A Fluorogenic Labeling of Live Viruses

Viruses are an important class of pathogens that can cause serious infectious diseases. The ability to directly analyze viral particles in real time is essential to understand their pathological functions. In this work, we developed a strategy for fluorogenic labeling of live viruses by using an optimal tetrazolate-functionalized AIEgen (Aggregation-induced emission luminogen), named PBET. Due to its AIE activities, this dye fluoresces weakly when dissolved in aqueous solution, thus providing dark fluorescence background. The fluorescence turn-on labeling is achieved by binding of PBET molecules into the outmost viral proteins (e.g., structural Capsid protein VP1), which triggers protein-induced fluorescence enhancement (PIFE) of PBET. Probably due to this PIFE/AIE-based sensing strategy, these PBET-labeled viruses can retain infectivity to a large extent, which is a great advantage for biologically friendly labeling. This fluorogenic labeling may find uses in imaging studies to combat virus-associated infectious diseases, especially those associated with previously unknown wild-type viruses.