Effects of major guidance parameters on aggregated magnetic particles during magnetic drug targeting

Abstract

Utilization of the aggregation phenomenon in magnetic nanoparticles (MNPs) under a magnetic field has been considered as an efficient mechanism to overcome the lack of actuation force and low imaging resolution for succesuful magnetic drug targeting (MDT). In previous studies, it is assumed that during MDT the aggregation happens in the chain shapes and they are in an equilibrium state and further aggregations do not occur. However, in reality, aggregated magnetic particles are in a non-equilibrium state due to the effects of blood flow and the time-varying magnetic field. As a result, further aggregation can occur. If the repeated aggregation of MNPs in the non-equilibrium state is not considered, it can cause the sticking and clogging phenomena inside the blood vessel, which can significantly affect targeting performance of MDT and raise the safety concerns about the method. Therefore, major paramters of the aggregated magnetic particles should be clearly examined under non-equilibrium state during MDT. Duing MDT, magnetic particle chains with individually different volumes can experience different magnetic field, magnetic field gradient, and flow rate. Therefore, in this paper, we have analyzed four main paramters that can influence the MDT, including chain length, magnetic field, magnetic field gradient, and flow rate. Finally, we have developed a MDT simulator to observe the aggregation phenomenon of magnetic particles and their targeting performance during steering in a Y-channel vessel using an intutive user interface. The results show that aggregation volume and targeting performance can be controlled by modulating the external magnetic field and magnetic field gradient. The proposed aggregation guidance studies can provide insightful guidelines for determining a magnetic drug targeting scheme.