a wide variety of cancer types [5], including hepatocellular carcinoma [6], lung carcinoma [7], breast cancer [8], melanoma [9], glioblastoma [10], pancreatic cancer [11], and head and neck cancer [12].…”