IROS 2025 Keynotes - Medical Robots: Li Zhang

Why It Matters

Magnetic, bio‑hybrid micro‑robots promise minimally invasive, patient‑specific therapies while mitigating immune response and enabling safe retrieval, potentially reshaping future surgical and drug‑delivery paradigms.

Key Takeaways

• Magnetic fields enable safe, fast actuation of micro‑robots
• Bio‑hybrid designs use algae or patient cells for biodegradability
• Endoscopic delivery shortcuts long travel distances for deep tissue targeting
• Modular robots separate magnetic propulsion from degradable therapeutic payload
• Ultrasound‑triggered glue allows in‑situ anchoring and retrieval of devices

Summary

Li Zhang’s IROS 2025 keynote highlighted the rapid evolution of miniature biomedical robots, emphasizing magnetic actuation, bio‑hybrid materials, and modular architectures for safe, targeted therapy. He traced the concept back to Richard Feynman’s swallowable‑surgery vision and described how his team fabricates helical micro‑bots using origami‑style thin‑film lithography, then powers them with rotating magnetic fields that mimic E.coli locomotion.

Key insights included the safety and speed of magnetic fields, the use of naturally derived scaffolds—spirulina algae and patient‑derived stem cells—to achieve biodegradability and low immunogenicity, and dual‑mode imaging (fluorescence and MRI) for real‑time tracking. The team demonstrated rapid endoscopic delivery of these bots to deep sites, followed by magnetic steering through tortuous lumens such as the 1‑4 mm bile duct, extending the reach of conventional endoscopy.

Notable examples featured spirulina‑based helices injected into mice, producing visible fluorescence and MRI contrast, and a modular robot that separates a magnetic propeller from a degradable therapeutic hydrogel. In rabbit models, the magnetic segment was retrieved via catheter under X‑ray fluoroscopy, while the therapeutic module was anchored using ultrasound‑triggered, temperature‑sensitive glue that melts at 45 °C.

The implications are profound: clinicians could perform minimally invasive, personalized interventions with reduced infection risk, while modular designs address safety concerns by allowing post‑treatment removal of magnetic material. Overcoming trade‑offs between actuation strength and biodegradability could accelerate translation of these micro‑robots into routine clinical practice.

Original Description

"Keynote Title: ""Magnetic Microrobots for Translational Biomedicine: From Individual and Modular Designs to Microswarms""

Speaker Biography

Li Zhang is a professor in the Department of Mechanical and Automation Engineering at the Chinese University of Hong Kong (CUHK). His main research interests include small-scale robotics and their clinical translation. He has authored or co-authored over 400 publications, including Science Robotics, Nature Machine Intelligence, Nature Materials, Nature Biomedical Engineering, Nature Synthesis, Nature Reviews Bioengineering as corresponding author. His research works on magnetic slime robot and microrobotic swarm for endovascular application at CUHK was selected as “Top 10 Innovation and Technology News in Hong Kong” in 2022, 2023 and 2024, respectively. Dr. Zhang is an ASME, HKIE and IEEE Fellow, and an Outstanding Fellow of the Faculty of Engineering at CUHK, and he was appointed as a Distinguished Lecturer by IEEE NTC in 2020 and 2021. He currently serves as Senior Editor of IEEE T-ASE and IEEE T-RO, and Associate Editor of Science Advances (AAAS).

Abstract

Robotics at small scales has attracted considerable research attention both in its fundamental aspects and the potential for biomedical applications. As the characteristic dimensions of the robots or machines scaling down to the milli-/microscale or even smaller, they are ideally suited to navigating in tiny and tortuous lumens inside the human body which are hard-to-reach using regular medical tools such as endoscopy. Although the materials, structural design, and functionalization of miniature robots have been studied extensively, several key challenges have not yet been adequately investigated for in vivo applications, such as controlled locomotion of the microrobots in dynamic physiological environment, in vivo tracking, the efficiency of therapeutic intervention, biosafety of the miniature agents, and autonomy levels of the microrobotic platform. In this talk, I will first present the recent research progress in development of magnetic microrobots, from the biohybrid designs, motion control, and the rise of intelligence to rapid endoluminal delivery using clinical intervention tools. Then the key challenges and perspective of using small-scale robots, from individual to microswarms, for clinical applications with a focus on endoluminal procedures will be discussed.