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[1] and confirm loss of bacterial viability.[2][3] There have, however, been studies which confirm the use of SYTOX dyes for live cell imaging of bacteria.[4]