Analyzing Amyloid Structures in a Tissue Section Using Fluorescence Lifetime Imaging Microscopy

Take a tissue section with amyloid aggregates representing abnormal protein deposits. 

The tissue is stained with the fluorescent dye heptamer-formyl thiophene acetic acid or hFTAA, which binds specifically to beta-sheet structures of amyloid fibrils. 

Image the slide using a confocal microscope equipped with a fluorescence lifetime imaging microscopy unit, which measures the fluorescence lifetime of the dye molecules.

Optimize the microscope settings for effective excitation of the dye molecules. 

When laser light illuminates the tissue, hFTAA excites and fluoresces.

Stronger dye binding in compact structures results in longer lifetimes, while weaker dye binding in less compact structures leads to shorter lifetimes.  

Later, the software generates a color-coded image of the aggregate.

Colors, such as red and yellow, appear in the periphery, indicating shorter fluorescence lifetimes that reflect less compact, unstable amyloid structures. 

While colors like blue and green in the core represent longer fluorescence lifetimes, reflecting more compact and stable amyloid structures.