The ability to monitor blood flow is critical to patient recovery and patient outcomes after complex reconstructive surgeries. Clinically available wired implantable monitoring technology requires careful fixation for accurate detection and needs to be removed after use. Here, we report the design of a pressure sensor, made entirely of biodegradable materials and based on fringe-field capacitor technology, for measuring arterial blood flow in both contact and non-contact modes. The sensor is operated wirelessly through inductive coupling, has minimal hysteresis, fast response times, excellent cycling stability, is highly robust, allows for easy mounting and eliminates the need for removal, thus reducing the risk of vessel trauma. We demonstrate the operation of the sensor with a custom-made artificial artery model and in vivo in rats. This technology may be advantageous in real-time post-operative monitoring of blood flow after reconstructive surgery.
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The authors declare that the data supporting the findings of this study are available within the paper and its Supplementary Information. Raw data generated for this study are available from the corresponding author on reasonable request.
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C.M.B. acknowledges postdoctoral fellowship support from the Swiss National Science Foundation (postdoc mobility fellowship no. P2EZP2_152118) and the European Commission (Marie Curie international outgoing fellowship grant no. 622362). L.B. and Y.K. acknowledge the Stanford ChEM-H Postdocs at the Interface seed grant. Part of this work was performed at the Stanford Nano Shared Facilities. A.C.H. acknowledges support from the National Science Foundation Graduate Research Fellowship (grant no. DGE-1147474).
Stanford University has filed a provisional patent application (62750518) related to this technology.
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Supplementary figures, table and discussion
Heart-pulse-rate measurement via external Doppler ultrasound during in vivo characterization
After 12 weeks of sensor implantation, the rat was able to move without any apparent limb impairment
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Boutry, C.M., Beker, L., Kaizawa, Y. et al. Biodegradable and flexible arterial-pulse sensor for the wireless monitoring of blood flow. Nat Biomed Eng 3, 47–57 (2019). https://doi.org/10.1038/s41551-018-0336-5
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