Continuous monitoring of deep-tissue haemodynamics with stretchable ultrasonic phased arrays

Chonghe Wang, Baiyan Qi, Muyang Lin, Zhuorui Zhang, Mitsutoshi Makihata, Boyu Liu, Sai Zhou, Yi hsi Huang, Hongjie Hu, Yue Gu, Yimu Chen, Yusheng Lei, Taeyoon Lee, Shu Chien, Kyung In Jang, Erik B. Kistler, Sheng Xu

Research output: Contribution to journalArticlepeer-review

46 Citations (Scopus)


Stretchable wearable devices for the continuous monitoring of physiological signals from deep tissues are constrained by the depth of signal penetration and by difficulties in resolving signals from specific tissues. Here, we report the development and testing of a prototype skin-conformal ultrasonic phased array for the monitoring of haemodynamic signals from tissues up to 14 cm beneath the skin. The device allows for active focusing and steering of ultrasound beams over a range of incident angles so as to target regions of interest. In healthy volunteers, we show that the phased array can be used to monitor Doppler spectra from cardiac tissues, record central blood flow waveforms and estimate cerebral blood supply in real time. Stretchable and conformal skin-worn ultrasonic phased arrays may open up opportunities for wearable diagnostics.

Original languageEnglish
Pages (from-to)749-758
Number of pages10
JournalNature biomedical engineering
Issue number7
Publication statusPublished - 2021 Jul

Bibliographical note

Funding Information:
We thank Z. Wu and L. Chen for guidance on the ultrasonic imaging algorithm and data processing; S. Xiang for feedback on manuscript preparation; and Y. Hu and Z. Liu for advice on the cardiac tissue Doppler experiments. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health (NIH). All biological experiments were conducted in accordance with the ethical guidelines of the NIH and with the approval of the IRB of the University of California, San Diego (IRB number 170812). We acknowledge support from the NIH (grant 1R21EB027303-01A1) and the Center for Wearable Sensors at the University of California, San Diego.

Publisher Copyright:
© 2021, The Author(s), under exclusive licence to Springer Nature Limited.

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Bioengineering
  • Medicine (miscellaneous)
  • Biomedical Engineering
  • Computer Science Applications


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