Imaging Amyloid-Beta Plaques in Brain Tissue Sections by Immunolabeling and Curcumin Staining

Start with brain sections from a neurodegenerative mouse model. 

Incubate with a detergent-supplemented blocking solution to increase tissue permeability and block non-specific binding. Discard the solution.

Introduce primary antibodies targeting amyloid-beta plaques. Incubate with agitation for antibodies to interact with amyloid-beta plaques, then wash.

Add red fluorophore-tagged secondary antibodies and incubate in the dark to allow the antibodies to interact.

Wash to remove unbound antibodies, followed by an alcohol wash.

Add curcumin, which binds beta-sheet-rich amyloids with high affinity, then wash.

Next, treat with increasing alcohol concentrations, dehydrating the brain sections. Add xylene to remove any traces of reagents. 

Mount a section on a slide and observe under a fluorescence microscope. 

Use a 590-nanometer wavelength laser to excite the red fluorophores on the secondary antibodies. Capture the image.

Switch to a 480-nanometer wavelength laser to excite the curcumin, emitting green fluorescence. 

Overlay the images; red and green fluorescence colocalization confirms amyloid-beta plaque in the brain tissue.