Assay Kits

Cell Viability & Cytotoxicity Assay Kits

SensoLyte® Assay kits for Cell Viability, Proliferation and Cytotoxicity

Cell health and metabolism can be affected by physical and chemical agents via a variety of mechanisms such as destruction of cell membranes, prevention of protein synthesis, or irreversible binding to receptors and so on. The monitoring of cell viability, proliferation and cytotoxicity is key to understanding cell health for basic research, toxicology and pharmacological studies.

These assays are widely used to study the impact of chemicals such as pollutants and pesticides on cells and for drug screening. In particular, these assays are used in cancer research and cancer drug discovery to evaluate both compound toxicity and tumor cell growth inhibition during drug development.

AnaSpec features Calcein AM and Lactate dehydrogenase(LDH)/Resorufin fluorescent based assay kits for easy and reliable monitoring of cell viability, proliferation and cytotoxicity.


  • Safety – non-radioactive, non-toxic
  • Convenience – Ready-to-use reagents, no labeling required
  • Accuracy – Correlate well with traditional isotope-based assays
  • High throughput screening of cell proliferation or cytotoxicity effect of a variety of compounds


Calcein AM assay

The SensoLyte® Calcein Cell Viability Assay Kit is a rapid and sensitive assay to detect viable cells, and can be used to study cell proliferation, cell cytotoxicity, cell invasion, cell adhesion and cell migration (chemotaxis).

Non-fluorescent Calcein AM is a cell-permeable compound that is converted to fluorescent Calcein, when hydrolyzed by intracellular esterases of living cells. The intensity of calcein’s bright green fluorescence is proportional to the number of live cells present and can be monitored at Ex/Em=494nm/520 nm.

Calcein is also photostable, is not influenced by intracellular pH and does not affect cell proliferation or cell viability.

Lactate dehydrogenase (LDH) activity measurement


Sensolyte™ Cell Viability and Cytotoxicity Assay Kits use a sensitive fluorimetric indicator, resazurin, to measure the activity of lactate dehydrogenase (LDH) in cytoplasm (for live cells) or the medium (for dead cells). The measurement of LDH activity is a well-substantiated method for the quantification of viable cell numbers and the monitoring of cell proliferation. The presence of cytoplasmic LDH in the culture medium caused by the damage of cell membrane integrity is a measurable indicator of cell death and cytotoxicity.


FRET substrates

FRET occurs between a peptide tagged to a donor and an acceptor when placed within 10-100Å of each other resulting in the donor’s excitation fluorescence to be quenched by the acceptor. Enzymatic hydrolysis of the peptide results in recovery of the donor fluorescence following spatial separation of the donor and acceptor upon energy transfer.

Dye (donor) Quencher (acceptor) Donor Ex/Em
SensoLyte® 390 Mca Dnp

 325/393 nm

SensoLyte® 490 EDANS DABCYL

 340/490 nm

SensoLyte® 520 5-FAM or HiLyte™ Fluor 488 QXL®520

 494/521 nm

SensoLyte® 570 5-TAMRA QXL®570

 547/574 nm


Fluorogenic substrates

These substrates do not require a quencher and contain a C-terminal dye that does not fluoresce until it is cleaved from the peptide (fluorescent form of dye is released).

Dye (donor) Donor Ex/Em
SensoLyte® AMC AMC

 351/430 nm

SensoLyte® AFC AFC

 382/480 nm

SensoLyte® Rh110 Rh110

 501/527 nm

  • Assay Kits

    Cell Biology & Protein analysis tools

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  • Catalog Peptides

    Comprehensive listing of signaling peptides

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