Carbon-nanotube based flexible electrodes for retinal recording and stimulation

A lingering technological bottleneck in the field of neuro-prosthetics is the quality of the stimulating electrodes. Such electrodes should be soft, micron in size and capable of injecting enough charge to evoke localized neuronal activity without causing tissue damage during extended operation (years). Carbon nanotubes have been shown over the past several years as a promising material in this realm. Here we present the use of carbon nanotubes for neuronal applications. Specifically, we show how this exciting material can be applied to fabricate a new flexible neuronal micro electrode device. The device is based entirely on carbon nanotube technology, where both the conducting traces and the stimulating electrodes consist of conducting carbon nanotube films embedded in a polymeric support. The use of carbon nanotubes bestows the electrodes flexibility and excellent electrochemical properties. Recording and stimulation tests with chick retinas were used to demonstrate the suitability of the new device for high-efficacy neuronal stimulation applications. Preliminary in-vivo examination of these surfaces show marked retina-carbon nanotube attachment. Finally, progress towards photo activated carbon nanotube electrodes is described.