Matthew effect: General design strategy of ultra-fluorogenic nanoprobes with amplified dark–bright states in aggregates

Abstract

Fluorescence imaging, a key technique in biological research, frequently utilizes fluorogenic probes for precise imaging in living systems. Tetrazine is an effective emission quencher in fluorogenic probe designs, which can be selectively damaged upon bioorthogonal click reactions, leading to considerable emission enhancement. Despite significant efforts to increase the emission enhancement ratio (I_AC/I_BC) of tetrazine-functionalized fluorogenic probes, the influence of molecular aggregation on the emission properties has been largely overlooked in these probe designs. In this study, we reveal that an ultrahigh I_AC/I_BC can be realized in the aggregate system when tetrazine is paired with aggregation-induced emission (AIE) luminogens. Tetrazine amplifies its quenching efficiency upon aggregation and drastically reduce background emissions. Subsequent click reactions damage tetrazine and trigger significant AIE, leading to considerably enhanced I_AC/I_BC. We further showcase the capability of these ultra-fluorogenic systems in selective imaging of multiple organelles in living cells. We term this unique fluorogenicity of AIE luminogen-quencher complexes with amplified dark-bright states as “Matthew effect” in aggregate emission, potentially providing a universal approach to attain ultrahigh I_AC/I_BC in diverse fluorogenic systems.