For the first time ever, scientists have 3D-printed an array of light sensors onto an eyeball-shaped surface. Eventually, a scaled-up version of the device could restore vision to the blind, or even improve the vision of sighted people.
New research published this week in Advanced Materials describes the device. Researchers at the University of Minnesota 3D-printed a light-sensitive array, comprised of silver particles and semiconducting materials, onto a domed surface made of glass. The printed material managed to cling to the rounded surface and convert light into electricity.
Though the device looks like an eyeball, it’s nowhere near the stage where it could be transplanted and made to work like a functional eye. Rather, it’s a proof-of-concept that paves a path forward as scientists work to develop a bonafide bionic eye.
To make it, a research team led by Michael McAlpine started with a hemispherical glass dome similar in shape and size to a human eyeball. Using a custom, multi-material 3D-printer, the team laid down a base, or scaffold, comprised of silver particles. Next, the researchers used semiconducting polymers to print photodiodes capable of converting light into an electrical current. The manufacturing process took about an hour.
The video here shows how they did it.
In tests, the researchers were able to achieve 25 per cent efficiency in converting light into electricity using 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,” said McAlpine in a statement. “Plus, we can easily print a semiconducting device on a curved surface, and they can’t.”
From here, the team would like to create a prototype in which the light receptors work with even greater efficiency. The researchers are also hoping to find a way to print on a soft round material, rather than glass, that can be implanted into a natural eye.
There’s still plenty of work to be done. The ability to print photosensitive arrays onto a rounded surface is hugely important, as it’s an approximation to how a natural eye actually works, converting incoming light into an electrical current that the brain’s visual cortex can understand.
Looking ahead, scientists will have to find a way to connect such a device to the brain, and “teach” it to process visual stimuli. That will likely take some time.
A device such as this could one day help the blind to see (after some extensive training), but it could also potentially enable some more transhumanistic applications, such as giving sighted people the ability to see with even greater clarity, or see light in different spectrums, such as infrared or ultraviolet light.
But we’re getting a bit ahead of ourselves. For now, let’s celebrate this latest achievement.