Adhesion-based capture and separation of cells for microfluidic devices

Cell separation and sorting in micro-assay devices must be performed using minimal sample sizes and few processing steps. To meet these requirements, a biomimetic approach to cell sorting is proposed based on adhesion rolling of cells along surfaces. This type of interaction is mediated by a special class of adhesion proteins on cell membranes and is responsible for localizing cells to particular tissues in vivo. To perform cell capture in a microdevice, raw sample can be flowed through microstructured fluidic channels, which serve as chromatographic "separation columns" and whose surfaces are coated with adhesion proteins. Targeted cells are captured by the flow structures and are permitted to roll slowly under shear from passing fluid. Among captured cells, differences in rolling speed provide the basis for segregating different populations. In this study, two prospective designs for microstructured fluidic channels were coated with E-selectin IgG chimera. The capture and enrichment of HL-60 and U-937 cells from flowing samples were demonstrated. Additionally, the difference in transit speed through one of the fluidic channels indicates that separation of enriched populations of these cells is feasible.