Ever since the digital revolution swept the planet, things have been built to last. You want that television to keep showing Sunday football games for decades, that light bulb to keep shining on the hot pockets in your refrigerator until they expire (never?), and that cell phone to keep connecting you to Facebook, at least until the next slightly better model comes out.
But now, researchers from the University of Illinois, Northwestern University and Tufts University are turning that paradigm on its head. They’re building electronics built not just to fail, but to dissolve away completely in the presence of water.
The possibilities are endless. Medical implants – sensors or thermal therapeutic devices, for example – could simply vanish once they are no longer needed. Environmental sensors could be deployed without the need to retrieve them ever. Hell, cell phones could disintegrate away into thin air once the next model gets released.
Led by John Rogers, the Lee J. Flory-Founder professor of engineering at the University of Illinois, the interdisciplinary team turned to magnesium – a metal already present throughout the human body. By making circuits just 20 nanometers thick, Rogers and company created a circuit that will dissolve completely in the human body. And by wrapping it in differing thicknesses and compositions of silk – a material already used for sutures and other medical applications – the team discovered they could use the material as a sort of fuse.
While Rogers and his team at Illinois worked on engineering the transient electronics, Yonggang Huang from Northwestern’s engineering school developed a model that accurately predicts how long the silk will take to disintegrate. And at Tufts, Fiorenzo Omenetto conducted a series of tests as a proof of principle.
What tests, you may ask?
The collaborators developed a device that would heat up inside of a mouse in order to kill bacteria that might try to attack a healing wound. Think of it as an artificial, localized fever. A wireless power source fed the small device, which heated the area for about two weeks. After that time, there were fewer traces of infection and the device nearly had completely disappeared without a trace.
What’s more, these new technologies are being developed with materials already common throughout the industrial world. That means that once perfected, it should be a cinch to get manufacturers to tweak their factories in order to start pumping out whatever Rogers, Huang and Omenetto can dream up.