Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

A fingertip-wearable microgrid system for autonomous energy management and metabolic monitoring

Nature Electronics volume 7, pages 788–799 (2024)Cite this article

Subjects

Abstract

Wearable health monitoring platforms require advanced sensing modalities with integrated electronics. However, current systems suffer from limitations related to energy supply, sensing capabilities, circuitry regulations and large form factors. Here, we report an autonomous and continuous sweat sensing system that operates on a fingertip. The system uses a self-voltage-regulated wearable microgrid based on enzymatic biofuel cells and AgCl-Zn batteries to harvest and store bioenergy from sweat, respectively. It relies on osmosis to continuously supply sweat to the sensor array for on-demand multi-metabolite sensing and is combined with low-power electronics for signal acquisition and wireless data transmission. The wearable system is powered solely by fingertip perspiration and can detect glucose, vitamin C, lactate and levodopa over extended periods of time.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on SpringerLink
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Principle and design of integrated fingertip-wearable microgrid.
Fig. 2: Characterization of the BFC and the flexible AgCl-Zn battery.
Fig. 3: In vivo energy harvesting and charging battery.
Fig. 4: Sensor operation with osmotically withdrawn sweat.
Fig. 5: Operation of the integrated fingertip-wearable microgrid system.

Similar content being viewed by others

Data availability

The data that support the findings of this study are available from the corresponding author upon request.

Code availability

The code for programming the MCU is available from the corresponding author upon request.

References

  1. Bariya, M., Nyein, H. Y. Y. & Javey, A. Wearable sweat sensors. Nat. Electron. 1, 160–171 (2018).

    Article  Google Scholar 

  2. Someya, T. & Amagai, M. Toward a new generation of smart skins. Nat. Biotechnol. 37, 382–388 (2019).

    Article  Google Scholar 

  3. Wang, W. et al. Neuromorphic sensorimotor loop embodied by monolithically integrated, low-voltage, soft e-skin. Science 380, 735–742 (2023).

    Article  Google Scholar 

  4. Chen, C., Ding, S. & Wang, J. Digital health for aging populations. Nat. Med. 29, 1623–1630 (2023).

    Article  Google Scholar 

  5. Kim, J., Campbell, A. S., de Ávila, B. E.-F. & Wang, J. Wearable biosensors for healthcare monitoring. Nat. Biotechnol. 37, 389–406 (2019).

    Article  Google Scholar 

  6. Gao, W. et al. Fully integrated wearable sensor arrays for multiplexed in situ perspiration analysis. Nature 529, 509–514 (2016).

    Article  Google Scholar 

  7. Hu, H. et al. A wearable cardiac ultrasound imager. Nature 613, 667–675 (2023).

    Article  Google Scholar 

  8. Kim, J. et al. Battery-free, stretchable optoelectronic systems for wireless optical characterization of the skin. Sci. Adv. 2, e1600418 (2016).

    Article  Google Scholar 

  9. Jiang, Y. et al. Wireless, closed-loop, smart bandage with integrated sensors and stimulators for advanced wound care and accelerated healing. Nat. Biotechnol. 41, 652–662 (2023).

    Article  Google Scholar 

  10. Shirzaei Sani, E. et al. A stretchable wireless wearable bioelectronic system for multiplexed monitoring and combination treatment of infected chronic wounds. Sci. Adv. 9, eadf7388 (2023).

    Article  Google Scholar 

  11. Nair, V. et al. Miniature battery-free bioelectronics. Science 382, eabn4732 (2023).

    Article  Google Scholar 

  12. Larcher, D. & Tarascon, J. M. Towards greener and more sustainable batteries for electrical energy storage. Nat. Chem. 7, 19–29 (2015).

    Article  Google Scholar 

  13. Gao, M. et al. Power generation for wearable systems. Energy Environ. Sci. 14, 2114–2157 (2021).

    Article  Google Scholar 

  14. Gong, S. & Cheng, W. Toward soft skin-like wearable and implantable energy devices. Adv. Energy Mater. 7, 1700648 (2017).

    Article  Google Scholar 

  15. Song, Y., Mukasa, D., Zhang, H. & Gao, W. Self-powered wearable biosensors. Acc. Mater. Res. 2, 184–197 (2021).

    Article  Google Scholar 

  16. Yin, L. et al. High performance printed AgO-Zn rechargeable battery for flexible electronics. Joule 5, 228–248 (2021).

    Article  Google Scholar 

  17. Yin, L. et al. Wearable E-skin microgrid with battery-based, self-regulated bioenergy module for epidermal sweat sensing. Adv. Energy Mater. 13, 2203418 (2023).

    Article  Google Scholar 

  18. Yin, L. et al. A self-sustainable wearable multi-modular E-textile bioenergy microgrid system. Nat. Commun. 12, 1542 (2021).

    Article  Google Scholar 

  19. Yu, Y. et al. Biofuel-powered soft electronic skin with multiplexed and wireless sensing for human-machine interfaces. Sci. Robot. 5, eaaz7946 (2020).

    Article  Google Scholar 

  20. Yin, L. et al. A passive perspiration biofuel cell: high energy return on investment. Joule 5, 1888–1904 (2021).

    Article  Google Scholar 

  21. Garland, N. T., Kaveti, R. & Bandodkar, A. J. Biofluid-activated biofuel cells, batteries, and supercapacitors: a comprehensive review. Adv. Mater. 35, 2303197 (2023).

    Article  Google Scholar 

  22. Yin, L., Kim, K. N., Trifonov, A., Podhajny, T. & Wang, J. Designing wearable microgrids: towards autonomous sustainable on-body energy management. Energy Environ. Sci. 15, 82–101 (2022).

    Article  Google Scholar 

  23. Bandodkar, A. J. et al. Soft, stretchable, high power density electronic skin-based biofuel cells for scavenging energy from human sweat. Energy Environ. Sci. 10, 1581–1589 (2017).

    Article  Google Scholar 

  24. Ates, H. C. et al. End-to-end design of wearable sensors. Nat. Rev. Mater. 7, 887–907 (2022).

    Article  MathSciNet  Google Scholar 

  25. Min, J. et al. An autonomous wearable biosensor powered by a perovskite solar cell. Nat. Electron. 6, 630–641 (2023).

    Article  Google Scholar 

  26. Song, Y. et al. 3D-printed epifluidic electronic skin for machine learning–powered multimodal health surveillance. Sci. Adv. 9, eadi6492 (2023).

    Article  Google Scholar 

  27. Wang, M. et al. A wearable electrochemical biosensor for the monitoring of metabolites and nutrients. Nat. Biomed. Eng. 6, 1225–1235 (2022).

    Article  Google Scholar 

  28. Min, J. et al. Skin-interfaced wearable sweat sensors for precision medicine. Chem. Rev. 123, 5049–5138 (2023).

    Article  Google Scholar 

  29. Saha, T. et al. Wearable electrochemical glucose sensors in diabetes management: a comprehensive review. Chem. Rev. 123, 7854–7889 (2023).

    Article  Google Scholar 

  30. Lv, J. et al. Sweat-based wearable energy harvesting-storage hybrid textile devices. Energy Environ. Sci. 11, 3431–3442 (2018).

    Article  Google Scholar 

  31. Ding, S. et al. Wearable microgrids empowered by single-atom materials. Innov. Mater. 1, 100023 (2023).

    Article  Google Scholar 

  32. Bariya, M. et al. Glove-based sensors for multimodal monitoring of natural sweat. Sci. Adv. 6, eabb8308 (2020).

  33. Taylor, N. A. S. & Machado-Moreira, C. A. Regional variations in transepidermal water loss, eccrine sweat gland density, sweat secretion rates and electrolyte composition in resting and exercising humans. Extrem. Physiol. Med. 2, 4 (2013).

    Article  Google Scholar 

  34. Brunmair, J. et al. Finger sweat analysis enables short interval metabolic biomonitoring in humans. Nat. Commun. 12, 5993 (2021).

    Article  Google Scholar 

  35. Sempionatto, J. R., Moon, J.-M. & Wang, J. Touch-based fingertip blood-free reliable glucose monitoring: personalized data processing for predicting blood glucose concentrations. ACS Sens. 6, 1875–1883 (2021).

    Article  Google Scholar 

  36. Moon, J.-M. et al. Non-invasive sweat-based tracking of l-dopa pharmacokinetic profiles following an oral tablet administration. Angew. Chem. Int. Ed. 60, 19074–19078 (2021).

    Article  Google Scholar 

  37. Lv, J. et al. Printable elastomeric electrodes with sweat-enhanced conductivity for wearables. Sci. Adv. 7, eabg8433 (2021).

    Article  Google Scholar 

  38. Saha, T. et al. Wireless wearable electrochemical sensing platform with zero-power osmotic sweat extraction for continuous lactate monitoring. ACS Sens. 7, 2037–2048 (2022).

    Article  Google Scholar 

  39. Milton, R. D., Giroud, F., Thumser, A. E., Minteer, S. D. & Slade, R. C. T. Bilirubin oxidase bioelectrocatalytic cathodes: the impact of hydrogen peroxide. Chem. Commun. 50, 94–96 (2014).

    Article  Google Scholar 

  40. Chen, X. et al. Stretchable and flexible buckypaper-based lactate biofuel cell for wearable electronics. Adv. Funct. Mater. 29, 1905785 (2019).

    Article  Google Scholar 

  41. Wang, C. et al. Monitoring of the central blood pressure waveform via a conformal ultrasonic device. Nat. Biomed. Eng. 2, 687–695 (2018).

    Article  Google Scholar 

  42. Derbyshire, P. J. et al. Lactate in human sweat: a critical review of research to the present day. J. Physiol. Sci. 62, 429–440 (2012).

    Article  Google Scholar 

  43. ÅStrand, I. Lactate content in sweat. Acta Physiol. Scand. 58, 359–367 (1963).

    Article  Google Scholar 

  44. Buono, M. J., Lee, N. V. L. & Miller, P. W. The relationship between exercise intensity and the sweat lactate excretion rate. J. Physiol. Sci. 60, 103–107 (2010).

    Article  Google Scholar 

  45. Liang, G. et al. Commencing mild Ag–Zn batteries with long-term stability and ultra-flat voltage platform. Energy Storage Mater. 25, 86–92 (2020).

    Article  Google Scholar 

  46. Bratsch, S. G. Standard electrode potentials and temperature coefficients in water at 298.15 K. J. Phys. Chem. Ref. Data 18, 1–21 (1989).

    Article  Google Scholar 

  47. Scharf, J. et al. Investigating degradation modes in Zn-AgO aqueous batteries with in situ X-ray micro computed tomography. Adv. Energy Mater. 11, 2101327 (2021).

    Article  Google Scholar 

  48. Van Hoovels, K. et al. Can wearable sweat lactate sensors contribute to sports physiology? ACS Sens. 6, 3496–3508 (2021).

    Article  Google Scholar 

  49. Jia, W. et al. Epidermal biofuel cells: energy harvesting from human perspiration. Angew. Chem. Int. Ed. 52, 7233 (2013).

    Article  Google Scholar 

  50. Saha, T., Fang, J., Mukherjee, S., Dickey, M. D. & Velev, O. D. Wearable osmotic-capillary patch for prolonged sweat harvesting and sensing. ACS Appl. Mater. Inter. 13, 8071–8081 (2021).

    Article  Google Scholar 

  51. Nyein, H. Y. Y. et al. A wearable patch for continuous analysis of thermoregulatory sweat at rest. Nat. Commun. 12, 1823 (2021).

    Article  Google Scholar 

  52. Yin, L. et al. A stretchable epidermal sweat sensing platform with an integrated printed battery and electrochromic display. Nat. Electron. 5, 694–705 (2022).

    Article  Google Scholar 

  53. Sempionatto, J. R. et al. An epidermal patch for the simultaneous monitoring of haemodynamic and metabolic biomarkers. Nat. Biomed. Eng. 5, 737–748 (2021).

    Article  Google Scholar 

Download references

Acknowledgements

This work was supported by the UCSD Center for Wearable Sensors and Samsung. We thank the Kraton Corporation for providing all the SEBS samples.

Author information

Author notes

  1. These authors contributed equally: Shichao Ding, Tamoghna Saha, Lu Yin.

Authors and Affiliations

  1. Aiiso Yufeng Li Family Department of Chemical and Nano Engineering, University of California San Diego, La Jolla, CA, USA

    Shichao Ding, Tamoghna Saha, Lu Yin, Ruixiao Liu, Muhammad Inam Khan, An-Yi Chang, Hyungjin Lee, Jiachi Zhou, Chuanrui Chen, Zhengxing Li, Chenyang Zhang, Sara Earney, Selene Tang, Omeed Djassemi, Xiangjun Chen, Muyang Lin, Samar S. Sandhu, Jong-Min Moon, Chochanon Moonla, Ponnusamy Nandhakumar, Kuldeep Mahato, Sheng Xu & Joseph Wang

  2. Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA

    Han Zhao & Ariane Sina Nazemi

  3. Department of Computer Science and Engineering, University of California San Diego, La Jolla, CA, USA

    Yuanzhe Liu

  4. Samsung Electronics, Suwon-si, Gyeonggi-do, Republic of Korea

    Youngmin Park

Authors
  1. Shichao Ding
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Tamoghna Saha
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Lu Yin
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Ruixiao Liu
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Muhammad Inam Khan
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. An-Yi Chang
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Hyungjin Lee
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Han Zhao
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Yuanzhe Liu
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Ariane Sina Nazemi
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. Jiachi Zhou
    View author publications

    You can also search for this author in PubMed Google Scholar

  12. Chuanrui Chen
    View author publications

    You can also search for this author in PubMed Google Scholar

  13. Zhengxing Li
    View author publications

    You can also search for this author in PubMed Google Scholar

  14. Chenyang Zhang
    View author publications

    You can also search for this author in PubMed Google Scholar

  15. Sara Earney
    View author publications

    You can also search for this author in PubMed Google Scholar

  16. Selene Tang
    View author publications

    You can also search for this author in PubMed Google Scholar

  17. Omeed Djassemi
    View author publications

    You can also search for this author in PubMed Google Scholar

  18. Xiangjun Chen
    View author publications

    You can also search for this author in PubMed Google Scholar

  19. Muyang Lin
    View author publications

    You can also search for this author in PubMed Google Scholar

  20. Samar S. Sandhu
    View author publications

    You can also search for this author in PubMed Google Scholar

  21. Jong-Min Moon
    View author publications

    You can also search for this author in PubMed Google Scholar

  22. Chochanon Moonla
    View author publications

    You can also search for this author in PubMed Google Scholar

  23. Ponnusamy Nandhakumar
    View author publications

    You can also search for this author in PubMed Google Scholar

  24. Youngmin Park
    View author publications

    You can also search for this author in PubMed Google Scholar

  25. Kuldeep Mahato
    View author publications

    You can also search for this author in PubMed Google Scholar

  26. Sheng Xu
    View author publications

    You can also search for this author in PubMed Google Scholar

  27. Joseph Wang
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

J.W., S.D., T.S. and L.Y. conceived the idea and designed the experiments. S.D. and T.S. conducted the experiments. J.W. supervised the work. S.D., T.S., L.Y., R.L., M.I.K., A.-Y.C., H.L., J.Z., C.C., Z.L., C.Z., S.E., S.T., O.D., X.C., M.L., S.S.S., J.-M.M., C.M. and P.N. performed the experiments. H.Z. and Y.L. contributed to the signal processing and app development. A.S.N. designed and programmed the electronics. Y.P., K.M., S.X. and J.W. provided suggestions for the experiment designs. S.D., T.S., L.Y. and J.W. wrote the paper with the assistance of the other coauthors.

Corresponding author

Correspondence to Joseph Wang.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature Electronics thanks Haibo Huang, Liping Xie and Hao Sun for their contribution to the peer review of this work.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Methods 1–7, References, Figs. 1–43 and Videos 1–3.

Reporting Summary

Supplementary Video 1

Powering of an LED bulb using a pair of AgCl-Zn batteries connected in series under bending and stretching.

Supplementary Video 2

Wearable fingertip microgrid worn on the finger.

Supplementary Video 3

The operation of wearable fingertip microgrid on-body testing.

Supplementary Code

Example code.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Ding, S., Saha, T., Yin, L. et al. A fingertip-wearable microgrid system for autonomous energy management and metabolic monitoring. Nat Electron 7, 788–799 (2024). https://doi.org/10.1038/s41928-024-01236-7

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41928-024-01236-7

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing