Full flow field measurements of bacteria flowing past a stationary micro-scale crude oil droplet with attached microbial aggregates and streamers

Using a microfluidics platform with continuously circulating fluidics system, a micro-scale crude oil droplet is pinned in a microfluidic channel and exposed to a flowing bacteria suspension cultured in situ for up to weeks at a time. Every 10 min to 1 hour, a high speed camera integrated with differential interference microscopy captures images at high frame rate at several locations to record the bacteria flowing toward the droplet (upstream), flowing past the stationary droplet, flowing past any droplet-attached aggregate/streamer structures/tails, and flowing downstream. A particle image velocimetry (PIV) - assisted particle tracking velocimetry (PTV) analysis using the bacteria as tracer particles over the entire captured region yields the full velocity field. These comprehensive velocity measurements will allow for detailed flow analysis and drag calculation to determine the hydrodynamical impacts of bacteria aggregations on micro scale oil droplets.