Bio-inspired Magnetic Helical Miniature Robots: Mechanisms, Control and Biomedical Applications

Abstract Inspired by bacterial motility mechanisms, Magnetic Helical Miniature Robots (MHMRs) exhibit promising applications in biomedical fields due to their efficient locomotion and compatibility with biological tissues. In this review, we systematically survey the basics of MHMRs, from propulsion mechanism, magnetization and control methods to biomedical applications, aiming to provide readers with an easily understandable overview and fundamental knowledge on implementing MHMRs. The MHMRs are actuated by rotating magnetic fields, achieving steering and rotation through magnetic torque, and converting rotation into forward motion through the helical structure. Magnetization methods for MHMRs are reviewed into three types: attaching magnets, magnetic coatings, and magnetic powder doping. Additionally, this review discusses the control methods for MHMRs, covering imaging techniques, path tracking control—including classical control algorithms and increasingly popular learning-based methods, and swarm control. Subsequently, a comprehensive survey is conducted on the biomedical applications of MHMRs in the treatment of vascular diseases, drug delivery, cell delivery, and their integration with catheters. We finally provide a perspective about future challenges in MHMR research, including enhancing functional design capabilities, developing swarm-assisted independent control mechanisms, refining in vivo imaging techniques, and ensuring robust biocompatibility for safe medical use.