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Cited by 55Advanced Sensor and Energy Harvesting MaterialsMicrofluidic and Capillary Electrophoresis ApplicationsBiosensors and Analytical Detection

MicroSweat: A wearable microfluidic patch for noninvasive and reliable sweat collection enables human stress monitoring

Open access
Shajari, Shaghayegh, Salahandish, Razieh, Zare, Azam, Hassani, Mohsen, Moossavi, Shirin, Munro, Emily, Rashid, Ruba, Rosenegger, David +2 more·2023·Advanced Science
DOI 10.1002/advs.202204171PMC PMC9982588
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Abstract

Stress affects cognition, behavior, and physiology, leading to lasting physical and mental illness. The ability to detect and measure stress, however, is poor. Increased circulating cortisol during stress is mirrored by cortisol release from sweat glands, providing an opportunity to use it as an external biomarker for monitoring internal emotional state. Despite the attempts at using wearable sensors for monitoring sweat cortisol, there is a lack of reliable wearable sweat collection devices that preserve the concentration and integrity of sweat biomolecules corresponding to stress levels. Here, a flexible, self‐powered, evaporation‐free, bubble‐free, surfactant‐free, and scalable capillary microfluidic device, MicroSweat, is fabricated to reliably collect human sweat from different body locations. Cortisol levels are detected corresponding to severe stress ranging from 25 to 125 ng mL −1 averaged across multiple body regions and 100–1000 ng mL −1 from the axilla. A positive nonlinear correlation exists between cortisol concentration and stress levels quantified using the perceived stress scale (PSS). Moreover, owing to the sweat variation in response to environmental effects and physiological differences, the longitudinal and personalized profile of sweat cortisol is acquired, for the first time, for various body locations. The obtained sweat cortisol data is crucial for analyzing human stress in personalized and clinical healthcare sectors.

AI snapshot

Written from the paper’s full text.

TL;DR

MicroSweat is a flexible, self-powered capillary microfluidic patch that reliably collects sweat from multiple body locations and enables ex-situ cortisol measurement for human stress monitoring. It reports body-location-specific sweat cortisol ranges that correlate nonlinearly with perceived stress scale scores, with armpit sweat showing the widest and most stress-compatible range.

Key findings

  • The patch is about 230 µm thick (about 310 µm with skin adhesives), collects up to 120 µL sweat, and supports chrono sampling with filling intervals up to 2 min ± 20 s for larger fibers, 1.25 min ± 15 s for medium fibers, and up to 3 s for smaller fibers.
  • Sweat cortisol ranges for severe/high stress were 25–125 ng mL⁻¹ averaged across multiple body regions and 100–1000 ng mL⁻¹ from the axilla; low and medium ranges were 1–5 and 5–25 ng mL⁻¹ for multiple locations, and 1–10 and 10–100 ng mL⁻¹ for armpits.
  • Cortisol concentration showed a positive nonlinear/exponential relationship with PSS stress scores. Females had higher mean sweat cortisol than males (55 ng mL⁻¹ vs 13.7 ng mL⁻¹), with significant sex differences overall (p < 0.05) and in armpits (p ≤ 0.01); age groups differed significantly (p < 0.05), especially in armpits (p < 0.01) and hands (p < 0.05), while body side differences were not significant (p > 0.05).
  • Average sweat collection times were 31.5 min for armpit (range 7–47 min), 33.1 min for lower back (10–55 min), 35 min for upper back (7–55 min), and 50 min for hand (15–60 min); the paper estimates future biosensor-integrated patches needing 5–10 µL could reduce testing to about 7–15 min.

Methods

  • MicroSweat was fabricated by one-step laser cutting and assembly of flexible polymer sheets, pressure-sensitive adhesives, transparent polyester, cellulose wicking pads, and nitrocellulose or glass microfiber storage fibers; sweat flow was optimized using an electric circuit analogy model and ANSYS FLUENT VOF simulations.
  • Human sweat was collected from 11 healthy volunteers (5 males, 6 females) during 30–60 min treadmill walking at low speed (level 5), with patches mounted on hands, armpits, forehead, and backs; PSS was assessed before exercise and one month after.
  • Stored sweat was recovered by centrifuging fibers at 11,000 rpm for 5 min, frozen at −80 °C, and analyzed for cortisol by ELISA; statistical analysis used R v.4.1.1 with two-tailed t-tests and F-tests at α = 0.05.

Limitations

  • The paper states that larger cohort studies are needed to address discrepancies and provide more robust support for claims about sex, age, and stress-level correlations, and notes that sweat cortisol reports are rare.
  • Evident from the text: human trials used a small sample (11 volunteers; longitudinal monitoring n = 3), sweating was induced only by treadmill exercise, and cortisol was measured ex situ by ELISA rather than by an integrated real-time wearable sensor.

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

Integrity signals

Registry

Crossref · 10.1002/advs.202204171

Cites

84 of 84 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 43 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    The mean difference in cortisol concentration between males and females is more highlighted in the armpit areas, showing a p-value ≤ 0.01.

    “When comparing different body locations, the mean value difference in cortisol concentration is more highlighted in the armpit areas, showing a p‐value ≤ 0.01 among male and female groups (Figure 7b).”
    Quote in the paperNot a substantial claim
  • Findingown data

    MicroSweat can simultaneously collect human sweat from different body locations, including sweat produced by eccrine and apocrine glands.

    “Figure 7a shows that the wearable MicroSweat patch developed in this study can simultaneously collect human sweat from different body locations, including the sweat produced by eccrine and apocrine glands.”
    Quote in the paperSubstantial claim
  • Findingown data

    MicroSweat preserves the concentration and integrity of sweat biomolecules.

    “preserve the concentration and integrity of sweat biomolecules corresponding to stress levels”
    • Also stated in: § Thin, Soft Microfluidic Devices for Sweat Sampling · boosted
      “This fiber saturation confirms the preservation of sweat molecule concentrations in these fibers.”
    Quote in the paperSubstantial claim
  • Findingown data

    MicroSweat enables sequential storage of sweat generated at different time points (Chrono sampling).

    “sequential storage of the sweat generated at different time points during the human test (Chrono sampling)”
    • Also stated in: § A Chrono Sampling of Sweat · plain
      “Chrono sampling of the human sweat by wearable MicroSweat.”
    Quote in the paperSubstantial claim
  • Findingnone given

    MicroSweat increases the volume of collected sweat up to 120 μL.

    “increasing the volume of collected sweat up to 120 µL”
    • Also stated in: § Intra‐Individual and Inter‐Individual Variations in Human Sweat Dynamics · plain
      “The relatively long collection period is only applied to the tests aiming to collect high sweat volume (about 120 µL) for further biomarker discovery.”
    Quote in the paperSubstantial claim
  • May combine two claims. 31
  • Classified as probably not a substantial claim. 22
  • The quote only partly states this claim. 1

  • May combine two claims.

    Findingown data

    MicroSweat is mechanically robust and flexible, withstanding 500 bending-releasing cycles.

    “MicroSweat is mechanically robust with a bendable structure that can be easily mounted and safely sealed on the skin surface of different body locations.”
    • Also stated in: § Thin, Soft Microfluidic Devices for Sweat Sampling · plain
      “Figure 1h–j shows the stability of MicroSweat during 500 bending‐releasing cycles.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    Storage fibers facilitate collection of sweat generated at different time intervals, with older sweat collected by earlier storage fibers and newer sweat stored in downstream storage fibers.

    “Therefore, storage fibers facilitate the collection of sweat generated at different time intervals. The older sweat is collected by the earlier storage fibers while the newer sweat is stored in the downstream storage fibers enabling the separation of the old and new sweat.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Variations of cortisol concentrations between the two age groups are highlighted in the armpit areas with a p-value < 0.01 and hand areas with a p-value < 0.05.

    “The difference in regional body locations highlights variations of cortisol concentrations between the two age groups in the armpit areas with a p‐value < 0.01 and hand areas with a p‐value < 0.05 (Figure 7f; see Table S6, Supporting Information, for more details on t‐test analysis).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingreasoning

    All bubbles flowing through the inlet channels into the main channel run out through the trigger valves and the storage chambers, enabling bubble-free sweat flow downstream of the main channel.

    “Meantime, all bubbles flowing through the inlet channels into the main channel run out through the trigger valves and the storage chambers. This enables bubble‐free sweat flow downstream of the main channel where future biosensors would be embedded.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Only the valves with lower hydrophobicity are opened, allowing the sweat to flow into the storage chambers.

    “Only the valves with lower hydrophobicity are opened (Figure 4e), allowing the sweat to flow into the storage chambers.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Filling time intervals for Chrono sampling are up to 2 min ± 20 s for larger fibers, 1.25 min ± 15 s for medium fibers, and up to 3 s for smaller fibers.

    “The interval time of up to 2 min ± 20 s for larger fibers, 1.25 min ± 15 s for medium fibers, and up to 3 s for the smaller fibers indicates the reliable and repeatable pattern for Chrono sampling of the sweat.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    There is intra-individual variation in sweat generation and collection as well as inter-individual variation depending on the body location.

    “The results of on‐human sweat collection tests show that there is an intra‐individual variation in sweat generation and collection as well as inter‐individual variation depending on the body location.”
    Quote in the paperSubstantial claim

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

    Findingown data

    Median cortisol concentrations slightly increase with increasing age.

    “The results show a slight increase in median cortisol concentrations with increasing age.”
    Quote in the paperNot a substantial claim

  • May combine two claims. The quote only partly states this claim.

    Findingown data

    Laser parameters were optimized, and the variation between channel widths in Ch1 to Ch7 is <±25 μm, indicating high reproducibility of creating microchannels.

    “Figure S1a‐d, Supporting Information, shows that the variation between the channel widths in Ch1 to Ch7 is <±25 µm, indicating high reproducibility of creating microchannels of the wearable MicroSweat patches.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The armpit body location has the highest rate of sweat generation, followed by LB and UB, with an almost two-minute time difference.

    “When comparing the average time of sweat generation, the armpit body location has the highest rate of sweat generation, followed by LB and UB, with an almost two‐minute time difference.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Sweat cortisol concentration averaged across multiple body locations ranges from 1 to 5 ng/mL for low stress, 5 to 25 ng/mL for medium stress, and 25 to 125 ng/mL for high stress.

    “The resulting sweat cortisol concentration for multiple body locations ranges from 1 to 5 ng mL−1 corresponding to low‐stress levels, 5 to 25 ng mL−1 corresponding to the medium stress level, and 25 to 125 ng mL−1 for high‐stress levels.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    A relative increase in armpit sweat cortisol from Monday to Friday is seen for all participants and appeared profound compared to other body locations.

    “A relative increase in the cortisol of the armpit sweat from Monday to Friday is seen for all participants and appeared to be profound compared to other body locations.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Most body locations demonstrate daily variation, with mean cortisol response higher in the morning than in the afternoon.

    “Most body locations also demonstrate this variation, with a mean value of cortisol response being higher in the morning than in the afternoon (Figure 8b).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    For armpit-only mean sweat cortisol, the ranges are 1-10 ng/mL for low stress, 10-100 ng/mL for medium stress, and 100-1000 ng/mL for high stress, with better compatibility with PSS test results.

    “These ranges, however, differ for the mean value of only armpits with wider ranges but better compatibility with the PSS test results, with 1–10 ng mL−1 for low‐stress levels, 10–100 ng mL−1 for medium‐stress levels, and 100–1000 ng mL−1 for high‐stress level.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    Human participant #1 expressed anxiety issues over a long period, leading to a high basal cortisol concentration.

    “This was detectable for human participant #1, who expressed anxiety issues over a long period, leading to a high basal cortisol concentration.”
    Quote in the paperNot a substantial claim

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

    Findingnone given

    The lateral flow nitrocellulose absorbs low volume of sweat (1-5 μL) while microfiber glass absorbs high volume of sweat (20-120 μL), for fibers with a specific size in this study.

    “The lateral flow nitrocellulose absorbs the low volume of sweat (1–5 µL) while the microfiber glass absorbs a high volume of sweat (20–120 µL), for fibers with a specific size in this study.”
    Quote in the paperNot a substantial claim

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

    Findingnone given

    The hydrophilicity of the TPE stems from the surfactant-free treatment, which makes the surface intact to various biomarkers.

    “The hydrophilicity of the TPE stems from the surfactant‐free treatment, which makes the surface intact to various biomarkers.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingnone given

    The wearable MicroSweat patch is a self-operated and electronic-free microfluidic system fabricated using a scale-compatible manufacturing process.

    “In summary, the wearable MicroSweat patch is a self‐operated and electronic‐free microfluidic system fabricated using a scale‐compatible manufacturing process.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The MicroSweat patch enabled measuring sweat cortisol levels in different body locations, with the most predictive cortisol concentration detectable in the armpits.

    “The MicroSweat patch enabled measuring sweat cortisol levels in different body locations, with the most predictive cortisol concentration detectable in the armpits.”
    Quote in the paperSubstantial claim

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

    Findingnone given

    It takes about 10 ± 5 s to mount the wearable MicroSweat patch on the skin.

    “It takes about 10 ± 5 s to mount the wearable MicroSwrat patch on the skin.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    In humans, stress increases circulating cortisol, and this increase is reflected as increased cortisol release from the sweat glands in the skin.

    “In humans, stress increases circulating levels of cortisol. This increase is also reflected as an increase in cortisol release from the sweat glands in the skin.[ 5 ]”
    • Also stated in: § Abstract · plain
      “Increased circulating cortisol during stress is mirrored by cortisol release from sweat glands, providing an opportunity to use it as an external biomarker for monitoring internal emotional state.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [5] O. Parlak, Sens Actuators Rep. 2021, 3, 100036.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Most current wearable sensors that contain electrodes on a flexible substrate are directly in contact with the skin to measure the cortisol response, and their temporal resolution of measured cortisol is often poor.

    “Most of the current wearable sensors that contained electrodes on a flexible substrate were directly in contact with the skin to measure the cortisol response.[ 8 ] Although they are simple structures that do not require a complicated fabrication process for creating sweat‐collection features on the device, the temporal resolution of their measured cortisol is often poor.[ 9 ]”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [8] a) Y. J. Hong, H. Lee, J. Kim, M. Lee, H. J. Choi, T. Hyeon, D.‐H. Kim, Adv. Funct. Mater. 2018, 28, 1805754. b) Y. Yang, Y. Song, X. Bo, J. Min, O. S. Pak, L. Zhu, M. Wang, J. Tu, A. Kogan, H. Zhang, T. K. Hsiai, Z. Li, W. Gao, Nat. Biotechnol. 2020, 38, 217; 31768044 c) H. B. Lee, M. Meeseepong, T. Q. Trung, B. Y. Kim, N. E. Lee, Biosens. Bioelectron. 2020, 156, 112133; 32174559 d) J. R. Sempionatto, M. Lin, L. Yin, E. De la Paz, K. Pei, T. Sonsa‐Ard, A. N. de Loyola Silva, A. A. Khorshed, F. Zhang, N. Tostado, S. Xu, J. Wang, Nat. Biomed. Eng. 2021, 5, 737; 33589782 e) W. Tang, L. Yin, J. R

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [9] E. J. M. Moonen, J. R. Haakma, E. Peri, E. Pelssers, M. Mischi, J. M. J. den Toonder, View 2020, 1, 20200077.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Most wearable sweat-collecting microfluidic devices used silicone elastomers and lithography approaches for chip fabrication, but the hydrophilic property of these materials is primarily temporal.

    “Most wearable sweat‐collecting microfluidic devices used silicone elastomers and lithography approaches for chip fabrication.[ 12 ] However, the hydrophilic property of these materials is primarily temporal.[ 13 ]”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [12] a) A. Martin, J. Kim, J. F. Kurniawan, J. R. Sempionatto, J. R. Moreto, G. Tang, A. S. Campbell, A. Shin, M. Y. Lee, X. Liu, J. Wang, ACS Sens. 2017, 2, 1860; 29152973 b) S. B. Kim, J. Koo, J. Yoon, A. Hourlier‐Fargette, B. Lee, S. Chen, S. Jo, J. Choi, Y. S. Oh, G. Lee, S. M. Won, A. J. Aranyosi, S. P. Lee, J. B. Model, P. V. Braun, R. Ghaffari, C. Park, J. A. Rogers, Lab Chip 2020, 20, 84; 31776526 c) J. Choi, D. Kang, S. Han, S. B. Kim, J. A. Rogers, Adv. Healthcare Mater. 2017, 6, 1601355. 28105745 d) J. T. Reeder, J. Choi, Y. Xue, P. Gutruf, J. Hanson, M. Liu, T. Ray, A. J. B. Bandodkar, source

      Not checked in the free run.

    • cites [13] a) S. B. Kim, Y. Zhang, S. M. Won, A. J. Bandodkar, Y. Sekine, Y. Xue, J. Koo, S. W. Harshman, J. A. Martin, J. M. Park, T. R. Ray, K. E. Crawford, K. T. Lee, J. Choi, R. L. Pitsch, C. C. Grigsby, A. J. Strang, Y. Y. Chen, S. Xu, J. Kim, A. Koh, J. S. Ha, Y. Huang, S. W. Kim, J. A. Rogers, Small 2018, 14, 1703334; b) J. D. Wang, N. J. Douville, S. Takayama, M. ElSayed, Ann. Biomed. Eng. 2012, 40, 1862. 22484830

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

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

    Interpretationcitation

    The higher sweat cortisol concentration in females versus males may be attributed to the larger pituitary gland volume in females as the primary regulatory organ of cortisol.

    “Except for the forehead, in both apocrine and eccrine sweat glands, sweat cortisol concentration is higher in females versus males, which may be attributed to the larger pituitary gland volume in females as the primary regulatory organ of cortisol.[ 22 ]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [22] a) F. P. MacMaster, M. Keshavan, Y. Mirza, N. Carrey, A. R. Upadhyaya, R. El‐Sheikh, C. J. Buhagiar, S. P. Taormina, C. Boyd, M. Lynch, M. Rose, J. Ivey, G. J. Moore, D. R. Rosenberg, Life Sci. 2007, 80, 940; 17174342 PMC1853319 b) A. Levine, O. Zagoory‐Sharon, R. Feldman, J. G. Lewis, A. Weller, Physiol. Behav. 2007, 90, 43. 17055006 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The poor temporal resolution of direct-contact cortisol sensors is due to environmental artifacts such as evaporation and contamination, discontinuous sweat flow causing bubble reading signals, mixing of new and old sweat, and loss of dynamic monitoring of sweat composition.

    “This is due to environmental artifacts such as evaporations and contamination issues, and discontinuous sweat flow, which causes bubble reading signals, mixing of new and old sweat, and losing dynamic monitoring of sweat for temporal variation in its composition.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [9] E. J. M. Moonen, J. R. Haakma, E. Peri, E. Pelssers, M. Mischi, J. M. J. den Toonder, View 2020, 1, 20200077.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

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

    Premisecitation

    Adenylate cyclase, a second messenger released by the pituitary gland, promotes different levels of sweat secretion in women versus men.

    “Moreover, adenylate cyclase, a second messenger released by the pituitary gland, promotes different levels of sweat secretion in women versus men.[ 23 ]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [23] S. Sasaki, J. Watanabe, H. Ohtaki, M. Matsumoto, N. Murai, T. Nakamachi, J. Hannibal, J. Fahrenkrug, H. Hashimoto, H. Watanabe, H. Sueki, K. Honda, A. Miyazaki, S. Shioda, Br. J. Dermatol. 2017, 176, 413. 27453364 source

      Not checked in the free run.

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

    Premisecitation

    Detection of cortisol as a stress biomarker in sweat is at the forefront of wearable stress detection devices currently in development.

    “Detection of cortisol as a stress biomarker in sweat is at the forefront of wearable stress detection devices currently in development.[ 20 ]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [20] C. Samson, A. Koh, Front. Bioeng. Biotechnol. 2020, 8, 1037. 32984293 PMC7492543 source

      Not checked in the free run.

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

    Interpretationnone given

    The insulating adhesive layer separates the skin from the microfluidic layers, eliminating or minimizing the effect of skin temperature on the collected sweat constituents.

    “In addition, the insulating adhesive layer separates the skin from the microfluidic layers, eliminating or minimizing the effect of skin temperature on the collected sweat constituents.”
    Quote in the paperNot a substantial claim

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

    Interpretationreasoning

    Multiple inlet reservoirs help faster sweat collection due to the plurality effects of several inlet reservoirs.

    “Having multiple inlet reservoirs, besides having the benefit of collecting sweat from different locations on the skin, can help with faster sweat collection due to the plurality effects of several inlet reservoirs.”
    Quote in the paperNot a substantial claim

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

    Interpretationnone given

    The wearable MicroSweat patch was fabricated in a process compatible with scale production of microfluidic devices.

    “Notably, the wearable MicroSweat patch was fabricated in a process compatible with the scale production of microfluidic devices.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Study design and conductnone given

    The numerical models are reliable, tested and verified for several microfluidic geometries and constitutions.

    “Given the reliability of the numerical models, tested, and verified for several microfluidic geometries and constitutions, numerical modeling was performed to study the effect of hydrophobic surfaces (two different contact angles 90o and 120o) on the function of delay valves.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation

    Vents located on top of the storage chambers that are <300 μm in diameter prevent sweat evaporation and help preserve the molecular contents of the sweat in the stored fibers.

    “The vents located on top of the storage chambers are <300 µm in diameter to prevent sweat evaporation (based on the Langmuir's free evaporation equation in vacuum[ 11 , 18 ] (see Section S4, Supporting Information) and help preserve the molecular contents of the sweat in the stored fibers.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [11] a) A. Kaushik, A. Vasudev, S. K. Arya, S. K. Pasha, S. Bhansali, Biosens. Bioelectron. 2014, 53, 499; 24212052 b) S. K. Arya, A. Dey, S. Bhansali, Biosens. Bioelectron. 2011, 28, 166; 21803565 c) A. Bhide, S. Cheeran, S. Muthukumar, S. Prasad, Biosensors (Basel) 2019, 9, 13. 30654428 PMC6468720 d) B. Jagannath, S. Muthukumar, S. Prasad, Anal. Chim. Acta 2018, 1016, 29; 29534802 e) H. J. Jang, T. Lee, J. Song, L. Russell, H. Li, J. Dailey, P. C. Searson, H. E. Katz, ACS Appl. Mater. Interfaces 2018, 10, 16233; 29701946 PMC6026499 f) K. H. Kim, S. H. Lee, S. E. Seo, J. Bae, S. J. Park, O. S. Kwo source

      Not checked in the free run.

    • cites [18] a) M. A. Khoshooei, J. Therm. Anal. Calorim. 2021, 147, 6015; b) S. F. Wright, D. Dollimore, J. G. Dunn, K. Alexander, Thermochim. Acta 2004, 421, 25; c) K. Chatterjee, D. Dollimore, K. Alexander, Instrum. Sci. Technol. 2001, 29, 133.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

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

    Premisecitation

    Salivary cortisol concentration increase is more prominent in aged women (>60) than young women (<30).

    “There is no other study comparing sweat cortisol levels in different ages, but the cortisol concentration analysis in salivary biofluid in the literature shows that the increase in the salivary cortisol concentration is more prominent in aged women (>60) than young women (<30).[ 25 ]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [25] M. Bakke, A. Tuxen, C. E. Thomsen, A. Bardow, T. Alkjaer, B. R. Jensen, Gerontology 2004, 50, 383. 15477699 source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Cortisol plays a significant role in organizing the body's response to physiological and psychological stressors.

    “Cortisol plays a significant role in organizing the body's response to physiological and psychological stressors.[ 22b ]”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [ 22b ]

      Not checked in the free run.

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

    Premisecitation

    Few studies have correlated cortisol concentrations and stress levels.

    “There are physiological and psychological methods for stress detection,[ 31 ] but few studies correlated the cortisol concentrations and stress levels (see Table S9, Supporting Information).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [31] N. Skoluda, J. Strahler, W. Schlotz, L. Niederberger, S. Marques, S. Fischer, M. V. Thoma, C. Spoerri, U. Ehlert, U. M. Nater, Psychoneuroendocrinology 2015, 51, 227. 25462896 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Sweat biomarker information from both apocrine and eccrine glands facilitates the creation of accurate sweat-based wearable diagnostic systems and could provide reliable sweat cortisol concentrations.

    “Sweat biomarker information from both apocrine and eccrine glands[ 21 ] facilitates the creation of accurate sweat‐based wearable diagnostic systems and could provide reliable sweat cortisol concentrations.[ 6e ]”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [21] T. Kaya, G. Liu, J. Ho, K. Yelamarthi, K. Miller, J. Edwards, A. Stannard, Electroanalysis 2019, 31, 411.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [ 6e ]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

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

    Premisecitation

    Nicolson et al. found no difference in salivary cortisol levels between males and females at all ages except for higher cortisol levels in old women than in old men.

    “In addition, they found no difference in salivary cortisol levels between males and females at all ages except for higher cortisol levels in old women than in old men.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [27] N. Nicolson, C. Storms, R. Ponds, J. Sulon, J. Gerontol.: Med. Sci. 1997, 52A, M68. 9060972 source

      Not checked in the free run.

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

    Premisecitation

    A physiological method previously subjected workers' stress levels to different stress levels equivalent to 0.5 to 4 ng/mL of salivary cortisol.

    “For instance, the result of a physiological method for the salivary cortisol previously subjected workers' stress levels to different stress levels equivalent to 0.5 to 4 ng mL−1 of salivary cortisol.[ 32 ]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [32] H. Jebelli, B. Choi, S. Lee, J. Constr. Eng. Manag. 2019, 145, 04019079.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Interpretationreasoning

    Armpits can be one of the most reliable body locations for future real-time monitoring of stress levels in different populations because of considerable change in cortisol levels compared to other body locations and better compatibility with general stress scale tests.

    “Therefore, armpits can be one of the most reliable body locations for future real‐time monitoring of stress levels in different populations because of i) a considerable change in cortisol levels compared to other body locations and ii) better compatibility with the general stress scale tests.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The exercise protocol used to induce sweating does not confound the relationship between sweat cortisol concentration and psychological stress measured by the PSS.

  • May combine two claims.

    Premisecitation

    The number of sweat glands and sweat rate might differ at each side of the body, but they seem to mostly affect sweat ions (excluding ions like Na+) with minimal effect on other biomarkers.

    “Although the number of sweat glands and sweat rate might differ at each side of the body, they seem to mostly affect the sweat ions (excluding ions like Na+)[ 28 ] with a minimal effect on other biomarkers.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [28] a) S. W. Harshman, R. L. Pitsch, Z. K. Smith, M. L. O'Connor, B. A. Geier, A. V. Qualley, N. M. Schaeublin, M. V. Fischer, J. J. Eckerle, A. J. Strang, J. A. Martin, PLoS One 2018, 13, e0203133; 30383773 PMC6211630 b) L. B. Baker, P. J. D. De Chavez, C. T. Ungaro, B. C. Sopena, R. P. Nuccio, A. J. Reimel, K. A. Barnes, Eur. J. Appl. Physiol. 2019, 119, 361. 30523403 PMC6373370 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Apocrine areas such as axillary areas are responsive to emotional sweating, and apocrine glands are activated by adrenergic stimulation and strongly respond to emotions such as stress.

    “The apocrine areas, such as the axillary areas are reported to be responsive to emotional sweating and the apocrine glands are activated by adrenergic stimulation and strongly respond to emotions such as stress.[ 33 ]”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [33] A. Zamkah, T. Hui, S. Andrews, N. Dey, F. Shi, R. S. Sherratt, Biosensors (Basel) 2020, 10, 40. 32316280 PMC7235866 source

      Not checked in the free run.

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

    Premisecitation

    Nicolson et al. showed no change in hypothalamic-pituitary-adrenal (HPA) activity and the subsequent release of cortisol from the adrenal gland until ages over 70.

    “In contrast, studying the effect of age on salivatory cortisol concentration by Nicolson et al.[ 27 ] showed no change in the hypothalamic‐pituitary‐adrenal (HPA) activity and the subsequent release of the steroid hormone cortisol from the outer cortex of the adrenal gland until the ages of over 70.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [27] N. Nicolson, C. Storms, R. Ponds, J. Sulon, J. Gerontol.: Med. Sci. 1997, 52A, M68. 9060972 source

      Not checked in the free run.

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

    Premisecitation

    During adolescence and beyond the age of 50, a gradual increase in salivary cortisol was observed for both males and females.

    “Similarly, during adolescence and beyond the age of 50, a gradual increase in salivary cortisol was observed for both males and females, which was argued to be attributed to the onset of puberty.[ 26 ]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [26] R. Miller, T. Stalder, M. Jarczok, D. M. Almeida, E. Badrick, M. Bartels, D. I. Boomsma, C. L. Coe, M. C. Dekker, B. Donzella, J. E. Fischer, M. R. Gunnar, M. Kumari, F. Lederbogen, C. Power, C. D. Ryff, S. V. Subramanian, H. Tiemeier, S. E. Watamura, C. Kirschbaum, Psychoneuroendocrinology 2016, 73, 16. 27448524 PMC5108362 source

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductcitation

    A urinary cortisol ELISA kit was selected due to its wide cortisol detection range of 0.47-200 ng/mL, meeting the needs of human skin cortisol concentration measurement, and previously used in other reports.

    “A urinary cortisol ELISA kit was selected due to its wide cortisol detection range of 0.47–200 ng mL−1, meeting the needs of human skin cortisol concentration measurement, and previously used in other reports.[ 23 ]”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [23] S. Sasaki, J. Watanabe, H. Ohtaki, M. Matsumoto, N. Murai, T. Nakamachi, J. Hannibal, J. Fahrenkrug, H. Hashimoto, H. Watanabe, H. Sueki, K. Honda, A. Miyazaki, S. Shioda, Br. J. Dermatol. 2017, 176, 413. 27453364 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationcitation

    Exciting opportunities are offered for non-invasive dynamic stress monitoring.

    “exciting opportunities are offered for non‐invasive dynamic stress monitoring.[ 8 , 37 ]”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [8] a) Y. J. Hong, H. Lee, J. Kim, M. Lee, H. J. Choi, T. Hyeon, D.‐H. Kim, Adv. Funct. Mater. 2018, 28, 1805754. b) Y. Yang, Y. Song, X. Bo, J. Min, O. S. Pak, L. Zhu, M. Wang, J. Tu, A. Kogan, H. Zhang, T. K. Hsiai, Z. Li, W. Gao, Nat. Biotechnol. 2020, 38, 217; 31768044 c) H. B. Lee, M. Meeseepong, T. Q. Trung, B. Y. Kim, N. E. Lee, Biosens. Bioelectron. 2020, 156, 112133; 32174559 d) J. R. Sempionatto, M. Lin, L. Yin, E. De la Paz, K. Pei, T. Sonsa‐Ard, A. N. de Loyola Silva, A. A. Khorshed, F. Zhang, N. Tostado, S. Xu, J. Wang, Nat. Biomed. Eng. 2021, 5, 737; 33589782 e) W. Tang, L. Yin, J. R

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [37] S. Upasham, A. Tanak, B. Jagannath, S. Prasad, Sci. Rep. 2018, 8, 16745. 30425312 PMC6233171 source

      Not checked in the free run.

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

    Premisecitation

    A nonlinear and differential relationship between human stress levels and salivary cortisol concentrations has been reported in another study.

    “Such a nonlinear and differential relationship between human stress levels and salivary cortisol concentrations has also been reported in another study.[ 34 ]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [34] M. Castro, P. C. L. Elias, C. E. Martinelli Jr, S. R. R. Antonini, L. Santiago, A. C. Moreira, Braz. J. Med. Biol. Res. 2000, 33, 1171. 11004717 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationown data

    These findings can be an essential basis for future detection of human stress levels using wearable microfluidic and sensor devices.

    “These findings can be an essential basis for the future detection of human stress levels using wearable microfluidic and sensor devices.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The exercise protocol used to induce sweating does not confound the relationship between sweat cortisol concentration and psychological stress measured by the PSS.

  • May combine two claims.

    Interpretationown data

    Compared to few flexible sensors and/or microfluidic devices in the literature for direct/indirect stress monitoring in sweat, this work presents a continuous sweat flow platform and comprehensively quantified sweat cortisol response regionally, individually including sex and age, and personally along with daily and longitudinally monitoring considerations.

    “Table S9, Supporting Information, shows that compared to the few flexible sensors and/or microfluidic devices currently in the literature[ 8 , 36 ] for either direct/indirect stress monitoring in sweat, this work presents continuous sweat flow platform and comprehensively quantified sweat cortisol response regionally, individually including sex, and age, and personally along with daily and longit”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [8] a) Y. J. Hong, H. Lee, J. Kim, M. Lee, H. J. Choi, T. Hyeon, D.‐H. Kim, Adv. Funct. Mater. 2018, 28, 1805754. b) Y. Yang, Y. Song, X. Bo, J. Min, O. S. Pak, L. Zhu, M. Wang, J. Tu, A. Kogan, H. Zhang, T. K. Hsiai, Z. Li, W. Gao, Nat. Biotechnol. 2020, 38, 217; 31768044 c) H. B. Lee, M. Meeseepong, T. Q. Trung, B. Y. Kim, N. E. Lee, Biosens. Bioelectron. 2020, 156, 112133; 32174559 d) J. R. Sempionatto, M. Lin, L. Yin, E. De la Paz, K. Pei, T. Sonsa‐Ard, A. N. de Loyola Silva, A. A. Khorshed, F. Zhang, N. Tostado, S. Xu, J. Wang, Nat. Biomed. Eng. 2021, 5, 737; 33589782 e) W. Tang, L. Yin, J. R

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [36] a) J. S. Nah, S. C. Barman, M. A. Zahed, M. Sharifuzzaman, H. Yoon, C. Park, S. Yoon, S. Zhang, J. Y. Park, Sens. Actuators, B 2021, 329, 129206; b) O. Parlak, S. T. Keene, A. Marais, V. F. Curto, A. Salleo, Sci. Adv. 2018, 4, eaar2904; 30035216 PMC6054510 c) B. Wang, C. Zhao, Z. Wang, K. A. Yang, X. Cheng, W. Liu, W. Yu, S. Lin, Y. Zhao, K. M. Cheung, H. Lin, H. Hojaiji, P. S. Weiss, M. N. Stojanović, A. J. Tomiyam, A. M. Andrews, S. Emaminejad, Sci. Adv. 2022, 8, eabk0967. 34985954 PMC8730602 source

      Not checked in the free run.

48 of 48

  • The paper relies on this without support.

    Wearable smartwatch physiological parameters are not direct stress signals; changes in them do not directly reflect internal state changes.

    “Wearable smartwatches provide noninvasive monitoring of physiological parameters that may indicate changes in stress state. These parameters, however, are not direct stress signals; thus, changes do not directly reflect internal state changes.”

  • The paper relies on this without support.

    Technologies for quantitative and longitudinal detection of stress biomarkers in sweat are in their infancy.

    “The technologies for quantitative and longitudinal detection of stress biomarkers in sweat are in their infancy.”

  • The paper relies on this without support.

    Material preparations and lithography processes require multistep processing, which is time-consuming and costly.

    “In addition, the material preparations and lithography processes require multistep processing, which is time‐consuming and costly.”

  • The paper relies on this without support.

    There is no other study comparing sweat cortisol levels in different ages.

    “There is no other study comparing sweat cortisol levels in different ages, but the cortisol concentration analysis in salivary biofluid in the literature shows that the increase in the salivary cortisol concentration is more prominent in aged women (>60) than young women (<30).[ 25 ]”

  • The paper relies on this without support.

    Reports on sweat cortisol levels are rare.

    “Specifically, reports on sweat cortisol levels are rare.”

  • The authors state this as an assumption.

    The sweat flow in the microchannels can be modeled as laminar, viscous, incompressible, fully developed flow, and end effects, surface roughness, and gravity can be ignored.

    “To use an electric circuit analogy, the assumption of laminar, viscous, and incompressible fully developed fluid flow was considered for the sweat flow in the microchannels. Furthermore, the microchannels' end effects, surface roughness, and the effect of gravity were ignored.[ 39 ]”

  • The paper relies on this without support.

    The exercise protocol used to induce sweating does not confound the relationship between sweat cortisol concentration and psychological stress measured by the PSS.

    “In this study, sweating is induced using physical exercise via a 30–60 min treadmill walking at low speed (level 5) while wearing the MicroSweat patches on different body locations, including hands, armpits, foreheads, and backs.”
7 of 7

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?

  • Only a few studies have focused on the relationship between biofluid signals and human health parameters, such as cortisol sensing and stress, glucose sensing and diabetes, or physiological data related to Parkinson's disease.

    “Only a few studies have focused on this, such as one recent work on cortisol sensing and its relation to human stress levels [129] and glucose sensing and its relation to diabetes levels in patients [252], or physiological data related to Parkinson’s disease [253].”

    From The emergence of AI-based wearable sensors for digital health technology: a review (2023) · cites this paper as [129]

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.

  • Figure 9 panels are assigned different measurements

    Minor

    The text assigns the multiple-body-location results to Figure 9a and the armpit results to Figure 9b. The caption instead assigns both 9a and 9b to the multiple-body-location results and 9c and 9d to the armpit results.

  • Figure 7 map is cited as panel i but caption labels it j

    Minor

    The discussion directs readers to Figure 7i for the map of individual cortisol concentrations, whereas the figure caption identifies that map as Figure 7j.

  • Figure 8a and 8b descriptions are reversed

    Minor

    The text identifies Figure 8a as the measurements at three times of day for individual participants and Figure 8b as the comparison across body locations. The caption assigns those descriptions to 8b and 8a, respectively.

  • PSS score of 13 receives conflicting stress classifications

    Minor

    The Experimental Section defines low stress as scores below 13, while the Figure 9 caption includes 13 in the low-stress range.

4 of 4

Cites

Flagged first, then by citations

1 of the 85 references couldn’t be matched to a known paper.

Research works printed but not linked: 2

  1. Cardinell B. A., 2019, CRC Crit. Rev. Bioeng., 47, 207
  2. Chiriac E., 2022, Micromachines (Basel), 13, 6

Cited by

Sorted by citations

Related

Authors
Shajari, S., Salahandish, R., Zare, A., Hassani, M., Moossavi, S., Munro, E., Rashid, R., Rosenegger, D., Bains, J. S., & Sanati Nezhad, A.
Affiliations
  • University of Calgary (CA)
  • SenseSi Co. Calgary Alberta T2L 1Y8 Canada
  • BioMEMS and Bioinspired Microfluidic Laboratory Department of Biomedical Engineering University of Calgary Calgary Alberta T2N 1N4 Canada
Corresponding author
Bains, Jaideep S.
ORCID
Venue
Advanced Science
Publisher
Wiley
Published
2022-12-03
Volume
10
Issue
7
Pages
e2204171-e2204171
ISSN
2198-3844 (ISSN-L)
DOI
10.1002/advs.202204171
PMC
PMC9982588
OpenAlex
W4310641398
Semantic Scholar
6bcc66437a69fbacc0e699b91d2337a7ef626e91
Cited by
55
References
85
Citations by year
2026: 13 · 2025: 14 · 2024: 15 · 2023: 12 · 2022: 1
FWCI
3.05
Type
journal article
Language
en
Open access
Licence
Locations
  • Advanced Science (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
  • University of Calgary
  • Alberta Innovates
  • Natural Sciences and Engineering Research Council of Canada
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 collection, wearable sensors, cortisol, stress monitoring, non-invasive biomarkers, capillary microfluidics, self-powered devices, Perceived Stress Scale
MeSH terms
Wearable Electronic Devices, Humans, Hydrocortisone, Sweat, Sweat Glands, Microfluidics

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.

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