Magnetophoretic Equilibrium of a Polydisperse Ferrofluid.

Andrey A Kuznetsov,Ivan A Podlesnykh

doi:10.3390/nano11112849

Abstract

The equilibrium concentration distribution of magnetic nanoparticles in a nonuniform magnetic field is studied theoretically. A linear current-carrying wire is used as a source of a nonuniform field. An exact solution for the concentration profile of a dilute monodisperse suspension is obtained within the framework of the continuous mass transfer theory. The applicability of this solution in a broad range of amperage values is tested using Langevin dynamics simulations. Obtained solution is also generalized for polydisperse suspensions. It is demonstrated that the particle size distribution in a polydisperse system strongly depends on the distance from the wire and in general does not coincide with the original distribution of a uniform suspension.

Highlights

Modern day magnetic nanomaterials stay firmly at the forefront of innovation in biotechnology and medicine [1,2,3,4]
The physical basis for many of their perspective biomedical applications is the phenomenon of magnetophoresis, that is, the motion of magnetic objects under the action of a nonuniform magnetic field
Magnetic bioseparation—a medical diagnostics method, in which magnetic particles are first mixed with biological material obtained from the patient’s body; the particles attach to cells or biomolecules of a certain type; and at the last stage, particles are separated from the mixture using a gradient field [5]

Summary

Introduction

Modern day magnetic nanomaterials stay firmly at the forefront of innovation in biotechnology and medicine [1,2,3,4]. A similar approach can be used to test the food quality [6]. Both micro- and nanoparticles can be used, but the latter are preferable, since they have a higher binding capacity due to higher surface-to-volume ratio [7]. Particle capture can occur either from the static volume of the mixture [8] or from the flow [9]. Another technique based on magnetophoresis is the magnetic drug targeting [10]. The idea is to accumulate drug-loaded nanoparticles injected into the bloodstream near a pathological site (for example, a tumor) using a magnetic field gradient

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