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Phase-separated porous nanocomposite with ultralow percolation threshold for wireless bioelectronics

Nature Nanotechnology (2024)Cite this article

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Abstract

Realizing the full potential of stretchable bioelectronics in wearables, biomedical implants and soft robotics necessitates conductive elastic composites that are intrinsically soft, highly conductive and strain resilient. However, existing composites usually compromise electrical durability and performance due to disrupted conductive paths under strain and rely heavily on a high content of conductive filler. Here we present an in situ phase-separation method that facilitates microscale silver nanowire assembly and creates self-organized percolation networks on pore surfaces. The resultant nanocomposites are highly conductive, strain insensitive and fatigue tolerant, while minimizing filler usage. Their resilience is rooted in multiscale porous polymer matrices that dissipate stress and rigid conductive fillers adapting to strain-induced geometry changes. Notably, the presence of porous microstructures reduces the percolation threshold (Vc = 0.00062) by 48-fold and suppresses electrical degradation even under strains exceeding 600%. Theoretical calculations yield results that are quantitatively consistent with experimental findings. By pairing these nanocomposites with near-field communication technologies, we have demonstrated stretchable wireless power and data transmission solutions that are ideal for both skin-interfaced and implanted bioelectronics. The systems enable battery-free wireless powering and sensing of a range of sweat biomarkers—with less than 10% performance variation even at 50% strain. Ultimately, our strategy offers expansive material options for diverse applications.

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Fig. 1: Schematic and fabrication of strain-insensitive PSPN with ultralow percolation thresholds.
Fig. 2: Phase-separation, electrical and mechanical characterization.
Fig. 3: Radiofrequency properties of the stretchable PSPN coils under tensile strain.
Fig. 4: Stretchable wireless powering system for wearable and implantable bioelectronics.
Fig. 5: Wireless stretchable bioelectronics for multiplexed biochemical sensing.

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Data availability

The main data supporting the results in this study are available within the paper and its Supplementary Information. Source data for Figs. 1–5 are provided with this paper. Source data are provided with this paper.

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Acknowledgements

Z. Yan acknowledges financial support from the start-up fund of the University of Missouri-Columbia. Z. Yan, P.-Y.C. and J.X. acknowledge the National Institute of Biomedical Imaging and Bioengineering (award number R01EB033371). The human study was supported by Z. Yan’s start-up fund. W.G. acknowledges support from National Institutes of Health grants (R01HL155815 and R21DK13266). P.-Y.C. acknowledges financial support from NSF ECCS 2229659. I.O. acknowledges financial support from the start-up fund of the University of Missouri-Columbia.

Author information

Author notes

  1. These authors contributed equally: Yadong Xu, Zhilu Ye, Ganggang Zhao.

Authors and Affiliations

  1. Department of Chemical and Biomedical Engineering, University of Missouri, Columbia, MO, USA

    Yadong Xu, Qihui Fei, Zehua Chen, Benton Berigan, Xiaoyan Qian, Lin Shi, Ilker Ozden & Zheng Yan

  2. Andrew and Peggy Cherng Department of Medical Engineering, Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA, USA

    Yadong Xu, Jiahong Li & Wei Gao

  3. Department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, IL, USA

    Zhilu Ye, Minye Yang, Yichong Ren & Pai-Yen Chen

  4. Department of Mechanical and Aerospace Engineering, University of Missouri, Columbia, MO, USA

    Ganggang Zhao, Yun Ling & Zheng Yan

  5. Department of Surgery-Transplant and Mary and Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, NE, USA

    Jingwei Xie

  6. Materials Science and Engineering Institute, University of Missouri, Columbia, MO, USA

    Zheng Yan

  7. NextGen Precision Health, University of Missouri, Columbia, MO, USA

    Zheng Yan

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Contributions

Z. Yan, Y.X., P.-Y.C. and Z. Ye conceived the idea and led research efforts. Y.X., Z. Ye, G.Z., Q.F., Z.C., J.L., M.Y., Y.R., Y.L., X.Q., L.S. and J.X. performed the experiments. J.L. conducted numerical simulations. I.O. and B.B. led animal studies and performed surgeries. Z. Yan, Y.X., Z. Ye and W.G. wrote the paper with assistance of the other coauthors.

Corresponding authors

Correspondence to Wei Gao, Pai-Yen Chen or Zheng Yan.

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Nature Nanotechnology thanks Michael Dickey, Chengkuo Lee and Xuechang Zhou for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary Tables 1 and 2, Figs. 1–31, Notes 1–4, references and video captions.

Reporting Summary

Supplementary Video 1

Demonstration of PSPN mechanical resilience.

Supplementary Video 2

ECG recording with strain-insensitive PSPN electrical wires.

Supplementary Video 3

Wireless control of the implanted optoelectronic system.

Supplementary Video 4

Wireless powering of the implanted optoelectronic system.

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Source Data Fig. 4

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Source Data Fig. 5

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Xu, Y., Ye, Z., Zhao, G. et al. Phase-separated porous nanocomposite with ultralow percolation threshold for wireless bioelectronics. Nat. Nanotechnol. (2024). https://doi.org/10.1038/s41565-024-01658-6

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