For the first time, scientists at the University of Minnesota have fully 3D printed an array of light receptors on a hemispherical surface. This discovery marks a major step toward developing a “bionic eye” that could one day help visually impaired people see or sighted people to have better vision.
The study has been published in Advanced Materials, a peer-reviewed scientific journal covering materials science on August 28th. The author also owns the patent for 3D-printed semiconducting devices.
“Bionic eyes are usually thought of as science fiction, but now we are closer than ever using a multimaterial 3D printer,” said Michael McAlpine, a co-author of the research and University of Minnesota Benjamin Mayhugh Associate Professor of Mechanical Engineering.
Scientists began with a hemispherical glass dome to demonstrate how they could surpass the challenge of printing electronics on a curved surface. Using their customized 3D printer, they started with a base ink of silver particles. The dispensed ink remained in place and dried evenly rather than running down the curved surface. The team then employed semiconducting polymer materials to print photodiodes, which change light into electricity. The whole process was completed in about an hour.
McAlpine said the most astonishing part of the process was the 25% efficiency in transforming the light into electricity they attained with the fully 3D-printed semiconductors.
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.
Michael McAlpine, Co-Author
McAlpine and his team are known for combining 3D printing, biology, and electronics on a single platform. They received global attention some years ago for printing a “bionic ear.” Since then, they have 3D printed life-like artificial organs for surgical practice, electronics directly on a moving hand, electronic fabric that could serve as “bionic skin,” and cells and scaffolds that could help people dealing with spinal cord injuries recover some function.
McAlpine’s interest to develop a bionic eye is slightly more personal.
“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?’” McAlpine said.
McAlpine says the following steps are to develop a prototype with more light receptors that are even more efficient. They also are keen to find a technique to print on a soft hemispherical material that can be implanted into a real eye.
McAlpine’s research team includes University of Minnesota mechanical engineering graduate student Ruitao Su, postdoctoral researchers Sung Hyun Park, Shuang-Zhuang Guo, Kaiyan Qui, Daeha Joung, Fanben Meng, and undergraduate student Jaewoo Jeong.
The study was sponsored by the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health (Award No. 1DP2EB020537), The Boeing Company, and the Minnesota Discovery, Research, and InnoVation Economy (MnDRIVE) Initiative through the State of Minnesota.
3D-printed prototype for bionic eye