“Matthew Effect in Aggregate Emission”: General Design Strategy of Fluorogenic Bioorthogonal Nanoprobes with Ultrahigh Emission Enhancement

Fluorescent imaging, a key technique in life science research, frequently utilizes fluorogenic probes for precise imaging in living systems. Tetrazine is an effective emission quencher in the design of fluorogenic probes, which can be selectively damaged upon bioorthogonal click reactions, leading to considerable emission enhancement. Despite significant efforts to increase the emission enhancement ratio (IAC/IBC) of tetrazine-functionalized fluorogenic probes, the influence of molecular aggregation on the emission properties has been largely overlooked in the design of these probes. In this study, we reveal that an ultrahigh IAC/IBC can be realized in the aggregate system when tetrazine is paired with aggregation-induced emission luminogens (AIEgens). Tetrazine can increase its quenching efficiency upon aggregation and drastically reduce background emissions. Subsequent click reactions damage tetrazine and trigger significant AIE, leading to considerably enhanced IAC/IBC. We further showcase the capability of these ultra-fluorogenic systems in selective imaging of multiple organelles in living cells. We propose the term "Matthew Effect in Aggregate Emission" to describe the unique fluorogenicity of these probes, potentially providing a universal approach to attain ultrahigh emission enhancements in diverse fluorogenic aggregate systems.