Magnetically actuated microrobots have become a research hotspot in recent years due to their tiny size, untethered control, and rapid response capability. Moreover, an increasing number of researchers are applying them for micro-/nano-manipulation in the biomedical field. This survey provides a comprehensive overview of the recent developments in magnetic microrobots, focusing on materials, propulsion mechanisms, design strategies, fabrication techniques, and diverse micro-/nano-manipulation applications. The exploration of magnetic materials, biosafety considerations, and propulsion methods serves as a foundation for the diverse designs discussed in this review. The paper delves into the design categories, encompassing helical, surface, ciliary, scaffold, and biohybrid microrobots, with each demonstrating unique capabilities. Furthermore, various fabrication techniques, including direct laser writing, glancing angle deposition, biotemplating synthesis, template-assisted electrochemical deposition, and magnetic self-assembly, are examined owing to their contributions to the realization of magnetic microrobots. The potential impact of magnetic microrobots across multidisciplinary domains is presented through various application areas, such as drug delivery, minimally invasive surgery, cell manipulation, and environmental remediation. This review highlights a comprehensive summary of the current challenges, hurdles to overcome, and future directions in magnetic microrobot research across different fields.

Inspired by insects in nature, an increasing number of soft robots have been proposed to mimic their locomotion patterns. As a wireless actuation method, the magnetic actuation technique has been widely applied to drive soft magnetic robots for diverse applications. Although recent works on soft materials have stimulated the development of soft robots, it is challenging to achieve the efficient movement of soft robots for in vivo biomedical application. Inspired by centipede locomotion, a soft octopodal robot is designed in this paper. The robot is fabricated by mixing magnetic particles with silicone polymers, which is then magnetized by a specific magnetic field. The prototypes can be actuated by an external magnetic field (5–8 mT) produced by custom-made electromagnetic coils. Experimental results show that the soft robot can move at a high speed in the range of 0.536–1.604 mm/s on different surfaces, including paper, wood, and PMMA. This indicates that the soft robot can achieve comparable speeds to other robots, while being driven by a lower magnitude, resulting in energy savings. Furthermore, it achieves a high speed of 0.823 mm/s on the surface of a pig colon. The fine capabilities of the soft robot in terms of crossing uneven biological surfaces and carrying external loads are demonstrated. The results indicate that the reported soft robot exhibits promising applications in the biomedical field.

In recent years, the rising incidence of gastrointestinal (GI) cancer has triggered an urgent need for effective early intervention strategies. Traditional endoscopic techniques often cause patient discomfort, and it is difficult to navigate deep regions of complex organ structures. This work proposes a kind of bio-inspired magnetic soft robot (BMSR) to address these challenges. The design of the BMSRs is inspired by the rolling motion of the golden wheel spider. Two six-degree-of-freedom (6-DOF) robotic arms are used, where one arm is responsible for real-time manipulation of the BMSRs, and the other is dedicated to monitoring their status. Under the actuation of an external rotating magnetic field, the BMSRs can flexibly climb on inclined surfaces at any angle, involving the inverted surface. Through the powerful output force, the BMSRs can overcome the mobility barrier induced by different human organs, including mucus, folds, and height differences of up to 8 cm. Such an exceptional mobility enables the BMSRs to deliver drugs in the targeted complex GI environment. Moreover, in combination with an endoscope, it provides real-time visual feedback for precise navigation. In vitro animal experiments validate the feasibility of BMSRs, paving a way for their usage in minimally invasive GI treatment. This work advances the potential applications of magnetic soft robots in the biomedical field.

Inflammatory bowel disease (IBD) management requires long‐term, localized drug delivery to mitigate the severe side effects of systemic treatments. Bridging this gap, we present a biomimetic, starfish‐inspired magnetic soft robot for precise navigation, secure attachment, and sustained therapy within the gastrointestinal tract. Mimicking Acanthaster planci , our robot features a multi‐arm structure with inward‐facing microspines, enabling a wide grasping range and firm adhesion to intestinal tissue. Fabricated from a polymer‐magnetic composite and engineered with prestressed joints, the robot is actuated by a programmable magnetic field to perform complex locomotion, including rolling and walking, for targeted site navigation. Upon arrival, it firmly attaches to deploy a localized drug payload over an extended period. The entire treatment process is monitored by position sensing of the magnetic soft robot using ultrasound (US) imaging technique. The US images facilitate real‐time navigation and accurate localization of the soft robot at designated target locations. Moreover, biosafety was confirmed via zebrafish embryo assays, while drug release kinetics were characterized across different hydrogel membranes. Ex vivo demonstrations in porcine intestines validated the robot's capabilities in targeted residency and targeted sustained drug delivery. This platform represents a remarkable step toward intelligent, minimally invasive systems for automated and personalized IBD treatment.