First Principles Model of Magnetic Nanoparticle Behavior in Various Fluid Environments

Magnetic nanoparticles (MNP’s) have garnered lots of interest in various bioengineering fields for applications such as targeted drug delivery and cell manipulation. Characterization of MNP behavior in magnetic fields is an important step towards realizing these applications. This model will allow particle design to be optimized and rapidly prototyped as part of a magnetic system. The MNP’s considered in this model are spheres comprised of magnetic cores encapsulated by a non-magnetic material. In this model, four forces are considered to be acting on each particle; the force due to a magnetic gradient, dipole-dipole interactions, steric hindrance, and viscous drag. The model is a quasi-steady-state model, since the particles are assumed to reach steady-state velocity very quickly due to their small mass, meaning acceleration terms are set to zero. The model was verified with velocity and chaining length comparisons, as a reference to chaining behaviors, to PLGA nanoparticles with magnetic cores. An example of particle design in an inhomogeneous fluid environment is shown to demonstrate the ability to use the model to influence particle design.