High-Resolution SPECT Imaging of Stimuli-Responsive Soft Microrobots

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Materials Science

Background:

• Untethered small-scale robots show promise for medicine but face clinical translation barriers.
• High-resolution in vivo tracking and imaging are critical limitations for micro- and nanorobots.
• Current imaging techniques hinder the clinical application of miniaturized robotic systems.

Purpose of the Study:

• To investigate the incorporation of radioactive compounds into soft thermoresponsive magnetic microrobots.
• To enable single-photon emission computed tomography (SPECT) imaging of these microrobots in vivo.
• To optimize microrobot design and radioactive labeling for enhanced imaging contrast and retention.

Main Methods:

• Development of four distinct microrobotic platforms with varying hydrogel structures.
• Evaluation of four technetium-99m (^99mTc)-based radioactive compounds for optimal retention and imaging.
• Implementation of single-photon emission computed tomography (SPECT) for imaging and tracking.

Main Results:

• Achieved imaging of individual microrobots down to 100 µm in diameter.
• Successfully tracked shape-switching capabilities (tubular to planar) of labeled microrobots.
• Demonstrated effective retention of ^99mTc colloid within the hydrogel structure.

Conclusions:

• Radioactive labeling of soft magnetic microrobots is feasible for high-resolution in vivo imaging.
• This approach addresses a critical barrier for the clinical translation of micro- and nanorobots.
• The developed platforms show potential for advanced biomedical applications requiring precise robotic control and imaging.