Cool Jobs: Making electronics to wear
UNIVERSITY OF ILLINOIS
This is one in a series on careers in science, technology, engineering and mathematics made possible with generous support from Alcoa Foundation.
Could keeping track of your health be as easy as wearing a temporary tattoo? Materials scientist John Rogers thinks so.
In his lab at the University of Illinois at Champaign-Urbana, Rogers and his team design electronic devices unlike anything in an Apple store. Their inventions hardly look like electronics at all. Most electronics are boxy, fragile things that have to be handled with care. For a tablet or a cell phone, a minor accident, like spilling water, can quickly turn catastrophic.
But the inventions from Rogers’ lab are more like high-tech stickers. These adhesive patches, crisscrossed with miniature wires, stick to the skin for weeks at a time. They can survive the wear and tear of life. Already, the scientists have programmed the devices to take a wide variety of measurements. These include temperature, blood pressure and skin moisture levels (or hydration). Rogers says he wants his sensors to look more like parts of living organisms and less like traditional computers.
“We’re driving the technology by thinking outside the box,” he says.
Stretchy, wearable electronics interest researchers from a variety of fields. Rogers is a materials scientist, which means he looks for smart ways to use, understand and even create the materials used to build things.
Developing these devices is appealing, says Rogers, because it has the potential to improve health care. Instead of trudging to the clinic or hospital for every checkup, a patient might be able to download data from a stick-on device and send it to the hospital. This technology offers the potential for more measurements and fewer trips to the doctor.
Here, Rogers and two other researchers who work on stretchy electronics describe these skin-like devices — as well as what their future may hold.
How to harvest energy from the body
As a young girl growing up in Turkey, Canan Dagdeviren received a book about the scientist Marie Curie from her father. Curie was the first woman to win a Nobel prize, one of the highest honors given to a scientist. (Curie actually won two.)
“I think my dad was thinking I would get inspiration from her,” recalls Dagdeviren, who does research on wearable electronics at Harvard University and MIT, both in Cambridge, Mass. “But when I read the book, I fell in love with her husband because he discovered the piezoelectric effect.”
A childhood infatuation with Pierre Curie led Canan Dagdeviren to become interested in the piezoelectric effect. The French physicist had shared its discovery with his brother Jacques Curie.
In the late 19th century, French scientist Pierre Curie and his brother Jacques showed that some crystals generate sparks when they’re under pressure. Sparks mean electricity. So piezoelectric crystals turn mechanical energy, which comes from motion, into electricity. Scientists have looked to piezoelectric materials in recent years as a potential power source for wearable electronics.
Dagdeviren suspects piezoelectric materials could capture energy from movement in the human body. Even at rest, the body is constantly in motion. Lungs expand and contract as you breathe. The heart beats. Blood streams through your veins and arteries. All of these are examples of mechanical energy, or the energy associated with motion, location or both.
As a graduate student, Dagdeviren studied with John Rogers in Illinois. She designed devices that could be used inside the body. Her inventions converted the movements of the lungs, heart and diaphragm into electricity. This technology might one day provide power to devices like pacemakers, which help the heart keep up a steady rhythm. Right now, pacemakers need batteries that have to be replaced every five to 10 years. Dagdeviren’s system wouldn’t need batteries.
“You can generate power, and use this power to run your personal electronics,” she says.
Dagdeviren was inspired to create the devices after learning that her grandfather died from heart failure. He had been only 28 years old. “I promised to do something to work on that,” she says. “Scientists are usually inspired by nature. However, my research is inspired by the diseases of my family members.”
Can a beating heart supply energy to a device in the body? This thin device, created by Canan Dagdeviren, is a first step toward making that a reality.
Three years ago, her aunt died of a brain tumor. Now, Dagdeviren is building a sensor that can be implanted in the brain to detect — and perhaps even fix — problems with cells there.
“I remember how much I loved my aunt and the great time we spent together. I don’t want any other people to experience those kinds of moments.”
Wearable, flexible electronics could make it possible to constantly monitor the body. Usually, we take measurements like temperature or blood pressure at a single moment in time. But that snapshot may not tell the whole story. If a person is wearing a sensor, a doctor can study a stream of data and look for patterns.
“Our organs and our bodies speak to us,” Dagdeviren says. “I use my devices to understand what they’re saying.”
Watching the sun
Madhu Bhaskaran works at RMIT University in Melbourne, Australia. Her projects are also advancing the next generation of flexible electronics. In recent years, she and her colleagues have developed new ways to add gizmos that conduct electricity to stretchy materials. They’ve been studying different kinds of oxide materials, which get their name from the fact that they contain oxygen.
Too much fun in the sun can be a bad thing. Scientists are working on sensors to tell sunbathers when their sun exposures are reaching worrisome levels.
ZEROONE / FLICKR (CC BY-SA 2.0)
“All electronic devices rely on oxide materials,” she notes. Silicon dioxide is one example. In nature, this material is found as sand. Scientists can create large crystals of silicon dioxide, called quartz. Thin slivers of quartz are often used in tiny electronic devices. Recently, a team in Bhaskaran’s lab, led by scientist Philipp Gutruf, found a way to transfer those slices of crystal to flexible materials. Their process resulted in a skin-like, flexible device using zinc oxide that could save lives.
This wearable, stretchy device detects danger at the skin. It picks up the chemical signal of toxic gases. It also measures ultraviolet (UV) radiation, invisible energy that damages the skin and can cause skin cancer. The sun produces UV radiation, so people who spend a lot of time outdoors should pay close attention to protecting their skin. The device can help people avoid dangerous levels of UV radiation.
The sensor’s design allows it to bend and flex as a person moves. Bhaskaran says their device can bend thanks to “microtectonics.”
“Microtectonics behave just like tectonic plates that make up the earth’s crust,” she says. “They can slide over each other when stretched. This type of surface allows the device to stretch and bend while still functioning.” That means it can be stuck directly to the skin with an adhesive, or stitched onto clothes.
Madhu Bhaskaran holds a flexible electronic device that can be worn on the skin and track harmful UV rays.
Companies have talked to the scientists about selling the device, but Bhaskaran says consumers won’t see it in stores for at least five years. She says she’s excited to see what other new stretchy electronics emerge during that time.
“Scientists expect to transform today’s science fiction into tomorrow’s reality,” she says.
Beyond skin deep
John Rogers, in Illinois, has been studying and developing stretchy electronics for more than 15 years. But this summer, he broke a record. And he did it while on vacation in Florida. He had been wearing one of his devices on his arm, stuck on like a patch. He wasn’t measuring anything in particular, but he did make sure it could send signals to his cell phone. Rogers’ goal was to see how long it would remain stuck to his arm.
Finally, after a swim in the ocean, the device lost its stickiness like an old Band-Aid. It had been on for four weeks. No one in his lab had ever worn one of the gadgets for such a long time.
“I wear them all the time,” says Rogers. “I think most of the students like to wear them. If you do this kind stuff, you have to get into it. There’s nothing that beats your own experience.”
After the device came off, he noticed changes in his skin. “You could feel with your fingers where it had had been. It was noticeably rougher than the surrounding skin.” At first, he worried that he’d had some type of bad reaction. Then, he realized that the rough patch was where dead skin cells had built up. He removed them with a piece of Scotch tape.
This tiny device is worn inside the brain. It has been designed to track pressure and temperature inside the brains of people with traumatic brain injuries.
JOHN ROGERS, UNIVERSITY OF ILLINOIS
“Experiencing that for yourself is an important part of the engineering process,” he says.
Right now, his skin sensors are able to make a wide variety of measurements. They can measure temperature, skin stiffness, hydration, and other qualities. But he’s not content to stop there.
“How do you go beyond that?” he asks. You just push the field forward.
He and his team are now creating skin-like devices to sample fluids like sweat or blood for medical tests. They’re also designing stretchy devices that dissolve over time. He and his team unveiled one of those in mid-January. They designed a device that measures pressure and temperature inside the human brain for peoplewho have suffered a traumatic brain injury. Once it has done its job, the sensor dissolves in cerebrospinal fluid.
Doctors might use other, similar devices inside the body to monitor how a transplanted organ responds to a new host, for example. Environmental scientists might use them to track the changes in a sensitive ecosystem.
Earlier this year, Rogers and his team developed wearable devices for hard surfaces, like fingernails or teeth. These gadgets could collect health data, he says. But they can also send and receive wireless signals, like cell phones. Some smartphones can even be used to make payments like a credit card, simply by swiping them across a sensor. So imagine this: One day, instead of using a card or cash, you might pay using a small chip mounted onto your teeth. No more swiping a card; you’d only have to smile.
Rogers says the scientists in his lab are people eager to use science to solve problems.
“They’re inspired by the implications of science around new technology,” he says. “Filling up journals with new science is great. But if it never goes beyond that, it’s not very satisfying. I think it’s important to get things out into the real world.”