Evans blue

Evans Blue is a dye that is also known as Direct Blue 53 or C.I. Direct Blue 53. It is a diazo dye that was first synthesized in the early 20th century and has been used in a variety of applications, including as a histology stain and in the measurement of blood plasma volume.

History

Evans Blue was first synthesized in the early 20th century. It is named after H. M. Evans, a British histologist who first used the dye in his research.

Chemical Properties

Evans Blue is a diazo dye, which means it is composed of two nitrogen atoms connected by a double bond. It has a molecular weight of 961.82 g/mol and a chemical formula of C34H24N6Na4O14S4. The dye is blue in color and is soluble in water.

Applications

Evans Blue has been used in a variety of applications. In histology, it is used as a stain to highlight certain structures in tissue samples. In medicine, it is used in the measurement of blood plasma volume. The dye binds to albumin, a protein in the blood, and can be measured to determine the volume of plasma in the blood.

In research, Evans Blue has been used to study the blood-brain barrier. The dye is unable to cross the barrier, so its presence in the brain can indicate a breach in the barrier.

Safety

While Evans Blue is generally considered safe for use in research and medical applications, it can cause skin and eye irritation. It is also harmful if swallowed or inhaled.

See Also

• Histology
• Blood-brain barrier
• Albumin