Fig. 3

Mixture of infused fluorescent microbeads in-vivo. (A): left image: Composite images of adherent infused fluorescent 1 μm microbeads, middle image: green fluorescent (560 nm) microbeads, and right image: red fluorescent microbeads (> 600 nm). Notice that the green/yellow microbeads in the composite image represent green beads visible (green channel) and, due to an optical overlap of the 560 nm emission spectrum are also visible in the red channel. In the composite picture, these appear as yellow-green, clearly distinguishable from the red fluorescent microbeads. The orange microbeads result from a positional overlap between 2 different beads (in red and green channel repsectively). (B), (C), and (D): Show a sequence of intravital microscopy images of a microbead moving along the vascular endothelium. Images in (B) and (D), represent the image sequences displaying the location (red circles) of the fluorescent bead visible only in image sequence (C) (yellow circles). Bright-field illumination wavelength range: 400–550 nm (B). Filters: band-pass filter: 565/24 nm (C) and long-pass filter: 600 nm (D). Microbeads: excitation 488 nm / emission 645 nm (C) and excitation 540 nm / emission 560 nm (D). Exposure: 40 ms; frame rate: 16.7 fps. Please note that since all images are captured on monochrome cameras in the MSIVM system, no color images can be generated directly. We used image processing to add color for visualization purposes only. White dotted lines indicate the approximate position of the vascular wall