Cyanoditolyl tetrazolium chloride has been used to measure the redox activity of tumor cells. It has also been employed for direct epifluorescent microscopic enumeration of respiring bacteria in food samples and environmental samples, especially water samples. Reveals a quantitative methodology for measuring marine bacteria. These methods yield 80% activity in 2 to 10 minutes. Cell samples mixed with CTC can be stored refrigerated or frozen in liquid nitrogen for at least 4 weeks without a significant loss of cells.

Micrograph: E.coli bacteria in CTC

Formazan fluoresces in solid state Exc max: 450nm Emiss max: 630nm