Transdermal Microfluidic Continuous Monitoring Systems

Cunningham, David

doi:10.1002/9780470567319.ch7

Cited by 4 publications

(4 citation statements)

References 55 publications

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“…The impressive success of the noninvasive biosensing GlucoWatch (Cygnus) system is because it relies on reverse iontophoresis. Since the cells membrane is negatively charged, the commented device cycles a ∼0.5 mA cm −2 DC between two gel swabs on the skin [ 65 ]. Abundant Na + ions into the ISF (~ 140 mM) are moved electrophoretically to the cathode, while anions are electrorepulsed, e.g., Cl − , ascorbate, urate [ 65 ].…”

Section: Sweat Gland Physiology and Web's Sweat Samplingmentioning

confidence: 99%

“…Since the cells membrane is negatively charged, the commented device cycles a ∼0.5 mA cm −2 DC between two gel swabs on the skin [ 65 ]. Abundant Na + ions into the ISF (~ 140 mM) are moved electrophoretically to the cathode, while anions are electrorepulsed, e.g., Cl − , ascorbate, urate [ 65 ]. Cations present at sweat ducts and hair follicles pass through the paracellular spaces among cells, while neutral molecules like glucose and others get out to the skin surface at a rate proportional to the applied potential, e.g., 15–150 nL of ISF at 0.3 mA by 3 min [ 65 ].…”

Section: Sweat Gland Physiology and Web's Sweat Samplingmentioning

confidence: 99%

“…Abundant Na + ions into the ISF (~ 140 mM) are moved electrophoretically to the cathode, while anions are electrorepulsed, e.g., Cl − , ascorbate, urate [ 65 ]. Cations present at sweat ducts and hair follicles pass through the paracellular spaces among cells, while neutral molecules like glucose and others get out to the skin surface at a rate proportional to the applied potential, e.g., 15–150 nL of ISF at 0.3 mA by 3 min [ 65 ]. Two remarkable works made in Prof. Wang's Lab are examples of wearable ionophoresis-sampler biosensors (Fig.…”

Section: Sweat Gland Physiology and Web's Sweat Samplingmentioning

confidence: 99%

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

Pérez

Orozco

2022

Microchim Acta

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Smart electronic devices based on micro-controllers, also referred to as fashion electronics, have raised wearable technology. These devices may process physiological information to facilitate the wearer's immediate biofeedback in close contact with the body surface. Standard market wearable devices detect observable features as gestures or skin conductivity. In contrast, the technology based on electrochemical biosensors requires a biomarker in close contact with both a biorecognition element and an electrode surface, where electron transfer phenomena occur. The noninvasiveness is pivotal for wearable technology; thus, one of the most common target tissues for real-time monitoring is the skin. Noninvasive biosensors formats may not be available for all analytes, such as several proteins and hormones, especially when devices are installed cutaneously to measure in the sweat. Processes like cutaneous transcytosis, the paracellular cell–cell unions, or even reuptake highly regulate the solutes content of the sweat. This review discusses recent advances on wearable devices based on electrochemical biosensors for biomarkers with a complex blood-to-sweat partition like proteins and some hormones, considering the commented release regulation mechanisms to the sweat. It highlights the challenges of wearable epidermal biosensors (WEBs) design and the possible solutions. Finally, it charts the path of future developments in the WEBs arena in converging/emerging digital technologies. Graphical abstract

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Section: Sweat Gland Physiology and Web's Sweat Samplingmentioning

confidence: 99%

Section: Sweat Gland Physiology and Web's Sweat Samplingmentioning

confidence: 99%

Section: Sweat Gland Physiology and Web's Sweat Samplingmentioning

confidence: 99%

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

Pérez

Orozco

2022

Microchim Acta

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“…One region of the optical spectrum with untapped potential for continuous measurement of physiological information is the short-wavelength infrared (SWIR), 3 , 4 which typically incorporates 900 to 1700 nm light. In this region, there are key absorption peaks for biological molecules, such as glucose, urea, triacetin, and water 3 , 5 , 6 . However, changes in these peaks cannot easily be isolated using traditional broad light-emitting diodes (LEDs) and a single photodiode, causing them to become confounding variables for one another.…”

Section: Introductionmentioning

confidence: 99%

Miniaturized short-wavelength infrared spectrometer for diffuse light applications

Westover,

Westhoff,

Poff

et al. 2023

Adv. Photon. Nexus

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A miniaturized short-wavelength infrared spectrometer for use with diffuse light was created by combining a thin form factor carbon nanotube composite collimator, a linear variable filter, and an InGaAs photodiode array. The resulting spectrometer measures 3 mm × 4 mm × 14 mm and shows a significant improvement in resolution over a spectrometer without the collimator when used with diffuse light. Its small size and high throughput make it ideal for applications such as wearable optical sensing, where light from highly scattering tissue is measured. Plethysmographic measurements on the wrist were demonstrated, showing rapid data collection with diffuse light.

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