Three Dimensional Aggregation of Magnetic Particles

TL;DR

This paper demonstrates that dynamic magnetic fields combined with dissipative forces can create stable 3D aggregation points for magnetic particles inside the body, overcoming static field limitations.

Contribution

It introduces a theoretical framework for designing magnetic fields that enable 3D particle aggregation in biological fluids using dynamic fields and dissipative forces.

Findings

Stable 3D aggregation points are achievable with dynamic magnetic fields.

The framework accurately predicts parameters for particle aggregation.

Potential applications include targeted drug delivery and tissue engineering.

Abstract

Magnetic drug delivery is a promising therapeutic because of magnetic fields' ability to permeate unperturbed in human tissue. One of the long-standing challenges in magnetic drug delivery is the inability to generate 3D aggregation non-invasively within the interior of the body. Earnshaw's theorem, which proves the impossibility of creating an energetic minimum in a curl-free and divergence-free field such as a magnetic field. However, one of the assumptions of Earnshaw's theorem is a static field. Here we show that it is possible to utilize a dynamically changing field and a dissipative force such as the drag, which is generally present, to create a stable aggregation point for magnetic particles. We also introduce a theoretical framework for designing the suitable magnetic fields for controlling a given magnetic particle in a particular fluid. This framework enables accurate determination of the necessary parameters for aggregation across a wide variety of magnetic particles and across multiple biologically-relevant fluids. By coating magnetic particles with desired therapeutic agents or attaching them to cells, a new class of treatment methodologies can be created in therapies such as targeted drug delivery and cell-based therapies. By dynamically changing the aggregation point, agents can also be guided along a particular path in the body. This technique of using dissipative forces to create a stable 3D aggregation point for particles could possibly be extended to a broad range of applications such as microscopic and macroscopic manipulation, robotics, guided self-assembly, magnetic plasma confinement, tissue engineering, and ion traps for quantum computers.