Recent Progress on the Development of Magnetically-Responsive Micropillars: Actuation, Fabrication, and Applications

Stimuli-responsive micro-pillared structures can perform complex and precise tasks at the microscale through dynamic and reversible deformation of the pillars in response to external triggers. Magnetic field is one of the most common actuation strategies due to its incomparable advantages such as instantaneous response, remote and nondestructive control, and superior biocompatibility. Over the past decade, many researches are attempted to design and optimize magnetically-responsive micropillars for a wide range of applications and great progresses are accomplished. In this review, the most important aspects of recent progress of magnetically-responsive micropillars are covered to give a comprehensive and systematical introduction to this new field, from the actuation mechanisms, fabrication methods, and deformation patterns to the practical applications. The increasingly maturing fabrication techniques can provide low-cost and large-scale magnetic micropillars with homogeneous responses. Some advanced techniques are developed to fabricate micropillars with programmable and reprogrammable responses for site-specific and reconfigurable actuations. On the other hand, practical applications for particle/droplet/light manipulation, flow generation, miniature swimming/climbing/carrying microrobots, tunable adhesion, cellular probe, fog collector, and anti-ice surfaces are also summarized. Finally, current challenges that limit the industrial implementation are discussed and the authors' perspectives on the future directions of magnetically-responsive micropillars are stated.

Automated summary

Stimuli-responsive micro-pillared structures can achieve complex and precise tasks at the microscale by deforming their pillars in response to external triggers. Magnetic field is a common and advantageous actuation strategy with instant response, remote control, and biocompatibility. This review comprehensively introduces recent progress in magnetically-responsive micropillars, covering their actuation mechanisms, fabrication methods, deformation patterns, and practical applications, such as particle manipulation, miniature robots, and anti-ice surfaces. The challenges and future directions for industrial implementation are also discussed.