Volume 11, Number 3 • Fall 2003 • Moving Forward

Technology Opportunity Showcase highlights some unique technologies that NASA has developed and which we believe have strong potential for commercial application. While the descriptions provided here are brief, they should provide enough information to communicate the potential applications of the technology. For more detailed information, contact the person listed. Please mention that you read about it in Innovation.

Nanotechnology Vision Chip

NASA seeks to license or codevelop its Nanotechnology Vision Chip, a unique technology for stimulating retinal neural cells using an array of carbon nanotubes (CNTs). Developed at NASA Ames Research Center, in conjunction with Stanford University School of Medicine, the Vision Chip is designed to restore vision in patients suffering from age-related macular degeneration, the number-one cause of blindness in the elderly. Other potential applications include traumatic eye damage and ophthalmologic research.

The Vision Chip consists of an array of electrically conductive CNT towers grown directly on the surface of a silicon chip. Each CNT tower in the array is connected to its own electrical circuit, so that electrical signals generated by the pixels of a light detector (such as a charge-coupled device (CCD) chip, worn by the patient) can be transmitted to the CNT towers. For the intended application, thousands of CNT towers are closely spaced in an array, to match the spacing of the neurons within the retina.

The device is designed for implantation into the retina, so that the CNT towers come in direct contact with the retinal neurons. Electrical signals generated by a CCD camera are delivered to the implanted device via telemetry. Prototypes have used towers that are 100 microns in diameter and approximately 150 microns tall. Small chips (50–150 microns tall) with arrays of towers spaced 10–25 microns apart are under development. Optimization of dimensions and spacing serves to maximize “cross talk” within the retinal layer, producing a sharper image for the patient.

In an alternate version of this technology, the CNT towers may be implanted only partway into the retina and coated with special growth factors to stimulate growth of retinal neurons toward the CNT towers. CNTs provide a highly biocompatible surface and may be doped with a variety of growth factors and cytokines to stimulate attachment of neural cells to the CNT towers. With this enhancement, only minimal penetration of the retinal tissue (25–50 microns) may be needed to promote neural cell/CNT tower connections and restore vision.

Short-term in vitro tests of the implant materials with retinal ganglion cells suggest excellent biocompatibility. Additional in vitro and in vivo tests are underway.

The benefits of the technology are numerous. It can allow for vision restoration in cases of macular degeneration. Small, nano-sized components allow for an image resolution density similar to that of native retinal photoreceptors. *

For more information, contact Lisa Williams, NASA Ames Research Center, at 650/604-2954, liwilliams@mail.arc.nasa.gov. Please mention you read about it in Innovation.