An innovative microfluidic high-throughput device for shear dependent analyses of leukocyte adhesion and transendothelial migration

Leukocytes adhesion and extravasation process through a membrane is one of the most interesting phenomena to observe for in vitro studies of the mechanisms ruling the inflammatory reaction. Such studies are usually performed in a parallel flow-chamber, where cells, forced to flow in suspension, are free to interact with a specifically coated surface. The aim of the present study is the design of a high-throughput microdevice oriented to improve the efficiency and the efficacy of shear dependent adhesion and transmigration assays: it consists of several parallel flow-chambers, combined in a micro-fabricated glass device and completed with a PDMS gasket and a polymeric membrane. The design is intended to save cell culture medium and reagents involved in a standard assay: using a flow rate of 450-600 l/min, three high efficiency tests can be performed at the same time and on the same device, each corresponding to a different level of wall shear stress and obtaining for each one a triplicated result. Numerical fluid dynamic simulations have been carried out to improve the design, and experimental microPIV analyses have been performed to evaluate the local fluid dynamics in the test chamber. Results suggest that the microdevice can improve the efficiency of the technics and the reliability of the data commonly obtained with adhesion and transmigration assays.