The 1% aqueous solution of toluidine blue is a versatile tool in histology and cytology. Toluidine blue is a basic thiazine dye that shows high affinity for acidic tissue components, especially nucleic acids. Therefore, it is particularly useful for staining cell nuclei, which appear intensely blue.

In addition, toluidine blue is known for its metachromatic properties. This means that it has the ability to take on different colors depending on the chemical properties of the structures to which it binds. This allows for differential staining of different cell and tissue types.

Toluidine blue also has a high affinity for mast cells and can therefore be used to identify them. Because mast cells play a role in many inflammatory and allergic processes, toluidine blue is an important tool in pathology and immunology.

The 1% aqueous solution of toluidine blue provides sufficient concentration for clear and differential staining, while offering enough flexibility to address the specific needs of a variety of experimental protocols. It should be used by trained professionals in an appropriate laboratory setting.