Sensing Technology Breakthroughs in Medical Wearables

Sensing technology breakthroughs in medical wearables expand potential applications for personalized data collection, remote monitoring, and precision medicine

Several recent advances in wearable technologies may mean that healthcare leaders are getting closer to seeing wearables as a core part of precision medicine. Newly developed battery- and chip-free wearables and improved adhesion technology are examples of recent advances in wearable technologies. These advances may break barriers to widespread use of wearables in health monitoring platforms.

One recent advance in wearable technology comes from the Massachusetts Institute of Technology (MIT), where engineers have developed a wireless, wearable electronic sensor that does not require batteries or chips.

Taking Smart Devices to the Next Level: Smart Skin Medical Wearables

Many wearable sensors communicate wirelessly using Bluetooth chips, which in turn require a battery to function. Even without Bluetooth chips, most wearables today require a battery or must be attached to an external power source to function. MIT researchers have developed a type of flexible electronic e-skin that, according to a recent press release, “opens a path toward chip-free wireless sensors.”

At the center of this study, explained in an article published Aug. 18 in Science, is the use of a material called gallium nitride. The researchers were able to use gallium nitride, a type of film with piezoelectric properties, to both produce an electrical signal in response to mechanical strain and to vibrate in response to electrical signals. This enabled development of a type of sensor that vibrates in response to someone’s heartbeat or the content of sodium in their sweat, that then transmits an electrical signal detected wirelessly.

“Chips require a lot of power, but our device could make a system very light without having any chips that are power-hungry,” said the study’s senior author, Jeehwan Kim, PhD, an associate professor at MIT. “You could put it on your body like a bandage, and paired with a wireless reader on your cellphone, you could wirelessly monitor your pulse, sweat, and other biological signals.”

While using piezoelectrics for medical technologies is not new, the bandage developed recently at MIT that uses piezoelectrics has been fine-tuned for sensitivity, according to MIT News, and can be applied many different ways.

“If there is any change in the pulse, or chemicals in sweat, or even ultraviolet exposure to skin, all of this activity can change the pattern of surface acoustic waves on the gallium nitride film,” noted Yeongin Kim, PhD, the first author of the MIT study, now assistant professor in the Department of Electrical and Computer Engineering at the University of Cincinnati. “And the sensitivity of our film is so high that it can detect these changes.”

The MIT e-skin patch adds to a body of developing innovations in biomarker detection wearables.

“Intertwined with concepts of telehealth, the internet of medical things, and precision medicine, wearable sensors offer features to actively and remotely monitor physiological parameters. Wearable sensors can generate data continuously without causing any discomfort or interruptions to daily activity, thus enhancing the self-monitoring compliance of the wearer, and improving the quality of patient care,” wrote University of California San Diego (UCSD) researchers last year for Nature Biomedical Engineering, at the time they announced their continuous health monitoring skin patch.

New Adhesive Technology for Medical Wearables Tested at McGill University

One of the barriers to wider adoption of skin patch-type medical wearables is the bioadhesive used. A recent advance in this area comes from McGill University in Canada. Researchers there found that by using ultrasound waves to create tiny bubbles, they could directly control how sticky medical adhesives were.

Many wearable monitors require the use of glues and adhesive stickers. These adhesives can be difficult to use, especially on patients with moist skin, which is common during many different illnesses. The poor adhesiveness of some bioadhesives can make their utility unpredictable, influencing not only the future of wearables but also many existing monitoring systems.

“We were surprised to find that by simply playing around with ultrasonic intensity, we can control very precisely the stickiness of adhesive bandages on many tissues,” said Zhenwei Ma, PhD, in a McGill University statement. Ma is the first author of the study, also published in Science, that outlines the researchers’ findings.

Because medical adhesives are used in a variety of different ways, including permanent tissue repair, wound management, and the attachment of wearable electronics, this breakthrough will affect not only wearables but also many other aspects of medical technology. “This paradigm-shifting technology will have great implications in many branches of medicine,” said coauthor Zu-hua Gao, MD, PhD, FRCPC, of the Department of Pathology and Laboratory Medicine at the University of British Columbia. “We’re very excited to translate this technology for applications in clinics for tissue repair, cancer therapy, and precision medicine.”

Are We Moving Toward Wearable Labs?

A map shows where academic and industrial partners are collaborating as part of a National Science Foundation consortium toward an in-depth understanding of the core disciplines needed for personalized technology that promotes in-place healthcare. (Image: Center to Stream Health in Place)

Several institutions have received millions to advance at-home healthcare through the development of clinically validated technologies that remotely monitor patient health, according to a California Institute of Technology (Caltech) news release in July 2021. The map above shows investigator locations across the United States as of Aug. 24.

“The idea is to go from bench to bedside. In order to accelerate knowledge transfer between academia and the medical field, we are collaborating with medical schools to have direct input in and access to clinical trials,” said Chiara Daraio, director of the Caltech site of the Center to Stream Healthcare in Place (C2SHIP), and a G. Bradford Jones Professor of Mechanical Engineering and Applied Physics. C2SHIP is a National Science Foundation (NSF) consortium.

While there remain many questions and uncertainties in medical diagnostics, cybersecurity, data manipulation, and the economic and social impact of remote healthcare, hospital-grade wearables are quickly advancing for patient monitoring. Likewise, consumer medical wearables are becoming more sophisticated.

Google sister company Verily recently received US Food and Drug Administration (FDA) clearance to use its smartwatch and software as a prescription-only wearable to detect certain abnormal heart rhythms, reported Fierce Biotech in July. In addition, Bloomberg has reported that the newest of the popular Apple Watches, set to be released in September 2022, is designed with a body-temperature sensor, new fitness tracking features, and expanded women’s health features.

We may be years away from wearable labs, but the features and technology on both consumer- and clinical-focused wearables continue to expand. The personalized data collection capabilities of these technologies will serve as essential building blocks for personalized medicine and, eventually, precision medicine. Healthcare leaders should anticipate that wearable technologies will play a greater role in the use of precision medicine as technological breakthroughs continue to occur.

—Caleb Williams