alamarBlue HS Cell Viability Assay Reagent is a ready-to-use resazurin-based solution that utilizes the reducing power of viable cells to quantitatively detect viability. , which can be used as an indicator of cell health. Once inside living cells, resazurin is reduced to resorufin, a red, highly fluorescent compound. High background fluorescence caused by various contaminants can degrade the performance of resazurin-based reagents. To improve performance, the company developed an innovative purification process that removes these contaminants. This highly purified, non-toxic resazurin is used in standard alamarBlue formulations to create the multi-component alamarBlue HS cell viability assay. Changes in cell viability can be easily detected using absorbance- or fluorescence-based microplate readers. alamarBlue HS Cell Viability Assay has broad applicability and can be used with a variety of human and animal cell lines, bacteria, plants, and fungi.

Features of alamarBlue HS Cell Viability Assay Reagent include:
•Removal of contaminants in resazurin — Background fluorescence reduction by >50%
• Signal-to-background ratio increased by >100% — resulting in a larger assay signal window
• Highly sensitive reagent with linear response — Lower detection limit as low as 20 cells/well
>• Convenient load-and-read format — no mixing, no washing, no cell lysis required, and compatible with fluorescence or absorbance-based instruments
• Measures multiple cell types Viability—including mammalian cells, bacteria, plants, and fungi

Measuring changes in cell viability is a fundamental method for assessing cell health, determining genotoxicity, and evaluating anticancer drugs. Cell health can be monitored by detecting changes in several key indicators, including cell membrane integrity, DNA synthesis, DNA content, enzyme activity, ATP content, and changes in the cell's reducing environment.

Monitoring changes in a cell's reducing environment or metabolic activity using resazurin-based reagents is a well-established and reliable indicator of cell viability or death. Once inside a living cell, the reducing environment of the cell reduces resazurin to resorufin, a red, highly fluorescent compound. As living cells continuously convert resazurin to resorufin, the overall fluorescence intensity of the culture medium surrounding the cells increases. In addition, the conversion of resazurin to resorufin produces a significant color change, so cell viability can also be measured using an absorbance-based microplate reader.

As a result of the synthesis and production processes, all resazurin-based reagents contain detectable amounts of resorufin contamination. The amount of contamination varies widely depending on material source and production conditions, resulting in differences in detectable background fluorescence. More importantly, resorufin contamination will reduce the signal-to-background ratio and dynamic range of the assay. The company has developed an innovative process that can remove resorufin contamination, thereby obtaining high-purity resazurin used in alamarBlue HS cell viability detection reagents.

alamarBlue HS Cell Viability Assay Reagent is a complete and non-toxic sample-and-assay reagent that does not require cell lysis. The highly purified resazurin used in alamarBlue HS reagent reduces background fluorescence by >50% and increases signal-to-background ratio by >100%. Because cell lysis is not required, the diluted alamarBlue HS solution can be removed and replaced with complete growth medium for further cell culture. Like alamarBlue reagents, alamarBlue HS reagents exhibit a broad cell viability detection time window for a variety of organisms, allowing quantitative measurements of cell viability and proliferation in a variety of human and animal cell lines, bacteria, plants, and fungi.