Rabbit anti mouse cd31 primary antibody

All mice were housed at the University of Washington in a pathogen-free environment under protocols approved by the Institutional Animal Care and Use Committee (IACUC). C57BL6 wild type mice (Charles River, Wilmington, MA) were injected through the tail vein with 100 μl of 2 mg/ml nanoparticles. Each animal was euthanized at 0.5 h and 2 h post-injection and brain tissues were dissected. Tissues were then embedded in OCT and kept frozen at −80°C until needed. The frozen tissues were sliced in 12 μm thick sections and mounted onto glass slides. Slides were then washed with TBS with 0.025% Triton X-100 and blocked in 10% normal serum with 1% BSA in tris(hydroxymethyl)aminomethane-buffered saline (TBS) for 2 h. Slides were then rinsed and stained with rabbit anti-mouse CD31 primary antibody and goat anti-rabbit Fc secondary antibody-FITC conjugate according to instructions provided by Abcam. Cover slips were then mounted on microscope slides using Prolong Gold antifade solution containing DAPI for cell nuclei staining. Images were acquired on an LSM 780 NLO confocal fluorescence microscope (Carl Zeiss Inc., Peabody, MA) equipped with a 63 x oil immersion lens and appropriate filters.