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A laser-engraved wearable sensor for sensitive detection of uric acid and tyrosine in sweat


Wearable sweat sensors have the potential to provide continuous measurements of useful biomarkers. However, current sensors cannot accurately detect low analyte concentrations, lack multimodal sensing or are difficult to fabricate at large scale. We report an entirely laser-engraved sensor for simultaneous sweat sampling, chemical sensing and vital-sign monitoring. We demonstrate continuous detection of temperature, respiration rate and low concentrations of uric acid and tyrosine, analytes associated with diseases such as gout and metabolic disorders. We test the performance of the device in both physically trained and untrained subjects under exercise and after a protein-rich diet. We also evaluate its utility for gout monitoring in patients and healthy controls through a purine-rich meal challenge. Levels of uric acid in sweat were higher in patients with gout than in healthy individuals, and a similar trend was observed in serum.

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Fig. 1: Schematics of the sweat sensor for metabolic and nutritional management.
Fig. 2: Schematics and characterization of the LEG-based UA and Tyr sensor.
Fig. 3: Design and characterization of the LEG-based vital-sign sensors.
Fig. 4: Design and characterization of the microfluidic system.
Fig. 5: In vivo system validation of the lab on the skin.
Fig. 6: Non-invasive gout management using the sweat sensor.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon request.

Code availability

The custom code used to program microcontroller is available from the corresponding author upon request.


  1. 1.

    Wang, T. J. et al. Metabolite profiles and the risk of developing diabetes. Nat. Med. 17, 448–453 (2011).

    PubMed  PubMed Central  Google Scholar 

  2. 2.

    Suhre, K. et al. Human metabolic individuality in biomedical and pharmaceutical research. Nature 477, 54–60 (2011).

    CAS  PubMed  Google Scholar 

  3. 3.

    Illig, T. et al. A genome-wide perspective of genetic variation in human metabolism. Nat. Genet. 42, 137–141 (2010).

    CAS  PubMed  Google Scholar 

  4. 4.

    Wu, G. Amino acids: metabolism, functions, and nutrition. Amino Acids 37, 1–17 (2009).

    PubMed  Google Scholar 

  5. 5.

    Kim, D. H. et al. Epidermal electronics. Science 333, 838–843 (2011).

    CAS  PubMed  Google Scholar 

  6. 6.

    Someya, T., Bao, Z. & Malliaras, G. G. The rise of plastic bioelectronics. Nature 540, 379–385 (2016).

    CAS  Google Scholar 

  7. 7.

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

    CAS  PubMed  Google Scholar 

  8. 8.

    Heikenfeld, J. et al. Wearable sensors: modalities, challenges, and prospects. Lab Chip 18, 217–248 (2018).

    CAS  PubMed  PubMed Central  Google Scholar 

  9. 9.

    Park, S. et al. Self-powered ultra-flexible electronics via nano-grating-patterned organic photovoltaics. Nature 561, 516–521 (2018).

    CAS  PubMed  Google Scholar 

  10. 10.

    Son, D. et al. An integrated self-healable electronic skin system fabricated via dynamic reconstruction of a nanostructured conducting network. Nat. Nanotechnol. 13, 1057–1065 (2018).

    CAS  PubMed  Google Scholar 

  11. 11.

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

    PubMed  PubMed Central  Google Scholar 

  12. 12.

    Hua, Q. et al. Skin-inspired highly stretchable and conformable matrix networks for multifunctional sensing. Nat. Commun. 9, 244 (2018).

    PubMed  PubMed Central  Google Scholar 

  13. 13.

    Wang, C. et al. User-interactive electronic skin for instantaneous pressure visualization. Nat. Mater. 12, 899–904 (2013).

    CAS  PubMed  Google Scholar 

  14. 14.

    Yang, Y. & Gao, W. Wearable and flexible electronics for continuous molecular monitoring. Chem. Soc. Rev. 48, 1465–1491 (2019).

    CAS  PubMed  Google Scholar 

  15. 15.

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

    CAS  PubMed  PubMed Central  Google Scholar 

  16. 16.

    Lee, H. et al. A graphene-based electrochemical device with thermoresponsive microneedles for diabetes monitoring and therapy. Nat. Nanotechnol. 11, 566–572 (2016).

    PubMed  Google Scholar 

  17. 17.

    Koh, A. et al. A soft, wearable microfluidic device for the capture, storage, and colorimetric sensing of sweat. Sci. Transl. Med. 8, 366ra165 (2016).

    PubMed  PubMed Central  Google Scholar 

  18. 18.

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

    Google Scholar 

  19. 19.

    Choi, J., Ghaffari, R., Baker, L. B. & Rogers, J. A. Skin-interfaced systems for sweat collection and analytics. Sci. Adv. 4, eaar3921 (2018).

    PubMed  PubMed Central  Google Scholar 

  20. 20.

    Emaminejad, S. et al. Autonomous sweat extraction and analysis applied to cystic fibrosis and glucose monitoring using a fully integrated wearable platform. Proc. Natl Acad. Sci. USA 114, 4625–4630 (2017).

    CAS  PubMed  Google Scholar 

  21. 21.

    Bandodkar, A. J. et al. Battery-free, skin-interfaced microfluidic/electronic systems for simultaneous electrochemical, colorimetric, and volumetric analysis of sweat. Sci. Adv. 5, eaav3294 (2019).

    PubMed  PubMed Central  Google Scholar 

  22. 22.

    Nakata, S. et al. A wearable pH sensor with high sensitivity based on a flexible charge-coupled device. Nat. Electron. 1, 596–603 (2018).

    Google Scholar 

  23. 23.

    Heikenfeld, J. et al. Accessing analytes in biofluids for peripheral biochemical monitoring. Nat. Biotechnol. 37, 407–419 (2019).

    CAS  PubMed  Google Scholar 

  24. 24.

    Lee, H. et al. Wearable/disposable sweat-based glucose monitoring device with multistage transdermal drug delivery module. Sci. Adv. 3, e1601314 (2017).

    PubMed  PubMed Central  Google Scholar 

  25. 25.

    Jia, W. et al. Electrochemical tattoo biosensors for real-time noninvasive lactate monitoring in human perspiration. Anal. Chem. 85, 6553–6560 (2013).

    CAS  PubMed  Google Scholar 

  26. 26.

    Feig, D. I., Kang, D. H. & Johnson, R. J. Uric acid and cardiovascular risk. N. Engl. J. Med. 359, 1811–1821 (2008).

    CAS  PubMed  PubMed Central  Google Scholar 

  27. 27.

    Gagliardi, A. C., Miname, M. H. & Santos, R. D. Uric acid: A marker of increased cardiovascular risk. Atherosclerosis 202, 11–17 (2009).

    CAS  PubMed  Google Scholar 

  28. 28.

    Bhole, V., Choi, J. W., Kim, S. W., de Vera, M. & Choi, H. Serum uric acid levels and the risk of type 2 diabetes: a prospective study. Am. J. Med. 123, 957–961 (2010).

    CAS  PubMed  PubMed Central  Google Scholar 

  29. 29.

    Kodama, S. et al. Association between serum uric acid and development of type 2 diabetes. Diabetes Care 32, 1737–1742 (2009).

    CAS  PubMed  PubMed Central  Google Scholar 

  30. 30.

    Kohagura, K. et al. An association between uric acid levels and renal arteriolopathy in chronic kidney disease: a biopsy-based study. Hypertens. Res. 36, 43–49 (2013).

    CAS  PubMed  Google Scholar 

  31. 31.

    Terkeltaub, R. Update on gout: new therapeutic strategies and options. Nat. Rev. Rheumatol. 6, 30–38 (2010).

    CAS  PubMed  Google Scholar 

  32. 32.

    Major, T. J., Dalbeth, N., Stahl, E. A. & Merriman, T. R. An update on the genetics of hyperuricaemia and gout. Nat. Rev. Rheumatol. 14, 341–353 (2018).

    CAS  PubMed  Google Scholar 

  33. 33.

    Terkeltaub, R. A. Clinical practice. Gout. N. Engl. J. Med. 349, 1647–1655 (2003).

    CAS  PubMed  Google Scholar 

  34. 34.

    Smith, E. et al. The global burden of gout: estimates from the Global Burden of Disease 2010 study. Ann. Rheum. Dis. 73, 1470–1476 (2014).

    PubMed  Google Scholar 

  35. 35.

    Fernstrom, J. D. & Fernstrom, M. H. Tyrosine, phenylalanine, and catecholamine synthesis and function in the brain. J. Nutr. 137, 1539S–1547S (2007).

    CAS  PubMed  Google Scholar 

  36. 36.

    Russo, P. A., Mitchell, G. A. & Tanguay, R. M. Tyrosinemia: a review. Pediatr. Dev. Pathol. 4, 212–221 (2001).

    CAS  PubMed  Google Scholar 

  37. 37.

    Levine, R. J. & Conn, H. O. Tyrosine metabolism in patients with liver disease. J. Clin. Invest. 46, 2012–2020 (1967).

    CAS  PubMed  PubMed Central  Google Scholar 

  38. 38.

    D’Andrea, G. et al. Study of tyrosine metabolism in eating disorders. Possible correlation with migraine. Neurol. Sci. 29, S88–S92 (2008).

    PubMed  Google Scholar 

  39. 39.

    Capuron, L. et al. Chronic low-grade inflammation in elderly persons is associated with altered tryptophan and tyrosine metabolism: role in neuropsychiatric symptoms. Biol. Psychiatry 70, 175–182 (2011).

    CAS  PubMed  Google Scholar 

  40. 40.

    Itoh, S. & Nakayama, T. Amino acids in human sweat. Jpn. J. Physiol. 2, 248–253 (1952).

    CAS  PubMed  Google Scholar 

  41. 41.

    Liappis, N., Kelderbacher, S. D., Kesseler, K. & Bantzer, P. Quantitative study of free amino acids in human eccrine sweat excreted from the forearms of healthy trained and untrained men during exercise. Eur. J. Appl. Physiol. Occup. Physiol. 42, 227–234 (1979).

    CAS  PubMed  Google Scholar 

  42. 42.

    Reeder, J. T. et al. Waterproof, electronics-enabled, epidermal microfluidic devices for sweat collection, biomarker analysis, and thermography in aquatic settings. Sci. Adv. 5, eaau6356 (2019).

    PubMed  PubMed Central  Google Scholar 

  43. 43.

    Nyein, H. Y. Y. et al. A wearable microfluidic sensing patch for dynamic sweat secretion analysis. ACS Sens. 3, 944–952 (2018).

    CAS  PubMed  Google Scholar 

  44. 44.

    Imani, S. et al. A wearable chemical–electrophysiological hybrid biosensing system for real-time health and fitness monitoring. Nat. Commun. 7, 11650 (2016).

    CAS  PubMed  PubMed Central  Google Scholar 

  45. 45.

    Ye, R., James, D. K. & Tour, J. M. Laser-induced graphene. Acc. Chem. Res. 51, 1609–1620 (2018).

    CAS  PubMed  Google Scholar 

  46. 46.

    Lin, J. et al. Laser-induced porous graphene films from commercial polymers. Nat. Commun. 5, 5714 (2014).

    CAS  PubMed  PubMed Central  Google Scholar 

  47. 47.

    Li, G., Mo, X., Law, W.-C. & Chan, K. C. Wearable fluid capture devices for electrochemical sensing of sweat. ACS Appl. Mater. Interfaces 11, 238–243 (2018).

    PubMed  Google Scholar 

  48. 48.

    Harvey, C. J., LeBouf, R. F. & Stefaniak, A. B. Formulation and stability of a novel artificial human sweat under conditions of storage and use. Toxicol. In Vitro 24, 1790–1796 (2010).

    CAS  PubMed  Google Scholar 

  49. 49.

    Shao, Q., Liu, G., Teweldebrhan, D. & Balandin, A. A. High-temperature quenching of electrical resistance in graphene interconnects. Appl. Phys. Lett. 92, 202108 (2008).

    Google Scholar 

  50. 50.

    Snakenborg, D., Klank, H. & Kutter, J. P. Microstructure fabrication with a CO2 laser system. J. Micromech. Microeng. 14, 182–189 (2004).

    CAS  Google Scholar 

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This work was supported by a California Institute of Technology Startup grant, the Rothenberg Innovation Initiative (RI2) program, the Carver Mead New Adventures Fund and an American Heart Association grant 19TPA34850157 (all to W.G.). Y.S., X.B. and M.W. acknowledge the China Scholarship Council (CSC) for financial support. J.T. was supported by the National Science Scholarship (NSS) from the Agency of Science Technology and Research (A*STAR) Singapore. We gratefully acknowledge critical support and infrastructure provided for this work by the Kavli Nanoscience Institute and Jim Hall Design and Prototyping Lab at Caltech, and we gratefully thank M. Hunt and B. Dominguez for their help. This project benefited from the use of instrumentation made available by the Caltech Environmental Analysis Center and we gratefully acknowledge guidance from N. Dalleska. We also thank Z. Wang for valuable inputs in patch pattern design.

Author information




W.G. and Y.Y. initiated the concept. W.G., Y.Y., Y.S., X.B., T.K.H. and Z.L. designed the experiments; Y.Y., Y.S., X.B. and J.M. led the experiments and collected the overall data; O.S.P., L.Z. and Y.Y. performed the flow simulation and modeling; J.M. performed the circuit design and test; M.W., J.T. and A.K. contributed to sensor characterization and validation; W.G., Y.Y., Y.S., X.B., J.M., O.S.P., L.Z. and H.Z. contributed the data analysis and co-wrote the paper. All authors provided the feedback on the manuscript.

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Correspondence to Wei Gao.

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Supplementary Figs. 1–41, Supplementary Tables 1–4 and Supplementary Note 1.

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Yang, Y., Song, Y., Bo, X. et al. A laser-engraved wearable sensor for sensitive detection of uric acid and tyrosine in sweat. Nat Biotechnol 38, 217–224 (2020).

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