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Cytological and Biomolecular Measuring Procedures

Working Group 8.32

Microfluidic flow cytometers


  RWTH Aachen Universität, Institut für Werkstoffe der Elektrotechnik

Microfluidic chip for optical and AC impedance counting of cells up to 100 MHz

The Working Group develops microfluidic flow cytometers for cell counting. Counting speed and resolution of these devices are comparable with conventional instruments. Applications range from differentiation of blood cells to diagnostic parameters of infectious diseases. Counting and differentiation of particles uses optical as well as electrical detection.

The small size of microfluidic components offer distinct advantages compared to conventional sensors. Low production costs allow usage as disposable units, and integration in lab-on-chip systems for near-patient testing.

The measurement of the impedance change with direct current when particles pass through a measurement orifice allows differentiation of particles by volume only. Using AC impedance measurements at alternating currents up to 100 MHz, the signals furnish information about the interior of the cell. At these frequencies, a small stray capacitance of the electrodes allows sensitive particle detection, which can more easily be implemented in microstructures.


Simon P, Frankowski M, Bock N, Neukammer J.
Label-free whole blood cell differentiation based on multiple frequency AC impedance and light scattering analysis in a micro flow cytometer.
Opens external link in new windowLab Chip 16 (2016) 2326-2338.

Frankowski M, Simon P, Bock N, El-Hasni A, Schnakenberg U, Neukammer J.
Simultaneous optical and impedance analysis of single cells: A comparison of two microfluidic sensors with sheath flow  focusing.
Opens external link in new windowEngineering in Life Sciences 15 (2015) 286-296.

Theisen J, Schmidt M, Ragusch H, Neukammer J, Kummrow A.
Verfahren zum hydrodynamischen Fokussieren eines Fluidstroms und Anordnung.
Opens external link in new windowPatent DE 10 2007 017 318.2 (2014).

Frankowski M, Theisen J, Kummrow A, Simon P, Ragusch H, Bock N, Schmidt M, Neukammer J.
Microflow cytometer with integrated hydrodynamic focusing.
Opens external link in new windowSensors 13 (2013) 4674-4693.

Frankowski M, Bock N, Kummrow A, Schädel-Ebner S, Schmidt M, Tuchscheerer A, Neukammer J.
A Microflow Cytometer Exploited for the Immunological Differentiation of Leukocytes.
Opens external link in new windowCytometry A 79A (2011), 613-624.

Kummrow A, Theisen J, Frankowski M,Tuchscheerer A, Yildirim H, Brattke K, Schmidt M, Neukammer J.Microfluidic structures for flow cytometric analysis of hydrodynamically focussed blood cells fabricated by ultraprecision micromachining.
Opens external link in new windowLab Chip 9 (2009), 972-981.