How to choose the best cell viability assay for your experiments
A cell viability assay is often based on assaying cellular metabolism and enzyme activity, ie measuring factors that reflect the number of living cells in a population. You can use these assays to help determine whether cells are alive, metabolically active and capable of dividing. These assays are particularly useful in assessing the cytotoxic effects of drugs and other compounds, helping you assess treatment effects and screen potential drug candidates.
We’ve created this guide to streamline the selection process and help you find the assay that will best aid your research.
What do you need to consider when choosing a cell viability assay?
Cell viability assays can help by measuring the following processes in cells. Knowing what aspect of cell health you need to investigate will help you narrow down your wealth of options and choose the right assay for you.
- Cellular enzyme activity
- Intracellular esterase activity
- ATP/ADP levels
- Glycolytic flux and oxygen consumption
How do I measure cellular enzyme activity?
You can use dye reduction assays to measure cellular enzyme activity. Tetrazolium cell viability assays rely on cellular dehydrogenases to form a colored formazan product, which is measured by absorbance. Other assays use the reduction of resazurin, by electron acceptance from the mitochondrial respiratory chain, to form the fluorescent resorufin.
How can our dye reduction assays help?
Our highly cited assay kits are fast and easy to use, often featuring no-wash protocols to save you time. Assays are available with colorimetric and fluorometric readouts as well as various assay platforms, so you’re sure to find an assay that suits your experiments.
MTS Assay Kit (Cell Proliferation) (Colorimetric)
- Single, ready-to-use reagent
- Generates a colored dye based on the reduction of the MTS tetrazolium compound
- Readout by absorbance at 490-500nm
Cell Counting Kit 8 (WST-8 / CCK8)
- No-wash assay with a single 1-4 hour incubation step
- CCK8 tetrazolium in solution is very stable with low cytotoxicity, making it useful for long-time-scale cell number monitoring
- Colorimetric readout at 460 nm
Resazurin Assay Kit (Cell Viability)
- No-wash assay
- Fluorescent readout enables multiplexing with other assays
- Compatible with plate reader, microscope and flow cytometer
How can quantifying esterase activity help me measure cell viability?
Live cells typically have constantly active esterases, making esterase activity a useful substrate for distinguishing live from dead cells. Esterase cleavage assays can help you measure esterase activity as an indication of live cell number. Esterase cleavage assays use Calcein and similar hydrophobic dyes, which diffuse into cells and are cleaved by intracellular esterases in live cells. The hydrophilic fluorescent product is retained in the cell and can be quantified with flow cytometry or fluorescence microscopy.
How can our esterase cleavage assays help?
Our sensitive esterase cleavage assays are fast, safe and easy to use. For nonradioactive quantification, colorimetric assays are available.
Calcein AM Assay Kit (Fluorometric)
- Simple, extremely sensitive assay
- Measures viability in adherent and suspension cells
How do I measure ATP levels?
ATP’s presence in cells is a strong indicator of cellular viability and metabolic activity. ATP assays can help you measure ATP levels in cells. Most assays use a cell membrane permeabilization agent to release ATP; light is produced using ATP-dependent luciferase. Other ATP assays use the ATP-dependent phosphorylation of glycerol (or other substrates).
How can our ATP assays help?
Our ATP assays feature simple no-wash protocols to help you progress faster.
Luminescent ATP Detection Assay Kit
- No-wash assay
- Luciferase enzyme produces a signal proportional to the amount of ATP released
- Compatible with luminometric plate readers
ATP Assay Kit (Colorimetric/Fluorometric)
- Mix-and-read, no-wash assay with one 30-minute incubation step
- Colorimetric (570 nm) or fluorometric (Ex/Em 535/587 nm) readout
How do I measure cellular metabolic activity?
Oxygen consumption and glycolysis assays can help you measure the level of cellular metabolic activity and, therefore, cell viability. Basic analysis of intracellular oxygen levels and glycolysis activity can be a springboard to deeper investigation.
How can our oxygen consumption and glycolysis assays help?
Our oxygen consumption and glycolysis assays use rapid mix-and-read protocols to save you time and streamline your workflow. Our kits are compatible with plate readers.
Extracellular Oxygen Consumption Assay
- Mix-and-read, no-wash assay
- Real-time analysis: dye signal (Ex/Em 380/650 nm) increases as respiration lowers oxygen levels
- Suitable for plate reader
Intracellular Oxygen Concentration Assay
- Easy, mix-and-read, no-wash assay
- Dye fluorescence (Ex/Em 340/642) is quenched by intracellular oxygen
- Suitable for plate reader
Glycolysis Assay [Extracellular acidification]
- Easy mix-and-read, no-wash assay
- Lactate production causes extracellular acidification and increased dye fluorescence (Ex/Em 340-380/615 nm)
- Suitable for plate reader
