A wireless body area sensor network based on stretchable passive tags

Abstract

A body area sensor network (bodyNET) is a collection of networked sensors that can be used to monitor human physiological signals. For its application in next-generation personalized healthcare systems, seamless hybridization of stretchable on-skin sensors and rigid silicon readout circuits is required. Here, we report a bodyNET composed of chip-free and battery-free stretchable on-skin sensor tags that are wirelessly linked to flexible readout circuits attached to textiles. Our design offers a conformal skin-mimicking interface by removing all direct contacts between rigid components and the human body. Therefore, this design addresses the mechanical incompatibility issue between soft on-skin devices and rigid high-performance silicon electronics. Additionally, we introduce an unconventional radiofrequency identification technology where wireless sensors are deliberately detuned to increase the tolerance of strain-induced changes in electronic properties. Finally, we show that our soft bodyNET system can be used to simultaneously and continuously analyse a person’s pulse, breath and body movement.

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Fig. 1: A bodyNET consisting of stretchable on-skin sensors and flexible silicon circuits on clothes.
Fig. 2: Design and experimental verification for the stretchable RFID system.
Fig. 3: Design of the stretchable sensor target and flexible initiator.
Fig. 4: A bodyNET to measure and display human body movement, pulse and breathing simultaneously.

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.

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Acknowledgements

This research was supported by Samsung Electronics. X.C. acknowledges financial support from the Agency for Science, Technology and Research (A*STAR) under its AME Programmatic Funding Scheme (project no. A18A1b0045). N.M. acknowledges funding support from an overseas fellowship from the Japan Society for the Promotion of Science (JSPS). A.S.Y.P., Z.B. and N.M. acknowledge support from Stanford Precision Health and Integrated Diagnosis Center for seed funding support. The authors thank S. Taheri, W. Wang, J. Kim, B. Chu, Y. Zheng, J. Kang, Y. Kim, H.-C. Wu, J. Xu, T. Lei, Y. Liu, Z. Liu, G. Chen, Y. Jiang and B. Murmann for experimental assistance and insightful discussions. The authors also thank Dupont for providing the stretchable conductor inks.

Author information

S.N., N.M., W.B. and Z.B. generated the design concept. S.N. designed the overall system architecture and verified this architecture through circuit simulation. S.N. designed, fabricated and tested the flexible readout circuits. S.N. and N.M. fabricated the intrinsically stretchable sensor tags, developed the Bluetooth user interfaces and performed all the system measurements and daily physiological signal monitoring. L.B. helped in the design and fabrication of strain sensors. N.M., S.N., Y.Y. and J.L. helped to prepare the three-dimensional schematics and carried out device photography. S.W., J.W., Y.J. and X.Y. contributed to the material choice of stretchable tags. A.S.Y.P. commented on the RFID system design. S.N., N.M., Z.B. and J.B.-H.T. wrote the manuscript. Z.B. and X.C. supervised the project. All authors reviewed and commented on the manuscript.

Correspondence to Xiaodong Chen or Zhenan Bao.

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Supplementary information

Supplementary Information

Supplementary Figs. 1–16, Supplementary Tables 1–2 and Supplementary Notes 1–2.

Reporting Summary

Supplementary Movie 1

Display of pulse waves measured from our bodyNET by an oscilloscope.

Supplementary Movie 2

A demonstration of a bodyNET containing five sensing nodes, including one pulse node, one breathing node and three body movement nodes.

Supplementary Movie 3

A demonstration of a sensor node with a built-in seven-segment display to measure respiration.

Supplementary Movie 4

A demonstration of a sensor node located at the neck to measure head movement.

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