Development of an ultrasensitive in vitro assay to monitor growth of primary cell cultures with reduced mitotic activity

Primary cell cultures, such as isolated epithelial cells, neuronal cells, or hepatocytes are characterized by a very low mitotic activity. Monitoring of small changes in cell numbers requires staining with a DNA-specific dye with an extremely high sensitivity and a low inter- and intraassay variability. For this purpose, an ultrasensitive in vitro assay has been developed based on the fluorescent nucleic acid stain PicoGreen™. PicoGreen™ has been shown to detect as little as 0.5 ng pure DNA or 10 2 cells (interassay SD