A quinoline-based indicator for NAD(P)H multimodal detection in vitro and in vivo: Spectrophotometry and visible near-infrared dual-channel lighting-up fluorescence imaging

Nicotinamide adenine dinucleotide (phosphate) (NAD(P)H/NAD(P)+) is crucial for oxidation-reduction equilibrium in all living cells, and disturbance of NAD(P)H/NAD(P)+ indicates many diseases. To accurately detect and track NAD(P)H in vitro and in vivo, we have developed a small organic dye (Rh-QL) based on intramolecular charge transfer (ICT) mechanism for multimodally detecting NAD(P)H by visible and near-infrared (Vis-NIR) dual-channel lighting-up fluorescence and by near-infrared spectrophotometry. This quinoline-based Indicator showed high selectivity and sensitivity toward NAD(P)H with a large redshift of absorption and dual-channel emissions at 580 nm and 750 nm, spatiotemporally and synchronously. For liquid samples, Rh-QL succeeded to screen NAD(P)H-related G6PD enzymatic activity by responsive absorption at 710 nm. In living cells, Rh-QL exhibited a good bio-compatibility and remarkable mitochondrial-targeted capacity to visualize intracellular endogenous and exogenous NAD(P)H variation utilizing Vis-NIR dual-channel fluorescence. In vivo, the near-infrared fluorescence was applied to differentiate tumor-bearing mice by NAD(P)H imaging. Moreover, “glycolysis” in both cancer cells and tumors of mice were traced to produce extra NAD(P)H using Rh-QL. As the first Vis-NIR dual-channel lighting-up probe to multimodally detect and track NAD(P)H in vitro and in vivo, it is appealing for high efficiency in understanding NAD(P)H-related physiological and pathological processes of disease diagnosis and therapy. [Display omitted] •A visible and near-infrared dual-emitting fluorescence probe (Rh-QL) was developed to multimodally detect NAD(P)H.•Fluorescence emitted at 580 nm and 750 nm, spatiotemporally and synchronously, with high selectivity, sensitivity.•G6PD enzymatic activity was screened successfully by the responsive absorption at 710 nm.•Rh-QL succeeded to visualize intracellular NAD(P)H variation with bio-compatibility and mitochondrial targeted capacity.•Rh-QL was successfully applied to differentiate tumor-bearing mice and traced NAD(P)H level by NAD(P)H imaging in vivo.