Nanotechnology breakthrough will lead to a better artificial retina for visually impaired

(c) American Chemical Society

 
Scientists from Hebrew University of Jerusalem researchers in collaboration with colleagues from Tel Aviv University and Newcastle University, have developed a new light-sensitive film that could one day form the basis of a prosthetic retina to help people suffering from retinal damage or degeneration.





The retina, a thin cellular layer in the back of the eye composed of light-sensitive rods and cones, converts images to electrical impulses and sends the information to the brain. Damage to the retinal cells from conditions such as macular degeneration, retinitis pigmentosa and others leads to visual impairment or even total blindness. In the United States alone, age-related macular degeneration (AMD) affects as many as 15 million Americans, with over 200,000 new cases diagnosed every year.

Scientists around the world are currently designing a variety of medical devices to counter the effects of retinal disorders by sending visual signals to the brain, usually referred to as bionic eyes. One of them, the ARGUS-II, is an approved device for use in patients with advanced retinitis pigmentosa, in the United States and in Europe. But these silicon-chip based solutions are typically hampered by their size, use of rigid parts, or requirement of external wiring such as to energy sources.

In this new study, the scientists developed a novel approach for retina stimulation, with their device being able to absorb light and stimulate neurons without using wires or external power sources. The researchers combined semiconductor nanorods and carbon nanotubes to create a wireless, light-sensitive, flexible implantable film. The film transforms visual cues to electric signals, mimicking the function of the photo-sensitive cells in the retina. Therefore, it could potentially form part of a future prosthetic device that will replace the damaged cells in the retina.

The researchers tested the new device on light-insensitive retinas from embryonic chicks and observed a neuronal response triggered by light. According to the researchers, the new device is compact, capable of higher resolution than previous designs, and is also more effective at stimulating neurons. While much work remains until this can provide a practical solution, with additional research, the researchers hope their carbon nanotube-semiconductor nanocrystals film will one day effectively replace damaged retinas in humans.

The researchers received funding from the Israel Ministry of Science and Technology, the European Research Council and the Biotechnology and Biological Sciences Research Council.

The research was published in Nano Letters as “Semiconductor Nanorod-Carbon Nanotube Biomimetic Films for Wire-Free Photostimulation of Blind Retinas.”

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