Physicochemical Principles of dyes used In Microbiology

The use of dyes in the identification processes in microbiology is based on the physicochemical properties of these substances. In the field of physics, optics explains how all objects are observable depending on the wavelengths that are absorbed and transmitted within the so-called "visible spectrum". These transitions are, in turn, due to chemical compounds and the electronic movements within atoms. Likewise, when a dye interacts with a cell or tissue, reactions occur that depend on functional chemical groups called chromophores and auxochromes.

Depending on the chemical compounds that constitute them, the dyes can be acidic, basic or neutral and this connotation is due to the active part of the dye and the reaction it causes on the microbial cells.

On the other hand, stains in microbiology can be simple or differential, depending on whether the entire sample is stained with one or more dyes. In the first case is the example of the lactophenol blue staining and in the second, the Gram staining.

This article describes the main colorations used in microbiology and explains the physical and chemical foundations of these processes.