Basic stain

Basic stain 

* These are cationic.

* Their chromogen has  a positive charge on ionization.

* They have affinity for the negatively charged molecules such as nucleic acids, many proteins, and the surfaces of bacterial and archaeal cells.

* Basic stains can stain bacterial cells as they possess negative charge.

* Examples : Methylene blue, basic fuchsin, crystal violet, safranin, malachite green.