For John Rogers, the inspi­ra­tion to develop ground-​​breaking stretch­able cir­cuits that are com­pat­ible with human tissue came from an unlikely source.

A kid’s tem­po­rary tattoo was a great model,” said Rogers, a mate­rials sci­en­tist and former MacArthur Foun­da­tion “genius” grant recip­ient. Tem­po­rary tat­toos con­form to human skin without any neg­a­tive impli­ca­tions. Once applied, people forget they’re even there and they even­tu­ally wash off without a trace. If he could make an elec­tronic device that worked the same way, he real­ized, it could open up a world of opportunities.

Rogers noted that over the past sev­eral decades, the devices pro­duced by the elec­tronics industry con­tinue to get smaller, faster, and cheaper. How­ever, they’ve also remained rigid, rec­tan­gular, and everlasting—features that aren’t com­pat­ible with the nat­ural processes of the human body.

Unless you change the form factor, you’re lim­ited because devices are mis­matched to the char­ac­ter­is­tics of human skin,” Rogers said.

Rogers’ stretchy, flex­ible cir­cuits have much in common with tem­po­rary tat­toos. Photo cour­tesy of MC10.

Rogers, a pro­fessor at the Uni­ver­sity of Illi­nois, Urbana-​​Champaign, described his pio­neering research Thursday after­noon to a packed audi­ence at Raytheon Amphithe­ater. His talk marked the eighth install­ment in North­eastern University’s Pro­files in Inno­va­tion Pres­i­den­tial Speakers Series. North­eastern Uni­ver­sity Pres­i­dent Joseph E. Aoun hosts the series, which is designed to bring the world’s most cre­ative minds to campus for con­ver­sa­tions on inno­va­tion and entre­pre­neur­ship. Pre­vious speakers include cell biol­o­gist Jeanne Lawrence, Aereo CEO Chet Kanojia, and IBM Watson cre­ator David Fer­rucci.

Rogers said that he’s impressed with Northeastern’s co-​​op pro­gram, adding that he’s seen the value first­hand since he’s employed North­eastern co-​​op stu­dents at his com­pa­nies, which include Cambridge-​​based MC10 and the former Natick-​​based Active Impulse Sys­tems. “Both of those com­pa­nies have ben­e­fitted tremen­dously from co-​​ops from North­eastern,” he said. “Our expe­ri­ence is that the stu­dents are really tal­ented (and) high energy.”

Aoun noted that Rogers’ approach is moti­vated by both tra­di­tional mea­sures of aca­d­emic suc­cess as well as a use-​​inspired drive to solve the world’s grand challenges—which happen to align with the university’s mis­sion. “We quan­tify suc­cess not only by the pub­li­ca­tions and the cita­tions but also by the impact,” Aoun said.

For his part, Rogers’ devices are cer­tainly making an impact.

Sil­icon is the pre­dom­i­nant mate­rial in today’s stan­dard elec­tronic devices, and it’s typ­i­cally con­sid­ered about as rigid and immove­able as any solid avail­able. How­ever, that’s only because the sil­icon wafers the industry is using are so thick, Rogers explained. Make them thinner—roughly one-​​tenth the width of a human hair—and silicon’s prop­er­ties begin to change rather rad­i­cally, he said.

First off, it becomes extremely flex­ible. Indeed, a one-​​micron-​​thick wafer of sil­icon col­lapses under its own weight, Rogers said. While it still isn’t itself inher­ently stretchy, it can be applied onto a stretched-​​out rubber sub­strate, which when relaxed gives the sil­icon some­thing of an accor­dion effect.

Second, thin sil­icon wafers can be dis­solved in water and broken down into a bio­com­pat­ible mate­rial. “If the sil­icon is thin enough, then reac­tions that you would ordi­narily ignore become impor­tant,” he said. While a thick chunk of sil­icon may take 1,000 years to decom­pose, Rogers’ 35-​​nanometer-​​thick devices do so in less than a couple of weeks–a fea­ture that has obvious impli­ca­tions for both the envi­ron­ment and bio­com­pat­ible devices.

Using this plat­form, Rogers and his team are devel­oping a range of devices with appli­ca­tions in the health­care, sports, gaming, and even energy indus­tries. His team has used them to fly a minia­ture heli­copter, play video games, and col­lect mechan­ical and cardio-​​electric data from the body.

So, how exactly do you power these wear­able devices? That was one ques­tion asked during a Q-​​and-​​A fol­lowing Rogers’ talk. In response, he admitted this is per­haps one of the most pressing chal­lenges cur­rently facing his lab. Three options have so far emerged: micro-​​distributed bat­teries, in which pieces of the bat­tery are spread around a sur­face; har­vesting the body’s nat­ural mechan­ical energy; and wire­less power coming from our smart­phones and other mobile devices.

Sev­eral ques­tions came in from those fol­lowing the event via social media, one being whether Rogers’ cir­cuits will help advance evidence-​​based research on wear­able health­care devices.

We think we have a device plat­form that will allow you to col­lect clinical-​​quality data that’s mul­ti­modal in terms of the mea­suring capabilities—continuously,” Rogers answered. “It opens up a whole set of new oppor­tu­ni­ties. You’re going to have a tremen­dous amount of data.” Over time, he added, the utility of all that data will only increase in terms of how health­care workers will be able to inte­grate it into clin­ical solutions.

After the discussion, Rogers, left, spoke with students like Shashank Dotia, center, DMSB'16, during a reception. Photo by Brooks Canaday.

After the dis­cus­sion, Rogers, left, spoke with stu­dents like Shashank Dotia, center, DMSB’16, during a recep­tion. Photo by Brooks Canaday.