A NIR dual-channel fluorescent probe for the detection of cyanide in living cells

This study details the design and synthesis of a near-infrared (NIR) dual-channel cyanide detection fluorescent probe based on triphenylamine-hemicyanine. TPA-CY successfully utilizes the NIR fluorescence properties of triphenylamine-hemicyanine conjugates, showcasing good selectivity and sensitivity, facilitating the visual monitoring of cyanide anions in living cells. Interaction between TPA-CY and CN^- occurs rapidly, within a mere 25 s. The sensitivity of TPA-CY to cyanide ions is good, with detection thresholds reaching 0.60 µM and 0.66 µM for UV and fluorescence spectra, respectively. The detection mechanism of this probe is the nucleophilic addition of CN^- to the C = N bond, which hindered intramolecular charge transfer. Moreover, the probe's efficacy in tracking cyanide radicals in biological systems is validated through live cell imaging.