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bioRxiv · 10.1101/2022.02.11.480088

Navigation of Ultrasound-controlled Swarmbots under Physiological Flow Conditions

Fonseca, A. D. C.·Kohler, T.·Ahmed, D.
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Abstract

Navigation of microrobots in living vasculatures is essential in realizing targeted drug delivery and advancing non-invasive surgeries. We developed acoustically-controlled "swarmbots" based on the self-assembly of clinically-approved microbubbles. Ultrasound is noninvasive, penetrates deeply into the human body, and is well-developed in clinical settings. Our propulsion strategy relies in two forces: the primary radiation force and secondary Bjerknes force. Upon ultrasound activation, the microbubbles self-assemble into microswarms, which migrate towards and anchor at the containing vessels wall. A second transducer, which produces an acoustic field parallel to the channel, propels the swarms along the wall. We demonstrated cross- and upstream navigation of the swarmbots at 3.27 mm/s and 0.53 mm/s, respectively, against physiologically-relevant flow rates of 4.2 - 16.7 cm/s. Additionally, we showed swarm controlled manipulation within mice blood and under pulsatile flow conditions of 100 beats per minute. This capability represents a much-needed pathway for advancing preclinical research. TeaserNavigation of ultrasound-guided microrobots inside artificial blood vessels overcoming physiological conditions, including high flow rates, pulsatile flow regimes, and high cell concentrations of blood.

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Fonseca, A. D. C., Kohler, T., Ahmed, D.. 2022-02-14. Navigation of Ultrasound-controlled Swarmbots under Physiological Flow Conditions. https://doi.org/10.1101/2022.02.11.480088

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