(224d) Micro and Nanoparticle Trapping and Manipulation with Fluid Flow

The ability to trap and control the motion of single particles has led to key advances in science and engineering. Particle trapping is a pervasive technology that underlies nanoscience and biological analysis. In this presentation, I will introduce two new microfluidic methods based on the sole action of hydrodynamic forces for the confinement and manipulation of micro- and nanoscale particles in free-solution. Both trapping methods utilize an automated feedback-control mechanism for active control of fluid flow within microchannels using an integrated on-chip metering valve. The first method is the “hydrodynamic trap” where a target particle is confined at a microchannel junction by actively controlling the stagnation point of a planar extensional flow field This method enables trapping, 2-D manipulation, stretching and sorting of objects ranging from single molecules to individual cells using the sole action of fluid flow. The second method is the “microfluidic Wheatstone bridge” which facilitates rapid sampling of particles, cells and droplets in continuous flow for monitoring and analysis. This dynamic sampling method allows for "on-demand" trapping of multiple particles at the “bridge” channel without stopping or diverting the main sample stream. Currently, we are pushing the limits of these methods for confining small nanoparticles (< 50 nm) and large macromolecules. We anticipate that these microfluidic-based techniques will enable new scientific studies in the fields of catalysis, colloidal science, polymer dynamics, single molecule studies, systems biology, and cellular mechanics.

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2.   M. Tanyeri, M. Ranka, N. Sittipolkul and C. M. Schroeder, Lab on a Chip (2011) 11, 1786.