Peptide-aggregation-induced emission (AIE) luminogen (AIEgen) conjugates are widely used in the bioimaging field for their good resistance to photobleaching, red and near-infrared light emission, good biocompatibility, etc. However, their
peptides are mainly negatively charged and the positively charged
peptide-AIEgen conjugates are rarely used in in vivo imaging due to their high non-specific interaction with
protein to cause "false-positive" results and their potential risk of triggering
hemolysis. Herein, we introduce a black hole quencher 3 (BHQ3) to RVRRGFF-AIE (FA) to build a "turn-on" probe, named BHQ3-RVRRGFF-AIE (BFA). Compared with FA, BFA has advantages in the anti-interference ability for different
proteins and many
solution environments. But, both BFA and FA have high risks of inducing
hemolysis, which restricts their further application. Through co-assembly with poly-γ-
glutamic acid (γ-
PGA),
molecular probes BFA and FA are formed into
PGA-BFA and
PGA-FA nanoparticles with high biocompatibility and suppressed
phototoxicity. Cell studies show that
PGA-BFA can discriminate
cancer cells with high
furin expression from low
furin-expressed
cancer cells and normal cells. In vivo studies show that
PGA-BFA can light up tiny
tumors in the abdominal cavity with a better
tumor-to-intestine ratio (3.14) than that of
PGA-FA (1.47), which is helpful for the accurate excision of tiny
tumors. This study will advance the development of constructing good biosafety probes with a high signal-to-noise ratio for fluorescence image-guided
cancer surgery.