Microfluidic Device And Assay For Mimicking The Leukocyte-Endothelium Interactions In Vivo

There is no in vitro model that allows investigation of the entire leukocyte adhesion cascade. In this study we present a novel microvasculature network based microfluidic device (MFD) that enables a single assay to study the entire cascade. Our modified Geographic Information System (GIS) approach was used to digitize the microvascular networks and generate the MFD using soft‐lithography based microfabrication. The MFD consisted of vascular channels seeded with endothelial cells, in communication with the tissue compartment filled with chemoattractant (fMLP) via a 3µm porous barrier. Leukocytes were flowed on activated endothelial cells under physiologic flow conditions. Leukocytes rolling, adhesion and migration was imaged as a function of time and position in the MFD and compared with in vivo data from mouse cremaster muscle. Our findings indicate that in MFD rolling and adhesion patterns are in agreement with the in vivo data, with 50% of adhered leukocytes migrating from the vascular channels into the tissue compartment after 120min. Furthermore, we blocked the individual steps treating endothelial cells with E‐selectin and ICAM‐1antibody and leukocytes with wortmanin, showing that we can respectively reduce rolling to ~20%, adhesion to ~50%, and migration to ~18% of their original values. In conclusion, this device more realistically mimics geometric and physiologic characteristics of an in vivo microvascular network for studying the entire leukocyte cascade during inflammation. Grant Funding Source : Supported by NIH