John Rogers has a patch on his forearm about the size of a quarter. It’s reminiscent of a child’s temporary tattoo meant to look like a miniature sand dollar. But Rogers, an engineer at the University of Illinois at Urbana-Champaign, is actually wearing an electronic device “that allows wireless data transmission and storage – about 100 kilobytes, for things like passwords and medical identifiers,” he says.
Rogers and his team are pioneering flexible wearable electronics, designed to continuously collect and transmit data from the human body. They have teamed up with cosmetic company L’Oreal USA to help researchers and consumers better understand human skin.
For L’Oreal, wearable sensors are the key to learning about what makes skin healthy and beautiful. The devices can measure minute changes in skin’s temperature caused by changes in blood flow, without changing the conditions of the skin itself. More blood flow in the skin can mean that it’s healthy, Rogers says, but can also indicate inflammation, so patients can track their relative measurements over time to keep their skin healthy for longer.
The devices can also measure skin hydration—a big goal for a company that specializes in making penetrating lotions and lightweight moisturizers. “These devices help researchers look at efficacies of lotions, giving them the ability to make long-lasting improvements in how they hydrate the skin,” Rogers says.
Flexible electronics already being used in R&D
L’Oreal has developed a partnership with Rogers’ lab–while the University of Illinois technically owns the products, the team from L’Oreal has brought their extensive expertise in skin health and appearance (the university and L’Oreal are working on filing joint patents for the sensors they have developed). But L’Oreal is already using these devices in its research and development for new products, Rogers says. The next step is to bring the electronics directly to consumers who want to add some science to their beauty routine. “You could imagine because the devices are so low in cost, [L’Oreal] might sell them together with a cosmetic product or lotion,” Rogers says. “The consumer could use the device to determine hydration state of their skin as well as which type and how much lotion to apply to achieve a desired hydration state.”
“Flexible electronics will allow consumers to integrate the wearable on any part of their body, without feeling anything,” says Guive Balooch, the vice president of L’Oreal’s Technology Incubator, with whom Rogers is collaborating. The circuits are made from narrow strands of metallic conductors like gold, interwoven with and embedded in “nanoribbons” of silicon. The thin, breathable devices can be worn for weeks on end, even in the shower, Rogers says. And all the data that the devices collect can be sent via Bluetooth to a computer or smart phone, provided that it’s close enough.
Since L’Oreal is most interested in measurements and characteristics of the skin, flexible electronics offer a unique way to collect data. Rigid electronics can’t gather information continuously because they can’t stretch and deform to move with the skin. But the flexible electronics have the same mechanical properties as skin, expanding and twisting with it for continuous contact and monitoring.
But to get the average person to buy them or wear them in a visible location on the body, the devices also have to be attractive, says Balooch. Rogers has experimented with putting a design over the circuitry to make its look like a temporary tattoo. Consumers could place these on various parts of the body to monitor environmental exposure to pollution or UV rays from the sun, collecting that data over time to coach them towards habits that are better for their skin. These devices would probably would be too conspicuous to wear on the face, however, so consumers could also use them at home to get a quick measurement of the skin on the face during their typical beauty routine then remove them before going outside. L’Oreal won’t say exactly when they’re planning to start selling these devices, but it may be as soon as the next year.
The patch on Rogers’ arm.
With devices that can continuously take so many precise measurements, Rogers naturally wants to take them beyond cosmetics, and apply them to a medical setting. “With these devices, you should be able to take full vital sign measurements continuously. Just a patch on your wrist could measure everything you might be interested in—blood pressure, blood oxygenation, heart rate, respiration rate, echocardiogram characterization, even brain waves,” Rogers says. “You could take all the large-scale clinical equipment in a hospital and collapse it all down into skin-like patches,” he says, which would enable doctors to continuously monitor patients even after they are discharged from the hospital. These innovations are happening simultaneously with the skincare applications, he says.
The fact that the sensors don’t use wires could also be a big boon in a hospital setting, allowing doctors to monitor vitals in delicate areas of the body even on the elderly or premature infants without wires’ added weight and pull. “Premature babies require a lot of monitoring, but their skin is fragile and their musculature is not well developed. The tape and wires currently used in the NICU is quite frightening,” Rogers says. “We want to get rid of all that hardware and replace is with patches in different parts of the body and provide continuous data in the ICU setting, where you don’t need long-range data transmission.” Rogers hopes to start testing the devices in a children’s hospital this summer.
A wireless way to take an echocardiogram to monitor the heart.
Though most of his efforts have been directed at a clinical setting, Rogers predicts that flexible electronics could also be used as a new way for humans to interface with machines. His team has shown that devices like these could allow users to control a video game or drone with gestures. They could also be used in fashion—“ You could embed the device with LEDs that light up in some responsive manner, either as a way to convey an emotional state or as an indicator with wireless communication link,” Rogers says. These projects aren’t in development, he adds, but a company that wanted to start selling devices like these could probably do so in just a few years.
Further in the future, the devices could be a new, non-invasive way for machines to interact with the brain. Neuroscientists could replace the wire-covered caps used for electroencephalograms (EEGs) with tiny, high-density electronics that would allow them to see deep within the brain without radiation or a single incision. From there, the devices could go beyond just measuring brain waves—they could start manipulating them. “The question is what do you do when you could put a million transistors on the forehead? There are certainly interesting things that could come from that, but no one has thought through it carefully yet because it simply hasn’t been possible,” Rogers says.
