Dipolar Rings of Microscopic Ellipsoids: Magnetic Manipulation and Cell Entrapment

TL;DR

This paper investigates the self-assembly, manipulation, and application of microscopic ferromagnetic ellipsoid rings, demonstrating their potential for biological cell entrapment and release using magnetic fields.

Contribution

It introduces a theoretical model for ring deformation and demonstrates magnetic control of fragile ferromagnetic rings for cell manipulation.

Findings

Successful formation of dipolar rings from ferromagnetic ellipsoids

Controlled shape deformation of rings via external magnetic fields

Effective capture and release of biological cells using magnetic rings

Abstract

We study the formation and dynamics of dipolar rings composed by microscopic ferromagnetic ellipsoids, which self-assemble in water by switching the direction of the applied field. We show how to manipulate these fragile structures and control their shape via application of external static and oscillating magnetic fields. We introduce a theoretical framework which describes the ring deformation under an applied field, allowing to understand the underlying physical mechanism. Our microscopic rings are finally used to capture, entrap and later release a biological cell via magnetic command, i.e. performing a simple operation which can be implemented in other microfluidic devices which make use of ferromagnetic particles.