Resazurin

Resazurin is a chemical compound commonly used as an oxidation-reduction indicator in various biochemical and cell biology applications. It is a blue dye that is reduced to a pink-colored compound called resorufin in the presence of viable cells, making it a useful tool for assessing cell viability and cytotoxicity.

Chemical Properties

Resazurin has the chemical formula C₁₂H₇NO₄ and a molecular weight of 229.19 g/mol. It is a member of the phenoxazine family and is known for its distinctive blue color in its oxidized form. Upon reduction, it turns pink, indicating the presence of metabolically active cells.

Applications

Cell Viability Assays

Resazurin is widely used in cell viability assays, such as the Alamar Blue assay. In these assays, resazurin is added to cell cultures, and its reduction to resorufin is measured using a fluorescence or absorbance plate reader. The degree of reduction correlates with the number of viable cells, allowing researchers to assess cell proliferation and cytotoxicity.

Microbial Testing

In microbiology, resazurin is used to test the viability of bacterial and fungal cultures. It is often included in culture media to monitor the growth and metabolic activity of microorganisms. The color change from blue to pink indicates active microbial metabolism.

Bioremediation Studies

Resazurin is also employed in bioremediation studies to evaluate the metabolic activity of microorganisms involved in the degradation of environmental pollutants. The reduction of resazurin serves as an indicator of microbial activity and the effectiveness of bioremediation processes.

Mechanism of Action

The reduction of resazurin to resorufin is a result of cellular redox reactions. In metabolically active cells, NADPH and other reducing agents donate electrons to resazurin, converting it to the pink-colored resorufin. This process is indicative of cellular respiration and metabolic activity.

Safety and Handling

Resazurin is generally considered safe to handle in laboratory settings, but appropriate safety precautions should be taken to avoid inhalation, ingestion, or skin contact. It should be stored in a cool, dry place, away from light to prevent degradation.

See Also

• Cell viability assay
• Cytotoxicity
• Alamar Blue assay
• Resorufin
• Microbial viability
• Bioremediation