All-carbon-nanotube flexible multi-electrode array for neuronal recording and stimulation

Abstract

Neuro-prosthetic devices aim to restore impaired function through artificial stimulation of the nervous system. A lingering technological bottleneck in this field is the realization of soft, micron sized electrodes capable of injecting enough charge to evoke localized neuronal activity without causing neither electrode nor tissue damage. Direct stimulation with micro electrodes will offer the high efficacy needed in applications such as cochlear and retinal implants. Here we present a new flexible neuronal micro electrode device, 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. As opposed to contemporary flexible neuronal electrodes, the technology presented here is both robust and the resulting stimulating electrodes are nearly purely capacitive. Recording and stimulation tests with chick retinas were used to validate the advantageous properties of the electrodes and demonstrate their suitability for high-efficacy neuronal stimulation applications.Electronic supplementary materialThe online version of this article (doi:10.1007/s10544-013-9804-6) contains supplementary material, which is available to authorized users.

Syringe-injectable mesh electronics integrate seamlessly with minimal chronic immune response in the brain

“…900 nm and widths of 20 μm. We have also used polyimide flexible thin-film probes with thicknesses, 25 μm, comparable to the lower end of the range, 20-100 μm used in reported studies (29,30,32,33); the width of these thin-film probes, 500 μm, was comparable to the outer diameter of the capillary needle that was used for injection of mesh electronics, ca. 650 μm.…”

“…These data further showed NF signals within the mesh electronics interior at all times, and that the interior NF signal is the same as baseline at 3 mo. The horizontal brain slices described above provide detailed information about the local tissue/probe interfaces for the mesh electronics and flexible thin-film implants and also allow comparison with previous studies of more rigid conventional probes (29,30,32,33). These horizontal sections cannot, however, provide a global view of the probe/tissue interface, which typically extends millimeters in depth in the mouse brain.…”

Novel interfaces for light directed neuronal stimulation: advances and challenges

“…The device was successfully applied for recording and stimulation of a chick retina. 182 To conclude, photoactive surfaces have an enormous potential in the realm of neuronal interfaces. The emergence of novel nanomaterials, combined with the implementation of flexible and transparent device support, offers exciting new solutions addressing issues such as efficient light harvesting and transduction to electrical signals, long-term biocompatibility and stability, small size, and improved mechanical properties.…”

“…Promising directions for future nanostructured photoactive neuronal interfaces include utilization of photo-responsive nanowires, 180 carbon nanotubes (CNTs), 181 and flexible support materials. 182 Incorporation of CNTs in the design of a photoactive interface is an approach to enhance the photocurrent and increase biocompatibility. Intensive investigations over the past decade have explored the unique properties of CNTs for neuronal interfacing, including enhanced electrochemical properties, biocompatibility and durability, as well as high electrical conductivity.…”

“…Recently, our group has developed a flexible electrode array suited for neuronal recording and stimulation and composed entirely of CNTs. 182 Our technology is simple, robust and the resulting stimulating electrodes are nearly purely capacitive. The device was successfully applied for recording and stimulation of a chick retina.…”