Intelligent Fluorescence Probe with Turn-on Properties By a See-Saw Balance of Visible and Near-infrared Fluorescence

Bioimaging requires probes for tracing, especially in the near-infrared (NIR) region. Herein, A Schiff base dye conjugated with both pyrene and a cyanine (cy7) NIR fluorophores has been synthesized, which showed a novel see-saw fluorescent performance via the combination of aggregation-induced emission (AIE) and aggregation-caused quenching (ACQ). The new dye is always switched on in terms of fluorescence by the see-saw balance of the visible and NIR fluorescence. The system is fluorescent in the visible region when it is it is its aggregated state as a result of AIE while it emits NIR fluorescence in the single molecule state. The as-prepared dye has many potential applications, especially in the field of bioimaging, which was confirmed by invitro cell experiments.