2019, Shi, Fukun, Zhuang, Jie, Kolb, Juergen F.

Normal and cancer cells, which were grown in monolayers, were investigated and discriminated by electrical bioimpedance spectroscopy (EBIS) before and after exposures to nanosecond pulsed electric fields (nsPEFs). Bioimpedance data were analysed with a Cole-Cole model and the principal component analysis (PCA). Normal and cancer cells could be clearly distinguished from each other either from Cole parameters (R 0, a, t) or from two dominant principal components. The trend of changes for Cole parameters indicated distinctively different post-nsPEF-effects between normal and cancer cells. PCA was also able to distinguish characteristic impedance spectra 30 min after exposures. The first principal component suggested that post-nsPEF-effects for normal cells were revealed especially at lower frequencies. The results indicated further that the extracellular resistance, which is dominated by cell-cell connections, might be an important factor with respect to selective nsPEF-effects on cancer cells that are organized in a monolayer or a tissue, respectively. Accordingly, the results support the application of EBIS as an early, non-invasive, label-free, and time-saving approach for the classification of cells to provide in particular predictive information on the success of cancer treatments with nsPEFs. © 2019 IOP Publishing Ltd.

2022, von Woedtke, T., Laroussi, M., Gherardi, M.

Plasma medicine refers to the application of nonequilibrium plasmas at approximately body temperature, for therapeutic purposes. Nonequilibrium plasmas are weakly ionized gases which contain charged and neutral species and electric fields, and emit radiation, particularly in the visible and ultraviolet range. Medically-relevant cold atmospheric pressure plasma (CAP) sources and devices are usually dielectric barrier discharges and nonequilibrium atmospheric pressure plasma jets. Plasma diagnostic methods and modelling approaches are used to characterize the densities and fluxes of active plasma species and their interaction with surrounding matter. In addition to the direct application of plasma onto living tissue, the treatment of liquids like water or physiological saline by a CAP source is performed in order to study specific biological activities. A basic understanding of the interaction between plasma and liquids and bio-interfaces is essential to follow biological plasma effects. Charged species, metastable species, and other atomic and molecular reactive species first produced in the main plasma ignition are transported to the discharge afterglow to finally be exposed to the biological targets. Contact with these liquid-dominated bio-interfaces generates other secondary reactive oxygen and nitrogen species (ROS, RNS). Both ROS and RNS possess strong oxidative properties and can trigger redox-related signalling pathways in cells and tissue, leading to various impacts of therapeutic relevance. Dependent on the intensity of plasma exposure, redox balance in cells can be influenced in a way that oxidative eustress leads to stimulation of cellular processes or oxidative distress leads to cell death. Currently, clinical CAP application is realized mainly in wound healing. The use of plasma in cancer treatment (i.e. plasma oncology) is a currently emerging field of research. Future perspectives and challenges in plasma medicine are mainly directed towards the control and optimization of CAP devices, to broaden and establish its medical applications, and to open up new plasma-based therapies in medicine.