Trx-red (NBL-SS perchlorate) is a red-emitting fluorescent probe derivatized from the nile blue fluorophore. Trx-red is used for selectively imaging thioredoxin (Trx) in live cells and in vivo (Λex=615 nm, Λem=661 nm)[1].
Trx-red (NBL-SS) displayed multiple favorable properties, such as red emission, fast response, and high fluorescence signal. Thioredoxin (Trx) is a ubiquitous redox-regulating protein essentially involved in cell growth, differentiation, and death[1]. When HeLa cells are incubated with Trx-red (NBL-SS; 5 μM; 0-30 min), a clear time-dependent increase of the fluorescence is observed[1].
Trx-red (NBL-SS; 10 μM; 30 min) is also suitable to image thioredoxin in 6 day-old zebrafish larvae[1].
[1]. Huiyi Jia, et al. Fluorophore-Dependent Cleavage of Disulfide Bond Leading to a Highly Selective Fluorescent Probe of Thioredoxin. Anal Chem. 2019 Jul 2;91(13):8524-8531.