CoChat
Sign Up
Cited by 1,308Advanced Sensor and Energy Harvesting MaterialsMicrofluidic and Capillary Electrophoresis ApplicationsBiosensors and Analytical Detection

A soft, wearable microfluidic device for the capture, storage, and colorimetric sensing of sweat

Open access
Koh, Ahyeon, Kang, Daeshik, Xue, Yeguang, Lee, Seungmin, Pielak, Rafal M., Kim, Jeonghyun, Hwang, Taehwan, Min, Seunghwan +14 more·2016·Science Translational Medicine
DOI 10.1126/scitranslmed.aaf2593PMC PMC5429097
Open this paper in CoChat — free account

Abstract

A soft, skin-mounted microfluidic device captures microliter volumes of sweat and quantitatively measures biochemical markers by colorimetric analysis.

AI snapshot

Written from the paper’s full text.

TL;DR

A soft, skin-mounted microfluidic device captures sweat through microchannels and reservoirs and colorimetrically quantifies sweat rate, total loss, pH, chloride, lactate, and glucose, with optional NFC smartphone readout. Human testing during controlled cycling and a 104-km outdoor bicycle race demonstrated feasibility, though the colorimetric chemistry limits real-time and time-dependent marker tracking.

Key findings

  • The device retained ~50 μL of sweat, corresponding to 1 to 6 hours of exercise depending on sweat loss and mounting location; sweat rates were 12 to 120 μL/hour per cm².
  • In 9 subjects during controlled cycling at 38°C and 50% relative humidity, lower-back sweat rates were typically ~2.3-fold greater than volar forearm rates; large-harvesting-area devices agreed with absorbent pads, and colorimetric chloride, lactate, and pH results agreed with laboratory analysis.
  • In 12 cyclists during the 104-km El Tour de Tucson, devices collected sweat without detachment, leakage, or reported discomfort; older subjects (50–69 years) had greater sweating rates than younger subjects (10–29 years), and males had greater rates than females.
  • Colorimetric assays covered pH 5.0–7.0, lactate 1.5–100 mM, and glucose with an LOD of ~200 μM; image analysis could resolve 0.5 pH units and 0.2, 0.3, and 0.1 mM changes in chloride, lactate, and glucose, respectively, corresponding to a 1% change in the R channel.

Methods

  • Soft lithography fabricated multilayer PDMS microfluidic devices with a skin adhesive layer, colorimetric reagent reservoirs, serpentine sweat-volume channel, and optional NFC electronics; in vitro testing used an artificial sweat-pore system with a syringe pump.
  • Indoor human study: 9 healthy subjects exercised on cycle ergometers under controlled 38°C and 50% relative humidity, with devices on the lower back and volar forearm and two harvesting areas; results were compared with absorbent pads and laboratory chemical analysis.
  • Outdoor human study: 12 healthy volunteers wore devices on the lower back and volar forearm during a 104-km bicycle race; sweat images were captured by smartphone and digital single-lens reflex cameras, and Pearson/Spearman correlation analyses were performed using SAS and JMP.

Limitations

  • Stated: the colorimetric schemes do not afford real-time tracking of changes in analyte concentration, and the current channel/reservoir designs cannot easily provide time-dependent marker concentration information.
  • Stated: limitations are primarily in the range of chemical reagents available for accurate colorimetric analysis at relevant concentrations; further field studies are needed to demonstrate accuracy in realistic, demanding scenarios.
  • Stated and evident: the small sample size only partially demonstrated correlations across individual subjects, and glucose in healthy subjects fell below the LOD for both image and laboratory analysis; small harvesting areas yielded somewhat higher inferred sweat rates, perhaps due to altered perspiration behavior caused by the device’s physical presence.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1126/scitranslmed.aaf2593

Cites

56 of 56 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 22 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Conformal contact of the adhesive layer inhibited lateral flow of sweat from outside the defined openings, ensuring fluid from the harvesting area dominated the sweat sample.

    “The conformal contact of the adhesive layer inhibited lateral flow of sweat from regions located outside the defined openings, ensuring fluid issuing from the harvesting area dominated the sweat sample (fig. S3).”
    Quote in the paperSubstantial claim
  • Findingreasoning

    Quantitative colorimetric assay reagents in the reservoirs enabled assessment of pH and concentrations of glucose, lactate, and chloride through enzymatic or chromogenic reactions.

    “Quantitative colorimetric assay reagents in the reservoirs enabled assessment of pH and the concentration of selected essential markers, including glucose, lactate, and chloride, through either enzymatic or chromogenic reactions.”
    Quote in the paperSubstantial claim
  • Findingcitation

    The acrylic adhesive exhibited about 5 times greater adhesion force than typical medical adhesives such as Tegaderm (1.02 N).

    “This adhesive exhibited about 5 times greater adhesion force than typical medical adhesives such as Tegaderm (1.02 N) (33).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [33] Klode J Schöttler L Stoffels I Körber A Schadendorf D Dissemond J Investigation of adhesion of modern wound dressings: a comparative analysis of 56 different wound dressings Journal of the European Academy of Dermatology and Venereology 25 933 939 2011 21062365 source

      Not checked in the free run.

  • Findingown data

    A medical-grade acrylic adhesive film ensured stable, strong, seamless adhesion (~5.7 N) of the device to skin without irritation, even at regions of substantial hair coverage or in the presence of sweat.

    “A medical-grade acrylic adhesive film ensured stable, strong and seamless adhesion (~5.7 N) of the device to the skin without irritation in a manner that offered compatibility with skin, even at regions of substantial hair coverage or in the presence of sweat (fig. S2).”
    Quote in the paperSubstantial claim
  • Findingcitation

    The maximum normal and shear stresses at the device/phantom skin interface were far below the threshold for somatosensory perception of forces (20 kPa) during ~30% stretch of the skin.

    “The maximum normal and shear stresses at the device/phantom skin interface were far below the threshold for somatosensory perception of forces (20 kPa) during ~30% stretch of the skin (fig. S4) (37).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [37] Lee CH Ma Y Jang KI Banks A Pan T Feng X Kim JS Kang D Raj MS McGrane BL Morey B Wang X Ghaffari R Huang Y Rogers JA Soft core/shell packages for stretchable electronics Adv Funct Mater 25 3698 3704 2015 source

      Not checked in the free run.

  • May combine two claims. 29
  • Classified as probably not a substantial claim. 14
  • The quote only partly states this claim. 1

  • May combine two claims.

    Findingcitation

    The soft epidermal microfluidic device adheres and conforms to skin and captures and routes sweat through microchannels and reservoirs using capillarity and natural perspiration pressure (~70 kPa) for volumetric assessment and chemical analysis in situ.

    “The soft, epidermal microfluidic device technology introduced here adheres and conforms to the skin in a manner that captures and routes sweat through a network of microchannels and reservoirs—using a combination of capillarity and action of the natural pressure (~70 kPa) associated with perspiration—for volumetric assessment and chemical analysis in situ (13).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [13] Sonner Z Wilder E Heikenfeld J Kasting G Beyette F Swaile D Sherman F Joyce J Hagen J Kelley-Loughnane N Naik R The microfluidics of the eccrine sweat gland, including biomarker partitioning, transport, and biosensing implications Biomicrofluidics 9 031301 2015 26045728 PMC4433483 source

      Not checked in the free run.

    • Rests on an assumption: The pressure that drives fluid flow through the device arises from the action of the sweat glands themselves, assisted by capillary effects in the microchannels and the materials embedded within them.

  • May combine two claims.

    Findingcitation

    The specific device designs can retain ~50 μL of sweat, corresponding to an effective working time of 1 to 6 hours depending on sweat loss rate and mounting location (12 to 120 μL/hour per cm2).

    “The specific designs described can retain ~50 μL of sweat corresponding to an effective working time of 1 to 6 hours of exercise, depending on the rate of sweat loss and the mounting location on the body (12 to 120 μL/hour per cm2) (32).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [32] Sato K Sato F Individual variations in structure and function of human eccrine sweat gland Am J Physiol Regul Integr Comp Physiol 245 R203 R208 1983 6881378 source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Findingnone given

    The colorimetric schemes embedded in the current devices did not afford real-time tracking of changes in analyte concentration.

    “Hence, the colorimetric schemes embedded in the current devices did not afford real-time tracking of changes in analyte concentration.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    A water-responsive chromogenic reagent in the serpentine channel allowed determination of the extent of filling with sweat, which could be converted to overall sweat rate and volume.

    “A water-responsive chromogenic reagent in the serpentine channel allowed determination of the extent of filling with sweat, which could be converted to overall sweat rate and volume.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingcitation

    The elastomeric microfluidic devices exhibited an effective modulus of ~0.16 MPa, comparable to human skin and previously reported epidermal devices.

    “These elastomeric microfluidic devices exhibited an effective modulus of ~0.16 MPa, comparable to human skin and previously reported epidermal devices (37, 38).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [37] Lee CH Ma Y Jang KI Banks A Pan T Feng X Kim JS Kang D Raj MS McGrane BL Morey B Wang X Ghaffari R Huang Y Rogers JA Soft core/shell packages for stretchable electronics Adv Funct Mater 25 3698 3704 2015 source

      Not checked in the free run.

    • cites [38] Liang X Boppart S Biomechanical properties of in vivo human skin from dynamic optical coherence elastography IEEE Trans Biomed Eng 57 953 959 2010 19822464 PMC3699319 source

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    The water vapor loss showed little dependence on the length of the outlet channel, whereas backpressure was linearly proportional to this length according to calculations for a model system.

    “The water vapor loss showed little dependence on the length of the outlet channel, whereas backpressure was linearly proportional to this length according to calculations for a model system (fig. S8 and Fig. 2B).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The technology capitalized on NFC schemes to launch image capture and analysis software on an external device and/or to read temperature from an integrated sensor.

    “Our technology capitalized on NFC schemes to launch image capture and analysis software on such an external device and/or to read temperature from an integrated sensor (movies S1 and S2).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Calculations indicated that vapor loss with 100-μm-wide channels was ~3.2-fold lower than with 800-μm-wide channels, while 25-μm-wide channels differed by only ~1.1-fold from 100-μm-wide channels.

    “Our calculations further indicated that the vapor loss with 100-μm-wide channels was ~3.2-fold lower than with 800-μm-wide channels, while 25-μm-wide channels differed by only ~1.1-fold from 100-μm-wide channels (Fig. 2B).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    A device (0.07 cm2 harvesting surface area) laminated on the perforated membrane captured dyed water pumped at 5.5 μl/hour, demonstrating the first step in quantitative analysis of liquid uptake.

    “A device (0.07 cm2 of harvesting surface area) laminated on the perforated membrane captured dyed water pumped at 5.5 μl/hour (Fig. 2G), demonstrating the first step in quantitative analysis of liquid uptake (movie S3).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The experiments revealed negligible loss of water vapor and no fluid leakage under these conditions.

    “The experiments revealed negligible loss of water vapor and no fluid leakage under these conditions.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    The reservoirs fill within ~0.3 to 3.2 hours at these sweating rates, with times that scale linearly with reservoir volume.

    “The reservoirs fill within ~0.3 to 3.2 hours at these sweating rates, with times that scale linearly with reservoir volume.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    For widths under 100 μm, backpressure notably increased and bending deformation of the device was obstructed, with negligible effects on vapor loss.

    “For widths under 100 μm, the backpressure notably increased and bending deformation of the device was obstructed, with negligible effects on vapor loss.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Human studies presented subsequently showed volumetric sweat harvesting rates of ~1.2 to 12 μl/hour, corresponding to linear filling rates of ~0.07 to 0.7 mm/min along the serpentine channels.

    “For a device layout with harvesting area (~10 mm2), the human studies presented subsequently showed volumetric sweat harvesting rates of ~1.2 to 12 μl/hour, corresponding to linear filling rates of ~0.07 to 0.7 mm/min along the serpentine channels.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The experimentally determined harvested liquid volume in the channel is consistent with the input volume introduced by the syringe pump and with linear hydrodynamic flow in the microfluidic channel.

    “As shown in movie S3, the experimentally determined harvested liquid volume in the channel is consistent with the input volume introduced by the syringe pump and with linear hydrodynamic flow in the microfluidic channel.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The volume change increased with the aspect ratio (AR; width to height); for AR 5 the volume change was about fivefold greater than for AR 3.3.

    “The volume change increased with the aspect ratio (AR; width to height). For example, the volume change for AR 5 (width, 1.5 mm; height, 300 μm) was about fivefold greater than that for AR 3.3 (width, 1.0 mm; height, 300 μm).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Sweat could continue to travel slowly through the channel by spontaneous internal flow (0.68 μl/hour), with the possibility of a ~2% reading error.

    “The sweat could, however, continue to travel slowly through the channel by spontaneous internal flow (0.68 μl/hour), with the possibility of a ~2% reading error (fig. S11, E and F).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    This artifact does not occur in channels without the hydrogel; its effect could be eliminated, for practical purposes, by patterning the hydrogel into short segments.

    “This artifact does not occur in channels without the hydrogel; its effect could be eliminated, for practical purposes, by patterning the hydrogel into short segments (fig. S12).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The colorimetric sensing approach allowed simple, rapid quantitative assessment of instantaneous rate and total volume of sweat loss, pH, and concentration of chloride, lactate, and glucose in sweat.

    “The colorimetric sensing approach allowed simple, rapid quantitative assessment of instantaneous rate and total volume of sweat loss, the pH, as well as the concentration of chloride, lactate, and glucose in the sweat (Fig. 3A).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Glucose concentration could also be analyzed by an enzymatic reaction.

    “Glucose concentration could also be analyzed by an enzymatic reaction (Fig. 3D).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Recording color changes and converting them into quantitative information were accomplished by digital image capture and analysis.

    “Recording color changes and converting them into quantitative information were accomplished by digital image capture and analysis.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingcitation

    The previously reported ultrathin NFC electronics integrated on the top of the microfluidic device enabled wireless communication to external devices, with stable operation and a soft, biocompatible set of mechanical properties, even under a 30% strain condition.

    “The previously reported ultrathin NFC electronics (39) integrated on the top of the microfluidic device enabled wireless communication to external devices, with stable operation and a soft, biocompatible set of mechanical properties, even under a 30% strain condition (39).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [39] Kim J Banks A Cheng HY Xie ZQ Xu S Jang KI Lee JW Liu ZJ Gutruf P Huang X Wei PH Liu F Li K Dalal M Ghaffari R Feng X Huang YG Gupta S Paik U Rogers JA Epidermal electronics with advanced capabilities in near-field communication Small 11 906 912 2015 25367846 source

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    In the presence of chloride ions, iron ions (Fe2+) bind with TPTZ, whereas Hg2+ participates as HgCl2, thereby inducing a change in color from transparent to blue.

    “In the presence of chloride ions, iron ions (Fe2+) bind with TPTZ, whereas Hg2+ participates as HgCl2, thereby inducing a change in color from transparent to blue as shown in Fig. 3G.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The NFC electronics facilitated image capture, and built-in sensors provided wireless, digital data on skin temperature.

    “The NFC electronics facilitated image capture, and built-in sensors provided wireless, digital data on skin temperature (fig. S15 and movie S2).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    The calibration curve in Fig. 4C captures the pseudo-linearities associated with the serpentine shape of the channel.

    “The calibration curve in Fig. 4C captures the pseudo-linearities associated with the serpentine shape of the channel.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The device could reliably measure changes of 0.5 pH units and 0.2, 0.3, and 0.1 mM of chloride, lactate, and glucose concentrations, respectively, corresponding to a 1% change in the R channel of the RGB images.

    “We could reliably measure changes of 0.5 pH units and 0.2, 0.3, and 0.1 mM of chloride, lactate, and glucose concentrations, respectively, corresponding to a 1% change in the R channel of the RGB images.”
    Quote in the paperSubstantial claim

  • The quote only partly states this claim.

    Findingown data

    In nine human subjects during intermediate-level cycle ergometer exercise under 38°C and 50% relative humidity, sweat rates measured on the lower back were typically about 2.3-fold greater than on the volar forearm.

    “Although the rates exhibited great variation among individual subjects, those measured on the lower back were typically ~2.3-fold greater than on the volar forearm, consistent with expectations from studies using conventional techniques (54).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [54] Smith CJ Havenith G Body mapping of sweating patterns in male athletes in mild exercise-induced hyperthermia Eur J Appl Physiol 111 1391 1404 2011 21153660 source

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    Devices on 12 volunteer riders in the El Tour de Tucson competitive long-distance outdoor bicycling race performed as anticipated, successfully collecting sweat with regional colorimetric change without patch detachment, even with substantial changes in temperature and humidity.

    “In all cases, the devices performed as anticipated, successfully collecting sweat with regional colorimetric change without patch detachment, even with substantial changes in temperature and humidity.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Older subjects (ages 50 to 69 years) had greater rates of sweating than younger subjects (ages 10 to 29 years).

    “Older subjects (ages 50 to 69 years) had greater rates of sweating in comparison to that of younger subjects (ages 10 to 29 years), and male subjects exhibited greater rates of sweating than females (Fig. 6E).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingnone given

    The reported embodiments can detect sweat volume and rate, as well as glucose, creatinine, lactate, chloride, and pH.

    “The reported embodiments can detect sweat volume and rate, as well as several key markers including glucose, creatinine, lactate, chloride, and pH.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The devices accurately captured sweat volume and rate information continuously, without the need for removal.

    “Furthermore, the devices accurately captured the volume and rate information continuously, without the need for removal.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Specially formulated PDMS variants offer optical transparency, ease of patterning into microfluidic systems, biocompatibility, and favorable mechanics (low modulus ~145 kPa; high elasticity up to ~200% strain at break).

    “Specially formulated variants of PDMS offer physical characteristics that are attractive for this application, including optical transparency, ease of patterning into microfluidic systems, biocompatibility, and favorable mechanics (low modulus, ~145 kPa; high elasticity, up to ~200% strain at break) (35).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [35] Lee JN Park C Whitesides GM Solvent compatibility of poly (dimethylsiloxane)-based microfluidic devices Anal Chem 75 6544 6554 2003 14640726 source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductown data

    Reference marks on the top of the device platform included a white dot and black crosses for color balancing to allow accurate color extraction under arbitrary lighting conditions.

    “Reference marks on the top of the device platform (Fig. 1B) included a white dot and black crosses for color balancing to allow accurate color extraction under arbitrary lighting condition (fig. S6).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    The crosses helped determine the position and orientation from the images.

    “The crosses also helped determine the position and orientation from the images (fig. S7).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Decreasing the cross-sectional area of the channel increases the filling rate proportionally.

    “Decreasing the cross-sectional area of the channel increases the filling rate proportionally.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationnone given

    Three factors determine the resolution in determination of sweat rate: the rate of fluid flow into the reservoirs and serpentine channel, the harvesting area, and the time and spatial resolution of the camera system and image analysis software.

    “Regarding device design, three factors determine the resolution in determination of sweat rate: (i) the rate of fluid flow into the reservoirs and the serpentine channel, (ii) the harvesting area, and (iii) the time and spatial resolution of the camera system and image analysis software.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The concentration of chloride ions serves as a marker of cystic fibrosis and altered electrolyte levels correspond to a sodium ion imbalance.

    “The concentration of chloride ions serves as a marker of cystic fibrosis and altered electrolyte levels correspond to a sodium ion imbalance (17).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [17] Jadoon S Karim S Akram MR Kalsoom Khan A Zia MA Siddiqi AR Murtaza G Recent developments in sweat analysis and its applications 2015 2015 7 PMC4369929 25838824 source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductown data

    A white dot in the middle of the device and four black crosses distributed near the center established values for 100% and 0% in %RGB coordinates, respectively.

    “In particular, a white dot in the middle of the device and four black crosses distributed near the center established values for 100% and 0% in %RGB coordinates, respectively (Fig. 4B).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    The angle of the filling front (the leading edge of the color change) in the serpentine channel defined the volume of sweat collected, thereby allowing calculation of total sweat loss and, with the time interval, total sweat rate.

    “The angle of the filling front (the leading edge of the color change) in the serpentine channel defined the volume of sweat collected, thereby allowing calculation of total sweat loss and, with the time interval, total sweat rate.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    Compared to previously described technologies for sweat analysis using porous materials and fabrics or hydrogels as fluidic interfaces, our systems are unique in their use of fully integrated, soft microfluidics consisting of a network of functionalized channels and reservoirs for sweat capture, routing, and storage with spatially separated regions for analysis.

    “Compared to previously described technologies for sweat analysis consisting of porous materials and fabrics or hydrogels as fluidic interfaces, our systems are unique in their use of fully integrated, soft microfluidics consisting of a network of functionalized channels and reservoirs for sweat capture, routing, and storage with spatially separated regions for analysis.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationnone given

    The limitations of the current devices are primarily in the range of chemical reagents available for accurate colorimetric analysis of markers at relevant ranges of concentration.

    “The limitations of the current devices are primarily in the range of chemical reagents that are available for accurate colorimetric analysis of markers at relevant ranges of concentration.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    The correlation between variations in marker analysis across individual subjects was only partially demonstrated because of the small sample size.

    “The correlation between variations in marker analysis across individual subjects was only partially demonstrated because of the small sample size.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Interpretationnone given

    The microfluidic channel/reservoir designs reported here cannot be easily designed to provide information on time-dependent changes in marker concentration detection.

    “However, the microfluidic channel/reservoir designs reported here cannot be easily designed to provide information on time-dependent changes in marker concentration detection.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    The experimental conditions, including temperature, humidity, time course of application of device, and weight of absorbing Webril pads for sweat collection were all controlled and documented.

    “The experimental conditions, including temperature, humidity, time course of application of device, and weight of absorbing Webril pads for sweat collection were all controlled and documented.”
    Quote in the paperNot a substantial claim
43 of 43

  • The paper relies on this without support.

    The pressure that drives fluid flow through the device arises from the action of the sweat glands themselves, assisted by capillary effects in the microchannels and the materials embedded within them.

    “The pressure that drives fluid flow arises from the action of the sweat glands themselves, assisted by capillary effects in the microchannels and the materials embedded within them.”

  • The paper relies on this without support.

    Sweat pH is an index of hydration state.

    “In sweat, pH is often considered an index of hydration state.”

  • The paper relies on this without support.

    Glucose concentration in sweat is typically one order of magnitude lower than in plasma.

    “We note that glucose concentration in sweat is typically one order of magnitude lower than in plasma;”

  • The paper relies on this without support.

    The conventional absorbing pad and laboratory analysis methods provide accurate reference measurements of sweat rate and marker concentrations.

    “We compared the performance of the device in situ to conventional procedures that use absorbing pads applied onto the skin with subsequent weighing and laboratory-based analyses, such as spectrophotometry.”
    “Concentrations of the markers chloride, glucose, lactate, and pH obtained by the colorimetric readouts demonstrated excellent agreement with conventional laboratory analysis of sweat collected from absorbing pads as shown in Fig. 5F.”

  • The paper relies on this without support.

    Sweat marker concentrations are indicative of health and disease status.

    “The epidermal microfluidic devices introduced here represent versatile platforms for evaluating athletic performance and monitoring health and disease status.”

  • The paper relies on this without support.

    The physical presence of the device does not significantly alter local sweat rate or composition when large harvesting areas are used.

    “Devices with small harvesting areas yielded somewhat higher inferred rates than those with larger harvesting areas, perhaps due to alternations in perspiration behavior caused by the physical presence of the device (Fig. 5E) (55).”

  • The paper relies on this without support.

    The constituent materials of the device are biocompatible and safe for prolonged skin contact.

    “The soft mechanical properties, biocompatible constituent materials, digitally analyzable colorimetric responses, and overall careful optimization of structural, evaporative and fluidic properties are integral to the effectiveness of these devices and differentiate them from other sweat analysis technologies.”

  • The paper relies on this without support.

    The tested populations (nine indoor subjects and 12 outdoor cyclists) are representative of the broader populations for whom the device is intended.

    “The epidermal microfluidic devices introduced here represent versatile platforms for evaluating athletic performance and monitoring health and disease status.”
8 of 8

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Stated sample volume exceeds each reservoir's geometric capacity

    Minor

    A circular chamber 4 mm in diameter and 300 μm deep has a geometric volume of about 3.8 μL, before accounting for the paper inside it. That is less than the stated 5 to 10 μL of sweat needed to fill each reservoir's cellulose matrix.

1 of 1

Cites

Flagged first, then by citations

2 of the 58 references couldn’t be matched to a known paper.

Research works printed but not linked: 1

  1. White F. M., Fluid Mechanics (McGraw-Hill Higher Education, ed. 7, 2010).

Cited by

Sorted by citations

Related

Authors
Koh, A., Kang, D., Xue, Y., Lee, S., Pielak, R. M., Kim, J., Hwang, T., Min, S., Banks, A., Bastien, P., Manco, M. C., Wang, L., Ammann, K. R., Jang, K.-I., Won, P., Han, S., Ghaffari, R., Paik, U., Slepian, M. J., Balooch, G., Huang, Y., & Rogers, J. A.
Affiliations
  • University of Illinois Urbana-Champaign (US)
  • Northwestern University (US)
  • L’Oréal Technology Incubator, San Francisco, CA 94107, USA.
  • L'Oréal (France) (FR)
  • L’Oréal Early Clinical, Clark, NJ 07066, USA.
  • University of Arizona (US)
  • MC10 (United States) (US)
  • Hanyang University (KR)
Corresponding author
  • Koh, Ahyeon
  • Kang, Daeshik
  • Rogers, John A.
ORCID
Venue
Science Translational Medicine
Publisher
American Association for the Advancement of Science (AAAS)
Published
2016-11-23
Volume
8
Issue
366
Pages
366ra165-366ra165
ISSN
  • 1946-6234 (ISSN-L)
  • 1946-6242
DOI
10.1126/scitranslmed.aaf2593
PMC
PMC5429097
OpenAlex
W2552540631
Semantic Scholar
84a9944cb082f216174ed23bb7d69071b54fd62b
Cited by
1,308
References
58
Citations by year
2026: 86 · 2025: 129 · 2024: 149 · 2023: 153 · 2022: 168 · 2021: 160 · 2020: 150 · 2019: 162 · 2018: 103 · 2017: 47 · 2016: 1
FWCI
50.08
Type
journal article
Language
en
Open access
Licence
www.sciencemag.org/about/science-licenses-journal-article-reuse (vor, 365 d)
Locations
  • Science Translational Medicine (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
  • KAIST Institutional Repository (KAIST) (submittedVersion)
Funders
  • Global Research Laboratory Program (K20704000003TA050000310)
  • National Research Foundation of Korea
  • NIH (R01EB019337)
Topics
  • Physical Sciences › Engineering › Biomedical Engineering › Advanced Sensor and Energy Harvesting Materials
  • Physical Sciences › Engineering › Biomedical Engineering › Microfluidic and Capillary Electrophoresis Applications
  • Physical Sciences › Engineering › Biomedical Engineering › Biosensors and Analytical Detection
Keywords
sweat analysis, colorimetric sensing, sweat collection, stretchable electronics, wireless communication, chloride determination, lactate measurement, sweat pH, glucose, sweat rate, health monitoring, cycling, sweat loss
MeSH terms
Smartphone, Wearable Electronic Devices, Adolescent, Adult, Aged, Child, Chlorides, Colorimetry, Equipment Design, Female, Glucose, Humans, Hydrogen-Ion Concentration, Image Processing, Computer-Assisted, Male, Middle Aged, Sweat, User-Computer Interface, Biosensing Techniques, Lactic Acid, Microfluidics, Young Adult, Lab-On-A-Chip Devices

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-09.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-09.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review