Isolated tissue or single cells have increasingly come into focus for the development of sensor devices connected to pharmacological screening, medical diagnostics, or safety technology. The utilization of complete cells offers the advantage of a broad sensitivity to a multitude of substances and environmental factors like electro-magnetic fields. Furthermore, the cell itself provides the transduction mechanism that links the molecular recognition of a test substance to a measureable event. When using electrically active cells like neurons or muscle cells, the physiological response to an exogenous challenge is apparent in a modification of the electrical signals generated by the cells.

Electrical activity can be registered in real-time by extracellular electrodes that contact the cell membrane that is the site of origin of the electrical signals. The cells are directly cultivated on a chip carrying an array of microelectrodes (Microelectrode Array, MEA). Since the cells do not need to be sacrificed for the recording procedure, long-term use of the cell chip is feasible. The combination of chip and cell culture thus is an interesting concept suitable for detecting the presence of physiologically active compounds or (as investigated at presence) of electromagnetic fields.

Extracellular recordings with microelectrode Arrays. (A) 60-channel MEA-Chip, Multichannel Systems GmbH Reutlingen. (B) Single cell coupled to a substrate-embedded microelectrode. [figures: Andreas W. Daus, Dissertation, 2013]

Recent publications:

A. W. Daus, P. G. Layer, C. Thielemann, 2012. A spheroid-based biosensor for the label-free detection of drug-induced field potential alterations. Sensors and Actuators B, 165: 53– 58.

C. Nick, R. Joshi, J.J. Schneider, and C. Thielemann, Three-Dimensional Carbon Nanotube Electrodes for extracellular Recording of Cardiac Myocytes, Biointerphases, 2012.

A. W. Daus, M. Goldhammer, P.G. Layer, C. Thielemann, Electromagnetic exposure of scaffold-free three-dimensional cell culture systems, 2011, Bioelectromagnetics, 32: 351–359.

A. Daus, Leben auf dem Mikrochip – Biosensoren auf der Basis von Mikroelektroden-Arrays. Labor&More 8/2012.

Optical Waveguide Microscopy