An aldehyde group-based P-acid probe for selective fluorescence turn-on sensing of cysteine and homocysteine

Under the optimized conditions, the fluorescence response of probe is directly proportional to the concentration of Cys in the range of 4-95 nM L−1, with a detection limit 3.0 nM. In addition, the sensing system exhibits good selectively toward Cys and Hcy in the presence of other amino acids. It has been successfully applied for bioimaging of Cys and Hcy in living cells with low cell toxicity.