Blood Cell Capture In a Gradient Dielectrophoretic Microchannel

Biological fluids can be considered to contain information-rich mixtures of biochemicals and particles that enable clinicians to accurately diagnose a wide range of pathologies. Rapid and inexpensive analysis of blood and other bodily fluids is a topic gaining substantial attention in both science and medicine. Current limitations to these analyses include long culture times, expensive reagents, and the need for specialized laboratory facilities and personnel. Improving these tests and overcoming their limitations would allow faster and more widespread testing for disease and pathogens, potentially providing a significant impact for healthcare, especially in developing nations. One line of development involves microfluidic approaches that provide unique advantages over entrenched technologies, including rapid analysis times, microliter sample and reagent volumes, and portability. The present study focuses on the isolation and concentration of human blood cells from small-volume samples of diluted whole blood. Separation of cells from the matrix of whole blood was accomplished using DC insulator-based gradient dielectrophoresis in a converging, sawtooth-patterned microchannel. The channel design enabled high-resolution capture by exploiting variations in the characteristic physical properties of cells and other bioparticles. Reproducible capture occurred at specific locales within the channel, over a global applied voltage range of 200 to 700 V. Separation was achieved in isotonic buffers, allowing capture of whole cells.