Gold Immunostaining of Exosomal Sections: A Technique to Visualize Diagnostic Markers in Exosomal Lumen

To begin, incubate grids containing 60-nanometer thick unstained sections in 50-microliter drops of 0.02 M glycine for 10 minutes to quench the free aldehyde groups. Then, rinse the sections in 100 microliters of distilled water three times for 10 minutes each. Following the last rinse, incubate the sections for 1 hour at room temperature in PBS containing 1% BSA. Then, incubate the grids in 50- to 100-microliter drops of an anti-KRS antibody for 1 hour.

Next, wash the grids five times for 10 minutes each in a drop of PBS containing 0.1% BSA. Then, transfer the grids to a drop of an appropriate secondary antibody and incubate the sections for 1 hour at room temperature. Now, wash the grids five times for 10 minutes each with a separate drop of PBS containing 0.1% BSA. Double stain the sections with 2% uranyl acetate for 20 minutes in the dark, followed by Reynold's lead citrate for 10 minutes. Place the stained section into a transmission electron microscope and view the sample using 80 kV and image them using the microscope software.