CortiWatch: Watch-Based Cortisol Tracker

Abstract

Sweat-based analytics have recently caught the attention of researchers and medical professionals alike because they do not require professionally trained personnel or invasive collection techniques to obtain a sample. The following presents a small form-factor biosensor for reporting physiological ranges of cortisol present in ambient sweat (8–151 ng/ml). This device obtains cortisol measurements through low volumes of unstimulated sweat from the user’s wrist. We designed a potentiostatic circuit on a printed circuit board to perform electrochemical testing techniques. The detection modality developed for quantifying sensor response to varying cortisol concentrations is a current based electrochemical technique, chronoamperometry (CA). From the results, the sensor can detect cortisol in the physiologically relevant ranges of cortisol; thus, the sensor is a noninvasive, label free, cost-effective solution for tracking cortisol levels for circadian diagnostics.

Lay abstract

Cortisol, typically referred to as the ‘stress hormone’, plays a large role in typical body function. Cortisol matches the human sleep cycle, provides alertness, and is excreted by the adrenal cortex. The adrenal cortex is responsible for some of the body’s hormonal secretions and can malfunction or fail with age or due to an autoimmune disorder. Our group has developed a wrist worn biosensor to monitor cortisol noninvasively with low volumes of sweat. The required sample is of low volume that no exercise or physical exertion is required for collection. The device allows researchers and users alike to determine cortisol concentration and thus monitor adrenal gland functionality.

Keywords:

• chronoamperometry
• circadian cycle
• cortisol
• portable watch

Supplementary data

To view the supplementary data that accompany this paper please visit the journal website at:www.tandfonline.com/doi/suppl/10.4155/fsoa-2019-0061

Author contributions

S Prasad conceived the work. P Rice, S Upasham, B Jagannath and M Pali performed the experiments. S Upasham, B Jagannath and P Rice wrote the paper, and all authors reviewed the work.

Financial & competing interests disclosure

S Prasad has a significant interest in Enlisense LLC, a company that may have a commercial interest in the results of this research and technology. The potential individual conflict of interest has been reviewed and managed by The University of Texas at Dallas and played no role in the study design; in the collection, analysis and interpretation of data; in the writing of the report, or in the decision to submit the report for publication. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The authors state that they have obtained appropriate institutional review board approval or have followed the principles outlined in the Declaration of Helsinki for all human or animal experimental investigations. In addition, for investigations involving human subjects, informed consent has been obtained from the participants involved. Human subject studies were performed according to the protocol no. IRB 18–116, approved by the IRB board at UT Dallas. Written informed consent was obtained prior to data collection.