Imaging-Guided, Bioresorbable Acoustic Hydrogel Microrobots

Micro- and nanorobots offer promising solutions for disease diagnosis, precision drug delivery, and minimally invasive surgery, yet challenges remain in achieving stable propulsion in vivo, real-time deep tissue imaging, and precise remote control. We present a hydrogel-based, imaging-guided, bioresorbable acoustic microrobot (BAM), designed for stable navigation in complex biological environments. Constructed using two-photon polymerization, BAM integrates magnetic nanoparticles and therapeutic agents into its hydrogel matrix for precision control and drug delivery. Besides, a two-step surface treatment method conferring BAMs with a hydrophobic inner surface to enhance microbubble retention and a hydrophilic outer surface to reduce aggregation—ensures multi-day functionality and timely degradation. Additionally, a unique dual-opening cavity design boosts the propulsion efficiency of BAMs in complex biofluids. The entrapped microbubbles also provide high-contrast ultrasound imaging for real-time tracking and wireless magnetic navigation. Moreover, the hydrolysis-driven biodegradability of BAM ensures its safe dissolution post-treatment, posing no risk of long-term residual harm. In vitro and in vivo studies demonstrate BAM’s potential for transforming minimally invasive medical interventions and targeted therapies.