Images are acquired from fixed and living heart tissue using fiber-optics and laser-scanning confocal microscopy, respectively. Three sets of images denoted as CCM, FCMtopical, FCMcarrier were stored for subsequent analyses.
The imaging protocol was based on topical application of 3 or 10 kDa dextran conjugated to Alexa Fluor 488 (Invitrogen, Carlsbad, CA, 125 μg/mL) via pipette to the tissue regions prior to imaging. Immediately following, images were acquired using the fiber-optics confocal microscopy system equipped with a custom fiber-optics microprobe (UltraMiniO; Mauna Kea Technologies, Paris, France). Using this imaging protocol, we acquired two-dimensional images sequences of the tissue regions at a lateral resolution (xy dimensions), optical sectioning (z), field of view (xy), frame rate, and z-scan range of 1.8 μm, 10 μm, 169 by 120 μm, 12 Hz and 50 μm, respectively. Example images from image sequences were stored as FCMtopical.