Multimodal Imaging, Drug Delivery, and On-Board Triggered Degradation in Soft Capsule Rolling Microrobots

Abstract

In the rapidly advancing field of medical microrobotics, designing robots capable of addressing various challenges—such as imaging, biodegradation, and multifunctionality—is crucial. Departing from conventional research that often focuses on isolated aspects of microrobot functionality, this study presents an innovative approach to comprehensive microrobot design. Soft capsule microrobots that integrate capabilities such as magnetic navigation, autonomous maneuverability, in situ biodegradation, biosafe imaging, and drug delivery are reported. These microrobots are fabricated within the range of 20–120 μm, with a notable throughput of ≈10²–10³ microrobots per second. Furthermore, their locomotion performance has been demonstrated to remain stable for a period exceeding 10 h, all while employing real-time optical closed-loop control. The incorporation of ultrasound contrast agents not only amplifies imaging resolution but also ensures imaging contrast stability in a biological environment for over a period of 3 h. Second, the intentional integration of enzyme-loaded nanometric polymersomes establishes a self-contained, biodegradable system, accentuating the microrobots’ capacity to degrade without the addition of high enzyme concentrations. This integrated approach lays the groundwork for minimally invasive treatments toward personalized and targeted medicine.