Methylglyoxal (MGO), a ubiquitous metabolite produced by living cells, plays a poorly understood role in numerous diseases, such as diabetes, and is implicated in chemotherapy resistance. Until now, there hasn’t been a good way to monitor MGO in living cells. David A. Spiegel and Tina Wang of Yale University and colleagues have synthesized a molecule that selectively attaches to MGO and renders the complex fluorescent (J. Am. Chem. Soc. 2013, DOI: 10.1021/ja406077j). This development could allow scientists to begin studying MGO’s biological actions in situ. The fluorescent sensor, methyl diaminobenzene-BODIPY, or MBo, is a derivative of another fluorescent marker that is used to detect NO. The researchers demonstrated the effectiveness of the sensor in cell cultures: They soaked living cells in MBo, then treated them with MGO. The more MGO they added, they found, the brighter the sensor fluoresced. The researchers also note that the sensor is highly selective for MGO over other dicarbonyls and experiences minimal interference from NO in cellular settings. Paul J. Thornalley, at the University of Warwick, in England, notes that, although promising, the sensor needs to be improved for practical use.