Abstract
Micro-electrode arrays (MEAs) and micro-electrodes are used in a variety of medical applications for recording action potentials or stimulating neurons. To have an excellent signal-to-noise ratio, the contact between the neuronal tissue and the micro-electrodes must be very close. Therefore, a flexible MEA with a large number of electrodes on a large area is necessary. In this work, a flexible micro-electrode array (MEA) with an integrated flexible CMOS-chip was designed and fabricated. By connecting several of these MEAs by a bus system, the number of electrodes and therefore the spatial resolution can be increased extremely. Because of the small size of the micro-electrodes (<120 µm) each electrode needs a high charge delivery capacity and a high “true” surface area for stimulation, respectively. This can be obtained by coating the electrodes by disordered multi-walled carbon nanotubes (MWCNTs). Direct current pulsed Electrophoretic Deposition (EPD) has been proved successfully for the aforementioned application. The effective deposition time and the pulse width were figured out to create ideal MWCNT-electrode properties, particularly, with regard to the enhancement of the “true” surface area, microscopic homogeneity and reproducibility of the layer.
Highlights
Micro-electrodes and micro-electrode arrays (MEAs) are very important in a variety of medical applications like cochlear implants, retinal implants or deep brain stimulators
Micro-electrode arrays (MEAs) and micro-electrodes are used in a variety of medical applications for recording action potentials or stimulating neurons
The CMOS–chip used in our work is the same one which was used in the epiretinal implant of Rössler, et al [4]
Summary
Micro-electrodes and micro-electrode arrays (MEAs) are very important in a variety of medical applications like cochlear implants, retinal implants or deep brain stimulators. The Argus II epiretinal prosthesis system shows the highest electrode number It has 60 platinum electrodes on a flexible polyimide substrate which are connected to the control electronics via metal lines. Chader et al estimate that a MEA with approximately 1000 electrodes could give good functional vision as reading ability and face recognition [7] Such high numbers of electrodes can no longer be connected via single metal lines to the electronic components. Electrodes and electronics are on a single CMOS-chip, having a size of 3 mm × 3.1 mm This implant is non-flexible and has a very small sight of view. A purely optical subretinal prosthesis was developed by Palanker et al [8] This prosthetic system has an array of silicon islands which are connected via flexible silicon membranes. It is not possible to use state-of-the-art CMOS
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
