Independent Positioning of Magnetic Nanomotors

Abstract

There is considerable interest in powering and maneuvering nanostructures remotely in fluidic media using noninvasive fuel-free methods, for which small homogeneous magnetic fields are ideally suited. Current strategies include helical propulsion of chiral nanostructures, cilia-like motion of flexible filaments, and surface assisted translation of asymmetric colloidal doublets and magnetic nanorods, in all of which the individual structures are moved in a particular direction that is completely tied to the characteristics of the driving fields. As we show in this paper, when we use appropriate magnetic field configurations and actuation time scales, it is possible to maneuver geometrically identical nanostructures in different directions, and subsequently position them at arbitrary locations with respect to each other. The method reported here requires proximity of the nanomotors to a solid surface, and could be useful in applications that require remote and independent control over individual components in microfluidic environments.

In-situ particles reorientation during magnetic hyperthermia application: Shape matters twice

“…drug delivery or enhanced resonance imaging). Efforts to improve the efficiency of nanomagnets for MPH include fine-tuning of the size8/anisotropy9 and of the interaction conditions10 (to optimize the dose/response ratio); efforts for achieving accurate MNRBs applications include the geometrical design of optimized structures (examples are helical structures for independent positioning11 or particle-aggregation for improved imaging contrast12). The objective of the present work is to report on the synergy between heat release and self-induced directional reorientation that controls the magnetic behaviour of magnetic nanorods under an AC field during a hyperthermia process.…”

Wireless actuation with functional acoustic surfaces

“…An alternative scheme is the wireless actuation via physical fields, such as magnetic fields, which provide large forces, fast response, and accurate control. [1][2][3][4][5] However, magnetic fields are in general not sufficiently selective to address individual actuators at the same time, 6 thus making multiple degrees-of-freedom (DoFs) control difficult. 7 Recently, we have adopted a different approach based on structured light fields to realize many-DoFs soft sub-millimeter robots made of liquid crystalline elastomers.…”

Recent developments in magnetically driven micro- and nanorobots

“…This actuation mode could be exploited for releasing the swimmers when they are blocked or stuck due to strong interactions with a surface or dust particles. Recently, Ghosh and co-workers demonstrated the independent surface-assisted magnetic manipulation of identical helical nanomotors in size and shape, but with different easy magnetization axis [81]. This method could be employed to remotely control individual machines among a swarm of nanomotors.…”