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Miniaturized electromechanical devices for the characterization of the biomechanics of deep tissue


Evaluating the biomechanics of soft tissues at depths well below their surface, and at high precision and in real time, would open up diagnostic opportunities. Here, we report the development and application of miniaturized electromagnetic devices, each integrating a vibratory actuator and a soft strain-sensing sheet, for dynamically measuring the Young’s modulus of skin and of other soft tissues at depths of approximately 1–8 mm, depending on the particular design of the sensor. We experimentally and computationally established the operational principles of the devices and evaluated their performance with a range of synthetic and biological materials and with human skin in healthy volunteers. Arrays of devices can be used to spatially map elastic moduli and to profile the modulus depth-wise. As an example of practical medical utility, we show that the devices can be used to accurately locate lesions associated with psoriasis. Compact electronic devices for the rapid and precise mechanical characterization of living tissues could be used to monitor and diagnose a range of health disorders.

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Fig. 1: Millimetre-scale electromechanical systems for sensing of soft-tissue elastic moduli.
Fig. 2: Experimental and simulation results of the device operation.
Fig. 3: Modulus measurements on hydrogels and on porcine and human skin.
Fig. 4: Designs for modulus sensing and depth profiling of multilayer samples.
Fig. 5: Measurements of skin lesions via miniaturized designs of the EMM sensors.
Fig. 6: Multiplexed arrays of EMM sensors for spatial mapping of tissue modulus.

Data availability

The data supporting the results in this study are available within the paper and its Supplementary Information. The raw patient data are available from the authors, subject to approval from Northwestern University’s Institutional Review Board.


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This work was supported by the Querrey/Simpson Institute for Bioelectronics at Northwestern University. We acknowledge the use of facilities in the Micro and Nanotechnology Laboratory for device fabrication and the Frederick Seitz Materials Research Laboratory for Advanced Science and Technology for device measurement at the University of Illinois at Urbana-Champaign. E.S., K.Y., D.L., J.Z. and X.Y. acknowledge the support from City University of Hong Kong (grant nos. 9610423, 9667199, 9667221), Research Grants Council of the Hong Kong Special Administrative Region (grant no. 21210820), and Shenzhen Science and Technology Innovation Commission (grant no. JCYJ20200109110201713). Z.X. acknowledges support from the National Natural Science Foundation of China (grant no. 12072057) and Fundamental Research Funds for the Central Universities (grant no. DUT20RC(3)032). S.M.W. acknowledges support of the MSIT (Ministry of Science and ICT), Korea, under the ICT Creative Consilience programme (IITP-2020-0-01821), supervised by the IITP (Institute for Information & Communications Technology Planning & Evaluation), and support by the Nano Material Technology Development Program (2020M3H4A1A03084600) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT of Korea. Y.M. acknowledges the support from the Natural Science Foundation of China (nos. 51961145108 and 61975035) and the Science and Technology Commission of Shanghai Municipality (nos. 19XD1400600 and 20501130700). Y.H. acknowledges support from the NSF (CMMI1635443).

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Authors and Affiliations



E.S., Z.X., W.B., X.Y., Y.H. and J.A.R. designed the research. E.S., Z.X., W.B., H.L., X.N., Y.X., J.M.B., Y.L., H.-Y.C., J.-H.K., S.M., S.M.W., X.Z., D.J.M., M.H., S.X., J.-K.C., X.Y., Y.H. and J.A.R. performed the research. E.S., Z.X., W.B., B.J., R.A., K.Y., D.L., J.Z. Y.M., X.G., J.-K.C., X.Y., Y.H. and J.A.R. analysed the data. Z.X., E.S., B.J., R.A., X.G., Y.H. and J.A.R. performed structural designs and mechanical modelling. E.S., Z.X., W.B., X.Y., Y.H. and J.A.R. wrote the paper.

Corresponding authors

Correspondence to Jan-Kai Chang, Xinge Yu, Yonggang Huang or John A. Rogers.

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The authors declare no competing interests.

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Peer review information Nature Biomedical Engineering thanks Jianyong Ouyang, Levent Beker and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary methods, figures, tables and video captions.

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Supplementary Video 1

Vibration of a magnet in slow motion at 50 Hz and sine-wave voltage amplitude of 5 V, captured using a high-speed camera.

Supplementary Video 2

Visualization of the vibration of a magnet in slow motion at 50 Hz on artificial skin, with a travelling amplitude of ~300 μm.

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Song, E., Xie, Z., Bai, W. et al. Miniaturized electromechanical devices for the characterization of the biomechanics of deep tissue. Nat Biomed Eng 5, 759–771 (2021).

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