Bidirectional Propulsion of Arc‐Shaped Microswimmers Driven by Precessing Magnetic Fields

Abstract

The development of magnetically powered microswimmers that mimic the swimming mechanisms of microorganisms is important for lab‐on‐a‐chip devices, robotics, and next‐generation minimally invasive surgical interventions. Governed by their design, most previously described untethered swimmers can be maneuvered only by varying the direction of applied rotational magnetic fields. This constraint makes even state‐of‐the‐art swimmers incapable of reversing their direction of motion without a prior change in the direction of field rotation, which limits their autonomy and ability to adapt to their environments. Also, due to constant magnetization profiles, swarms of magnetic swimmers respond in the same manner, which limits multiagent control only to parallel formations. Herein, a new class of microswimmers are presented which are capable of reversing their direction of swimming without requiring a reversal in direction of field rotation. These swimmers exploit heterogeneity in their design and composition to exhibit reversible bidirectional motion determined by the field precession angle. Thus, the precession angle is used as an independent control input for bidirectional swimming. Design variability is explored in the systematic study of two swimmer designs with different constructions. Two different precession angles are observed for motion reversal, which is exploited to demonstrate independent control of the two swimmer designs.

Artificial flexible sperm-like nanorobot based on self-assembly and its bidirectional propulsion in precessing magnetic fields

“…In the experiments, the nanorobot was actuated to swim in the horizontal plane (XY) and was investigated from the top view. Apart form the elastohydrodynamics, a simplified undulatory propagation modelling could also be used 33 , 34 . Swimming of the nanorobot in the X direction can be simplified into two orthogonal components in the XY and XZ planes.…”

Artificial Flexible Sperm-like Nanorobot Based on Self-assembly and Its Magnetically Actuated Propulsion Property

“…and was investigated from the top view. Apart form the elastohydrodynamics, a simpli ed undulatory propagation modelling could also be used 33,34 . Swimming of the nanorobot in the X direction can be simpli ed into two orthogonal components in the XY and XZ planes.…”

Propulsion of an elastic filament in a shear-thinning fluid

“…Propulsion of these flexible structures, also known as elastohydrodynamic propulsion, [24][25][26][27][28][29][30][31][32][33][34] emerges as a result of the interplay between hydrodynamic and elastic forces. More recent studies have examined factors such as variable bending stiffness, 18,35 intrinsic curvatures, [36][37][38] and magnetic particle geometries 39 to enhance elastohydrodynamic propulsion.…”