Evaluation of impedance spectroscopy for the characterization of small biological samples in tissue-based test systems

Marker free techniques are needed for the construction of efficient tissue-based test and sensor systems. In principle biological tissue can be characterized by impedance spectroscopy. In this paper we investigate by simulation how sensitive parameters of small biological tissue samples can be determined by impedance spectroscopy under optimal measurement conditions. Further, we experimentally evaluate whether the effects of different clinical relevant radio therapy variants on 3D in vitro tumor models are determinable and distinguishable by impedance spectroscopy using a tissue-based test system. The simulations demonstrate that changes in tissue parameters related to the extracellular space are determinable with a high sensitivity. The experiments show that the effect of different radiation dose levels on 3D in vitro tumor models can be determined and distinguished by using a capillary measurement system and impedance spectroscopy. These results are relevant for the development of tissue-based test and sensor systems using impedance spectroscopy to evaluate personalized therapy variants or new therapy approaches.