Kinetics of Aggregation and Magnetic Separation of Multicore Iron Oxide Nanoparticles: Effect of the Grafted Layer Thickness.

In this work, we have studied field-induced aggregation and magnetic separation-realized in a microfluidic channel equipped with a single magnetizable micropillar-of multicore iron oxide nanoparticles (IONPs) also called "nanoflowers" of an average size of 27 ± 4 nm and covered by either a citrate or polyethylene (PEG) monolayer having a thickness of 0.2⁻1 nm and 3.4⁻7.

Two-stage kinetics of field-induced aggregation of medium-sized magnetic nanoparticles.

The present paper is focused on the theoretical and experimental study of the kinetics of field-induced aggregation of magnetic nanoparticles of a size range of 20-100 nm. Our results demonstrate that (a) in polydisperse suspensions, the largest particles could play a role of the centers of nucleation for smaller particles during the earliest heterogeneous nucleation stage; (b) an intermediate stage of the aggregate growth (due to diffusion and migration of individual nanoparticles towards the aggregates) is weakly influenced by the magnetic field strength, at least at high supersaturation;

Microfluidic separation of magnetic nanoparticles on an ordered array of magnetized micropillars.

Microfluidic separation of magnetic particles is based on their capture by magnetized microcollectors while the suspending fluid flows past the microcollectors inside a microchannel. Separation of nanoparticles is often challenging because of strong Brownian motion. Low capture efficiency of nanoparticles limits their applications in bioanalysis.