alamarBlue® is a redox indicator that yields a colorimetric change and a fluorescent signal in a response to a metabolic activity. It is a proven safe and non-toxic dye used for quantitative analysis of cell viability and cell proliferation, for cytokine bioassays and in vitro cytotoxicity studies.

Applications:

• Cell proliferation determinations—alamarBlue® is water soluble, stable in culture and non-toxic
• Cell viability assays, including cytotoxicity—metabolic activity and dye generation changes in proportion to altered viability and cell damage
• Cytokine assays—measure cytokine-induced proliferation and recover and expand cells at the end of the study if desired

alamarBlue® as a Cell Viability Assay Reagent
The alamarBlue® assay is based on the ability of metabolically active cells to convert the reagent into a fluorescent and colorimetric indicator. Damaged and non-viable cells have lower innate metabolic activity and thus generate a proportionally lower signal. The non-toxic nature of alamarBlue® permits long-term exposure of cells and measurement can be made over time or as end point measurements; cells grown in the presence of alamarBlue® were found to produce similar numbers of viable cells as control cells, as determined by flow cytometric analysis of CD44, CD45RB and CD4 antigens.

A Safe, Convenient, and Versatile Assay
alamarBlue® is an indigo-colored liquid dye that has been shown to effectively measure innate metabolic activity in animal, fungal and bacterial cells. Since alamarBlue® is non-toxic, the effector cells may be recovered for further analysis or cell expansion at the end of the study, if desired. alamarBlue® is highly water soluble and thereby eliminates time consuming wash and extraction steps. The homogeneous assay format is fast and involves adding the single reagent directly to either cell suspension or attached cells in full medium. The protocol is readily amenable to automation and so particularly useful for high-throughput assays. The ability to detect the alamarBlue® indicator by either fluorescence or spectroscopy provides compatibility with flow cytometry, plate readers and microscopy.

Experimental Detection of alamarBlue®
• Fluorometry: By excitation at 530 – 560 nm and emission at 590 nm
• Spectrophotometry: By absorbance measurements at 570 nm and 600 nm