Prolonged and localized sweat stimulation by iontophoretic delivery of the slowly-metabolized cholinergic agent carbachol

Simmers, Phillip; Li, S. Kevin; Kasting, Gerald B.; Heikenfeld, Jason

doi:10.1016/j.jdermsci.2017.10.013

Cited by 65 publications

(68 citation statements)

References 36 publications

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“…Besides systemic sweat generation related to exercise, stress and extreme conditions, drug‐induced sweat production using, for example, iontophoresis provides a means for very localised sweat generation. Recent studies have demonstrated the integration of iontophoretic sweat generation and sensing in a single platform, and the extension of iontophoresis‐induced sweat generation for up to 24 hours . Progress in real‐time sweat sampling and analysis with wearable devices continues to grow, as does our knowledge of the value of this body fluid for obtaining non‐invasive biochemical information.…”

Section: Discussionmentioning

confidence: 99%

Wearable Platform for Real‐time Monitoring of Sodium in Sweat

et al. 2018

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A fully integrated and wearable platform for harvesting and analysing sweat sodium concentration in real time during exercise has been developed and tested. The platform was largely produced using 3D printing, which greatly simplifies fabrication and operation compared to previous versions generated with traditional production techniques. The 3D printed platform doubles the capacity of the sample storage reservoir to about 1.3 ml, reduces the assembly time and provides simple and precise component alignment and contact of the integrated solid-state ion-selective and reference electrodes with the sorbent material. The sampling flowrate in the device can be controlled by introducing threads to enhance wicking of sweat from the skin, across the electrodes to the storage area. The platform was characterised in the lab and in exercise trials over a period of about 60 minutes continuous monitoring. Sweat sodium concentration was found to rise initially to approximately 17 mM and decline gradually over the period of the trial to about 11-12 mM.

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Section: Discussionmentioning

confidence: 99%

Wearable Platform for Real‐time Monitoring of Sodium in Sweat

et al. 2018

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“…5−7 However, realizing effective sweat sampling remains a fundamental challenge in noninvasive chemo/biosensing. 8 Previous studies have mainly relied on either physical or chemical stimulation procedures (e.g., exercise, 9,10 heat, 11 and iontophoresis 12 ) to induce sweat production in substantial volumes (∼50 μL). While useful for infrequent analysis in laboratory settings, challenges remain when implementing these methods in the context of (semi)continuous measurements: exercise requires strenuous physical activity, which may not be suitable for all potential users (especially the bedridden, neonatal, or elderly populations); heat can lead to exhaustion and discomfort, which could cause noncompliance if used in a device for patients; and iontophoresis has numerous challenges related to the integration of device-and circuit-level stimulating components, which are currently being addressed.…”

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confidence: 99%

Natural Perspiration Sampling and in Situ Electrochemical Analysis with Hydrogel Micropatches for User-Identifiable and Wireless Chemo/Biosensing

et al. 2019

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Recent advances in microelectronics, microfluidics, and electrochemical sensing platforms have enabled the development of an emerging class of fully integrated personal health monitoring devices that exploit sweat to noninvasively access biomarker information. Despite such advances, effective sweat sampling remains a significant challenge for reliable biomarker analysis, with many existing methods requiring active stimulation (e.g., iontophoresis, exercise, heat). Natural perspiration offers a suitable alternative as sweat can be collected with minimal effort on the part of the user. To leverage this phenomenon, we devised a thin hydrogel micropatch (THMP), which simultaneously serves as an interface for sweat sampling and a medium for electrochemical sensing. To characterize the performance of the THMP, caffeine and lactate were selected as two representative target molecules. We demonstrated the suitability of the sampling method to track metabolic patterns, as well as to render sample-to-answer biomarker data for personal monitoring (through coupling with an electrochemical sensing system). To inform its potential application, this biomarker sampling and sensing system is incorporated within a distributed terminal-based sensing network, which uniquely capitalizes on the fingertip as a site for simultaneous biomarker data sampling and user identification.

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“…Carbachol—a slowly-metabolized cholinergic agent—has been shown to provide localized sweat stimulation when delivered iontophoretically ( S2 Fig ) [ 22 ]. Carbachol was sourced in bulk form (active pharmaceutical agent) from a local compounding pharmacy.…”

Section: Methodsmentioning

confidence: 99%

“…It takes about 15–30 minutes to produce an adequate sweat response in most people. After reaching a peak sweat rate, sweat rate begins to slowly decline over hours or even days [ 22 ].…”

Section: Methodsmentioning

confidence: 99%

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

et al. 2018

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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.

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Prolonged and localized sweat stimulation by iontophoretic delivery of the slowly-metabolized cholinergic agent carbachol

Cited by 65 publications

References 36 publications

Wearable Platform for Real‐time Monitoring of Sodium in Sweat

Wearable Platform for Real‐time Monitoring of Sodium in Sweat

Natural Perspiration Sampling and in Situ Electrochemical Analysis with Hydrogel Micropatches for User-Identifiable and Wireless Chemo/Biosensing

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

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