Development of a novel microcapillary array: Characterization of in vitro 3D tissue models by bioimpedance spectroscopy

Automated screening of the selectivity, toxicity, metabolism and absorption of drugs could support the development of novel innovative diagnosis and therapeutics. The biotechnological research demands on effective methods and technologies for characterization and biomonitoring of living cells and tissues. Therefore, a bioelectronic microstructure for monitoring 3D in vitro tissues or cell-coupled microcarriers beads by impedance spectroscopy and/or potential recording has been developed and fabricated. The feasibility of the capillary measurement system has been demonstrated using various 3D tissue models e.g. breast cancer tumor spheroids and 3D heart muscle cell aggregates. The antiproliferative influence of gene therapeutical agents in tumours or the beta-receptor inhibitor interaction in heart muscles resulting in altered synchronized contractions could be shown using a four electrode configuration in a glass capillary with an inner diameter of 300 mu m. The prototype of a microcapillary array has been fabricated using a biocompatible polymer with parallel oriented capillaries with diameters of 100 mu m, 200 mu m, 300 mu m and 400 mu m and implemented platinum microelectrodes. The in vitro tissues can be positioned synchronously by hydrodynamic pressure in culture medium. The dielectric attributes of the living system can be monitored in an electric field by impedance spectroscopy according to a frequency range.