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Fluorescent and Colorimetric Assay Kits

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96992 Cell Counting Kit - 8 for quantitation of viable cell number in proliferation and cytotoxicity assays Cell Counting Kit-8 (CCK-8) allows convenient assays using WST-8 (2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt), which produces a water-soluble formazan dye upon bioreduction in the presence of an electron carrier, 1-Methoxy PMS. CCK-8 solution is added directly to the cells, no pre-mixing of components is required. WST-8 is bioreduced by cellular dehydrogenases to an orange formazan product that is soluble in tissue culture medium. The amount of formazan produced is directly proportional to the number of living cells. Since the CCK-8 solution is very stable and it has little cytotoxicity, a longer incubation, such as 24 to 48 hours, is possible.
Cell Counting Kit-8 allows sensitive colorimetric assays for the determination of the number of viable cells in the proliferation and cytotoxicity assays. The detection sensitivity is higher than any other tetrazolium salts such as MTT, XTT or MTS.
03285 Cell Counting Kit sufficient for 500 tests The Cell Counting Kit (CCK) is utilized for the fluorometric detection of living cell numbers. The amount of a fluorescent dye, calcein, produced from calcein-AM (3′,6′-Di(O-acetyl)-2′,7′-bis[N,N-bis-(carboxymethyl) aminomethyl]-fluorescein, tetraacetoxymethyl ester) by esterases in cells is directly proportional to the number of viable cells in a culture medium. Since calcein-AM is highly lypohilic because of the acetoxymethy groups in the molecule, it can rapidly permeate into the cytoplasm through the cell membrane. The CCK assay does not require any radioisotopes (such as in the [3H]- thymidine incorporated assay) or a solubilization procedure (such as in the MTT assay). Therefore, it allows the users to obtain highly reproducible and accurate cell proliferation assay results.
04511 Live/Dead Cell Double Staining Kit suitable for fluorescence The Live/Dead Cell Double Staining Kit is utilized for simultaneous fluorescence staining of viable and dead cells. This kit contains calcein-AM and propidium iodide (PI) solutions, which stain viable and dead cells, respectively. Calcein-AM, acetoxymethyl ester of calcein, is highly lipophilic and cell membrane permeable. Though calcein-AM itself is not a fluorescent molecule, the calcein generated from Calcein-AM by esterase in a viable cell emits a strong green fluorescence (λex 490 nm, λem 515 nm). Therefore, calcein-AM only stains viable cells. Alternatively, the nuclei staining dye PI cannot pass through a viable cell membrane. It reaches the nucleus by passing through disordered areas of dead cell membrane, and intercalates with the DNA double helix of the cell to emit red fluorescence (λex 535 nm, λem 617 nm). Since both calcein and PI-DNA can be excited with 490 nm light, simultaneous monitoring of viable and dead cells is possible with a fluorescence microscope. Using λex 545 nm, only dead cells can be observed.