This is actually the second in a two-part series on the continuing future of wearable tech. Part one (read here) explores what future wearables can look like and what they’ll accomplish.
Aug. 23, 2022 Grab your smartphone. Yes, youve held it one thousand times, its as an extension of one’s hands. But lets do an experiment: Grab it by both ends and stretch it out so far as it’ll go. Now twist it. Wrap it around your forearm. Cool, right? Now allow it snap back.
Wait, what can you mean your phone wont bend and stretch?
That little exercise in imagination illustrates whats possible in the realm of wearables gadgets we wear near or on the skin we have. Today, smartwatches and phones remain hard, inflexible blocks of plastic and metal. Tomorrow, all that may change.
In wearables, flexibility, stretchability, and washability are key requirements, says Veena Misra, PhD, a professor of electrical engineering at NEW YORK State University and director of the ASSIST Center, a federally funded research institute that develops wearables to assist health.
We have been seeing these types of developments over the board, Misra says, and you could track that in the amount of [research] papers developing in wearables. That number is merely growing exponentially.
We have a tendency to think about wearables as fun consumer gadgets, but an evergrowing approach says they’ll drastically improve healthcare providing a car for continuous, long-term monitoring to predict adverse events and closely track disease, improving treatments and health outcomes worldwide.
For that to occur, wearables must work seamlessly with this bodies. Which means making conventionally hard, rigid devices and systems similar to human skin soft, bendable, and stretchable.
So how exactly does one manage that? By redesigning electronics at the molecular level, miniaturizing sensors, and creating unheard-of power sources to aid what engineers call a skin-like form factor.
To coin a phrase, it aint science fiction. Its happening these days, and the brand new products these advances will generate potentially starting in healthcare and crossing to the buyer wellness market could become as normal as that clunky, inflexible phone you cant deposit. Heres how.
HOW COME Form Factor Matter?
A wearable that conforms to the body is way better in two crucial ways: Its less obtrusive for an individual, and it permits a far more reliable measurement.
Sensors and sensor systems frequently have problems with mechanical mismatch, says Alper Bozkurt, PhD, a power engineer, and Misras colleague, at NC State and ASSIST. In case you have soft tissue thats active, but a rigid sensing device thats not active, your measurement might not be reliable.
Thats because all that extra banging around between your device as well as your body turns up as noise meaningless information that may distort the measurement and could result in false conclusions.
Then theres the human factor, Bozkurt notes the problem of compliance.
Among the challenges is, we design things in the lab, test everything, and take it to your medical operators, plus they raise their eyebrows and say, No, my patients will not wear this, Bozkurt says. You cannot imagine another for wearables without solving the compliance issue.
People want a tool thats comfortable, doesnt stand out, and requires little interaction, Bozkurt says. We call it wear-and-forget. You may compare this to wearing a Band-Aid sure, you see it occasionally, but mostly it fades in to the background, without interfering together with your daily tasks and without others even noticing its there.
A wristwatch might seem comfortable enough, but applications extend beyond just what a wristwatch can enable, notes Michael Daniele, PhD, a new member of the NC State / ASSIST team, who studies soft nanomaterials to engineer devices that monitor, mimic, or supplement body functions.
Wearable devices are increasingly being developed to greatly help patients and also treat them with techniques where the patient’s comfort is really a priority, he says.
Take the usage of electrodes and electronics in lower-limb prosthetic sockets for example, he says. Picture several metal screws pressing into your limb you are supporting all your weight with, or picture filling your shoe having an selection of rocks. That is the state of wearables for this type of user.
OK, JUST HOW CAN YOU Make Electronics Soft and Stretchy?
A proven way would be to take hard things used to monitor health like silicon chips and make sure they are so thin they become flexible. One of the primary to demonstrate this type of material technology in skin-like wearable devices was John Rogers, PhD, in 2011, in a landmark Science paper titled Epidermal Electronics.
Wed been pretty active for the reason that field for several years, says Rogers, who at that time was at the University of Illinois and contains since moved to Northwestern University. But we realized that even silicon which a lot of people think about as an extremely rigid, brittle rock-like material could be converted to forms and shapes, and at thicknesses that ensure it is bent and even stretched.
Rogers, whose team has several applications in development, uses an etching strategy to shave off the top of a semiconductor wafer.
As it happens all of the action in those integrated circuits is going on on that very-near-surface layer, he says. All the silicon underneath is merely serving as a mechanical support.
That critical layer is then embedded into an elastic polymer matrix, Rogers explains, permitting them to design fully functioning systems that may bend, twist, and stretch.
Still others work with a different approach, building electronic parts from scratch out of materials which are inherently soft and stretchy polymers. This is actually the sort of work Stanford chemical engineer Zhenan Bao, PhD, does, utilizing a selection of polymers with conducting properties.
Inside our work, we gain a simple understanding on how best to design plastic molecules so they have the functions and properties we wish, Bao says. For skin-like electronics, the plastics were created on a molecular level to be conductive, elastic, and soft.
Among the newest creations out of Baos lab is a polymer that lights up, enabling skin-like visual displays. She imagines a skin patch with the display directly on it, or going further, a telehealth appointment where in fact the doctor could see and have the texture of the patients skin with a three-dimensional, lifelike display. Example: One exam to check on for severe fluid retention in heart failure patients would be to press on your skin to see if it bounces back, Bao says. The individual would wrap an electric sticker around their leg and press onto it to create a display for the off-site doctor. The physician can feel on the display the texture of your skin that the individual would feel, she says from the remote location.
Needless to say, that is still a long way away, Bao notes. But that’s what I believe will be possible that may be enabled by skin-like displays and sensors.
More Wild Advances: Liquid Metals, Plasma Bonding, Chemical Sensors
Still other developments are continuing. Advancements in liquid metals enable stretchable conductive wires. Textile-based, moisture-resistant antennas can transmit data while worn near to the skin. Methods like water vapor plasma bonding attach thin metals to soft polymers without losing flexibility or using temperature and pressure that may damage super-thin electronics.
Sensors are improving too thats the part that interacts with whatever youre attempting to measure. Most commercial wearable sensors are mechanical (used to track exercise) or optical (heartbeat, pulse oximetry). But chemical sensors come in development to measure internal markers in your body as well. They are critical in revealing the entire picture of one’s health, says Joseph Wang, a health care provider of science and professor of nanoengineering at the University of California, NORTH PARK, who has published research on biosensors and wearable devices.
For instance, a growth in lactate and drop in blood circulation pressure often means you have septic shock. Measuring potassium levels can provide information about heartrate changes. And combining blood circulation pressure and glucose measurements may reveal more about metabolic health than each one alone. In the event that you combine them, you obtain better evidence, Wang says.
That’s where the brand new tech will get really geeky. Chemical sensors are produced from many of the most exotic nano materials, including graphene, carbon nanotubes, and gold nanoparticles, Daniele says. Some (glucose sensors specifically) use enzymes that bind to focus on molecules. Others use aptamers, short single strands of DNA or RNA.
Chemical sensors typically use body fluid such as for example sweat, saliva, tears, or as may be the case for continuous glucose monitors interstitial fluid (the liquid between your cells within your body).
The majority of the things you intend to measure in blood youll have the ability to do in interstitial fluid when you have the sensor technology, says Jason Heikenfeld, PhD, a professor of electrical engineering at the University of Cincinnati. Consider having a complete blood workup done simply by gaining a skin patch, no blood sample required.
Heikenfeld in addition has investigated sweat, which appears ideal for measuring hormone levels (such as for example the ones that regulate stress, sex, and sleep) and prescription drug monitoring that’s, monitoring degrees of a drug in your body and tracking how quickly its metabolized, he says.
Sweat sensors could also find a invest at-home tests, Heikenfeld says. If there is a peoples choice award for bio fluids, sweat would win, he says. We dont wish to accomplish blood, dont desire to drool in a cup, dont desire to wreck havoc on a urine stick. Tears, forget it. The test will be a simple patch you slap on your own arm; collect some fluid, put it within an envelope, and mail it to a lab.
Wearable Power Sources: Beyond AA Batteries
If you wish to develop a stretchable, flexible digital camera, youll require a stretchable, flexible, and also washable solution to power it. A lot of todays wearables, like smartwatches, are powered by really small but nonetheless rigid batteries, Bao says. Hence the bulky form.
Theres certainly a large demand for high-energy density, truly flexible batteries, she says.
This demand has prompted researchers from around the world to build up batteries that may stretch and flex. To mention only a few recent examples, Canadian researchers developed a flexible, washable battery that may stretch to double its original length but still function. In Singapore, scientists created a paper-thin biodegradable zinc battery that you could bend and twist and also cut with scissors like any little bit of paper and it’ll still work. Still others are engineering batteries into long strips which you can use in smart clothing.
Another option is wireless power, Bao says. The battery doesn’t need to stay the device it could be in your clothes or your pocket but still power the sensors. Baos lab at Stanford is rolling out a sticker-like wearable called BodyNet which can be charged using radio-frequency identification, exactly the same technology used to regulate keyless entry to locked rooms.
Still others like Misra and her colleagues at ASSIST are exploring battery alternatives like energy harvesting, or converting body heat, solar technology, or movement into power.
Misra is focusing on a power generator that may convert the temperature difference in the middle of your skin and the area into energy to power a tool. You’ve got a skin temperature of, say, 98.6 degrees, she says. The temperature in your room is most likely about 70 degrees Fahrenheit. And that temperature difference of 28 degrees could be dropped across a tool called a thermoelectric generator, that may convert that energy difference into power.
Consider: Forget about fretting about the battery dying, getting wet, or needing to be recharged. The body may be the battery, Misra says.
For wearables to seriously reach their full potential, all of the parts must are more power-efficient and get together in a flexible, stretchable package, Misra says. In addition they should be designed so that millions, or even billions, of individuals would want to put them on.
In the same way important: Devices destined for the medical world must definitely provide top-quality data. If the collected data isnt gold standard, what good could it be? And all that data must be converted into useful information. Thats where data analytics, machine learning, and artificial intelligence can be found in. They are not unsolvable problems, Misra says, but theyre exciting issues that most of the community is focusing on.
Important thing: Our wearable future is well coming.