New wearable patch can monitor blood pressure, caffeine levels
University of California San Diego engineers have developed a skin patch that can be worn on the neck to track blood pressure and heart rate while monitoring the user's glucose, lactate, alcohol or caffeine levels.
"Intertwined with concepts of telehealth, the Internet of medical things, and precision medicine, wearable sensors offer features to actively and remotely monitor physiological parameters," wrote the research team in a study published in Nature Biomedical Engineering this week.
"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," they continued.
WHY IT MATTERS
According to the university, the engineers' device is the first to monitor cardiovascular signals at the same time as multiple biochemical levels in the human body.
"The novelty here is that we take completely different sensors and merge them together on a single small platform as small as a stamp," said Joseph Wang, a professor of nanoengineering at UC San Diego and co-corresponding author of the study, in a statement.
"We can collect so much information with this one wearable, and do so in a noninvasive way, without causing discomfort or interruptions to daily activity."
The researchers point out that heart rate and blood pressure can both dynamically and directly reflect the physiological status of the body – and that biomarker levels can help with patient monitoring. A less intrusive device like a patch, they say, can be particularly advantageous for infants.
"By integrating different sensing modalities on a single flexible, skin-worn, tattoo-like patch, vulnerable patients – from neonates to the elderly – can leverage their monitoring device with minimal discomfort or obtrusiveness," they wrote.
The device uses ultrasonic transducers to monitor blood pressure and heart rate, along with electrochemical sensors to measure the levels of biomarkers.
The team was interested in the biomarkers of glucose, lactate, caffeine and alcohol, because they can impact blood pressure.
"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," said first co-author Juliane Sempionatto, a nanoengineering Ph.D. student, in the press release announcing the patch.
One of the biggest challenges, said researchers, was eliminating signal interference, as well as physically shielding the chemical sensors from the blood pressure sensor.
"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 first co-author Muyang Lin, a nanoengineering Ph.D. student.
The device design is still ongoing: right now, the sensor needs to be connected to a power source and a benchtop machine to display its readings. The team is eventually aiming to put all of these on the patch and make everything wireless.
"We want to make a complete system that is fully wearable," Lin said.
THE LARGER TREND
Wearable patches are particularly attractive, given their convenience and relative noninvasiveness. And amidst the COVID-19 pandemic, some providers are also relying on them to help detect early patient deterioration and reduce transmission risks.
ON THE RECORD
"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 Ph.D. student at UCSD and first co-author on the study.
The device, Yin continued, could "serve as a great tool for remote patient monitoring, especially during the COVID-19 pandemic when people are minimizing in-person visits to the clinic."