Engineering microfluidics based technologies for rapid sorting of white blood cells

Abstract

Blood is a valuable resource rich in cellular populations reflective of the immediate immune and inflammatory status of the body. Much of this information is contained in the nucleated White Blood Cells (WBCs). Current WBC isolation techniques are time consuming and result in artifactual changes in WBC gene expression. Using engineering approaches and basic fluid flow phenomenon in the microscale we have developed a microfluidic sorting device that can isolate WBC sub-populations rapidly based on size. This technique relies on osmosis to amplify size differences between different cell populations to ensure clear separation of different sub-populations based on size. The dynamics of cell size increase is determined in a microfluidic cell docking device which can be used to study instantaneous and time-dependent increase of cells to changing extra-cellular tonicity. Sorting is then accomplished in a microfluidic spiral sorter that exploits the balance between inertial lift forces and Dean's forces that developed in the microchannels. This paper demonstrates proof-of-concept of the ability to measure osmosis dependent cell size increase using MOLT-3 cells and sorting using 15 and 25 μm beads and confirms that this method holds promise for WBC sorting. © 2010 Springer-Verlag.