alamarBlue assay for assessment of cell proliferation using a BMG LABTECH microplate reader

AE Markaki Dept of Engineering, University of Cambridge 06/2009



This application note shows that the reducing environment of cells can be accurately monitored using a BMG LABTECH microplate reader. The attraction of the alamarBlue® assay is that it incorporates a nontoxic reagent which allows continuous monitoring of cell proliferation on the same samples using either fluorescence or absorbance.

BMG LABTECH’s readers are flexible multifunctional microplate readers that have six different measurement modes in one instrument: fluorescence intensity, time-resolved fluorescence, luminescence, fluorescence polarization, AlphaScreen® and absorbance. With two optional onboard injectors and a standard 45°C incubation chamber, BMG LABTECH microplate readers can easily become fully automated to perform any cell-based assays.

A variety of methods have been developed to measure cell proliferation in whole population of cells. One method quantifies the reducing environment of the cells. It relates to the fact that metabolizing cells maintain a reducing environment within their cytosol and this reduced state can be measured spectrophotometrically through the conversion of fluorometric/colorimetic redox indicators such as alamarBlue®.


The assay was tested in human osteoblast cells (HOb 406-05a) grown on two substrates. Cell viability was assessed every 24-36 h over a culture period of 17 days. Cells were incubated with the alamarBlue® dye for 4 h before exchanging the medium and measurement of the fluorescent signal by the BMG LABTECH microplate reader.


The nontoxic reagent in combination with the stable measurements of the reader allowed for continuous monitoring of cell viability and revealed differences in the suitability of two differing culturing substrates.

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