Microfluidic particle separation arrays are capable of passive sorting of microparticles or cells by size while avoiding blockage. Despite the usefulness of boundaries for concentration and parallel integration of arrays, separation efficiency is severely degraded in the areas adjacent to the boundaries due to the aberrant fluid flow found there. This letter shows how to eliminate this problem by modifying the boundary interface. At each row the boundary is moved by a specific amount to ensure a linear change in flux from row to row, which leads to uniform flow patterns and improved separation characteristics throughout the array.
Copyright (2009) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters, 94:1, 013510, and may be found at http://dx.doi.org/10.1063/1.3068750.