Magnetically Driven Micro and Nanorobots

Abstract

Manipulation and navigation of micro and nanoswimmers in different fluid environments can be achieved by chemicals, external fields, or even motile cells. Many researchers have selected magnetic fields as the active external actuation source based on the advantageous features of this actuation strategy such as remote and spatiotemporal control, fuel-free, high degree of reconfigurability, programmability, recyclability, and versatility. This review introduces fundamental concepts and advantages of magnetic micro/nanorobots (termed here as “MagRobots”) as well as basic knowledge of magnetic fields and magnetic materials, setups for magnetic manipulation, magnetic field configurations, and symmetry-breaking strategies for effective movement. These concepts are discussed to describe the interactions between micro/nanorobots and magnetic fields. Actuation mechanisms of flagella-inspired MagRobots (i.e., corkscrew-like motion and traveling-wave locomotion/ciliary stroke motion) and surface walkers (i.e., surface-assisted motion), applications of magnetic fields in other propulsion approaches, and magnetic stimulation of micro/nanorobots beyond motion are provided followed by fabrication techniques for (quasi-)spherical, helical, flexible, wire-like, and biohybrid MagRobots. Applications of MagRobots in targeted drug/gene delivery, cell manipulation, minimally invasive surgery, biopsy, biofilm disruption/eradication, imaging-guided delivery/therapy/surgery, pollution removal for environmental remediation, and (bio)sensing are also reviewed. Finally, current challenges and future perspectives for the development of magnetically powered miniaturized motors are discussed.

Tethered and Untethered 3D Microactuators Fabricated by Two-Photon Polymerization: A Review

“…For turning these microactuators into realistic applications, more effective, wireless, and milder stimuli should be further developed [158]. Considering that one important application of outfield driven microactuators is drug delivery in medical field [159], we think that magnetic and ultrasound driving will be the focus of research [160][161][162]. Moreover, electric driving and the multi-field coupling method are promising future directions.…”

Dental Robotics: A Disruptive Technology

“…Under an adequate environment, magnetic fields harmlessly and easily infiltrate the majority of synthetic and biological materials and can guide particle mobility in the confined area [ 107 ]. Although robots have been developed for particular tasks including multimodal locomotion, manipulation of cells and particles, and targeted cargo delivery [ 111 ], however, their applications for chemical and physical biofilm disruption remain to be investigated. For instance, Hwang and colleagues [ 82 ] designed catalytic antimicrobial robots (CARs) that controllably, effectively, and accurately removed, degraded, and killed biofilms from surfaces.…”

Recent progress in magnetic applications for micro- and nanorobots

“…Recently, scientists began to explore more complex structures of magnetic MNRs, such as flagella-driven magnetic microswimmers and magnetic micro-and nanomotors. In the article of Zhou et al [55], several kinds of MNRs driven by magnetic force and the development of a micromotor driven by magnetic force were discussed. Yang et al [56] and Chen et al [57] also analyzed and summarized magnetic MNRs.…”