Acceptor-donor-acceptor structured deep-red AIE photosensitizer: Lysosome-specific targeting, in vivo long-term imaging, and effective photodynamic therapy

Photosensitizers (PSs) with aggregation-induced emission (AIE) feature show promising applications in fluorescence imaging-guided photodynamic therapy (PDT) in virtue of their enhanced fluorescence and phototoxicity in aggregate state. Seeking the ideal AIE luminogens (AIEgens) with good capability of generating reactive oxygen species is still urgent. Here we rationally synthesized an acceptor-donor-acceptor (A-D-A) structured AIEgen (BTZPP) and then prepared it into nanoparticles (NPs) through a simple re-precipitation procedure. The obtained BTZPP NPs show a deep-red emission peaked at 635 nm, a large Stokes shift of 195 nm, and a high 1O2 generation quantum yield of 72.3%. Moreover, these NPs can selectively target lysosomes in live cells and image mouse tumor with a high contrast and long-term tracking (up to 14 days) capability. The high-efficiency imaging-guided PDT against cancer cells and tumors is successfully demonstrated in vitro and in vivo.