Sweating Out the Circadian Rhythm: A Technical Review

Abstract

Circadian dysfunction or dysregulation is associated with many chronic morbidities. Current state-of-art technologies do not provide an accurate estimation of the extent of disease affliction. Recent advances call for using wearables for improving management and diagnosis of circadian related disorders. Sweat contains an abundance of relevant biomarkers like cortisol, DHEA, and so forth, which could be leveraged toward tracking the user's chronobiology. In this article, we provide a review of the key developments in the field of wearable sensors for circadian technologies. We highlight the value of using sweat along with portable electronics toward developing state-of-the-art platforms for efficient diagnosis and management of chronic conditions. Finally, we discuss challenges and opportunities for using wearable sweat sensors for circadian diagnosis and disease management.

Passive Sweat-Based Pruritic Cytokine Detection and Monitoring System

“…The benefits of the sensing system can be attributed to the electrochemical detection modality used, which makes the response sensitive, highly specific, label-free, provides easy coupling to portable electronics, offers wide dynamic ranges, provides ability to work with low sample volumes, and is easy to fabricate or mass-produce. 32 Correlation studies between benchtop and portable device.-The performance of the commercial or standard potentiostat (Gamry Inc.) and the portable benchtop system was compared using correlation studies and Bland-Altman analysis. The following section explores the performance between the two systems with respect to the four different simulated flaring profiles.…”

Wearable electrochemical biosensors to measure biomarkers with complex blood-to-sweat partition such as proteins and hormones

“…For instance, levels of cytokines showed a good correlation in a healthy woman, i.e., IL1α, IL-1β, IL-6, TNF-α, IL-8, TGF-β [ 50 ] and older adults, i.e., IL-6, IL-10, TNF-α [ 51 ], as similarly as cortisol from sweat behaves during exercise [ 52 ], heating [ 53 ], stress or nutritional challenges [ 54 ]. The last is also true when the quoted above analytes are sensed electrochemically in a continuous real-time manner by a wearable device during infections like COVID-19, i.e., IL-6, IL-8, IL-10, TNF-α [ 55 ] or during circadian rhythm, i.e., cortisol; dehydroepiandrosterone (DHEA), and neuropeptide Y (NPY) [ 56 , 57 ]. Again, the protein content analysis into sweat must be assessed carefully because the synthesis of analytes such as cytokines may be local.…”

“…Consistently, either cortisol or DHEA increased after exercise, suggesting the reliability of the SLOCK system to avoid background associated with variables like motion, heat, and receptor degradation [ 107 ]. WEB-SPE technology for hormone sweat monitoring that controls the circadian rhythm was reviewed recently [ 57 ]. The enlargement of the scope analysis of the SLOCK platform for cytokines present at eccrine secretion was made recently by Prof Prasad's lab researchers.…”

State of Sweat: Emerging Wearable Systems for Real-Time, Noninvasive Sweat Sensing and Analytics

“…This perspective offers an overview of the current state-of-the-art for wearable sweat biosensors, with particular emphasis on the application use cases for these sensors. The nascent field is of considerable interest with recent reviews ,,,− contextualizing the progress of wearable sweat sensors within the scope of skin-interfaced devices, ,,,,, sensing technologies, ,,,− specific applications, ,,,,,,, material systems, , and fabrication methods . By contrast, this perspective highlights the most advanced translational embodiments spanning the fundamental use cases for these platforms in relationship to sensing targets.…”