A Tiny Robot Fish Powered by Sound

Nature Video
Nature VideoMar 16, 2026

Why It Matters

It opens a pathway for minimally invasive, ultrasound‑controlled drug delivery, potentially transforming targeted therapies and reducing systemic side effects.

Key Takeaways

  • Tiny acoustic robot swims using ultrasound‑driven bubble jets.
  • Flexible membrane with micro‑holes traps air bubbles for thrust.
  • Different bubble sizes resonate at specific frequencies for tunable motion.
  • Designed as a “stingray bot” that could navigate human body.
  • Potential for capsule‑delivered, targeted drug delivery via sound power.

Summary

Researchers have unveiled a micrometer‑scale acoustic robot that propels itself solely with ultrasound‑induced bubble jets. Dubbed the “stingray bot,” the device is a thin, flexible sheet perforated with thousands of microscopic holes that trap air bubbles, allowing it to swim without onboard power.

When high‑frequency ultrasound passes through the surrounding liquid, each trapped bubble vibrates and ejects a tiny jet of fluid, generating thrust. Because bubble size determines resonant frequency—much like a bell’s pitch—different sections of the robot activate at distinct frequencies, producing a coordinated undulating motion that mimics a stingray’s fin.

The bubbles are smaller than a human hair and less than a tenth of a millimeter deep, creating visible jets under a particle‑laden fluid. By sweeping ultrasound frequencies, the three fin sections fire sequentially, enabling precise control of direction and speed without any wires or batteries.

The technology promises a new class of soft, wireless medical microrobots that could be swallowed in a dissolvable capsule and navigate internal tissues to deliver drugs directly where needed, leveraging the safety and penetrative ability of diagnostic ultrasound.

Original Description

An ultrasound-powered robot fish?! Meet Stingraybot - a clever little device filled with bubbles. Something like this could one day be swimming through your digestive tract, according to the scientists who invented it.
Produced and presented by Shamini Bundell
Research footage from Acoustic Robotics Systems Laboratory
Stock images from Getty Images / ITN / Vincent Isore/IP3
Music from Triple Scoop Music / Bella Ruse
Supervising Producers: Dan Fox & Maren Hunsberger
From Shi, Z., Zhang, Z., Schnermann, J. et al. Ultrasound-driven programmable artificial muscles. Nature 646, 1096–1104 (2025)
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