Medical microrobots hold great potential for minimally invasive procedures and targeted therapy thanks to their ability to access and operate in hard-to-reach parts of the body. The success of these tiny robots, however, is contingent on being able to control them accurately from outside the body.

Pane et al. proposed a new way to improve the visibility of microrobots in the body by looking at their peculiar motions using contrast-enhanced ultrasound tracking.

“We navigated our microrobot in diverse physiological conditions, simulating the disturbances arising from different anatomical environments,” said author Stephano Pane. “Our approach enabled rejection of most of the ultrasound noise and allowed us to see and follow our tiny robot during its exploration.”

The researchers navigated a helical propeller in chicken breast tissue and tissue-mimicking phantoms, which simulate certain acoustic and physical properties of tissue. They aimed to reproduce realistic environmental conditions responsible for possible disturbance to ultrasound imaging and tracking.

They compared their proposed technique to color Doppler imaging, considered to be the gold standard for motion-based imaging of microrobots. An acoustic phase-based imaging strategy provided better tracking in both static and dynamic environments.

“I believe that the imaging techniques that we proposed have a wide spectrum of applications, which include intravascular tracking of surgical devices,” said Pane.

Future research will seek to improve the time performance of the proposed tracking systems and develop three-dimensional tracking strategies to progress towards more relevant clinical scenarios.

Source: “Contrast-enhanced ultrasound tracking of helical propellers with acoustic phase analysis and comparison with color Doppler,” by S. Pane, M. Zhang, V. Iacovacci, L. Zhang, and A. Menciassi, APL Bioengineering (2022). The article can be accessed at