CellEvent Senescence Green Flow Cytometry Assay Kit can analyze cells by detecting the hydrolytic activity of β-galactosidase senescence. The kit contains optimized buffers and fluorescein-based reagents, which contain two galactopyranoside groups and are specific targets of β-galactosidase. Activation of β-galactosidase is often used as a biomarker of senescent cells. This hydrolase is located in lysosomes and converts β-galactoside to monosaccharides under acidic pH conditions. The digested product remains in the cell due to covalent binding to intracellular proteins and emits a fluorescence signal with an upper absorption/emission wavelength of 490/514 nm.

CellEvent Senescence Green Flow Cytometry Detection Kit features include:
•Flow cytometry analysis to detect fluorescence emitted by β-galactosidase hydrolysis
•Fixed cell detection
•Multiple Color Compatible

Normal cells have a limited lifespan. When they reach their value-added limit (often called the Hayflick limit), they begin to enter the senescence stage, during which they maintain metabolic activity and cell death does not occur. These senescent cells have specific phenotypic characteristics, such as the appearance of multinucleated cells, increased vacuolation, expression of pH-dependent β-galactosidase, and morphological changes in cell enlargement and elongation. They may play a role in tumor suppression, tumor progression, aging, and tissue repair through multiple mechanisms.

Beta-galactosidase is present in lysosomes and converts beta-galactosidase into monosaccharides under acidic pH conditions. Lysosome activity is better at pH 4, but routine measurements are usually performed at pH 6. Studies have shown that β-galactosidase activity in senescent cells is generally twice that of presenescent cells, regardless of the pH used in the assay.

Traditionally, the chromogenic substrate of β-galactosidase, 5-bromo-4-chloro-3-indole-β-D-galactopyranoside (x-gal), is often used to detect cells in vitro metabolic activity. After hydrolysis by β-galactosidase, x-gal will produce a blue precipitate, which is not suitable for flow cytometry analysis. Therefore, we developed a sensitive fluorescent substrate for β-galactosidase that can be used for flow cytometry analysis to detect senescent cells.