Dynamic characterization of the phagocytic process utilizing an automated microfluidic platform

Abstract Phagocytosis is a complex pathway that involves removal of pathogens, foreign particles, or cell debris through engulfment by unique cell types. Such innate responses provide the first line of immune defense with evidence showing their critical involvement in prevention of chronic inflammation or autoimmune disease, tissue remodeling and removal of apoptotic tumor cells following therapeutic intervention. Traditional tools evaluate cell behavior in bulk context thus masking inherent cellular heterogeneity or employ end-point assays thus losing temporal process dynamics. Moreover, non-adherent immune cells are mobile complicating single cell analysis. Characterizing functional changes with single cell resolution requires precise spatial cell positioning, controlled micro-environment and high-throughput multiplexed measurement. We developed a novel microfluidic approach to trap single non-adherent immune cells in a microfluidic platform capable of perfusion-based media supply with gas and temperature control. The device is comprised of a controller system and optically transparent microfluidic plates, each with four culture chambers. Each chamber [dimension: 3mm × 3mm × 40μm (L × W × H)] contains a trap array tailored to the dimensions of the cells of interest. Each unit can be addressed by programmable manipulation of up to six reagents, enabling uninterrupted real-time live cell imaging assays in response to changing conditions. To demonstrate utility, the platform was used in conjunction with fluorescent markers to monitor the phagocytic process in real-time via, including temporal changes in morphology and the rate of phagosome formation/inhibition in the presence of different stimuli and concentration.