CyQUANT™ Cell Proliferation Assays

Since the amount of DNA in cells is highly regulated, methods to detect DNA content offer improved accuracy over metabolism-based cellular proliferation or cytotoxicity assays, which can be affected by cell changes that are unrelated to cell number. CyQUANT cell proliferation assays use cell-permeant, DNA-binding dyes that enhance fluorescence when bound to nucleic acids to measure cellular DNA content. The resulting fluorescent signal can be compared to standards to determine cell number, enabling fast and sensitive microplate assays to measure cell proliferation and cytotoxicity.

Choose from a range of CyQUANT cell proliferation assays based on experimental needs and workflows.

The CyQUANT and CyQUANT NF (No Freeze) cell proliferation assays provide cell proliferation measurements based on the total cell count, including both live and dead cells. The CyQUANT Direct Cell Proliferation Assay only detects live, healthy cells by using a masking dye that blocks staining of dead cells with compromised membranes, providing measurement of both cellular proliferation and cytotoxicity.

CyQUANT Cell Proliferation Assay

The CyQUANT Cell Proliferation Assay (Cat. No. C7026) enables precise DNA measurement for total cell count using the green-fluorescent CyQUANT GR dye and allows for the convenient freezing and storage of samples for up to four weeks. Easily compare multiple samples with minimal hands-on time by freezing, lysing, and reading fluorescence on a standard microplate reader.

Features of the CyQUANT Cell Proliferation Assay include:

• Direct DNA measurement—utilizes the green-fluorescent CyQUANT GR dye (ex/em 480/520 nm), a proprietary dye with strong fluorescence enhancement when bound to nucleic acids, for accurate measurement of DNA content to count both live and dead cells
• Broad linear range—quantify 50 to 50,000 cells per well without relying on metabolic activity
• Quickly compare samples—compare multiple samples in a microplate format with minimal hands-on time; simply remove media, freeze and lyse cells, then read fluorescence on a standard microplate reader with a fluorescein filter
• Convenient sample storage—freeze and store time course samples for up to four weeks, enabling batch analysis and direct comparison of samples taken at different time points
• Comprehensive kit—includes the CyQUANT GR dye, cell lysis buffer, and bacteriophage λ DNA as a reference standard; extra CyQUANT Cell Lysis Buffer available separately (Cat. No. C7027)

CyQUANT NF (No Freeze) Cell Proliferation Assay

The CyQUANT NF (No Freeze) Cell Proliferation Assay (Cat. Nos. C35006 and C35007) offers a streamlined protocol for total cell count by eliminating the freeze-thaw cell lysis step of the original CyQUANT Cell Proliferation Assay using a cell-permeant DNA-binding dye and a plasma membrane permeabilization/dye delivery reagent. This sensitive and rapid cell counting assay provides a wide detection range and is completed in just one hour without the need for cell lysis.

Features of the CyQUANT NF Cell Proliferation Assay include:

• Streamlined protocol—eliminates the freeze-thaw cell lysis step using the cell-permeant and green-fluorescent CyQUANT NF DNA-binding dye (ex/em 480/520 nm) in combination with a plasma membrane permeabilization reagent for accurate measurement of DNA content to count both live and dead cells
• Wide detection range—linear detection range from 100 to 20,000 cells per well in a 96-well microplate
• Sensitive and rapid assay—more sensitive than MTT or alamarBlue™ assays, complete proliferation protocol in just one hour
• No cell lysis required—eliminates the need for cell lysis, long incubations, radioactivity, or stain removal

CyQUANT Direct Cell Proliferation Assay

The CyQUANT Direct Cell Proliferation Assay (Cat. Nos. C35011, C35012, and C35013) provides a simple, no-wash, add-and-read workflow ideal for high-throughput screening cellular proliferation and cytotoxicity assays. This assay uses a green- or red-fluorescent cell-permeant DNA-binding probe that enters all cells and a cell-impermeant background suppressor that blocks staining in dead cells or cells with compromised membranes, ensuring that only live, healthy cells are stained. The assay measures changes in cell proliferation as well as cytotoxicity to allow for accurate assessment of cell growth, viability, and compound toxicity.

Features of the CyQUANT Direct Cell Proliferation Assay include:

• Dual measurement—assesses both cell proliferation and membrane integrity, staining only live, viable cells
• Convenient workflow—no washes, cell lysis, temperature equilibrations, or radioactivity required; ideal for high-throughput screening
• Two fluorescent options—available in green CyQUANT Direct (ex/em 508/527 nm) and red CyQUANT Direct Red (ex/em 622/645 nm) for multiplexing with other fluorescent dyes or proteins; can switch between HTS and HCS plate readers if multiplex assays require different platforms
• Wide detection range—linear detection from less than 100 to 20,000 cells per well in most cell types
• Rapid and easy protocol—no-wash, homogeneous format with a fast proliferation protocol; simply mix the probe and suppressor, add to cells, incubate for one hour, and measure fluorescence
• Stable signal—fluorescent signal remains stable for several hours, providing workflow flexibility
• Multiplexing capability—compatible with spectrally distinct fluorescent probes or luminescence assays because cells are not lysed, allowing use with different platforms
• Correlation with metabolic assays—excellent concordance with metabolism- or energy (ATP)-based cell health assays for reliable comparison of historical data