Maintenance notice in CEST time zone (1:00 - 3:30 AM August 16, 2026): Our website is scheduled for maintenance. The website will be available, but some functions may experience errors. We appreciate your patience and understanding.
Traditional cell counting methods take time and effort to carry out for any meaningful number of samples, making them unfeasible for large scale / high-throughput experiments such as screening methods. Spectrophotometric cell counting methods, however, due to their use of absorbance / fluorescence / chemiluminescence measurement as a direct representation of relative cell number, allow for high-precision results to be obtained with minimal time and effort on the part of the experimenter. Here at TCI, we offer all three: an absorbance-based cell counting reagent (Product No. M3353), a fluorescence-based cell counting reagent (Product No. R0195), and a chemiluminescence-based cell counting reagent (Product No. A3495 and A3519) to suit your individual needs.
ATP-Luciferase cell viability assay solution (Product No. A3519 and A3495) allows for the quick (on the order of 10 minutes) measurement of large numbers of samples at once.
This reagent is based on the chemistry of the firefly luciferase reaction. Luciferase oxidizes its substrate luciferin in the presence of ATP and molecular oxygen, giving off light of roughly 560nm in the process. The linearity of this luminescence is preserved over a wide range of ATP concentrations, and can be used as an indicator of relative ATP concentration over this range. As the intracellular concentration of ATP does not vary significantly over the course of the cell cycle, the luciferase reaction, used to determine intracellular ATP concentration, can be used to indirectly measure relative cell numbers.1,2) In the case of this reagent linearity is preserved for between 20 and 10000 cells per well of a 96-well plate.
Measurement of chemiluminescence means no special filters are required. Additionally, this reagent, when added directly to culture medium, produces a color change from red to yellow that can be used as a visual guide to prevent double-dispensing.
MTT is a type of tetrazolium salt that is converted into formazan when taken up by living cells. This formazan can be dissolved in DMSO and the absorbance at 540 nm can be used to estimate the relative number of cells. MTT solution (Product No. M3353) consists of 5.0 mg/mL MTT dissolved in PBS.
Resazurin can be used to determine relative cell number, useful in the quantification of such phenomena as cell proliferation, viability, and cytotoxicity. When added to viable cells, blue, non-fluorescent resazurin undergoes a conversion to a highly fluorescent derivative. Both resazurin and its derivative are water soluble and have low toxicity, making it simple to handle and eliminating the washing, fixing, and extraction steps required for other commonly used cell proliferation assays.
Add resazurin solution (Product No. R0195) at a volume equal to 10% of the cell culture medium volume.
Return cells to the incubator and continue the incubation for 2-24 hours.
Measure the fluorescence intensity using 540-570 nm excitation and 590 nm emission wavelengths. *Absorbance measurement may also be used in place of fluorescence measurement to estimate cell number – use a 570nm filter.
Your session will timeout in 10 minutes. You will be redirected to the HOME page after session timeout. Please click the button to continue session from the same page. minute. You will be redirected to the HOME page after session timeout. Please click the button to continue session from the same page.