(610c) Magnetophoretic Capture of 5 Nm Sized Superparamagnetic Iron Oxide Nanoparticles Under Different Gradient Field Conditions

Authors: 
Gómez-Pastora, J., The Ohio State University
Wu, X., The Ohio State University
Weigand, M., The Ohio State University
Kim, J., Ohio State University
Zborowski, M., Cleveland Clinic Foundation
Moore, L., Cleveland Clinic
Chalmers, J. J., The Ohio State University
Superparamagnetic iron oxide nanoparticles (SPIONs) are widely employed in multiple fields, especially in biology and medicine where they can be used for diagnosis, therapy and disease monitoring due to their outstanding features. Among them, especially important are their high surface to volume ratio, their biocompatibility, their chemical stability and most importantly, superparamagnetism. However, the magnetic separation or manipulation of SPIONs with sizes below of 20 or 30 nm is very challenging as the magnetophoretic motion is hindered by thermal energy and viscous drag.

In this work, we report the magnetophoretic capture of 5 nm SPIONs under different variables and magnetic conditions. Particle suspensions with different concentrations were prepared and placed inside rectangular glass channels, which were then inserted into different separators. More specifically, the particle suspensions were placed inside different quadrupole magnetic sorters (QMS), designed to achieve different magnetic field and gradient conditions, rendering different magnetic forces acting on the SPIONs. The analysis of the SPIONs concentration levels over time and over the length of the glass channel was carried out by image processing.

Multiple variables and parameters were evaluated, including the initial SPIONs concentration, the temperature, the magnetic field and gradient and operation time. Our preliminary results suggest that for the trapping or capture of the SPIONs high magnetic gradients are imperative. Further exploration of the magnetic fields provided accurate quantitative data on the effect of the magnetic field on the SPIONs magnetophoretic motion. Furthermore, the particle separation is enhanced by increasing the initial particle concentration, which suggests that particle-particle interactions (magnetic coupling) is an essential phenomenon involved in the separation. Finally, the capture time has been calculated to be less than 10 minutes, which is a great advantage in comparison to other microfluidic separators that require longer operation times or low flow rates.