SYTOX

SYTOX (also known as SYTOX Green) is a high-affinity nucleic acid stain developed by biotechnology company Molecular Probes. Because the stain only penetrates cells with compromised plasma membranes, it can be used to investigate antibacterial mechanism of action and confirm loss of bacterial viability. There have, however, been studies which confirm the use of SYTOX dyes for live cell imaging of bacteria.

A comprehensive Study of Thiazole-Orange-Based DNA Dyes were published, involving SYBR Safe, SYBR Green, PicoGreen, SYTO-16, SYTO-9 and a new derivative TOPhBu. Here, the synthesis of these compounds are published and characterised spectro-scopically to quantify their fluorescence enhancement upon binding to double-stranded DNA. The ability of the dyes to detect DNA at low concentrations was evaluated using two new metrics, absolute fluorescence enhancement (AFE) and relativefluorescence enhancement (RFE). They were tested in qPCR experiments showing some important differences in the sensitivity and qPCR efficiency, which facilitate the DNA marker selection for analytical purposes.