Electronic tattoos and bandages embedded with biosensors are becoming a reality thanks to electrical engineers at Duke University.
They developed a print-in-place technique for electronics that can work on delicate surfaces such as human skin and paper.
Researchers prove fully printed electronics can be done
The technology could be used someday to embed electronic tattoos in people or create bandages that have embedded biosensors that are specific to what a patient needs. The engineers published their work in journal Nanoscale in July and journal ACS Nano 3 October.
“Over the years there have been a slew of research papers promising these kinds of ‘fully printed electronics,’ but the reality is that the process actually involves taking the sample out multiple times to bake it, wash it or spin-coat materials onto it,” Aaron Franklin, the James L. and Elizabeth M. Vincent Associate Professor of Electrical and Computer Engineering at Duke said in a press release highlighting the results of the work. “Ours is the first where the reality matches the public perception.”
Electronic tattoos have come a long way
The idea of electronic tattoos has been around since the late 2000's when John A. Rogers, then a professor at the University of Illinois created electronic tattoos that sit on the skin and are thin, flexible patches that contain the electronics. It sticks to the skin like a temporary tattoo. They are currently being commercialized and manufactured on a large scale, but they don't work in every instance.
“For direct or additive printing to ever really be useful, you’re going to need to be able to print the entirety of whatever you’re printing in one step,” said Franklin in the press release. “Some of the more exotic applications include intimately connected electronic tattoos that could be used for biological tagging or unique detection mechanisms, rapid prototyping for on-the-fly custom electronics, and paper-based diagnostics that could be integrated readily into customized bandages.”
Engineers rely on an ink containing silver nanowires
In the first phase of their work, which was published in July, the engineers developed an ink containing silver nanowires that can be printed on any substrate using an aerosol printer. The ink dries in under two minutes but retains its electrical performance. That's even after faced with a 50% bending strain over a thousand times. In the second phase, the engineers combine that with two other components that can be printed to create the transistors.
"Think about creating bespoke bandages that contain electronics like biosensors, where a nurse could just walk over to a work station and punch in what features were needed for a specific patient," said Franklin. "This is the type of print-on-demand capability that could help drive that."