Table 15.2 Molecular Probes assay kits for cell viability, cell counting and bacterial gram staining.

Cat. No. Kit Name Kit Components # Assays Assay Principle
Assay Kits for Mammalian Cells
L3224 LIVE/DEAD Viability/Cytotoxicity Kit 1000 microscopy assays, 1000 microplate assays or 300 flow cytometry assays Membrane-permeant calcein AM is cleaved by esterases in live cells to yield cytoplasmic green fluorescence, and membrane-impermeant ethidium homodimer-1 labels nucleic acids of membrane-compromised cells with red fluorescence.
L7013 LIVE/DEAD Reduced Biohazard Cell Viability Kit #1 100 microscopy assays or 100 flow cytometry assays Membrane-permeant SYTO 10 dye labels the nucleic acids of live cells with green fluorescence, and membrane-impermeant DEAD Red dye labels nucleic acids of membrane-compromised cells with red fluorescence. Subsequent fixation inactivates pathogens without distorting the staining pattern.
L23105
L34957
L34959
L34955
L23101
L23102
L10120
L10119
L34960
LIVE/DEAD Fixable Dead Cell Stain Kits * 200 flow cytometry assays (320 flow cytometry assays for the Sampler Kit L34960) Live cells react with the fluorescent reactive dye only on their surface to yield weakly fluorescent cells. Cells with compromised membranes react with the dye throughout their volume, yielding brightly stained cells. Subsequent fixation inactivates pathogens without distorting the staining pattern.
L7010 LIVE/DEAD Cell-Mediated Cytotoxicity Kit 2000 microscopy assays or 200 flow cytometry assays Target cells are preincubated with the green-fluorescent membrane stain DiOC18(3) and then mixed with effector cells in the presence of the red-fluorescent, membrane-impermeant propidium iodide. Live and dead target cells retain their green-fluorescent membrane stain; target and effector cells with compromised membranes exhibit red-fluorescent nucleic acid staining; live effector cells are nonfluorescent.
L7011 LIVE/DEAD Sperm Viability Kit 1000 microscopy assays or 200 flow cytometry assays Membrane-permeant SYBR 14 nucleic acid stain labels live sperm with green fluorescence, and membrane-impermeant propidium iodide labels the nucleic acids of membrane-compromised sperm with red fluorescence.
L34951 LIVE/DEAD Cell Vitality Assay Kit
  • Dodecylresazurin (C12-resazurin)
  • SYTOX Green nucleic acid stain
  • DMSO
  • Phosphate-buffered saline
  • Detailed protocols (Product Information Sheet)
1000 flow cytometry assays Metabolically active cells reduce C12-resazurin to red-fluorescent C12-resorufin, and cells with compromised membranes (usually late-apoptotic and necrotic cells) are labeled with the green-fluorescent SYTOX Green nucleic acid stain.
L34958 LIVE/DEAD Cell Vitality Assay Kit 200 flow cytometry assays Live cells are labeled with CellTrace calcein violet AM, and dead cells with the aqua-fluorescent reactive dye. Both stains are compatible with the 405 nm violet laser diode.
V23110 Vybrant Cell Metabolic Assay Kit 200 flow cytometry assays or 1000 microplate assays Nonfluorescent C12-resazurin is reduced to fluorescent C12-resorufin by viable cells; the resulting signal is proportional to the number of cells present.
V23111 Vybrant Cytotoxicity Assay Kit 1000 microplate assays Damaged and dying cells release glucose 6-phosphate into the surrounding medium, which is detected by an enzymatic process that leads to the reduction of resazurin into red-fluorescent resorufin.
Assay Kit for Yeast
L7009 LIVE/DEAD Yeast Viability Kit >1000 microscopy assays or 1000 microplate assays Plasma membrane integrity and metabolic function of fungi are required to convert the yellow-green–fluorescent intracellular staining of FUN 1 into red-orange–fluorescent intravacuolar structures; Calcofluor White M2R labels cell-wall chitin with blue fluorescence regardless of metabolic state.
L34952 LIVE/DEAD FungaLight Yeast Viability Kit *for flow cytometry* ~200 flow cytometry assays Membrane-permeant SYTO 9 dye generally labels all yeast in a population—those with intact membranes and those with damaged membranes. In contrast, propidium iodide penetrates only yeast with damaged membranes, causing displacement of the SYTO 9 stain.
F34953 FungaLight CFDA AM/Propidium Iodide Yeast Vitality Kit *for flow cytometry*
  • 5-carboxyfluorescein diacetate, acetoxymethyl ester (CFDA AM)
  • Propidium iodide
  • Dimethylsulfoxide (DMSO), anhydrous
  • Detailed protocols (Product Information Sheet)
~200 flow cytometry assays The cell-permeant CFDA AM is combined with the membrane integrity indicator propidium iodide to evaluate the vitality of yeast cells by flow cytometry or microscopy. With an appropriate stain mixture, esterase-active yeast with intact cell membranes stain fluorescent green, whereas yeast with damaged membranes stain fluorescent red.
Assay Kits for Bacteria
L7012 L7007 L13152 LIVE/DEAD BacLight Bacterial Viability Kit For Kit L7007 and L7012: >1000 microscopy assays, 1000 microplate assays or 200 flow cytometry assays

For Kit L13152: each applicator set allows ~1000 microscopy assays, 50 microplate assays or 10 flow cytometry assays

Membrane-permeant SYTO 9 dye labels live bacteria with green fluorescence; membrane-impermeant propidium iodide labels membrane-compromised bacteria with red fluorescence. In Kit L7007, the stains are supplied in a mixed, two-component formulation, whereas in Kit L7012 the stains are provided as separate solutions. In Kit L13152, the separate dyes are dry and premeasured into pairs of polyethylene transfer pipettes.
L34856 LIVE/DEAD BacLight Bacterial Viability and Counting Kit 100 flow cytometry assays Membrane-permeant SYTO 9 dye labels live bacteria with green fluorescence; membrane-impermeant propidium iodide labels membrane-compromised bacteria with red fluorescence. The calibrated suspension of polystyrene microspheres serves as a standard for the volume of suspension analyzed and is clearly distinguishable from stained bacteria in a fluorescence versus side scatter cytogram.
B34954 BacLight RedoxSensor Green Vitality Kit
  • RedoxSensor Green reagent
  • Propidium iodide, an indicator of membrane integrity
  • Sodium azide
  • Carbonyl cyanide 3-chlorophenylhydrazone (CCCP)
  • Detailed protocols (Product Information Sheet)
200 flow cytometry assays The RedoxSensor Green reagent reports reductase activity in both gram-positive and gram-negative bacteria (although differences in signal intensity may be observed based upon cell wall characteristics), providing an accurate view of this important aspect of bacterial vitality. Following reduction, the RedoxSensor Green reagent will produce a stable green-fluorescent signal (excitation/emission maxima ~490/520 nm) in 10 minutes that is compatible with formaldehyde fixation techniques.
B34956 BacLight RedoxSensor CTC Vitality Kit
  • 5-cyano-2,3-ditolyl tetrazolium chloride (CTC)
  • SYTO 24 green-fluorescent nucleic acid stain
  • 4',6-diamidino-2-phenylindole, dihydrochloride (DAPI)
  • Detailed protocols (Product Information Sheet)
50 tests by flow cytometry or microscopy

This kit contains 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) for detection of respiration-linked dehydrogenase activity. SYTO 24 and DAPI counterstains facilitate the differentiation of cells from debris and the calculation of total cell numbers.

B34950 BacLight Bacterial Membrane Potential Kit 100 flow cytometry assays

At low concentrations, DiOC2(3) exhibits green fluorescence in all bacterial cells, but it becomes more concentrated in healthy cells that are maintaining a membrane potential, causing the dye to self-associate and the fluorescence emission to shift to red. CCCP is included in the kit for use as a control because it eradicates the proton gradient, eliminating bacterial membrane potential.

V7023 ViaGram Red+ Bacterial Gram Stain and Viability Kit
  • DAPI
  • SYTOX Green nucleic acid stain
  • Texas Red-X conjugate of wheat germ agglutinin (WGA)
  • Sodium bicarbonate
  • BacLight mounting oil
  • Detailed protocols (Product Information Sheet)
200 microscopy assays Membrane-permeant DAPI labels live bacteria with blue fluorescence; membrane-impermeant SYTOX Green nucleic acid stain labels bacteria with compromised membranes with green fluorescence. Simultaneous Texas Red-X WGA staining produces red-fluorescent surface labeling of gram-positive bacteria.
L7005 LIVE BacLight Bacterial Gram Stain Kit >1000 microscopy assays, 1000 microplate assays or 200 flow cytometry assays When gram-negative and gram-positive bacteria are simultaneously stained with the membrane-permeant SYTO 9 dye and hexidium iodide, gram-negative bacteria fluoresce green and gram-positive bacteria fluoresce red.
B7277 Bacteria Counting Kit (Assays for Cell Enumeration, Cell Proliferation and Cell Cycle - Section 15.4) 100 flow cytometry assays The membrane-permeant SYTO BC stain labels both gram-positive and gram-negative bacteria with green fluorescence; the calibrated suspension of polystyrene microspheres serves as a standard for the volume of suspension analyzed.
ATP Assay Kit for All Cell Types
A22066 ATP Determination Kit
  • Luciferin
  • Luciferase
  • ATP
  • Dithiothreitol (DTT)
  • Reaction buffer
  • Detailed protocols ()
1000 microplate assays Luciferase catalyzes the chemiluminescent reaction of luciferin, ATP and oxygen, producing a photon and other chemical by-products. Stores of ATP are higher in viable cells; therefore, the signal strength correlates with population viability.
* The LIVE/DEAD Fixable Dead Cell Stain Kits are available in eight fluorescent colors (excitation/emission maxima): blue (350/450 nm, L23105), aqua (367/526 nm, L34957), yellow (400/575 nm, L34959), violet (416/451 nm, L34955), green (495/520 nm, L23101), red (595/615 nm, L23102), far red (650/665 nm, L10120) and near infrared (750/775 nm, L10119), as well as in the LIVE/DEAD Fixable Dead Cell Stain Sampler Kit (L34960), which contains all eight fluorescent fixable dead cell stains.