The new technology would use a light-sensitive, wireless, nanorod-nanotube film developed by an Israeli research team led by Professor Uri Banin of The Hebrew University in Jerusalem. The nanorod-nanotube film shows promise for being used in a prosthetic retina that could overcome retinitis pigmentosa and other conditions that can reduce vision or cause total blindness.
“This is a pioneering work demonstrating the use of highly tailored semiconductor nanocrystals in activation of biomedical functionalities,” said Prof. Banin in his team’s writeup of the research. “We hope this can lead to future implementation of this approach in retinal implants.”
The research was published recently in the journal Nano Letters, summarizing work by Banin along with colleagues from Tel Aviv University and Newcastle University.
Affects Millions In U.S.
In the United States alone, age-related macular degeneration (AMD) of the retina — the thin layer of tissue at the inner surface of the eye — affects as many as 15 million Americans, with over 200,000 new cases diagnosed every year.
Composed of light-sensitive nerve cells, a normal, healthy retina works by converting images to electrical impulses and sending them to the brain. But over time, when macular degeneration sets in, the retina is less able to perform these functions.
Scientists have been working to design a variety of medical devices to counter the effects of retinal disorders by sending visual signals to the brain. Unfortunately, these silicon-chip based solutions are typically hampered by their size, use of rigid parts, or need for external wiring, such as to energy sources.
A Novel Approach
To overcome these limitations, Banin’s research team decided to look for other ways to achieve retinal stimulation.
Their device absorbs light and stimulates neurons without using wires or external power sources. It uses a combination of semiconductor nanorods and carbon nanotubes to create a wireless, light-sensitive, flexible implantable film.
Thusfar, the researchers have tested the new device on light-insensitive retinas from embryonic chicks and observed the response they were hoping for — a neuronal response triggered by light.
Mimicking Retina Cells
Their carbon nanotube-semiconductor nanocrystals film transforms visual cues to electric signals, mimicking the function of the photo-sensitive cells in the retina.
Therefore, the researchers conclude, it could potentially form part of a future prosthetic device that will replace the damaged cells in the retina.
According to the researchers, the new device is compact, capable of higher resolution than previous designs, and also more effective at stimulating neurons.
While much work remains before this technology can provide a practical solution, the researchers hope their nanotube-nanorod film will one day effectively replace damaged retinas in humans.
Funding for the work was provided by the Israel Ministry of Science and Technology, the European Research Council, and the Biotechnology and Biological Sciences Research Council.
The Hebrew University team consisted of Prof. Banin, the Alfred & Erica Larisch Memorial Chair in Solar Energy, and his graduate student Nir Waiskopf, at the Institute of Chemistry and the Harvey M. Krueger Family Center for Nanoscience and Nanotechnology.