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BP: Fachverband Biologische Physik

BP 15: Postersession III

BP 15.50: Poster

Dienstag, 13. März 2018, 14:00–16:00, Poster B

Label-free microfluidics using electrical impedance spectroscopy — •Armin Grundmann, Dario Anselmetti, and Martina Viefhues — Experimental Biophysics, Faculty of Physics, Bielefeld University, Bielefeld, Germany

Label-free detection of particles in microfluidic devices is an important step towards Lab-on-a-Chip devices, allowing for the analysis of unlabeled biomolecular samples. Using electrical impedance spectroscopy (EIS) we were able to detect both polystyrene beads and biological samples based on their (di)electrical properties. After successfully integrating this method into our microfluidics setup using a specially designed chip and holder system, we characterized it by simultaneously detecting impedance and fluorescence of fluorescent polystyrene beads. Thus, we investigated the dependencies of the detection on sample concentration, measurement signal frequency and external influences. To drive the samples during the measurements, hydrostatic pressure was applied, which also turned out to effect the signal. Using EIS we were then able to detect DNA and E. coli bacteria at various concentrations. While the detection of small sample concentrations has proven to be difficult, we obtained promising results for the detection of higher concentrations. Having found the optimal parameters and the minimal detectable sample concentration, we will be able to introduce EIS to microfluidic experiments for detection e.g. in separation applications.