Ex Vivo Fluorescence Microscopy of Murine Brain Tissue Sections

To begin, take the flash frozen brain stored in optimal cutting temperature compound out of 80 degrees Celsius storage, and place it inside the cryostat chamber. Allow the samples to warm to the chamber temperature. Using a single-edged razor, cut the brain coronally at the injection site.

Mount the sample onto the specimen disk using a small amount of optimal cutting temperature. Apply ample pressure with a chilled weight inside the chamber for stable mounting of the sample. Move the mounted sample and specimen disk onto the specimen head.

Trim the tissue to the desired depth by taking 20-micrometer sections. Once the desired depth is reached, adjust the cryostat to take five to seven micrometer sections of the sample. Then mount the sections onto the pre-labeled glass slide.

Fix the sections in the 4%paraformaldehyde for 15 minutes. After fixation, rinse this slide three times with DPBS. Add a 40-microliter drop of mounting medium containing DAPI onto the slide.

Carefully place a glass cover slip on top of the medium. Under fluorescence microscopy, visualize the tissue using DAPI and Cy5.5. In ex vivo fluorescence microscopy of tumor tissues, the observed CY 5.5 fluorescent signal confirmed the delivery of magnetic nanoparticles.