mHealth Wearable Boosts Remote Patient Monitoring, Connected Health

Researchers at the University of California San Diego (UC San Diego) have developed a mHealth wearable that uses a patch to monitor cardiovascular signs and multiple biomarkers simultaneously, signifying a breakthrough in remote patient monitoring and connected health.

The wearable is a product of collaboration between Joseph Wang, PhD and Sheng Xu, PhD, two UC San Diego nanoengineering professors.

Wang’s lab, which focuses on the development of wearables capable of monitoring multiple signals simultaneously in the body, joined forces with Xu’s lab, which has been developing soft, stretchy skin patches that monitor blood pressure.

Together, the researchers created the first stretchable wearable that can continuously track blood pressure and heart rate while also measuring multiple biochemical levels at the same time.

“We can collect so much information with this one wearable and do so in a non-invasive way, without causing discomfort or interruptions to daily activity,” Wang, who was co-corresponding author of the study, said.

“The novelty here is that we take completely different sensors and merge them together on a single small platform as small as a stamp,” continued Wang, who also serves director of the UC San Diego Center for Wearable Sensors.

The wearable is equipped with a blood pressure sensor and two chemical sensors. One chemical sensor measures glucose levels in interstitial fluid, and the other measures levels of caffeine, alcohol, and lactate (a biomarker for physical exertion), in sweat. The patch can measure three parameters at once, or one parameter from each sensor.

“Each sensor provides a separate picture of a physical or chemical change. Integrating them all in one wearable patch allows us to stitch those different pictures together to get a more comprehensive overview of what’s going on in our bodies,” said Xu, a co-corresponding author of the study published in Nature Biomedical Engineering.

The researchers were interested in measuring levels of caffeine, alcohol, and lactate because these biomarkers impact blood pressure.

“We chose parameters that would give us a more accurate, more reliable blood pressure measurement,” said co-first author Juliane Sempionatto, a nanoengineering PhD student in Wang’s lab.

“Let’s say you are monitoring your blood pressure, and you see spikes during the day and think that something is wrong. But a biomarker reading could tell you if those spikes were due to an intake of alcohol or caffeine. This combination of sensors can give you that type of information,” she said.

The mHealth patch could offer a convenient alternative for patients in intensive care units who need continuous monitoring of vital signs, eliminating the need for patients to be tethered to multiple hospital monitors and/or a catheter.

“This type of wearable would be very helpful for people with underlying medical conditions to monitor their own health on a regular basis,” said Lu Yin, a nanoengineering PhD student at UC San Diego and co-first author of the study.

Additionally, the mHealth wearable could allow physicians to leverage remote patient monitoring in their practices, Yin noted. This connected health device may be especially useful during COVID-19 when many patients are avoiding in-person visits.

The researchers tested the wearable by observing the biomarkers of subjects who wore the patch while performing several combinations of the following tasks: exercising on a stationary bicycle, eating a high-sugar meal, drinking an alcoholic beverage, and drinking a caffeinated beverage.

To determine whether the wearable gave accurate patient data, the researchers verified that the measurements collected from the patch matched measurements from the following commercial monitoring devices: blood pressure cuff, blood lactate meter, glucometer, and breathalyzer.

Measurements of the wearers’ caffeine levels were verified with measurements of sweat samples spiked with caffeine.

When designing the mHealth patch, the research team was met with several engineering challenges.

“Finding the right materials, optimizing the overall layout, integrating the different electronics together in a seamless fashion—these challenges took a lot of time to overcome,” said co-first author Muyang Lin, a nanoengineering PhD student in Xu’s lab.

The researchers are continuing to develop the wearable further. Ongoing work includes shrinking the blood pressure sensor electronics, because currently the sensor needs to be connected to a power source and a benchtop machine to display its readings. The team’s goal is to make the wearable completely wireless.

“We want to make a complete system that is fully wearable,” Lin said.

The development of wearable skin patch sensors has been underway for several years now, laying the groundwork for the new mHealth device.

Back in 2019, researchers from the Georgia Institute of Technology and Washington University worked on developing an mHealth wearable that would capture interstitial fluid to monitor patient’s biomarkers. The researchers hoped to design a patch that would allow clinicians to monitor patients at risk of developing cancer, heart disease, diabetes, and other health concerns.