In vivo and ex vivo optical imaging

Biotinylated peptide-SA-Cy5.5 (1.8 nmol), prepared by mixing 7.2 nmol of biotinylated peptide with 1.8 nmol of streptavidin-Cy5.5 in PBS overnight at 4 °C, was injected via the tail vein in an anesthetized mouse before imaging. Animals were placed in the supine, prone, or lateral position. Images were acquired by a Kodak IS2000MM image station (Rochester, NY) with a 625/20 band-pass excitation filter, 700WA/35 band-pass emission filter, and 150 W quartz. Halogen lamp light source was set to maximum. Images were captured at different time points with a CCD camera set at F stop = 0, FOV = 150, and FP = 0. Mean fluorescence intensity (MFI) was calculated by drawing the region of interest (ROI) of the mouse tumor using the Kodak ID 3.6 software. For ex vivo imaging, the mice were euthanized, and their organs were excised for imaging.