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Cited by 77Advanced Sensor and Energy Harvesting MaterialsNon-Invasive Vital Sign MonitoringElectrochemical sensors and biosensors

A review of sampling, energy supply and intelligent monitoring for long-term sweat sensors

Open access
Yang, Pufan, Wei, Gaofeng, Liu, Ang, Huo, Fengwei, Zhang, Zhinan·2022·npj Flexible Electronics
DOI 10.1038/s41528-022-00165-9
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Abstract

Sweat is a biofluid with rich information that can reflect an individual’s state of health or activity. But the real-time in situ sweat sensors lack the ability of long-term monitoring. Against this background, this article provides a holistic review on the necessary process and methods for sweat sensing, including sweat collection, composition analysis, energy supply, and data processing. The impacts of the environment in stimulating sweat production, providing energy supply, and intelligent health monitoring are discussed. Based on the review of previous endeavors, the future development in material, structure and artificial intelligence application of long-term sweat monitoring is envisioned.

AI snapshot

Written from the paper’s full text.

TL;DR

This review surveys the components needed for long-term wearable sweat sensing: sweat sampling/control, sweat composition and analytes, sustainable energy supply, and AI/ML-based intelligent monitoring. It argues that long-term sweat monitoring remains limited by collection efficiency, contamination, energy autonomy, unclear sweat–health relationships, and sensor accuracy.

Key findings

  • Sweat secretion rates can be lower than 10 nL min⁻¹ cm⁻² at low-secretion sites such as arm or leg, but can reach 100 nL min⁻¹ cm⁻² at high-secretion areas like palm and foot.
  • Sweat pH is generally reported as 4.2–7.8; sweat lactate concentration ranges from ~6 mM to ~100 mM; sweat cortisol is reported as 2.21 × 10⁻⁵ to 3.86 × 10⁻⁴ mM versus blood cortisol generally 1.24 × 10⁻⁴ to 4.0 × 10⁻⁴ mM.
  • For energy, woven lithium-ion fiber batteries reportedly retain 90.5% capacity after 500 charge–discharge cycles and over 80% after 100,000 bending cycles; TENG devices in the literature can supply energy for up to 72 h.
  • The review identifies a shift from uncontrolled sweat collection toward precise, controlled microfluidic/wettability-based sampling, and highlights biofuel cells, TENG, PENG, and WTEG as promising self-powered options, while noting that hybrid energy supply and energy management remain challenging.

Methods

  • Narrative review of wearable sweat sensors, covering sweat production/collection, composition analysis, energy supply/storage, and intelligent monitoring/data processing.
  • Bibliometric analysis using Web of Science for “wearable sweat sensor” and VOSviewer to create a network visualization map of the top 50 keywords.
  • No primary experimental data are reported; the paper synthesizes prior studies and discusses future directions in materials, structures, and artificial intelligence.

Limitations

  • The paper states that long-term sweat monitoring is still uncertain and affected by environmental contamination, equipment reliability, biocompatibility, energy supply, and system design; it also states that sweat composition differs by stimulation method and that no clear relationship exists between sweat signals and human health parameters.
  • The paper states that wearable sensor screening accuracy is unlikely to match special medical devices, so such sensors may provide only rough trend information; it also raises privacy and data-security risks for intelligent monitoring.
  • Evident from the text: this is a narrative review, not a systematic review; the bibliometric search is limited to Web of Science and the topic term “wearable sweat sensor,” with no formal inclusion/exclusion criteria or quality appraisal described.

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

Integrity signals

Registry

Crossref · 10.1038/s41528-022-00165-9

Cites

126 of 126 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 19 cited sources checked · 0 supported · 0 flagged

  • Findingreasoning

    Control of paper bases and fabrics for sweat collection remains a problem.

    “They have high hydrophilicity, a natural advantage for sweat collection, but control remains a problem.”
    Quote in the paperSubstantial claim
  • Findingnone given

    Sweat contains an abundance of small molecules.

    “sweat is a biological fluid with an abundance of small molecules that make it a potential choice for biofuel cells.”
    Quote in the paperSubstantial claim
  • Premisecitation

    Sweat contains abundant biomarkers such as ions and metabolites that can be used to track metabolism, fatigue, and stress.

    “Among the biological fluids, sweat contains an abundance of relevant biomarkers, such as ions and metabolites, that can be leveraged for tracking the user's metabolism, fatigue, and stress [17][18][19][20]”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [17][18][19][20]

      Not checked in the free run.

  • Interpretationnone given

    In vitro sweat collection methods including sweat-absorbent patches, armbands and microcatheters have the problem that sweat is lost during in vitro analysis after collection.

    “However, all methods have the problem that sweat is lost during the in vitro analysis after collection.”
    Quote in the paperSubstantial claim
  • Premisecitation

    The secretion mechanism of lactic acid into sweat is complex and still unclear.

    “However, the secretion mechanism of lactic acid into sweat is complex and still unclear 79 .”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [79] Jia, W. et al. Electrochemical tattoo biosensors for real-time noninvasive lactate monitoring in human perspiration. Anal. Chem. 85, 6553–6560 (2013). source

      Not checked in the free run.

  • May combine two claims. 29
  • Classified as probably not a substantial claim. 55

  • May combine two claims.

    Findingown data

    Bibliometric search on Web of Science identified relevant research on wearable sweat sensors since 2005, but only a few researchers focused on sweat sensing.

    “Searching on the subject of 'wearable sweat sensor' on the Web of Science website identified the presence of relevant research since 2005, but only a few researchers focused on sweat sensing.”
    Quote in the paperNot a substantial claim

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

    Findingown data

    VOSviewer keyword map core keywords are 'wearable,' 'sensor,' 'biosensor' and 'sweat.'

    “The core keywords observed are 'wearable,' 'sensor,' 'biosensor' and 'sweat.'”
    Quote in the paperNot a substantial claim

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

    Findingreasoning

    Research on wearable sweat sensors has grown rapidly in the past five years.

    “This significant work attracted the attention of many researchers and in the past five years, research on wearable sweat sensors has grown rapidly.”
    Quote in the paperNot a substantial claim

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

    Findingnone given

    Problems of low collection efficiency and poor results still exist.

    “However, problems of low collection efficiency and poor results still exist.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Findingnone given

    Paper bases and fabrics have high hydrophilicity.

    “They have high hydrophilicity, a natural advantage for sweat collection, but control remains a problem.”
    Quote in the paperSubstantial claim

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

    Findingnone given

    Traditional microfluidic technology remains a major contender for sweat collection but faces the problem of processing efficiency.

    “Traditional microfluidic technology remains a major contender for sweat collection but faces the problem of processing efficiency.”
    Quote in the paperNot a substantial claim

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

    Findingnone given

    Regarding sweat collection, a shift has occurred from extensive uncontrolled collection to more precise and controlled collection.

    “Regarding sweat collection, a shift has occurred from extensive uncontrolled collection to more precise and controlled collection.”
    Quote in the paperNot a substantial claim

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

    Findingnone given

    Specific differences occur in the composition of sweat obtained by different methods used to stimulate perspiration.

    “In addition, specific differences occur in the composition of sweat obtained by different methods used to stimulate perspiration; exploring and identifying these differences is a key area for future research.”
    Quote in the paperNot a substantial claim

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

    Findingnone given

    Contamination on the skin surface is a key challenge affecting the accuracy of the device.

    “Contamination on the skin surface is a key challenge affecting the accuracy of the device.”
    Quote in the paperNot a substantial claim

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

    Findingnone given

    Current wearable self-powered devices have good compatibility with wearable sweat sensors.

    “Current wearable self-powered devices have good compatibility with wearable sweat sensors.”
    Quote in the paperNot a substantial claim

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

    Findingnone given

    Noninvasive sweat analysis increases the chance of personal information theft.

    “Careful consideration must be given to the risk with intelligent monitoring of personal privacy being maintained, especially with noninvasive sweat analysis, which increases the chance of personal information theft.”
    Quote in the paperNot a substantial claim

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

    Findingnone given

    A single energy supply element cannot meet the demands faced with scenarios that require data transmission.

    “However, the problem is not only the energy supply of the device itself but also that a single energy supply element cannot meet the demands faced with scenarios that require data transmission.”
    Quote in the paperNot a substantial claim

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

    Findingnone given

    Sweat production is strongly coupled to movement and temperature.

    “In addition, because sweat production is strongly coupled to movement and temperature, PENG (piezoelectric nanogenerators) and WTNG (wearable thermoelectric generators) are energy supplies that should be further explored.”
    Quote in the paperNot a substantial claim

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

    Findingnone given

    Limitations remain in the accuracy of existing sensors.

    “While limitations remain in the accuracy of existing sensors, obtaining data is only one component of the original intention of sweat sensing and health monitoring.”
    Quote in the paperNot a substantial claim

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

    Findingnone given

    TENG has shown its potential in sweat sensing and monitoring.

    “At the same time, TENG, which has received much attention recently, has also shown its potential in sweat sensing and monitoring.”
    Quote in the paperNot a substantial claim

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

    Findingnone given

    Current analysis of sweat data is limited to visual presentation or simple statistical analysis.

    “The current analysis of sweat data is limited to visual presentation or simple statistical analysis.”
    Quote in the paperNot a substantial claim

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

    Findingnone given

    Both lactic acid and glucose have been demonstrated as potential fuels for the self-powered sensor.

    “Both lactic acid and glucose have been demonstrated as potential fuels for the self-powered sensor.”
    Quote in the paperNot a substantial claim

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

    Interpretationnone given

    Current real-time in situ sweat sensors lack the ability for long-term monitoring.

    “But the real-time in situ sweat sensors lack the ability of long-term monitoring.”
    Quote in the paperNot a substantial claim

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

    Interpretationnone given

    Current research has not found that pH value of sweat alone can reflect health or disease, but pH is an essential reference.

    “Although current research has not found that pH value of sweat alone can reflect the characteristics of health or disease, pH value is an essential reference.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Sweat secretion rates can be lower than 10 nL min−1 cm−2 at low secretion sites such as an arm or leg, but can reach 100 nL min−1 cm−2 at high secretion areas like the palm and foot.

    “Sweat secretion rates can be lower than 10 nL min -1 cm -2 at low secretion sites such as an arm or leg, but can reach 100 nL min -1 cm -2 at high secretion areas like the palm and foot 5 .”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [5] Nyein, H. Y. Y. et al. A wearable patch for continuous analysis of thermoregulatory sweat at rest. Nat. Commun. 12, 1823 (2021). source

      Not checked in the free run.

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

    Premisenone given

    The ions in sweat are thought to reflect the level of water and salt metabolism in the human body.

    “The ions in sweat are thought to reflect the level of water and salt metabolism in the human body.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Such in vitro collection methods cannot be accurately time-stamped, making it difficult to match sweat analysis results to the subject's state.

    “Further, such collection methods cannot be accurately time-stamped, making it difficult to match the results of the sweat analysis to the state of the subject.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisenone given

    Sodium ions can indirectly reflect the sweat rate of the human body and provide a reference for calibration of sweat monitoring.

    “Sodium ions can indirectly reflect the sweat rate of the human body and thus also provide a reference for calibration of sweat monitoring.”
    Quote in the paperNot a substantial claim

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

    Premisenone given

    Metabolites in sweat are represented by lactic acid and glucose.

    “The metabolites in sweat are represented by lactic acid and glucose.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    The current mechanism of potassium ion secretion in sweat is still uncertain, so the final potassium concentration in sweat may be maintained within the plasma potassium concentration range.

    “However, the current mechanism of potassium ion secretion in sweat is still uncertain, so the final potassium concentration in sweat may be maintained within the plasma potassium concentration range 76 .”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [76] Baker, L. B. Sweating Rate and Sweat Sodium Concentration in Athletes: A Review of Methodology and Intra/Interindividual Variability. Sport. Med. 47, 111–128 (2017). source

      Not checked in the free run.

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

    Interpretationnone given

    Core issues for long-term sweat monitoring include sweat collection and analysis, energy supply and management, and establishing the relationship between monitoring data and human health.

    “The core issues requiring attention relate to long-term monitoring, including the mechanism for collection and analysis of sweat, the supply and management of energy to the device, and the establishment of the relationship between monitoring data and human health.”
    Quote in the paperSubstantial claim

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

    Premisenone given

    Sweat and blood concentrations of calcium are correlated.

    “Sweat and blood concentrations of calcium are correlated.”
    Quote in the paperNot a substantial claim

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

    Premisenone given

    Sodium is the most common ion in human sweat and the primary indicator for levels of human water and salt metabolism.

    “The most common ion in human sweat, sodium is the primary indicator for levels of human water and salt metabolism.”
    Quote in the paperNot a substantial claim

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

    Premisenone given

    Excessive loss of sodium and potassium can lead to hyponatremia, muscle cramps, and dehydration.

    “Excessive loss of sodium and potassium can lead to hyponatremia, muscle cramps, and dehydration.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    The concentration of ions in sweat is much lower than in blood, but they can still reflect the state of the human.

    “Although the concentration of ions in sweat is much lower than in blood, they can still reflect the state of the human.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Abnormally high sweat chloride concentration is observed in cystic fibrosis patients, and sweat chloride analysis has been adopted as the gold standard for cystic fibrosis diagnosis.

    “Abnormally high sweat chloride concentration is observed in cystic fibrosis (CF) patients, and sweat chloride analysis has been adopted as the gold standard for cystic fibrosis diagnosis 75”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [75] O’Sullivan, B. P. & Freedman, S. D. Cystic fibrosis. Lancet 373, 1891–1904 (2009). source

      Not checked in the free run.

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

    Interpretationnone given

    A closed sweat collection system can effectively avoid external contamination.

    “The advantage to this method is that a closed sweat collection system can effectively avoid external contamination.”
    Quote in the paperNot a substantial claim

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

    Premisenone given

    It is generally believed that the pH value of human sweat is in the range of 4.2-7.8.

    “It is generally believed that the pH value of human sweat is in the range of 4.2-7.8.”
    Quote in the paperNot a substantial claim

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

    Interpretationnone given

    Local sweat differences are likely to occur based on factors such as different parts of the human body, different diets, and climate.

    “At the same time, local sweat differences are likely occur based on factors such as different parts of the human body, different diets, and climate.”
    Quote in the paperNot a substantial claim

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

    Premisenone given

    The concentration of cortisol in sweat ranges from 2.21 × 10−5 to 3.86 × 10−4 mM, with the largest concentration typically occurring in the morning.

    “The concentration of cortisol in sweat ranges from 2.21 × 10 -5 to 3.86 × 10 -4 mM, with the largest concentration typically occurring in the morning.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Li-ion batteries have high energy density, high power density and a long life cycle.

    “Li-ion batteries have high energy density, high power density and a long life cycle.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Liu 97

      Not checked in the free run.

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

    Premisenone given

    UA is a risk factor for cardiovascular disease, type 2 diabetes, and renal disease; it is also widely used in clinical settings to manage gout.

    “UA is a risk factor for cardiovascular disease, type 2 diabetes, and renal disease; it is also widely used in clinical settings to manage gout, the most common inflammatory arthritis, which affects tens of millions of people worldwide.”
    Quote in the paperNot a substantial claim

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

    Premisenone given

    Heavy metal ions are not ordinary human sweat metabolites, but the primary way to metabolize heavy metal ions is through sweat.

    “Heavy metal ions are not ordinary human sweat metabolites, but the primary way to metabolize heavy metal ions is through sweat.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Studies have shown a high correlation between the concentrations of alcohol in sweat and blood, which enables continuous noninvasive blood alcohol monitoring by monitoring sweat alcohol concentration.

    “Studies have shown a high correlation between the concentrations of alcohol in sweat and blood, which enables continuous noninvasive blood alcohol monitoring to be achieved by monitoring sweat alcohol concentration 91,92 .”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [91] Gamella, M. et al. A novel non-invasive electrochemical biosensing device for in situ determination of the alcohol content in blood by monitoring ethanol in sweat. Anal. Chim. Acta 806, 1–7 (2014). source

      Not checked in the free run.

    • cites [92] Davis-Martin, R. E., Alessi, S. M. & Boudreaux, E. D. Alcohol Use Disorder in the Age of Technology: A Review of Wearable Biosensors in Alcohol Use Disorder Treatment. Front. Psychiatry 12, 642813 (2021). source

      Not checked in the free run.

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

    Interpretationnone given

    Multichannel sweat composition analysis has become a relatively mature technology.

    “Multichannel sweat composition analysis has become a relatively mature technology, but the perceptual parameters required differ according to the specific health monitoring task.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationnone given

    Intrinsically flexible batteries still have certain technical difficulties, but structurally flexible batteries realized by island structures are relatively easy to implement.

    “Intrinsically flexible batteries still have certain technical difficulties, but structurally flexible batteries realized by island structures are relatively easy to implement.”
    Quote in the paperNot a substantial claim

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

    Interpretationnone given

    Compared with the activity of the whole body, sweat lactic acid may have a more direct relationship with the activity of the sweat glands themselves.

    “Compared with the activity of the whole body, sweat lactic acid may have a more direct relationship with the activity of the sweat glands themselves.”
    Quote in the paperNot a substantial claim

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

    Interpretationnone given

    Screening accuracy with wearable sensors is unlikely to match that required of special medical devices.

    “The challenges with this are that the targets that can be monitored are limited and screening accuracy with wearable sensors is unlikely to match that required of special medical devices.”
    Quote in the paperNot a substantial claim

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

    Interpretationnone given

    Flexible batteries are currently the best technical option for traditional sensors.

    “Flexible batteries are currently the best technical option for traditional sensors.”
    Quote in the paperNot a substantial claim

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

    Interpretationnone given

    A battery-free system is a simpler and more stable structure with a lower cost.

    “A battery-free system is a simpler and more stable structure with a lower cost.”
    Quote in the paperNot a substantial claim

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

    Interpretationnone given

    Deciding on the appropriate parameter to monitor depends on medical data providing sufficient theoretical analysis to identify the parameter and provide quantitative data regarding normal levels.

    “Deciding on the appropriate parameter to monitor, however, depends on the medical data to provide sufficient theoretical analysis to not only identify the parameter, but also to provide quantitative data regarding normal levels.”
    Quote in the paperNot a substantial claim

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

    Premisenone given

    The concentration range of lactic acid in sweat is ~6 mM to ~100 mM.

    “The concentration range of lactic acid in sweat ranges from ~6 mM to ~100 mM.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    A correlation between sweat glucose and blood glucose exists, and obtaining blood glucose values by detecting glucose in sweat is expected to replace conventional diabetes blood glucose monitoring practices.

    “A correlation between sweat glucose and blood glucose exists and obtaining blood glucose values by detecting glucose in sweat is thus expected to replace conventional diabetes blood glucose monitoring practices 83,84”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [83] Zhou, W. et al. Recent advances in flexible sweat glucose biosensors. J. Phys. D. Appl. Phys. 54, 423001 (2021). source

      Not checked in the free run.

    • cites [84] Yunos, M. F. A. M. & Nordin, A. N. Non-invasive glucose monitoring devices: A review. Bull. Electr. Eng. Inform. 9, 2609–2618 (2020). source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable), S4 (based).

    Interpretationnone given

    Medical knowledge may not be able to provide such information.

    “Unfortunately, medical knowledge may not be able to provide such information.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    The cortisol concentration in the blood is generally 1.24 × 10−4 to 4.0 × 10−4 mM.

    “In comparison, the cortisol concentration in the blood is generally 1.24 × 10 -4 to 4.0 × 10 -4 mM 88 .”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [88] Raul, J. S., Cirimele, V., Ludes, B. & Kintz, P. Detection of physiological concentrations of cortisol and cortisone in human hair. Clin. Biochem. 37, 1105–1111 (2004). source

      Not checked in the free run.

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

    Interpretationnone given

    The difference between sweat and blood cortisol concentrations may be related to type II 11β-hydroxysteroid-dehydrogenase (HSD) in the sweat ducts that converts cortisol into corticosterone.

    “This difference may be related to the type II 11β-hydroxysteroid-dehydrogenase (HSD) in the sweat ducts that converts cortisol into corticosterone.”
    Quote in the paperNot a substantial claim

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

    Interpretationnone given

    Sweat lactic acid can indirectly reflect the physical state of exercise.

    “Nonetheless, sweat lactic acid can indirectly reflect the physical state of exercise.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationnone given

    Existing self-powered systems can meet the energy requirements of the body surface sensor, but research on design is required to achieve a stable supply of energy.

    “While existing selfpowered systems can meet the energy requirements of the body surface sensor, research on design is required to achieve a stable supply of energy.”
    Quote in the paperSubstantial claim

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

    Interpretationnone given

    Most of the energy sources for TENG fabrics are low-frequency human motion and transformation of the motion to energy for a sensor remains to be studied.

    “However, most of the energy sources for TENG fabrics are low-frequency human motion and transformation of the motion to energy for a sensor remains to be studied.”
    Quote in the paperNot a substantial claim

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

    Interpretationreasoning

    Because TENG energy supply requires mechanical movement, the relationship between exercise and sweat in human health monitoring makes it a good alternative.

    “Because its energy supply requires mechanical movement, the relationship between exercise and sweat in human health monitoring makes it a good alternative.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    Typically, sweat production is accompanied by higher exercise intensity or ambient temperature, providing an energy source for various wearable self-powered devices.

    “Typically, sweat production is accompanied by higher exercise intensity or ambient temperature, providing an energy source for various wearable self-powered devices that can, in turn be used for sweat sensor monitoring.”
    Quote in the paperSubstantial claim

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

    Interpretationnone given

    The use of biofuel cells as a self-powered technology for sweat sensing has been studied and needs to now be tested in the context of applied use.

    “In summary, the use of biofuel cells as a self-powered technology for sweat sensing has been studied and needs to now be tested in the context of applied use.”
    Quote in the paperSubstantial claim

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

    Premisenone given

    TENG is one of the most popular devices in use for self-powered wearable systems.

    “TENG is also one of the most popular devices in use for selfpowered wearable systems.”
    Quote in the paperNot a substantial claim

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

    Interpretationcitation

    A hybrid energy supply could further enhance the stability of energy supply.

    “It is worth noting that a hybrid energy supply could further enhance the stability of energy supply 112 .”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [112] García Núñez, C., Manjakkal, L. & Dahiya, R. Energy autonomous electronic skin. npj Flex. Electron 3, 1 (2019). source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    A major advantage of the biofuel cell is that it can use the very substances the sensor is detecting, reducing the system's complexity and ensuring its stability.

    “A major advantage of the biofuel cell is that it can use the very substances the sensor is detecting, reducing the system's complexity and ensuring its stability.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Woven lithium-ion fiber batteries have a capacity retention that reaches 90.5% after 500 charge-discharge cycles, comparable to commercial batteries such as pouch cells, and over 80% capacity was maintained after bending the fiber for 100,000 cycles.

    “These batteries have a capacity retention that reaches 90.5% after 500 charge-discharge cycles, comparable to commercial batteries such as pouch cells.Over 80% capacity was maintained after bending the fiber for 100,000 cycles.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Peng et al. 99

      Not checked in the free run.

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

    Interpretationnone given

    Self-powered devices such as TENG, PENG, and WTEG all show potential in the field of sweat sensors.

    “Self-powered devices such as TENG, PENG, and WTEG all show potential in the field of sweat sensors.”
    Quote in the paperNot a substantial claim

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

    Interpretationreasoning

    With proper design, self-powered flexible sensors can meet the long-term monitoring goals of most applications.

    “With proper design, self-powered flexible sensors can meet the long-term monitoring goals of most applications.”
    Quote in the paperNot a substantial claim

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

    Interpretationnone given

    For textile wearable TENG, as long as the structure was not damaged, its long-term stability was satisfactory.

    “As long as the structure was not damaged, its long-term stability was satisfactory.”
    Quote in the paperNot a substantial claim

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

    Interpretationreasoning

    The correlation between the production of sweat and environmental factors makes it especially feasible to match the self-supply of the environment.

    “The correlation between the production of sweat and environmental factors makes it especially feasible to match the self-supply of the environment.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing). May combine two claims.

    Interpretationnone given

    Although the potential of textile TENG for sweat monitoring has been verified, more specific selectivity and stability research is required for further exploration.

    “Although the potential has been verified, more specific selectivity and stability research is required for further exploration.”
    Quote in the paperNot a substantial claim

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

    Interpretationreasoning

    The coordination of multiple energy supply systems can cover a broader range of sensor device usage requirements and avoid the limitations of a single self-supply system.

    “The coordination of multiple energy supply systems can cover a broader range of sensor device usage requirements and avoid the limitations of a single selfsupply system.”
    Quote in the paperSubstantial claim
67 of 67

  • The paper relies on this without support.

    Sweat composition obtained by iontophoresis differs from the composition of sweat spontaneously produced by the human body.

    “However, sweat composition obtained by iontophoresis differs from the composition of sweat spontaneously produced by the human body.”

  • The paper relies on this without support.

    Long-term continuous monitoring is required for wearable sensors to obtain sufficient data to accurately measure human health.

    “For wearable sensors, long-term continuous monitoring is required to obtain sufficient data to accurately measure human health.”

  • The paper relies on this without support.

    Due to current technology and data limitations, it is still difficult to directly obtain critical parameters that affect the state of the human body.

    “However, due to current technology and data limitations, it is still difficult to directly obtain critical parameters that affect the state of the human body.”

  • The paper relies on this without support.

    Most researchers currently study simple heart rate, electrocardiograms, blood oxygen levels, and other simple parameters.

    “Most researchers currently study simple heart rate, electrocardiograms, blood oxygen levels, and other simple parameters.”

  • The paper relies on this without support.

    The human body is a complex system and a variety of monitorable data is required to establish a comprehensive model of its health.

    “The human body is a complex system and a variety of monitorable data is required to establish a comprehensive model of its health.”

  • The paper relies on this without support.

    AI can be integrated into wearable sensors to improve the applied performance of wearable sensors for health monitoring.

    “Artificial intelligence (AI) can be integrated into wearable sensors to improve the applied performance of wearable sensors for health monitoring.”

  • The paper relies on this without support.

    The AI biosensor is a rapidly growing area of research.

    “The AI biosensor is a rapidly growing area of research.”

  • The paper relies on this without support.

    At present, there is no clear relationship between sweat signals and human health parameters.

    “At present, there is no clear relationship between sweat signals and human health parameters; yet many scholars have studied the relationship between sweat sugar and blood sugar.”

  • The paper relies on this without support.

    Many scholars have studied the relationship between sweat sugar and blood sugar.

    “At present, there is no clear relationship between sweat signals and human health parameters; yet many scholars have studied the relationship between sweat sugar and blood sugar.”

  • The paper relies on this without support.

    The analysis of blood glucose is a relatively mature applied model, for which physiological model-based algorithms and datadriven algorithms are used.

    “The analysis of blood glucose is a relatively mature applied model, for which physiological model-based algorithms and datadriven algorithms are used.”

  • The paper relies on this without support.

    The physiological model of the human body depends on many factors (e.g., gender, age, weight, meals, external environment).

    “The physiological model of the human body depends on many factors (e.g., gender, age, weight, meals, external environment).”

  • The paper relies on this without support.

    In the classic biological model, glucose, insulin, and glucagon must be considered comprehensively.

    “In the classic biological model, glucose, insulin, and glucagon must be considered comprehensively.”

  • The paper relies on this without support.

    Change in blood sugar levels has a certain degree of hysteresis, and the change of glucose in sweat depends on, and lags behind, the blood sugar, making it difficult to establish the model.

    “At the same time, change in blood sugar levels has a certain degree of hysteresis, and the change of glucose in sweat depends on, and lags behind, the blood sugar, making it difficult to establish the model.”

  • The paper relies on this without support.

    The complexity of the human body further makes the modeling accuracy insufficient.

    “The complexity of the human body further makes the modeling accuracy insufficient.”

  • The paper relies on this without support.

    In recent years, data-driven algorithms have been increasingly applied to various model predictions and this can build models even in the case of complex and unknown relationships of information that are more inline with reality.

    “In recent years, data-driven algorithms have been increasingly applied to various model predictions and this can build models even in the case of complex and unknown relationships of information that are more inline with reality.”
15 of 15

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?

  • Despite progress in wearable biosensors, there is a gap in the literature in finding a relationship between biofluid signals and human health parameters.

    “In addition, despite all the progress made in wearable biosensors, there is a gap in the literature in finding a relationship between biofluid signals and human health parameters [251].”

    From The emergence of AI-based wearable sensors for digital health technology: a review (2023) · cites this paper as [251]

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.

  • Reference 98 describes a battery, not a biofuel cell

    Minor

    The text calls the cited device a biofuel cell, while reference 98 identifies it as a fruit-based battery.

  • Bandodkar study is dated 2013, but reference 62 is from 2014

    Minor

    The cited reference is dated 2014, not 2013. Its title also describes a tattoo sodium sensor rather than the whole-body washdown method attributed to it.

  • Figure 6c cites a thermoelectric study for a TENG

    Minor

    The caption describes a textile-based TENG and dates reference 105 to 2018 in Nano Energy. Reference 105 instead describes a thermoelectric generator published in Applied Energy in 2020.

  • Figure 6a gives a different publication for reference 100

    Minor

    The caption assigns reference 100 to a 2021 Advanced Functional Materials publication, whereas the reference list places it in Joule.

  • Figure 6b gives a different year and journal for reference 103

    Minor

    The caption identifies reference 103 as a 2015 Biosensors and Bioelectronics work; the listed reference is a 2020 Science Advances paper.

  • Figure 6d gives a different year and journal for reference 111

    Minor

    The caption identifies reference 111 as a 2018 Nano Energy publication, but the reference list gives a 2021 Advanced Functional Materials publication.

  • Woven-battery study is attributed to a different author

    Minor

    The text attributes reference 99 to Peng et al., but the reference lists He et al.

7 of 7

Cites

Flagged first, then by citations

Research works printed but not linked: 3

  1. Matzeu, G., Florea, L. & Diamond, D. Advances in wearable chemical sensor design for monitoring biological fluids. Sensors Actuators. B Chem. 211, 403–418 (2015).
  2. Nguyen, B., Coelho, Y., Bastos, T. & Krishnan, S. Trends in human activity recognition with focus on machine learning and power requirements. Mach. Learn. Appl 5, 100072 (2021).
  3. Wu, H., Zhang, Y., Kjøniksen, A. L., Zhou, X. X. & Zhou, X. X. Wearable Biofuel Cells: Advances from Fabrication to Application. Adv. Funct. Mater. 2103976, 1–38 (2021).

Cited by

Sorted by citations

Related

Authors
Yang, P., Wei, G., Liu, A., Huo, F., & Zhang, Z.
Affiliations
  • Shanghai Jiao Tong University (CN)
  • Second Military Medical University (CN)
  • UNSW Sydney (AU)
  • Nanjing Tech University (CN)
Corresponding author
Wei, Gaofeng
ORCID
Venue
npj Flexible Electronics
Publisher
Springer Science and Business Media LLC
Published
2022-06-03
Volume
6
Issue
1
ISSN
2397-4621 (ISSN-L)
DOI
10.1038/s41528-022-00165-9
OpenAlex
W4282053000
Cited by
77
References
126
Citations by year
2026: 14 · 2025: 17 · 2024: 17 · 2023: 21 · 2022: 8
FWCI
4.58
Type
journal article
Language
en
Open access
Licence
Locations
  • npj Flexible Electronics (publishedVersion, cc-by)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
  • State Key Laboratory of Mechanical System and Vibration (MSVZD202108)
  • he open project of National Research Center for Translational Medicine,·Shanghai
Topics
  • Physical Sciences › Engineering › Biomedical Engineering › Advanced Sensor and Energy Harvesting Materials
  • Physical Sciences › Engineering › Biomedical Engineering › Non-Invasive Vital Sign Monitoring
  • Physical Sciences › Engineering › Electrical and Electronic Engineering › Electrochemical sensors and biosensors
Keywords
sweat sensors, long-term monitoring, sweat collection, energy supply, wearable health monitoring, artificial intelligence, flexible electronics

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 ›

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