Paper by two CoEs published

Frontiers in Neuroscience journal published 22.3.2019 our paper Microelectrode array with transparent ALD TiN electrodes that was made in co-operation by researchers from two CoEs; our Centre of Excellence in Body-on-Chip Research (CoEBoC) and the Finnish Centre of Excellence in Atomic Layer Deposition (ALDCoE).

Microelectrode arrays (MEAs) are widely used for electrophysiological recordings of neuronal and cardiac cells etc., and titanium nitride (TiN) is a common MEA electrode material whose high surface-area-ratio by columnar morphology lowers impedance and thus enables low noise recordings. However, in many studies it would be favorable to be able to image the cells by an inverted microscope and there the usually opaque electrodes are problematic as they hinder the visibility to the cells that are recorded. The existing transparent electrodes like indium tin oxide (ITO), unfortunately, suffer from relatively high noise levels.

In our solution, ALDCoE’s researchers from VTT Espoo used Millennium Technology Prize rewarded and in Finland invented atomic layer deposition (ALD) technique to deposit high quality TiN thin films that were thin enough to be still transparent but which already had the columnar morphology typical to thicker opaque TiN electrodes to lower the impedance below the impedance of ITO electrodes. Our researchers processed the ALD TiN thin film to MEA electrodes and verified the performance of the electrodes in neuronal cell experiments.

The co-operation got started when our researchers noticed a poster by VTT researchers in ALDCoE’s annual seminar. Thus, it is easy to say, that one should not look only what is happening outside the Finnish borders, but be aware of what is happening also inside Finland and take care that the potential Finnish co-operators know what you are doing.

Ryynänen T, Pelkonen A, Grigoras K, Ylivaara OME, Hyvärinen T, Ahopelto J, Prunnila M, Narkilahti S and Lekkala J (2019). Microelectrode Array With Transparent ALD TiN Electrodes. Front. Neurosci. 13:226.  doi: 10.3389/fnins.2019.00226