Analysis of forces acting on superparamagnetic beads in fluid medium in the presence of non uniform magnetic fields

Superparamagnetic micro beads offer some attractive applications in biological and biomedical fields. Some of the important applications include manipulation and separation of cells, isolation of specific cells, active drug delivery, magnetic cell separation, separation of proteins, and application of mechanical forces to cells, etc. When non uniform magnetic field is applied on the beads, they form crystalline structures depending on the applied magnetic field, gradient of the magnetic field and the magnetic and drag forces acting on the beads.;In the current research, focus has been on the analysis of the behavior of Superparamagnetic pure Iron and Iron Oxide beads immersed in fluid medium when placed in non uniform gradient fields. A COMSOL Multiphysics model was developed in 2D with Magnetostatics, Fluid Dynamics and Moving Mesh Mode for predicting the motion of magnetizable beads in gradient fields, considering the effects of fluidic drag forces on the beads in the micro system. The model was developed based on the real experimental setup.;The model comprises a micro system which consists of a gradient magnetic field (such as that produced by a solenoid or permanent magnet), magnetizable beads (Iron or Iron Oxide) and the fluid surrounding the beads. Beads located in the gradient field experience a magnetization, producing a lateral force that drives the beads along the field gradient to areas of higher field strength. The beads also experience a fluidic force which is predicted using Stoke's law for the drag on a sphere. A set of scalar variables and equations were setup in the model for calculating the magnetic force and the fluid drag force acting on the beads at respective mediums.;Statistical analysis was performed on the data obtained from COMSOL Modeling and was compared with the results obtained from the real experiment. Results from the real experiment obtained in the form of a movie are extracted using the software tool Video Spot Tracker and Image J. Looking at the characteristics of the beads and the variables in the equations, Analysis of Covariance (ANCOVA) was performed on the obtained data and the effects of various factors were investigated.;From the experiment a crystalline structure (hexagonal) was observed with 13 beads. The simulation built using COMSOL Multiphysics was able to prove the initial assumptions made. The statistical models built for all the three forces, magnetic attraction forces, interaction forces and drag forces are shown significant.