Magnetic manipulation of superparamagnetic nanoparticles in a microfluidic system for drug delivery applications

Magnetic nanoparticles (MNPs), such as superparamagnetic iron oxide nanoparticles (SPIONS), have attracted major interest, due to their small size and unique magnetic properties, for drug delivery applications. In this context, iron oxide nanoparticles of magnetite (Fe3O4) (150 nm magnetic core diameter), were used as drug carriers, aiming to form a magnetically controlled nano-platform. The navigation capabilities of the iron oxide nanoparticles in a microfluidic channel were investigated by simulating the magnetic field and the magnetic force applied on the magnetic nanoparticles inside a microfluidic chip. The simulations have been performed using finite element method (ANSY'S software). The optimum setup which intends to simulate the magnetic navigation of the nanoparticles, by the use of MRI-type fields, in the human circulatory system, consists of two parallel permanent magnets to produce a homogeneous magnetic field, in order to ensure the maximum magnetization of the magnetic nanoparticles, an electromagnet for the induction of the magnetic gradients and the creation of the magnetic force and a microfluidic setup so as to simulate the blood flow inside the human blood vessels. The magnetization of the superparamagnetic nanoparticles and the consequent magnetic torque developed by the two permanent magnets, together with the mutual interactions between the magnetized nanoparticles lead to the creation of rhabdoid aggregates in the direction of the homogeneous field. Additionally, the magnetic gradients introduced by the operation of the electromagnet are capable of directing the aggregates, as a whole, to the desired direction. By removing the magnetic fields, the aggregates are disrupted, due to the super paramagnetic nature of the nanoparticles, avoiding thus the formation of undesired thrombosis. (C) 2015 Elsevier B.V. All rights reserved.