What color does aniline blue stain collagen?

Aniline blue is a dye commonly used in histopathology to specifically stain collagen in tissue sections. When tissues are treated with aniline blue, the collagen fibers adopt a blue color. This property makes aniline blue particularly valuable in distinguishing collagen from other components within the tissue, as it provides a clear and distinct visual contrast against other cellular elements.

In the context of histological staining, the ability of a dye to interact with specific types of proteins or structures, like collagen, plays a crucial role in aiding pathologists and researchers in diagnosing various conditions. Aniline blue is used in various staining protocols, such as the Masson's trichrome stain, which differentiates connective tissue from other cell types. By effectively staining collagen blue, it allows for a more nuanced examination of the tissue architecture and any potential pathological changes present.