The core component of the water-soluble tetrazolium-8 CCK-8 kit, WST-8

WST-8 is a highly sensitive chromogenic reagent for cell metabolism, primarily used for precise detection of cell proliferation, toxicity, and viability. It is the core component of the most widely used CCK-8 kits in life science laboratories.

1. Basic product information

Chemical name: 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazole monosodium salt

Common abbreviation: WST-8 or Water-soluble tetrazolium-8

CAS number: 193149-74-5

Appearance: white to light yellow crystalline powder

Solubility: extremely soluble in water and PBS buffer solution (excellent water solubility)

II. Core Principles and Applications

WST-8 is an oxidation-reduction indicator.

Principle: Under the action of dehydrogenase and electron carriers (such as 1-Methoxy PMS) in the mitochondria of living cells, WST-8 is reduced to a water-soluble yellow formazan dye.

Quantitative relationship: The greater the number of living cells, the more vigorous the metabolism, the more yellow dye produced, and the darker the solution color. By reading the absorbance with a microplate reader, the relative number or activity of cells can be accurately calculated.

Core advantages (compared to traditional MTT method):

High water solubility: The product dissolves directly in water without the need to add organic solvents, greatly simplifying the operation steps and reducing cytotoxicity.

High sensitivity: With strong detection signals, it is more sensitive than MTS and XTT, making it suitable for the detection of a small number of cells or cells with slow proliferation.

Cell-friendly: It exhibits extremely low cytotoxicity, allowing the cells to be recovered and reused in other experiments (such as flow cytometry and PCR) after detection.

Good stability: The reagent kit can be directly added to the cell culture plate, and readings can be taken directly after incubation, making it suitable for high-throughput screening.

III. Main application areas

1. Basic medical and biological research (the primary scenario)

Cell proliferation assay: Investigating the effects of growth factors, cytokines, and gene overexpression/silencing on cell growth rate.

Cytotoxicity/Drug Sensitivity Testing: Assessing the cytotoxic effects of chemotherapy drugs, compounds, serum, viruses, etc. on cells (IC50 determination).

Cell viability/survival rate analysis: Assess the survival status of cells after treatments such as resuscitation, cryopreservation, radiation, and hypoxia.

High-throughput drug screening: used in pharmaceutical companies for large-scale screening of anti-tumor and antibacterial candidate compounds.

2. Other applications

Microbial activity detection: used to detect the number of viable bacteria, fungi, and other microorganisms or their metabolic activity.

Study on antioxidant capacity: As an indicator, it detects the ability of the sample to scavenge free radicals.

IV. Summary

WST-8 (26913-06-4) is a high-performance, water-soluble tetrazolium salt chromogenic reagent. Specifically designed for cell biology experiments, it serves as the core ingredient in the CCK-8 cell proliferation/toxicity assay kit. Due to its high sensitivity, excellent water solubility, and low toxicity, it has fully replaced the traditional MTT method and become the gold standard tool for cell function research and drug screening in global scientific research and pharmaceutical laboratories.