A new wearable sensor that measures the levels of inflammatory molecules in sweat could be used to monitor flares in people with inflammatory bowel disease (IBD), according to a new study.
The study, “A Sweat-based Wearable Enabling Technology for Real-time Monitoring of IL-1β and CRP as Potential Markers for Inflammatory Bowel Disease,” conducted by researchers at the University of Texas at Dallas (UT Dallas), was published in Inflammatory Bowel Diseases.
As its name suggests, IBD is characterized by excessive inflammation in the gastrointestinal (GI) tract. Within the body, inflammation is regulated by signaling molecules; two of these molecules known to play a role in IBD-associated inflammation are interleukin-1 beta (IL-1 beta) and C-reactive protein (CRP).
“We hypothesize that demonstrating real-time continuous monitoring of interleukin-1β (IL-1β) and C-reactive protein (CRP) may help create an enabling technology to track inflammation in IBD patients and identify flare-ups and assess efficacy of therapy,” the researchers wrote.
Performing this kind of real-time monitoring requires consistent access to a biological sample. That means that certain types of samples — blood, for example — are not well-suited for real-time monitoring.
As such, the researchers created a sensor device to detect these inflammatory molecules in passive sweat — that is, sweat secreted even in the absence of increased physical activity. According to the team, this is an important aspect for effective monitoring as some IBD patients may not be able to exercise at levels required to generate active sweat.
The device, called SWEATSENSER, is worn on a strap around the wrist like a watch. In simple terms, it works by using antibodies, or protein components of the immune system, specific to each of the target molecules. Its electrical systems allow the device to record when the antibodies bind their specific targets, and these measurements are used to calculate the concentration of the relevant molecule.
Sweat is collected on a removable strip that is incorporated in the device and that must be changed every day.
First, the researchers confirmed their device’s ability to detect both IL-1 beta and CRP in a battery of laboratory experiments using prepared solutions. Notably, SWEATSENSER was able to detect the two biomarkers with similar accuracy and precision to commonly used laboratory tests like enzyme-linked immunosorbent assays (ELISAs).
Then, the device was tested on 20 healthy volunteers (16 men, four women, with an age range of 18-65 years), none of whom had IBD or any other known disease.
In these experiments, the SWEATSENSER recorded little change in IL-1 beta levels in sweat over time — a mean concentration of 28 picograms/mL. Since these were healthy volunteers, IL-1 beta levels were not expected to fluctuate much over time; as such, the results indicate that the device is able to reliably measure levels of this inflammatory marker over time.
“This study provides a proof-of-feasibility of a wearable sweat-based technology that can enable real-time tracking and may be used for detection of IBD flare,” the researchers wrote. “Our next step is to test the device on IBD patients to further evaluate if the levels of the markers can be differentiated between healthy and IBD patient cohorts [groups].”
The researchers envision that the device could ultimately be used by people with IBD to monitor their disease and detect flares early — which could improve patient care and avoid symptom progression.
“It’s like the check-engine light in a car,” Shalini Prasad, PhD, the study’s senior author, said in a UT Dallas press release. “The warning signal doesn’t mean a patient is having a flare-up, but it could give the person the chance to intervene earlier, when the symptoms may be more responsive to treatment.”
“The device also could help doctors understand sooner whether a treatment is working,” Prasad added.
This study received financial support from EnLiSense — a company developing lifestyle-based sensors and devices, which was co-founded by Prasad — and from the Crohn’s & Colitis Foundation.
“A wearable microsensor device would have the potential to empower patients to be actively engaged in monitoring their disease and managing it,” said Gerard Honig, PhD, associate director of research innovation for the Crohn’s & Colitis Foundation.
“It would greatly facilitate clinical research and potentially could be used in the long term to facilitate proactive management, where you have a target biomarker level you’re trying to achieve over a certain period of time and you optimize care to get there,” Honig concluded.