Analytical Model for Magnetic Particle Transport in a Magnetically Biased Microfluidic System
University at Buffalo, US
microfluidic particle transport, magnetophoretic transport, magnetophoretic microsystem, magnetic transport, bioseparation, high gradient magnetic separation, magnetophoretic control
An analytical model is described for predicting the transport and capture of magnetic micro/nano-particles in a magnetophoretic microsystem that consists of an array of integrated soft-magnetic elements embedded beneath a microfluidic channel. The elements are polarized by a bias field, and produce a nonuniform field distribution that gives rise to a magnetic force on the particles as they flow through the microchannel. A linear magnetization model with saturation is used to model the magnetic response of the particles. Analytical expressions are presented for the magnetic field distribution in the microchannel, and the dominant magnetic and fluidic forces on the particles. The magnetic field and force expressions are verified using finite element analysis. These expressions are used in the equations governing particle motion, which are solved to predict particle trajectories in a practical microsystem. The analysis indicates that particle capture can be achieved in seconds, and that the particles exhibit an oscillatory motion as they traverse the microchannel. This model, being analytical in nature, enables rapid parametric analysis of system performance, and is superior to numerically based approaches for both small and large-scale simulations. It should be very useful in the development of novel magnetophoretic microsystems.
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Nanotech 2006 Conference Program Abstract