Scientists at Princeton University used off-the-shelf printing tools to create a functional ear that can "hear" radio frequencies far beyond the range of normal human capability.
The researchers' primary purpose was to explore an efficient and versatile means to merge electronics with tissue. The scientists used 3D printing of cells and nanoparticles followed by cell culture to combine a small coil antenna with cartilage, creating what they term a bionic ear.
"In general, there are mechanical and thermal challenges with interfacing electronic materials with biological materials," said Michael McAlpine, the lead researcher. "Previously, researchers have suggested some strategies to tailor the electronics so that this merger is less awkward. That typically happens between a 2D sheet of electronics and a surface of the tissue. However, our work suggests a new approach - to build and grow the biology up with the electronics synergistically and in a 3D interwoven format."
McAlpine's team has made several advances in recent years involving the use of small-scale medical sensors and antenna. Last year, a research effort led by McAlpine, Naveen Verma and Fio Omenetto of Tufts University, resulted in the development of a "tattoo" made up of a biological sensor and antenna that can be affixed to the surface of a tooth.
This project, however, is the team's first effort to create a fully functional organ: one that not only replicates a human ability, but extends it using embedded electronics. "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 said. "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."
Standard tissue engineering involves seeding types of cells, such as those that form ear cartilage, onto a scaffold of a polymer material called a hydrogel. However, the researchers said that this technique has problems replicating complicated three dimensional biological structures. Ear reconstruction "remains one of the most difficult problems in the field of plastic and reconstructive surgery," they said.
To solve the problem, the team turned to a manufacturing approach called 3D printing. These printers use computer-assisted design to conceive of objects as arrays of thin slices. The printer then deposits layers of a variety of materials – ranging from plastic to cells – to build up a finished product. Proponents say additive manufacturing promises to revolutionize home industries by allowing small teams or individuals to create work that could previously only be done by factories.
Creating organs using 3D printers is a recent advance; several groups have reported using the technology for this purpose in the past few months. But this is the first time that researchers have demonstrated that 3D printing is a convenient strategy to interweave tissue with electronics.
The technique allowed the researchers to combine the antenna electronics with tissue within the highly complex topology of a human ear. The researchers used an ordinary 3D printer to combine a matrix of hydrogel and calf cells with silver nanoparticles that form an antenna. The calf cells later develop into cartilage.
COMPAMED.de; Source: Princeton University