Medium and FITC-Ab were encapsulated in 50–70 μm diameter droplets (1x medium and 0.83 μg/ml FITC-Ab in-droplet) to visually assess medium contribution to fluorescence.

Fluorescence exposure and look-up-table (LUT) settings are standardized across all four media evaluated. The LUT values can be found in the upper left-hand corner of each image. Media under test included phosphate buffered saline (a), Rappaport-Vassiliadis (b), buffered peptone water (c), and tryptic soy broth (d).