The first-of-its-kind prototype for a “bionic eye” has been fully 3D printed by researchers at the University of Minnesota. The bionic eye was made by 3D printed an image sensing array of light receptors onto a glass hemisphere. This discovery could someday help blind people see or sighted people see better. It is a significant step towards making bionic eyes a reality.
The research was published in Advanced Materials, a peer-reviewed scientific journal covering materials science. Michael McAlpine, a co-author of the study and University of Minnesota Benjamin Mayhugh Associate Professor of Mechanical Engineering said:
“Bionic eyes are usually thought of as science fiction, but now we are closer than ever using a multimaterial 3D printer. “We have a long way to go to routinely print active electronics reliably, but our 3D-printed semiconductors are now starting to show that they could potentially rival the efficiency of semiconducting devices fabricated in microfabrication facilities. Plus, we can easily print a semiconducting device on a curved surface, and they can’t.”
How They Did It:
- To show how they could overcome the challenge of printing electronics on a curved surface they started with a hemispherical glass dome. The usual complications that arise when printing on a curved surface are that the material (ink) tends to drip down the curved surface, pulled by gravity.
- With their custom-built 3D printer they began with a base ink of silver particles. The dispensed ink stayed in place and dried uniformly. When they saw this had worked as the particles had not run down the curved surface, they proceeded to print the second layer.
- Next, they used semiconducting polymer materials to print photodiodes – which convert light into electricity.
The entire process from start to finish takes about an hour. The final product had a surprising 25 percent efficiency in converting the light into electricity they achieved with the fully 3D-printed semiconductors said McAlpine.
McAlpine and his team are not new to the world of medical 3D printing. They are well-known for integrating 3D printing, electronics, and biology on a single platform. A few years ago they received international attention for printing a “bionic ear.” In the time between the bionic ear and the bionic eye, they have 3D printed life-like artificial organs for surgical practice, electronic fabric that could serve as “bionic skin,” electronics directly on a moving hand, and cells and scaffolds that could help people living with spinal cord injuries regain some function.
McAlpine’s admits that his drive to create a bionic eye is a little more personal than everything else. He said, “My mother is blind in one eye, and whenever I talk about my work, she says, ‘When are you going to print me a bionic eye?'”
The teams next goals are to create a prototype with more light receptors that are even more efficient. They will also find a way to print on a soft hemispherical material that can be implanted into a real eye.