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 1.3-micrometre-thick elastic conductor for seamless on-skin and implantable sensors

Nature Electronics volume 5, pages 784–793 (2022)Cite this article

Subjects

Abstract

On-skin and implantable electronics require elastic conductors that are only a few micrometres thick and soft enough to form a seamless contact with three-dimensional structures. However, fabricating thin conductors that are mechanically durable and have consistent electrical properties with stretching is challenging. Here we report polydimethylsiloxane (PDMS)–gold conductors that are around 1.3 µm thick and have a controlled morphology of microcracks in the gold film. The microcracks are formed by evaporating a 50-nm-thick gold film onto a 1.2-µm-thick PDMS film that is supported during fabrication by a 100-µm-thick PDMS film on glass; thermal expansion of the thick PDMS film causes the evaporated gold to form a microcracked structure on the thin PDMS. The resulting conductors can be stretched by up to 300% and remain highly conductive after strain release. We use them to create on-skin electrodes that are breathable and water resistant, and can continuously record electrocardiogram signals. We also use the conductors to create on-skin sensors with less than 3 µm thickness that can detect small mechanical forces and create implantable nerve electrodes that can provide signal recording and stimulation.

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: Design of stretchable ultrathin conductors.
Fig. 2: Mechanism of microcracked morphology formation and mechanical/electrical characterization.
Fig. 3: On-skin sensors based on ultrathin conductors.
Fig. 4: Implantable neural interfaces based on ultrathin conductors.

Similar content being viewed by others

Data availability

The data that support the findings of this study are available from the corresponding authors on reasonable request.

Code availability

The codes used for analysing the neural signals are available from the corresponding authors upon reasonable request.

References

  1. Kim, D. H. et al. Dissolvable films of silk fibroin for ultrathin conformal bio-integrated electronics. Nat. Mater. 9, 511–517 (2010).

    Article  Google Scholar 

  2. Liu, J. et al. Syringe-injectable electronics. Nat. Nanotechnol. 10, 629–636 (2015).

    Article  Google Scholar 

  3. Lee, S. et al. Nanomesh pressure sensor for monitoring finger manipulation without sensory interference. Science 370, 966–970 (2020).

    Article  Google Scholar 

  4. Liu, Y. et al. Morphing electronics enable neuromodulation in growing tissue. Nat. Biotechnol. 38, 1031–1036 (2020).

    Article  Google Scholar 

  5. Jeong, J. W. et al. Materials and optimized designs for human-machine interfaces via epidermal electronics. Adv. Mater. 25, 6839–6846 (2013).

    Article  Google Scholar 

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

    Article  Google Scholar 

  7. Gao, W., Ota, H., Kiriya, D., Takei, K. & Javey, A. Flexible electronics toward wearable sensing. Acc. Chem. Res. 52, 523–533 (2019).

    Article  Google Scholar 

  8. Kang, S. K., Koo, J., Lee, Y. K. & Rogers, J. A. Advanced materials and devices for bioresorbable electronics. Acc. Chem. Res. 51, 988–998 (2018).

    Article  Google Scholar 

  9. Matsuhisa, N. et al. High‐transconductance stretchable transistors achieved by controlled gold microcrack morphology. Adv. Electron. Mater. 5, 1900347 (2019).

    Article  Google Scholar 

  10. Lee, G. H. et al. Stretchable anisotropic conductive film (S-ACF) for electrical interfacing in high-resolution stretchable circuits. Sci. Adv. 8, eabm3622 (2022).

    Article  Google Scholar 

  11. Jiang, Z. et al. Highly stretchable metallic nanowire networks reinforced by the underlying randomly distributed elastic polymer nanofibers via interfacial adhesion improvement. Adv. Mater. 31, e1903446 (2019).

    Article  Google Scholar 

  12. Matsuhisa, N. et al. Printable elastic conductors by in situ formation of silver nanoparticles from silver flakes. Nat. Mater. 16, 834–840 (2017).

    Article  Google Scholar 

  13. Kim, Y. et al. Stretchable nanoparticle conductors with self-organized conductive pathways. Nature 500, 59–63 (2013).

    Article  Google Scholar 

  14. 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).

    Article  Google Scholar 

  15. Chen, Z. et al. Three-dimensional flexible and conductive interconnected graphene networks grown by chemical vapour deposition. Nat. Mater. 10, 424–428 (2011).

    Article  Google Scholar 

  16. Choi, S. et al. Highly conductive, stretchable and biocompatible Ag–Au core–sheath nanowire composite for wearable and implantable bioelectronics. Nat. Nanotechnol. 13, 1048–1056 (2018).

    Article  Google Scholar 

  17. Jung, D. et al. Highly conductive and elastic nanomembrane for skin electronics. Science 373, 1022–1026 (2021).

    Article  Google Scholar 

  18. Liu, S., Shah, D. S. & Kramer-Bottiglio, R. Highly stretchable multilayer electronic circuits using biphasic gallium-indium. Nat. Mater. 20, 851–858 (2021).

    Article  Google Scholar 

  19. Ma, Z. et al. Permeable superelastic liquid-metal fibre mat enables biocompatible and monolithic stretchable electronics. Nat. Mater. 20, 859–868 (2021).

    Article  Google Scholar 

  20. Wang, Y. et al. Robust, self-adhesive, reinforced polymeric nanofilms enabling gas-permeable dry electrodes for long-term application. Proc. Natl Acad. Sci. USA 118, e2111904118 (2021).

    Article  Google Scholar 

  21. Lacour, S. P. et al. Mechanisms of reversible stretchability of thin metal films on elastomeric substrate. Appl. Phys. Lett. 88, 204103 (2006).

  22. Zhang, B. et al. Stretchable conductive fibers based on a cracking control strategy for wearable electronics. Adv. Funct. Mater. 28, 1801683 (2018).

    Article  Google Scholar 

  23. Liu, Z. et al. Highly stable and stretchable conductive films through thermal-radiation-assisted metal encapsulation. Adv. Mater. 31, e1901360 (2019).

    Article  Google Scholar 

  24. Johnston, I. D., McCluskey, D. K., Tan, C. K. L. & Tracey, M. C. Mechanical characterization of bulk Sylgard 184 for microfluidics and microengineering. J. Micromech. Microeng. 24, 035017 (2014).

    Article  Google Scholar 

  25. Liu, M., Sun, J. & Chen, Q. Influences of heating temperature on mechanical properties of polydimethylsiloxane. Sens. Actuator A Phys. 151, 42–45 (2009).

    Article  Google Scholar 

  26. Hadgraft, J. & Lane, M. E. Transepidermal water loss and skin site: a hypothesis. Int. J. Pharm. 373, 1–3 (2009).

    Article  Google Scholar 

  27. Geerligs, M. A literature review of the mechanical behavior of the stratum corneum, the living epidermis and the subcutaneous fat tissue (Philips Research, 2006).

  28. Lee, H. et al. Stretchable organic optoelectronic devices: design of materials, structures, and applications. Mater. Sci. Eng. 146, 100631 (2021).

    Article  Google Scholar 

  29. Miyamoto, A. et al. Inflammation-free, gas-permeable, lightweight, stretchable on-skin electronics with nanomeshes. Nat. Nanotechnol. 12, 907–913 (2017).

    Article  Google Scholar 

  30. Yang, X. et al. Bioinspired neuron-like electronics. Nat. Mater. 18, 510–517 (2019).

    Article  Google Scholar 

  31. Mariello, M., Kim, K., Wu, K., Lacour, S. P. & Leterrier, Y. Recent advances in encapsulation of flexible bioelectronic implants: materials, technologies and characterization methods. Adv. Mater. 34, e2201129 (2022).

    Article  Google Scholar 

  32. Zhang, Y. et al. Stretchable PDMS encapsulation via SiO2 doping and atomic layer infiltration for flexible displays. Adv. Mater. Interfaces 9, 2101857 (2022).

    Article  Google Scholar 

  33. Ji, S. et al. Water-resistant conformal hybrid electrodes for aquatic endurable electrocardiographic monitoring. Adv. Mater. 32, e2001496 (2020).

    Article  Google Scholar 

  34. Jiang, Y. et al. Stretchable, washable, and ultrathin triboelectric nanogenerators as skin-like highly sensitive self-powered haptic sensors. Adv. Funct. Mater. 31, 2005584 (2020).

  35. Liu, Z. et al. Surface strain redistribution on structured microfibers to enhance sensitivity of fiber-shaped stretchable strain sensors. Adv. Mater. 30, 1704229 (2018).

    Article  Google Scholar 

  36. Mariello, M., Fachechi, L., Guido, F. & De Vittorio, M. Conformal, ultra-thin skin-contact-actuated hybrid piezo/triboelectric wearable sensor based on AlN and parylene-encapsulated elastomeric blend. Adv. Funct. Mater. 31, 2101047 (2021).

    Article  Google Scholar 

  37. Park, J., Kim, D. & Kim, Y. T. Ultra-stretchable on-body-based soft triboelectric nanogenerator for electronic skin. Smart Mater. Struct. 29, 115031 (2020).

    Article  Google Scholar 

  38. Chu, Y. et al. Human pulse diagnosis for medical assessments using a wearable piezoelectret sensing system. Adv. Funct. Mater. 28, 1803413 (2018).

    Article  Google Scholar 

  39. Cianchetti, M., Laschi, C., Menciassi, A. & Dario, P. Biomedical applications of soft robotics. Nat. Rev. Mater. 3, 143–153 (2018).

    Article  Google Scholar 

  40. Chen, N. et al. Nanotunnels within poly(3,4-ethylenedioxythiophene)-carbon nanotube composite for highly sensitive neural interfacing. ACS Nano 14, 8059–8073 (2020).

    Article  Google Scholar 

  41. Rijnbeek, E. H., Eleveld, N. & Olthuis, W. Update on peripheral nerve electrodes for closed-loop neuroprosthetics. Front. Neurosci. 12, 350 (2018).

    Article  Google Scholar 

  42. Musick, K. M. et al. Chronic multichannel neural recordings from soft regenerative microchannel electrodes during gait. Sci. Rep. 5, 14363 (2015).

    Article  Google Scholar 

  43. Alahi, M. E. E. et al. Recent advancement of electrocorticography (ECoG) electrodes for chronic neural recording/stimulation. Mater. Today Commun. 29, 102853 (2021).

Download references

Acknowledgements

Parts of this work were conducted in RIKEN, Japan, supported by JSPS KAKENHI under grant nos. JP18H05469 and 17H06149. Parts of this work were conducted in Nanyang Technological University, Singapore, supported by the National Research Foundation Singapore (NRF) under NRF’s Medium Sized Centre: Singapore Hybrid-Integrated Next-Generation μ-Electronics (SHINE) Centre funding programme and the Agency for Science, Technology and Research (A*STAR) under its AME Programmatic Funding Scheme (Project #A18A1b0045; X.C.). Parts of this work were conducted in the University of Macau, China, supported by the Science and Technology Development Fund, Macau SAR (FDCT) (file nos. 0059/2021/AFJ and 0040/2021/A1). The implantable experiments were conducted in the National University of Singapore and they were supported by the National Research Foundation, Prime Minister’s Office, Singapore, under the NRF Investigatorship Programme (award no. NRF-NRFI05-2019-0003) and NUS NANONASH Programme (NUHSRO/2020/002/NanoNash/LOA; R143000B43114).

Author information

Authors and Affiliations

  1. Thin-Film Device Laboratory, RIKEN, Wako, Saitama, Japan

    Zhi Jiang, Kenjiro Fukuda & Takao Someya

  2. Innovative Center for Flexible Devices (iFLEX), School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore

    Zhi Jiang, Nuan Chen, Feilong Zhang, Shaobo Ji, Haicheng Li & Xiaodong Chen

  3. Department of Chemistry, National University of Singapore, Singapore, Singapore

    Zhigao Yi & Xiaogang Liu

  4. Department of Electromechanical Engineering and Centre for Artificial Intelligence and Robotics, University of Macau, Macau, People’s Republic of China

    Junwen Zhong

  5. State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China (UESTC), Chengdu, People’s Republic of China

    Rui Liao & Yang Wang

  6. Department of Electrical Engineering and Information Systems, The University of Tokyo, Tokyo, Japan

    Yan Wang, Tomoyuki Yokota & Takao Someya

  7. Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore

    Zhihua Liu & Xiaodong Chen

  8. Center for Emergent Matter Science, RIKEN, Wako, Saitama, Japan

    Junwen Zhong, Kenjiro Fukuda & Takao Someya

Authors
  1. Zhi Jiang
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Nuan Chen
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Zhigao Yi
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Junwen Zhong
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Feilong Zhang
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Shaobo Ji
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Rui Liao
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Yan Wang
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Haicheng Li
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Zhihua Liu
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. Yang Wang
    View author publications

    You can also search for this author in PubMed Google Scholar

  12. Tomoyuki Yokota
    View author publications

    You can also search for this author in PubMed Google Scholar

  13. Xiaogang Liu
    View author publications

    You can also search for this author in PubMed Google Scholar

  14. Kenjiro Fukuda
    View author publications

    You can also search for this author in PubMed Google Scholar

  15. Xiaodong Chen
    View author publications

    You can also search for this author in PubMed Google Scholar

  16. Takao Someya
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

Z.J., K.F., X.C. and T.S. conceived and designed the research. Z.J. designed the the ultrathin PDMS–Au and performed the characterization of the mechanical, electrical and morphological properties. Z.J., S.J. and F.Z. designed the on-skin ECG sensor and performed the related characterizations. Z.J. and J.Z. designed the ultrathin sensor and performed the related characterizations. Z.J. and N.C. designed and fabricated the neural electrodes, and N.C. and Z.Y. performed the implantable experiments. R.L. and Yang Wang performed the COMSOL simulations. Yan Wang, H.L., Z.L., T.Y. and K.F. assisted in the experiment or analysed the data. All the authors discussed the results and commented on the manuscript. Z.J., K.F., X.L., X.C. and T.S. wrote the manuscript. We would like to thank Y. Jiang, J. Yi, W. Li and C. Cao from Nanyang Technological University and G. Gammad from National University of Singapore for their technical support and discussion.

Corresponding authors

Correspondence to Kenjiro Fukuda, Xiaodong Chen or Takao Someya.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature Electronics thanks Xue Feng, Wei Gao, Massimo Mariello and the other, anonymous, reviewer(s) 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 Figs. 1–46, Tables 1 and 2 and experimental section.

Reporting Summary

Supplementary Video 1

Laminating the ultrathin PDMS film onto the thick PDMS-coated glass substrate.

Supplementary Video 2

Stretch test of the ultrathin conductor.

Supplementary Video 3

Adhesion test of the ultrathin electrode when the volunteer washed hands.

Supplementary Video 4

Adhesion test of the thick electrode when the volunteer washed hands.

Supplementary Video 5

Resistance measurement on the ultrathin electrode when moving the arm.

Supplementary Video 6

Demonstration of powering a liquid-crystal display using the ultrathin mechanical sensor.

Supplementary Video 7

Selective muscle activation by stimulating the nerve using the ultrathin neural electrodes.

Supplementary Video 8

Selective muscle activation by stimulating the nerve using thick electrodes.

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

Jiang, Z., Chen, N., Yi, Z. et al. A 1.3-micrometre-thick elastic conductor for seamless on-skin and implantable sensors. Nat Electron 5, 784–793 (2022). https://doi.org/10.1038/s41928-022-00868-x

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41928-022-00868-x

This article is cited by

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