Biohybrid microarrays - Impedimetric biosensors with 3D in vitro tissues for toxicological and biomedical screening

To investigate the effectiveness of potential anticancer therapeutics or th erapies, efficient screening methods are required. On the one hand, multice llular 3D aggregates (spheroids) are a powerful in vitro model for simulati ng, the in vivo situation and on the other hand, planar electrode structure s are generally highly suitable for automation and parallel testing. Here, the detection of the effect of active substances on spheroids positioned on electrodes of substrate integrated electrode arrays is exemplarily investi gated. As a 3D tissue model a reaggregation system of T47D clone 11 tumor c ells is used. The effect of cytotoxins (DMSO, Triton X-100) on spheroids ca n be detected by recording the effective impedance of planar electrodes cov ered by spheroids. The equivalent circuit model parameter of electrodes cov ered by cytotoxin treated spheroids are determined from recorded impedance spectra and compared to the parameter of electrodes covered by control sphe roids as well as not covered electrodes. Spheroids on electrodes mainly inf luence the electrode impedance in the frequency range of 10 kHz to 1 MHz. T he results are discussed in view of an optimal electrode/spheroid-interface for sensing the effects of therapeutics with high sensitivity.