Cincinnati is at the forefront of sweat

Cincinnati is at the forefront of studying chemicals in sweat and what it could mean for your health

By: Kristyn Hartman, 9-WCPO Cincinnati

September 24, 2018

CINCINNATI -- Dr. Jason Heikenfeld could be described as a sweat investigator.

The University of Cincinnati professor uses sensors to measure sweat, which can help monitor a variety of health components, from drugs in someone’s system to when a woman might be ovulating. 

Heikenfeld helped develop technology that measures chemicals in sweat from people’s abdomens, backs and forearms. The sensors measure different properties of sweat, because sweat picks up some of the smaller properties in the person’s bloodstream. 

“Sweat is a really rich biofluid,” Heikenfeld said. “It has biomarkers that tell you all about human physiology.” 

The device looks like a fitness band someone would wear on their arm, but it's no Fitbit; it's a gateway to sweat intelligence, and Cincinnati is on the leading edge globally. 

Heikenfeld said he first became introduced to studying sweat when researchers at Wright-Patterson Air Force Base wanted to monitor the performance of pilots. 

“We have 2,000 sensors on a plane, and only one on a pilot … the pilot is the performance bottleneck,” Heikenfeld said. “How can we monitor the pilot as well as we monitor the plane?” 

Scientists need to build sensors to sample the chemicals in sweat, and researchers must understand how to read the chemicals in order to measure its health applications, Heikenfeld said. 

The sensor was developed by Eccrine Systems, Inc., a Norwood-based company created from Heikenfeld’s research. 

CEO Gavi Begtrup said the sensor can tell a person whether they’re dehydrated, which could be useful for athletes or people who work in hot, physically demanding environments. 

Sweat loss is the major cause of dehydration in hot environments, Begtrup said… Full Article

Eccrine CSO improves access to sweat biomarkers

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Recent scientific publications by Eccrine co-founder and Chief Science Officer, Jason Heikenfeld, and his co-authors at the University of Cincinnati demonstrate new breakthroughs in sweat sensing. The first article demonstrates the ability to increase biomarker concentrations in sweat, improving detection. The second article establishes feasibility for reliable integration of sweat stimulants within a wearable device for use periods of 24 h or more, expanding the reach of sweat sensing devices into applications involving sedentary populations.


Enhancing glucose flux into sweat by increasing paracellular permeability of the sweat gland

Andrew Jajack, Michael Brothers, Gerald Kasting, Jason Heikenfeld

July 16, 2018

Abstract: Non-invasive wearable biosensors provide real-time, continuous, and actionable health information. However, difficulties detecting diluted biomarkers in excreted biofluids limit practical applications. Most biomarkers of interest are transported paracellularly into excreted biofluids from biomarker-rich blood and interstitial fluid during normal modulation of cellular tight junctions. Calcium chelators are reversible tight junction modulators that have been shown to increase absorption across the intestinal epithelium. However, calcium chelators have not yet been shown to improve the extraction of biomarkers. Here we show that for glucose, a paracellularly transported biomarker, the flux into sweat can be increased by >10x using citrate, a calcium chelator, in combination with electroosmosis. Our results demonstrate a method of increasing glucose flux through the sweat gland epithelium, thereby increasing the concentration in sweat. Future work should examine if this method enhances flux for other paracellularly transported biomarkers to make it possible to detect more biomarkers with currently available biosensors... Full Research Article


    Membrane isolation of repeated-use sweat stimulants for mitigating both direct dermal contact and sweat dilution

    P. Simmers, Y. Yuan, Z. Sonner, and J. Heikenfeld

    April 2018

    Abstract: With the device integration of sweat stimulation, sweat becomes a stronger candidate for non-invasive continuous biochemical sensing. However, sweat stimulants are cholinergenic agents and non-selective to just the sweat glands, and so, direct placement of sweat stimulants poses additional challenges in the possibility for uncontrollable transport of the stimulant into the body and challenges in contamination of the sweat sample. Reported here is membrane isolation of repeated-use sweat stimulants for mitigating direct dermal contact, dilution of the sweat stimulant, and contamination of the sweat sample. The membrane dramatically reduces passive diffusion of the sweat stimulant carbachol by roughly two orders of magnitude, while still allowing repeated sweat stimulation by iontophoretic delivery of the carbachol through the membrane and into the skin. Both in-vivo and in-vitro validation reveal feasibility for reliable integration of sweat stimulants within a wearable device for use periods of 24 h or more. In addition, advanced topics and confounding issues such as stimulant gel design, osmotic pressure, and ionic impurities are speculatively and theoretically discussed... Full Research Article