Projekt 5

TUMOR CHARACTERIZATION WITH IMPEDENCE SPECTROSCOPY

Electrochemical impedance spectroscopy (EIS) is a method that has been successfully used in industrial applications for some time. It can identify and analyze a conductive sample by observing its electrical properties. The material-specific, frequency-dependent impedance, also known as AC resistance, is determined by analyzing the relationship between the applied voltage and the measured current.A major advantage of EIS is the radiation-free measurement method, which does not change the sample and allows repetitive measurements in small time intervals.This is particularly advantageous when measuring biological tissue, as it allows metabolic parameters to be analyzed online. Compared to conventional measurement methods, the samples remain in their initial state after measurement in an EIS measurement, thus allowing multiple repetitions of the measurement of the same sample. Since biological samples are usually subject to natural variance, EIS has great application potential in the field of biomedicine and tumor diagnostics. While the first commercial systems are already in clinical use, research is still in its infancy, especially with regard to the diagnosis and monitoring of tumor patient therapy. Based on the cell-specific properties of relative permittivity and electrical conductivity, the goal is to use EIS to form a so-called cell-specific fingerprint of the vitality of a tumor cell, influenced by its current metabolic state. In this way, it would be possible to effectively differentiate cells in vitro and, in the long term, in vivo on the basis of both their cell type and their pathological state. The primary goal of the project is to optimize the existing measurement system and to extend it with regard to new approaches in the field of measurement methods. Furthermore, the sample-specific influencing factors on the relative permittivity and electrical conductivity, for example the cell type, the metabolites of the intermediary metabolism and the intercellular fluid, are to be identified and analyzed with regard to their weighting factor. Based on this, an analytical method for the reliable and reproducible identification of an unknown cell sample will be developed. This should be able to differentiate between neoplastic and healthy tissue and, in the case of neoplastic tissue, to track the effect of an applied chemotherapeutic agent in the time domain.