Microelectrode Arrays for Present and Future Electrophysiological Applications

In vitro diagnostic devices have highly esteemed platforms for toxicological testing, drug screening and even for theranostics. An extremely promising device type are microstructured devices, often referred to as biochips, that can be coupled with in vitro cell cultures. Employing microfluidic structures devices such as cell-chips and organ-on-a-chip devices have been developed to mimic the microenvironment of the human body. By implementing microelectrodes on the chip it is facile to utilize the benefits of microelectronics - the label-free, non-destructive, permanent real-time measurement of cellular processes. With electretic cells the action potential of cells can be directly measured, while other non-electrically cells can be measureds via their impedance. We will present devices on both concepts from our research. We will present sophisticated biomedical devices, were used to record the electrophysiological activity the neurite part of nerve cells of in real-time. With an axon isolation device a delicate microfluidics system is combined with microelectrodes inside of microchannels just large enough for axonal and dendritic structures. Also the biocompatibility of electrode materials is essential, and the relevance of cyclic voltammetry for checking the safe voltage range of microelecrtrodes will be explained with practical examples. Fabrication routes, benefits and limitations of microelectrode arrays. interdigitated electrode sensors and even 3D nanoelectrodedes will be discussed. An outlook on future devices featuring arrays 3D nanoelectrodes and microstructured guidance structures will be given.