The Vision Chip is an implantable device designed to transmit signals from a light detector or opto-electrical transducer to the retina in order to restore visual function in a diseased or damaged retina. The Vision Chip is based upon carbon nanotubes (CNTs) or CNT bundles, used as electrodes or as physical guides that transmit electrical signals or direct the growth of retinal cells to the chip. Additionally, the Vision Chip can be used as an electrical sensor for the retina in fundamental visual science research. The chip is targeted for treatment of Age-Related Macular Degeneration (AMD) or other degenerative diseases of the retina.
Technical Description of InventionDevice DesignThe Vision Chip consists of an array of electrically conducting or semi-conducting CNT "towers" (bundles of CNTs) projecting orthogonally from the surface of a silicon chip or similar solid support, with electrical connections to each CNT tower. The electrical connections allow for towers to be electrically stimulated independently of one another. An insulating layer covers the electrical circuitry in order to provide electrical isolation from the eye tissue. A key feature of the design is sufficient mechanical stability of the towers to permit insertion into retinal tissue, either from the anterior (epiretinal implantation) or the posterior (subretinal implantation) aspect of the retina, without breaking or dislodging the CNT towers. A ground electrode, or counter-electrode, is incorporated onto the Vision Chip, to optimize electrical stimulation and electrical sensing fiom eye tissue.
Device AssemblyCNT towers are synthesized directly on a silicon chip with patterned microcircuitry. Metals, a mixture of metals, or other suitable catalyst or catalysts are then deposited in a specific pattern onto the silicon chip. The deposition is accomplished through the technique of ion beam sputtering or other microfabrication techniques. CNT tower growth is then accomplished by the chemical vapor deposition technique or cold plasma technique. CNT towers only grow at sites of catalyst deposition. The arrangement of CNT towers, their diameter, their length, and the spacing between CNT towers can be optimized for the specific application. The conductivity of CNTs can be controlled by adjusting the growth conditions.
