This overview of slide staining originally appeared on wardsci.com.
The exact chemistry involved in most staining procedures is unknown. There is probably more than one type of chemical interaction occurring during any staining procedure. Interactions can be electrostatic, covalent, or based on physical properties that affect stain penetration, including texture, density and solubility.
One prevalent mechanism is thought to be the electrostatic interaction of the chromogen with tissue molecules leading to the classification of many stains as acidophilic or basophilic. Basic dyes color acidic molecules - for example, hematoxylin, stains DNA (an acid) dark blue. Acid dyes color more basic molecules - for example, eosin, makes most cytoplasms red/pink. Continue reading ‘Slide Stain Guide’
