hFTAA Staining of Amyloid Deposits: A Technique to Visualize Amyloid Fibrils Using Oligothiophene-Based Dye for Fluorescence Imaging in Tissue Sections

Prepare the luminescent conjugated oligothiophene solution by resuspending lyophilized hFTAA in two millimolar sodium hydroxide to prepare a 1 mg/mL stock solution. Transfer the stock solution to a glass vial, and store at four degrees Celsius.

If formalin-fixed, paraffin-embedded, sections are used, de-paraffinize in xylene overnight. On the day of staining, immerse the sections in consecutive baths of 99% ethanol, 70% ethanol, dH₂O, and PBS, for 10 minutes, each time. Then, allow the tissue sections to dry under ambient conditions.

While the tissue dries, prepare a working solution of hFTAA by diluting the stock 1:10,000 in PBS. When the tissue is dry, add droplets of the hFTAA working solution to each tissue section to cover it. Incubate for 30 minutes at room temperature.

Rinse off the staining solution with 500 microliters of PBS, and then, immerse the slide in the PBS bath for 10 minutes.

After allowing the section to dry under ambient conditions, mount using fluorescence mounting medium. Allow the mounting medium to settle overnight.

Amyloid detection can be performed directly after mounting, or even without mounting. However, if the goal of the experiment is to collect high-quality spectral information, overnight incubation is preferred.