Acidic Dye

∞ generated and posted on 2016.01.15 ∞

Microscopic stains possessing a negative charge and thereby which are able to bind to positively charged materials but are repelled by a specimen.

Acids tend to be negatively charged since they lose positively charged protons. As a consequence, Acidic Dyes bind to the positive charge of glass (as in microscope slide) rather than the negative charge of many specimens and therefore are the type of stain employed for negative staining.

Acid dyes are used particularly in negative staining.

See brightfield illumination and negative stain. Contrast with basic dye as well as with the concepts of acid fast and acidophile.