Implantable Motes

We are developing novel ultrasound-based implants for temperature and electrochemical sensing. Our goal is for the wearable ultrasound patch to communicate with these motes, which would provide in-vivo data from inside a wound. The motes harvest power from ultrasound waves and are designed for biocompatibility. They are extremely miniscule with a volume of under 1.5 mm3 and have integrated PZTs on them. Several motes can be operated within the FOV of the imager due to each mote’s unique signature. They can be identified in real time with information about relative position to nearby organs, due to the non-interfering operating principle with the imaging session. The temperature-sensing motes operate on an oscillator’s frequency shift due to temperature and the pH-sensing motes use an ISFET-REFET topology to measure the pH of the medium. The sensed data is then digitized and transmitted to the patch for further analysis. From a circuit design perspective, this work involves ultra-low power design methodology and novel front-end topologies.

Selected Publications

Zhang, Y., Muthuraman, P., Andino-Pavlovsky, V. et al.. Augmented ultrasonography with implanted CMOS electronic motes Nat Commun. 13, 3521 (Aug 2022) [Article]

Abstract

Modern clinical practice benefits significantly from imaging technologies and much effort is directed toward making this imaging more informative through the addition of contrast agents or reporters. Here, we report the design of a battery-less integrated circuit mote acting as an electronic reporter during medical ultrasound imaging. When implanted within the field-of-view of a brightness-mode (B-mode) ultrasound imager, this mote transmits information from its location through backscattered acoustic energy which is captured within the ultrasound image itself. We prototype and characterize the operation of such motes in vitro and in vivo. Performing with a static power consumption of less than 57 pW, the motes operate at duty cycles for receiving acoustic energy as low as 50 ppm. Motes within the same field-of-view during imaging have demonstrated signal-to-noise ratios of more than 19.1 dB at depths of up to 40 mm in lossy phantom. Physiological information acquired through such motes, which is beyond what is measurable with endogenous ultrasound backscatter and which is biogeographically located within an image, has the potential to provide an augmented ultrasonography.

Chen Shi et al.. Application of a sub–0.1-mm3 implantable mote for in vivo real-time wireless temperature sensing Sci. Adv.7. eabf6312 (Nov 2021) [Article]

Implantable Motes

Implantable Motes

Selected Publications

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