The chiral magnetic nanomotors

TL;DR

This paper investigates the behavior and optimal design of chiral magnetic nanomotors powered by rotating magnetic fields, providing theoretical insights that align with experimental observations and guiding future nanomotor fabrication.

Contribution

It offers a detailed theoretical analysis of nanomotor regimes, linking orientation and propulsion to magnetic and geometric properties, and suggests optimal design parameters.

Findings

Theoretical predictions match experimental data on nanomotor regimes.

Optimal nanomotor design involves hard magnetic materials like cobalt.

Helical angle of 35-45 degrees enhances propulsion efficiency.

Abstract

Propulsion of the chiral magnetic nanomotors powered by a rotating magnetic field is in the focus of the modern biomedical applications. This technology relies on strong interaction of dynamic and magnetic degrees of freedom of the system. Here we study in detail various experimentally observed regimes of the helical nanomotor orientation and propulsion depending on the actuation frequency, and establish the relation of these two properties with remanent magnetization and geometry of the helical nanomotors. The theoretical predictions for the transition between the regimes and nanomotor orientation and propulsion speed are in excellent agreement with available experimental data. The proposed theory offers a few simple guidelines towards the optimal design of the magnetic nanomotors. In particular, efficient nanomotors should be fabricated of hard magnetics, e.g., cobalt, magnetized transversally and have the geometry of a normal helix with a helical angle of 35-45 degrees.