Merging electronics with human tissue, scientists have used 3D printing tools to build a functioning ear.
Researchers at Princeton University reported that they created a functioning ear that that can "hear" radio frequencies beyond the range of normal human capability.
Using an off-the-shelf 3D printer, they printed both calf cells and silver nanoparticles, along with a cell culture, to merge a small antenna with cartilage -- essentially creating a bionic ear.
Princeton scientists used 3D printing to create a "bionic ear" made up of a coil antenna and cartilage. (Image: Frank Wojciechowski)
To create the antenna, the 3D printer built a matrix of hydrogel and calf cells with the nanoparticles. The calf cells later develop into cartilage.
"The design and implementation of bionic organs and devices that enhance human capabilities, known as cybernetics, has been an area of increasing scientific interest," the researchers wrote. "This field has the potential to generate customized replacement parts for the human body, or even create organs containing capabilities beyond what human biology ordinarily provides."
Two wires, the university noted, lead from the base of the ear, wind around the part that senses sound and connects to electrodes. Electrical signals produced by the ear could be connected to a person's nerve endings, much like a hearing aid, researchers added.
The ear, though now in early stages, could someday be used to restore or enhance human hearing.
According to Princeton, this is the researchers' first attempt at creating a fully functioning organ. And they took it one step further by extending the organ's capabilities beyond natural human abilities.
One of the reasons Princeton's researchers focused their efforts on building a functioning ear is because ear reconstruction is one of the most difficult problems in the areas of plastic and reconstructive surgery, the university said.
To take on the challenge, researchers used 3D printing, which is a high-tech manufacturing process that creates objects by laying down successive layers.
In this case, the 3D printer laid down layers of both plastics and cells to build the ear.
"In general, there are mechanical and thermal challenges with interfacing electronic materials with biological materials," said Michael McAlpine, an assistant professor of mechanical and aerospace engineering at Princeton University and the project's lead researcher. "Previously, researchers have suggested some strategies to tailor the electronics so that this merger is less awkward. Our work suggests a new approach -- to build and grow the biology up with the electronics synergistically and in a 3D interwoven format."
Manu Mannoor, a graduate student working on the project, said 3D printing opens up a whole new way to think about integrating technology with biology.
For instance, he said it may be possible to fix a patient's torn knee meniscus with a bionic replacement, which would use sensors to monitor strain on the new cartilage to hopefully prevent a future tear.