Acoustics, Dynamics, and Controls Commons^™

Dynamic Reversibility Of Hydrodynamic Focusing For Recycling Sheath Fluid, Nicole N. Hashemi, Peter B. Howell Jr., Jeffrey S. Erickson, Joel P. Golden, Francis S. Ligler

Nastaran Hashemi

The phenomenon of "unmixing" has been demonstrated in microfluidic mixers, but here we manipulate laminar flow streams back to their original positions in order to extend the operational utility of an analytical device where no mixing is desired. Using grooves in the channel wall, we passively focus a sample stream with two sheath streams to center it in a microchannel for optical analysis. Even though the sample stream is completely surrounded by sheath fluid, reversing the orientation of the grooves in the channel walls returns the sample stream to its original position with respect to the sheath streams. We demonstrate …