All eyes on the future: how 3D printing could turn fantasy real


Bionic eyes have long been regarded as exclusively existing in sci-fi books and movies, but now with the use of a multi-material 3D printer, these high-tech sight enhancers could be moving from the realm of fantasy to that of reality very soon.

The step toward the creation of functioning bionic eyes was taken with the successful 3D printing of prototype light receptors onto a curved surface.

This was one of the largest roadblocks to overcome, as printing electronics on a curved surface is a difficult feat. The process took about an hour and was done by using a hemispherical glass dome filled with a base ink of silver particles.

Silver particles were used because the silver stayed in place and dried uniformly instead of running down the curved surface of the glass.

The next step in the process was to use semiconducting polymer materials to print photodiodes, which convert light into energy. The prototype, which was successfully finished on Aug. 28, can successfully convert light at 25 percent efficiency.

There is still a long way to go to creating a prototype with light receptors that are more efficient, but this successful first step is a ray of hope for people with eye impairments.

Michael McAlpine, a co-author of the study and University of Minnesota Benjamin Mayhugh associate professor of mechanical engineering, said that his mother, who is blind in one eye, is always asking, “When are you going to print me a bionic eye?”

His mother’s blindness, caused during a surgery, is one of the driving forces behind the creation of the prototype.

McAlpine and his team are known for combining 3D printing, electronics and biology. In 2013, they gained international attention for printing a functioning bionic ear that could hear radio frequencies far beyond the normal human range.

In the time leading up to the prototype bionic eye, McAlpine and his team have 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,” according to a University of Minnesota research brief.

“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 can potentially rival the efficiency of semiconducting devices fabricated in microfabrication facilities,” McAlpine said.

At the core of all of McAlpine’s projects is the 3D printer. Back when the team printed its bionic ear, if the researchers hadn’t had the power of a 3D printer, they would have had to resort to standard tissue engineering, which involves seeding types of cells onto scaffolds of a polymer material called hydrogel. This technique is difficult and has problems when it comes to replicating complicated three-dimensional structures.

When using a 3D printer, the printer uses a computer assisted design to conceive objects as arrays of thin slices.

It then deposits layers of various materials from cells to plastic to build a finished product. The use of so many materials is what affords this style the title “multi-material 3D printing.”

According to a Princeton University article, “the process … promises to revolutionize home industries by allowing small teams or individuals to create work that could previously only be done by factories.”

So far, McAlpine has proven them right.

The research McAlpine and his team did for his prototype bionic eye was published on Aug. 28 in Advanced Materials, a peer-reviewed scientific journal.