Imagine electronic medical devices, implanted to heal wounds and then dissipating inside the human body. Environmental sensors dispersed over an oil spill, collecting data before dissolving into the earth. Or clandestine listening devices, sending recorded conversations back to military operatives and then vanishing before they can be found.
In the near-future, these three scenarios could become reality. All courtesy of a military-backed venture into “Transient Electronics.” The idea, in essence, is to flip the hallmark elements of electronics technology — durability and long lifespans — in favor of devices that actually disappear within a set period of time.
The technology behind the project, a collaborative effort by researchers at Northwestern University, the University of Illinois Urbana-Champaign and Tufts University, is described in a paper published this week in the journal Science.
“Historically, the field of electronics has been spectacularly successful because of devices that were stable over time,” Dr. John Rogers, a professor of engineering at the University of Illinois at Urbana-Champaign, says. “We wondered whether asking the opposite question of electronics could have interesting results.”
Turns out, it did. With funding from the National Science Foundation and military research agency DARPA, the team used “an eclectic mix” of biocompatible materials — which vary depending on the application — combined with nano-layers of silicon and encapsulated in silk. Every single part of each device, from sensors to power sources, dissolves over a period of time. Depending on how the devices are constructed (namely, how thick each layer is) they can last for hours, days, months or even years.
“The electronics are designed to be stable and fully-functional during their lifetime,” Rogers says. “It’s the lifetime itself that sets them apart from the devices that are being used today.”
Already, the team has developed and tested several device prototypes. In one particularly nifty instance, they used a mouse model to demonstrate that an implanted medical device could accelerate wound healing and kill bacteria, then dissolve once the job was done.
“Either these devices would be digested by the body, or they would dissolve within it,” Dr. Yonggang Huang, a professor of mechanical engineering at Northwestern, says of the technology. “We used only metals that already exist in the body, so we’re confident they can dissolve without concerns about toxicity.”
The medical implications of such devices are myriad. Implantable electronics could monitor vital signs, deliver medications or track patient recovery. The devices would also circumvent many existing challenges that hamper implantable electronics, namely concerns over longterm effects inside the body, as well as painful or costly implant removal and replacement.
In an environmental or military context, the devices have the potential to save money and time — not to mention lives. “Imagine an oil spill, dropping 100,000 sensors that give realtime information on an area during clean-up,” Rogers says. “Collecting them would be almost impossible, so what if you just didn’t need to?” The same is true, of course, for sensors dropped into combat regions — particularly urban areas or buildings, where collecting the devices is dangerous and preventing their detection is tricky.
The prospects of transient electronics are so far-ranging, and so far-out, that even the researchers behind them haven’t yet grasped every possibility. “Admittedly, we might not be perceiving all the potential uses,” Rogers says. “We’re still asking new questions.”
For now, the team is refining the devices, and evaluating how they operate and dissipate at various temperatures, in different environmental conditions and at several pH levels. They’re also conducting additional animal studies on medical implants, with an eye on human trials in coming years.
And fickle consumer tech aficionados, take note: Rogers also imagines a day where conventional consumer electronics, like smartphones or laptops, might also be designed with transience in mind. “Disposing of these devices is a major waste problem,” he says. “But the reality is, most people don’t want to keep their phone for more than a few years.”
This will open new doors to “planned obsolescence!” I find it hard to get durable electronics and electrical appliances as it is (such is the disposable nature of Chinese-manufactured products available at your local discount store). Imagine how this technology could be made available to industry to sure the electrical components in your car, refrigerator, HVAC unit, toaster, hair dryer, you name it, vaporizes, rendering them useless in a matter of years or after so many cycles/hours of use (after the warranty runs out, of course) making it too expensive to repair. The manufacturers can simply charge more money for items that will continue to operate after 2 years with the simple switch of a ‘chip.’ Wow, the possibilities are endless!