Eyes and Ears 3D-Printed From Flesh Could Boost Our Senses
Electronics often don’t mesh well with flesh and blood. Cochlear implants can irritate the scalp; pacemaker wires dislodge; VR headsets weigh heavily on the face. That’s why, for the past six years, Michael McAlpine has been Frankensteining alternatives. A mechanical engineer at the University of Minnesota, he creates prototypes of bionic body parts with nice, soft components—some of them alive.
The key to his electro-organic organs is his custom-made 3D printer, which McAlpine loads with silicones, metals, and human cells sourced from the university’s med school. (They come in a gel-like culture so they stay happy and functional, he says, while they’re handled.) His 3D-printed “ear,” made by enveloping a coil antenna in living matter, requires electrically conductive silver nanoparticles and cartilage-forming cells, while his “spinal cord” calls for neuron-forming cells and a translucent column of silicone. Whatever the desired organ, the computer-guided nozzles take up to an hour to extrude McAlpine’s goopy primordial ingredients into a mold. The result is then given a few weeks to rest in a nutrient-packed bath, which allows the cells to grow around and within any core electronics.
Professor McApline holding a model hand which has an electronic circuit 3D printed directly on it. This is a representation of the lab's ability to 3D print electronics directly on the body (on real skin, on a real hand).
One of Professor McAlphine's custom built 3D printers, which he uses to 3D print materials beyond the hard plastics that most commercial printers print. The printer seen here has been used to print biological materials (such as cells), electronic materials and devices, and soft materials like the silicone in the organ model.
A 3D printed prostate model (organ model) which is patient specific, in the sense that the lab used real patient MRI data to acquire the shape of the model, and then 3D printed a soft (silicone) model which feels like the tissue itself.
The lab's 3D printed bionic eye, which was made by 3D printing electronic devices (photodiodes) on the interior of a glass hemisphere.
Before they’re human-ready, though, these replacement bits first need to work well in rats and other animals, McAlpine says. While tests show that his imitation ear can successfully perceive music—a recording of “Für Elise”—he has yet to connect the prosthetic’s radio receivers to a living thing’s nervous system. Same goes for his latest creation, an eye filled with a web of photodetectors that can translate light into electrical signals—a first step to artificial vision.
Other researchers are excited by recent advances in lab-grown human organs, but McAlpine doesn’t think that should be the only goal. “I don’t know that you necessarily need to replace biology with more biology,” he says. He imagines enhancing his body parts with extrasensory capabilities, pointing to the medical tech company Second Sight, which thinks its retinal implant might one day allow blind people to see infrared wavelengths most of us can’t. “You could give impaired people superhuman abilities,” he says. “In the future, you’ll give the average person these abilities as well.” In McAlpine’s worst sci-fi nightmares, robots will be stronger and smarter than humans—so let’s start building bio-augmented cyborg defenders now.