What are amyloids?

Amyloids are protein polymers that are made up of linear, non-branching, rigid aggregated fibrils of indefinite length and approximately 7.5 to 10 nanometers in diameter. They are characterized by a fibrillar morphology and a β-sheet secondary structure called cross-β. Amyloids can be stained by certain dyes such as Congo red, and have a characteristic yellow-green birefringence when stained. Amyloids are produced in the bone marrow and function in a variety of physiological processes such as memory formation.