NMR Microscopy Measurements of Colloid Suspension Transport in Microfluidic Systems

Lead Investigator: Sarah L. Codd, Montana State University

NMR Microscopy methods can measure time and length scale dependence of transport in microfuidic channels. NMR chemical selectivity can differentiate between particle and fluid phases during viscous resuspension in a Couette, and MRI spatial sensitivity allows predicted particle ordering and non-uniform particle distribution to be observed. 

This research program will study the dynamics of hard sphere colloid suspension flows and sedimentation in capillaries (5-500μm dia) and Couette geometries (100-500μm gaps), establishing NMR microscopy as a useful technique for these systems and providing unique data for testing of conceptual and numerical models.  Preliminary data of blood flow in the same geometries will be obtained, with a view to resolving a conflict in the literature regarding the non-uniform distribution of erythrocytes across vessel lumens (the Fahraeus effect) and the impact of this on mixing at flow bifurcations. 

The results of this research will be used for a larger proposal to NASA (physics of fluids) that will propose studying complex systems such as colloidal suspension flows in porous media, blood flow in glass capillary networks, and bacterial suspension flow in micro-channels.  New knowledge in this area is directly relevant to future directions of the NASA Fluid Physics program in conducting fundamental research into the rheology and morphology of colloids and bioscience and engineering applications in microfluidics and �lab on a chip� technologies, flow and transport in bioreactors and cell cultures, and fluid physics aspects of biomedical processes.

This preliminary research will begin with the well defined flows of model solid spherical colloidal particles in a standard Couette geometry and sedimentation in single capillaries.