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Thioflavine S For Senile Plaques & Neurofibrillary Tangles In Alzheimer’s

Thioflavine S

For Senile Plaques & Neurofibrillary Tangles In Alzheimer's



  • Potassium permanganate, 0.25% in distilled water
  • Ethanol, 70%
  • Acetic acid, 0.25%
  • Bleach solution
    Potassium metabisulphite1g
    Oxalic acid1g
    Distilled water100mL
  • Blocking solution
    Sodium hydroxide1g
    Hydrogen peroxide, 30%3mL
    Distilled water100mL
  • Thioflavine S
    Thioflavine S0.0125g
    Ethanol, 50%100mL
  • Glycerine Water
    Distilled water1vol.

Tissue Sample

30µ free floating sections of neutral buffered formalin fixed tissue are suitable. If paraffin embedded, they should be carefully dewaxed and hydrated before staining, but should remain free floating.


  1. Place in potassium permanganate for 20 minutes.
  2. Rinse well with distilled water.
  3. Place in the bleach solution for 2 minutes.
  4. Rinse well with distilled water.
  5. Place in the blocking solution for 20 minutes.
  6. Rinse well with distilled water.
  7. Place in acetic acid solution for 5 seconds.
  8. Rinse well with distilled water.
  9. Mount sections on microscope slides using an adhesive, dry, then rehydrate.
  10. Place into thioflavine S solution for 3-5 minutes.
  11. Rinse twice with 50% ethanol.
  12. Rinse twice with distilled water.
  13. Mount in glycerine water or glycerine jelly.

Expected Results

With appropriate filters, amyloid fluoresces bright yellow.


  • Although the method specifies an aqueous mounting medium, either blotting and treating with xylene repeatedly until clear, or dehydrating with ethanol and clearing with xylene, then mounting with a fluorescence free resinous medium may be satisfactory.

Safety Note

Prior to handling any chemical, consult the Safety Data Sheet (SDS) for proper handling and safety precautions.


  1. Guntern, R., Bouras, C., Hof, P.R. & Vallett, P.G., (1992),
    An Improved Thioflavine S Method For Staining Neurofibrillary Tangles And Senile Plaques In Alzheimer’s Disease.