The first place idea came from Rachel Rosenzweig, Elena Iris Liang, and Mary Nora Dickson from the University of California Irvine with their submission entitled: “Engineering a Flexible Organic Photovoltaic Cell as an Artificial Retina to Restore Sight: A Promising Vision in Bio-nanoelectronics.”
One of the most exciting areas of Convergence Research, engineering the human body, is also one of the oldest. Hindu texts dating from approximately 1,000 BC detail how ant mandibles were used as sutures to clamp wounds shut. In 600AD, Mayans were replacing missing teeth with blue nacre shell that, over time, integrated into their jawbone. However, with modern understanding of material science, researchers are pushing the boundaries of what can be replaced and regrown.
“I am fascinated by how the world is characterized by materials,” Rachel Rosenzweig explains. “ For instance the Stone Age, Bronze Age, Iron Age, and now the Polymer/ Semiconductor Age is what define our society’s technological capabilities.”
Working with her team at the University of California Irvine, Ronsenweig’s material of choice is the solar panel. While solar panels are well known devices that capture light and convert it into electricity, they also loosely resemble the retina. Coating the inner eye, the retina is an exquisite layer of transparent tissue packed with about 120 millions photoreceptor cells that convert light into electric nerve impulses. Because it is so specialized, the retina cannot be replaced by other tissues and the roughly 15 million Americans suffering from retinal degeneration eventually go blind.
The only therapy for retinal blindness is an artificial retina where photodiodes, miniscule devices that also respond to light by producing electricity, replace photoreceptor cells. Although current models allows users to detect moving patterns on a screen and in some cases read large letters, they depend on cumbersome external wiring and may generate unwanted chemical reactions. The largest challenge of replacing a retina is restoring resolution. Like the amount of pixels on a computer screen, resolution of artificial retinas depends on the number of photodiodes: 60 restores the ability to differentiate areas of darkness and light while 1,500 photodiodes grants the ability to read letters.
To address these design challenges, Ronsenweig’s team is designing a soft and flexible organic solar panel made from “inexpensive, biocompatible, polymer based material.” Layering over and fusing with neurons that normally communicate with the retina, the organic solar panel responds to light by initiating nerve impulses that activate the visual system. Critically, using nanofabrication techniques, Ronsenweig’s team can assemble an array of 10,000 photodiodes, which will be “designed to have much greater resolution and color vision than previous artificial retinas.”
Ronsenweig’s team includes material scientists, chemical engineers, and biomedical engineers—all of whom have been intrigued “by the idea of inventing something completely new with novel scientific approaches for the benefit of humanity.” Rosenweig says, “ We all want to help people and combining our diverse scientific expertise and enthusiasm for a healthcare solution is a perfect fit.” In the future, the team plans on testing their artificial retinas with additional collaborators—scientists at the UC Irvine Gavin Herbert Eye Institute who specialize in retinal diseases and surgery.