A dual-response triphenylamine-based fluorescent probe for selective sensing of copper(II) and nitric oxide in live cells

• The fluorescent probe ( BQ ) possesses bi-functional properties and can selectively recognize Cu 2+ and NO. • BQ realized the detection of Cu 2+ and NO by the photoinduced electron transfer (PET) and the intramolecular charge transfer (ICT) mechanisms, respectively. • BQ specifically responses to Cu 2+ and NO with perfect selectivity, fast response time and reliability in broad pH range. • The fluorescent imaging function of BQ for Cu 2+ and NO tracking in RAW 264.7 cells has been successfully realized. The development of bifunctional fluorescent probes for rapid and sensitive detection of copper(II) and nitric oxide (NO) in vivo is of significant importance to better understand their roles in human health. In this paper, a novel dual-response triphenylamine-based fluorescent probe, BQ , was developed for the detection of Cu 2+ and NO in live cells. The sensing mechanism of the probe towards Cu 2+ can be attributed to the photoinduced electron transfer (PET) process of BQ- Cu 2+ , resulting in the remarkable quenching of the fluorescence emission. Meanwhile, the addition of NO can make the fluorescent wavelength of the probe red shift due to the intramolecular charge transfer (ICT) effect of BQ- NO, and the sensing mechanisms of BQ towards Cu 2+ and NO have been further confirmed by 1 H NMR and the high resolution mass spectrometry (HR-MS) analysis and the density functional theory (DFT) theoretical computation. Furthermore, BQ has the obvious advantages of high sensitivity, rapid fluorescent response, and reliability at physiological pH towards Cu 2+ and NO. It is noteworthy that BQ can be used as a sensor for the detection of Cu 2+ and NO in live RAW 264.7 cells by fluorescence imaging. A novel dual-response triphenylamine-based fluorescent probe, BQ , has been synthesized for the detection of Cu 2+ and NO. The recognition mechanism can be attributed to Cu 2+ can initiate the PET process of BQ , resulting in the remarkable quenching of the emission spectra. However, NO can enhance the ICT effect of BQ , resulting in red shift of emission spectrum. The superiority of the proposed probe, including high sensitivity, reliability at physiological pH, rapid fluorescence response and biocompatibility. More importantly, BQ was successfully applied to image Cu 2+ and NO in RAW 264.7 cells.