Using 3D printing technology, scientists from the University of Minnesota have created an array of photoreceptors on a hemispherical substrate. In the future, the technology will make it possible to create bionic eyes using 3D printing and return vision to completely blind people. In the future, bionic eyes, the researchers believe, will functionally be no different from real ones. And in some cases, perhaps, surpass the latter.
The living eye perceives light thanks to photoreceptor neurons located on the retina, which convert visible light into an electrical signal. In the model created on a 3D printer by scientists from the University of Minnesota, semiconductor diodes play the role of photoreceptor neurons.
In recent years, engineers have been actively exploring the possibility of creating bionic eyes. Some prototypes created in the past have been successfully tested in humans, but the manufacture of such prostheses is very expensive, since each device has to be assembled literally by hand. In the future, 3D printing technologies can significantly reduce the cost and simplify the process of creating such implants, making them available to a wider range of people in need.
In practice, it is very difficult to arrange a series of photoreceptor diodes on a curved surface. To solve the problem, scientists from Minnesota have created a 3D printer. Before printing, scientists applied a layer of silver nanoparticles to the inner surface of a glass hemisphere using a printer, and then on it, layer by layer, they increased the structure of a photoreceptor from semiconductor polymer ink developed by them. The whole process of creating the bionic eye took about 1.5 hours.
According to the head of the study, Michael McAlpin, the first prototype showed a 25 percent efficiency in converting visible light into electrical signals, which scientists believe is a very good result for the early stages of development.
“Our 3D-printed semiconductor photoreceptors are beginning to approach the efficiency of similar devices manufactured by existing industrial processes,” comments McAlpin.
“In addition, 3D printing allows semiconductor diodes to be deposited onto curved surfaces. Other technologies do not provide such an opportunity."
In the future, scientists plan to increase the number of artificial photoreceptors used. The more photoreceptors are used, the more efficiently the conversion of light into an electrical signal will be. McAlpin and his colleagues also want to improve the printing technology in order to be able to create semiconductor microdevices not on glass, but on a soft substrate, which in the future may become the basis for a future implant.
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Nikolay Khizhnyak