Dynamic characteristics of superparamagnetic iron oxide nanoparticles in a viscous fluid under an external magnetic field

Predicting the motion of superparamagnetic iron oxide nanoparticles (SPION) in biological systems is one of the most relevant parameters for the biomedical application of SPION. Recently, magnetic nanoparticles such as SPION have been utilized as the MR image contrast agent, targeted drug delivery, magnetic separation, biosensor, etc. Because the size of SPION is in the nanometer scale, it is difficult to test their dynamics under an external magnetic field experimentally. Moreover, when the SPION moves in a viscous fluid such as blood, the situation can be more complicated. To overcome these difficulties, we proposed a fast-solving technique combined with the finite-element method for analyzing the dynamic characteristics of SPION in a viscous fluid under an external magnetic field. Using this numerical modeling, the effective system dimension, external magnetic field, particle size, and trajectory of SPION can be estimated. To verify the proposed method, three magnetic systems with permanent magnet and micro capillary were tested.