Magnetic manipulation of liquid metals for soft robotics

Soft robots harness compliant materials and bio-inspired architectures to achieve safe, adaptive, and versatile functions in dynamic environments, enabling applications in minimally invasive surgery, wearable assistive devices, and confined-space exploration. Gallium-based liquid metals with metallic conductivity and liquid deformability constitute a transformative material platform for creating soft robots with enhanced performance and diverse manipulation strategies. Among them, magnetic manipulation is particularly attractive because it enables remote, non-contact, and energy-efficient control with high spatial precision. In this review, we summarize existing strategies for the preparation, integration, and patterning of magnetic liquid metals. We then illustrate the mechanisms of magnetic manipulation, including magnet and Lorentz force manipulation, and discuss the potential of multi-field manipulation. Furthermore, we systematically categorize the practical applications of magnetically actuated liquid metals in soft robotics into four types: droplet, slurry, particle, and composite, based on their composition and morphology. Finally, we highlight the key challenges in this field and provide perspectives on future research directions. This review aims to establish a systematic framework for understanding and advancing magnetically manipulated liquid metals in soft robotics, offering fundamental insights to stimulate interdisciplinary research and accelerate technological breakthroughs in this emerging field.