triphenyltetrazolium

Triphenyltetrazolium, often abbreviated as TTC, is a chemical compound with the molecular formula C19H15N4. It is a colorless, crystalline solid that is soluble in water and organic solvents. TTC is primarily known for its use as a redox indicator. In biological and chemical contexts, it undergoes reduction to form triphenylformazan, a red, water-insoluble compound. This color change is dependent on the presence of reducing agents, such as active enzymes or viable cells.

The application of triphenyltetrazolium as a viability stain is widespread in microbiology and plant physiology. When applied to living tissues or microorganisms, the tetrazolium salt penetrates cell membranes. Within metabolically active cells, enzymes in the electron transport chain reduce TTC to the red formazan. This results in the staining of viable cells or tissues a distinct red color, while dead or metabolically inactive cells remain unstained. This property makes TTC a useful tool for assessing cell viability, seed germination, and bacterial contamination.

Beyond viability staining, triphenyltetrazolium has found use in other analytical applications. It can be employed in enzyme assays where a reduction reaction is coupled to the production of a formazan product. In some instances, it has also been explored for its potential as a diagnostic agent. The intensity of the red color produced is often proportional to the level of metabolic activity or the concentration of reducing agents present.