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Author: Bekeschus, Sander × Author: Wende, Kristian × Has files: Yes × Type: article × Version: publishedVersion ×

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    Development of an electrochemical sensor for in-situ monitoring of reactive species produced by cold physical plasma
    (Amsterdam [u.a.] : Elsevier Science, 2021) Nasri, Zahra; Bruno, Giuliana; Bekeschus, Sander; Weltmann, Klaus-Dieter; von Woedtke, Thomas; Wende, Kristian
    The extent of clinical applications of oxidative stress-based therapies such as photodynamic therapy (PDT) or respiratory chain disruptors are increasing rapidly, with cold physical plasma (CPP) emerging as a further option. According to the current knowledge, the biological effects of CPP base on reactive oxygen and nitrogen species (RONS) relevant in cell signaling. To monitor the safety and the biological impact of the CPP, determining the local generation of RONS in the same environment in which they are going to be applied is desirable. Here, for the first time, the development of an electrochemical sensor for the simple, quick, and parallel determination of plasma-generated reactive species is described. The proposed sensor consists of a toluidine blue redox system that is covalently attached to a gold electrode surface. By recording chronoamperometry at different potentials, it is possible to follow the in-situ production of the main long-lived reactive oxygen and nitrogen species like hydrogen peroxide, nitrite, hypochlorite, and chloramine with time. The applicability of this electrochemical sensor for the in-situ assessment of reactive species in redox-based therapies is demonstrated by the precise analysis of hydrogen peroxide dynamics in the presence of blood cancer cells.
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    Oxygen atoms are critical in rendering THP-1 leukaemia cells susceptible to cold physical plasma-induced apoptosis
    ([London] : Macmillan Publishers Limited, part of Springer Nature, 2017-6-5) Bekeschus, Sander; Wende, Kristian; Hefny, Mohamed Mokhtar; Rödder, Katrin; Jablonowski, Helena; Schmidt, Anke; Woedtke, Thomas von; Weltmann, Klaus-Dieter; Benedikt, Jan
    Cold physical plasma has been suggested as a powerful new tool in oncology. However, some cancer cells such as THP-1 leukaemia cells have been shown to be resistant towards plasma-induced cell death, thereby serving as a good model for optimizing plasmas in order to foster pro-apoptotic anticancer effects. A helium/oxygen radio frequency driven atmospheric plasma profoundly induced apoptosis in THP-1 cells whereas helium, humidified helium, and humidified helium/oxygen plasmas were inefficient. Hydrogen peroxide – previously shown as central plasma-derived agent – did not participate in the killing reaction but our results suggest hypochlorous acid to be responsible for the effect observed. Proteomic analysis of THP-1 cells exposed to He/O2 plasma emphasized a prominent growth retardation, cell stress, apoptosis, and a pro-immunogenic profile. Altogether, a plasma setting that inactivates previously unresponsive leukaemia cells is presented. Crucial reactive species in the plasma and liquid environment were identified and discussed, deciphering the complexity of plasma from the gas phase into the liquid down to the cellular response mechanism. These results may help tailoring plasmas for clinical applications such as oxidation-insensitive types of cancer.