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Three-dimensional printing of soft hydrogel electronics

Nature Electronics volume 5, pages 893–903 (2022)Cite this article

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Abstract

Electronics based on hydrogels can have inherent similarities to biological tissue and are of potential use in biomedical applications. Ideally, such hydrogel electronics should offer customizable three-dimensional circuits, but making complex three-dimensional circuits encapsulated within a hydrogel matrix is challenging with existing materials and manufacturing methods. Here we report the three-dimensional printing of hydrogel electronics using a curable hydrogel-based supporting matrix and a stretchable silver–hydrogel ink. The supporting matrix has a yield stress fluid behaviour, so the shear force generated by a moving printer nozzle creates a temporary fluid-like state, allowing the accurate placement in the matrix of silver–hydrogel ink circuits and electronic components. After printing, the entire matrix and embedded circuitry can be cured at 60 °C to form soft (Young’s modulus of less than 5 kPa) and stretchable (elongation of around 18) monolithic hydrogel electronics, whereas the conductive ink exhibits a high conductivity of around 1.4 × 103 S cm−1. We use our three-dimensional printing approach to create strain sensors, inductors and biological electrodes.

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Fig. 1: Fabrication of hydrogel electronics via EM3DP.
Fig. 2: Rheological properties of the supporting matrix and conductive ink.
Fig. 3: Tensile mechanical properties of cured hydrogel matrices.
Fig. 4: Electrical properties of the Ag–hydrogel conductive ink and printed stretchable hydrogel electronics.
Fig. 5: Fabrication of functional hydrogel electronics.
Fig. 6: Biomedical applications of 3D printed all-hydrogel electrodes.

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Data availability

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

Code availability

The code used in this paper is available from the corresponding authors on reasonable request.

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Acknowledgements

We thank H. Chen for assistance with the 3D printers. We also acknowledge financial support for this research by the National Natural Science Foundation of China (nos. 51905446 and 31970129). We thank C. Zhang and L. Liu from the Instrumentation and Service Center for Physical Sciences at Westlake University for technical support in data acquisition and interpretation. We also thank the Research Center for Industries of the Future (RCIF), Westlake Laboratory of Life Sciences and Biomedicine, and Westlake Education Foundation at Westlake University for supporting this work.

Author information

Author notes

  1. These authors contributed equally: Yue Hui, Yuan Yao.

Authors and Affiliations

  1. Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering and Research Center for Industries of the Future, Westlake University, Hangzhou, China

    Yue Hui, Yuan Yao, Hehao Chen, Yetian Yu & Nanjia Zhou

  2. Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou, China

    Yue Hui, Yuan Yao, Hehao Chen, Yetian Yu & Nanjia Zhou

  3. School of Chemical Engineering and Advanced Materials, the University of Adelaide, Adelaide, South Australia, Australia

    Yue Hui

  4. Key Laboratory of RF Circuits and Systems of Ministry of Education, School of Electronics and Information, Hangzhou Dianzi University, Hangzhou, China

    Qilin Qian

  5. Research Center for the Industries of the Future and School of Life Sciences, Westlake University, Hangzhou, China

    Jianhua Luo & Liang Tao

  6. Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, China

    Jianhua Luo & Liang Tao

  7. Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, China

    Jianhua Luo & Liang Tao

  8. Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore

    Zheng Qiao

Authors
  1. Yue Hui
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Contributions

Y.H. and N.Z. designed the research. Y.H., Y. Yao and Z.Q. fabricated the materials and devices. Y.H., Y. Yao, H.C. and Y. Yu performed the general experiments. Y.H., Q.Q. and Y. Yao conducted the electrical experiments and simulation analysis. Y. Yao, Y.H., J.L. and L.T. designed the biological experiments. Y. Yao and J.L. conducted the biological experiments. Y.H., Y. Yao and N.Z. analysed the data. Y.H., Y. Yao and N.Z. wrote and revised the manuscript.

Corresponding authors

Correspondence to Yue Hui, Liang Tao or Nanjia Zhou.

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The authors declare no competing interests.

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Peer review information

Nature Electronics thanks Mahdi Bodaghi and Shaoxing Qu for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary Figs. 1–19 and and Tables 1–5.

Supplementary Video 1

EM3DP of hydrogel electronics.

Supplementary Video 2

LED lit up wirelessly by a printed hydrogel inductor.

Supplementary Video 3

A 3D inductor–LED device fabricated via the hybrid printing procedure.

Supplementary Video 4

Response of printed 3D inductor–LED device to compressive deformation.

Supplementary Video 5

Performance of printed hydrogel electronics under deformation cycles.

Supplementary Video 6

Mice hindlimb motion on sciatic nerve stimulation.

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Hui, Y., Yao, Y., Qian, Q. et al. Three-dimensional printing of soft hydrogel electronics. Nat Electron 5, 893–903 (2022). https://doi.org/10.1038/s41928-022-00887-8

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