(193n) Anomalous Diffusion of Magnetic Nanoparticles On a Microfluidic Sytem Under a Variable Magnetic Field

Microfluidic devices has been the focus of attention in different areas, such as chemistry, biology, bioengineering and health sciences in past few years due to the numerous advantages in sample preparation, characterization and analysis. Despite of these characteristics, the separation and mixing of particles or fluids are quite difficult to achieve in such devices due to the diffusive regimen. As a possible solution to this problem, some authors have proposed magnetic-field based separation and mixing. As a result, studies on the behavior of diffusion as a function of the applied magnetic field on this type of systems are of great interest.

In this work, we have studied the behavior of an aqueous suspension of magnetic nanoparticles flowing through a microfludic system in the presence of an externally imposed magnetic field. We have measured the concentration profile across the microsystem and adjusted the diffusion coefficient to a non-regular diffusive regime.

 The experimental work has involved the synthesis of magnetic nanoparticles and the analysis of particles transport under the influence of different magnetic fields and flow conditions. The nanoparticles used in this study are particles of magnetite, synthesized by the coprecipitation method and stabilized with an electrolyte to screen electrostatic interactions. Core-shell magnetic nanoparticles are also considered. In order to verify our model we have develop numerical simulations using COMSOL Multiphysics to corroborate the behavior of the microfluidic system and the concentration profile.

 The simulation and experimental results are compared in order to analyze the non-regular diffusive regime. The results obtained indicate an anomalous diffusion regime in the presence of an external magnetic field in this type of systems.