'Matthew Effect': General Design Strategy of Fluorogenic Bioorthogonal Nanoprobes with Ultrahigh Emission Enhancement

Abstract

Fluorescence imaging frequently utilizes fluorogenic probes for precise imaging. Tetrazine is an effective emission quencher in the design of fluorogenic probes, which can be selectively damaged upon bioorthogonal click reactions, leading to turn-on emissions. Despite significant efforts to increase the emission enhancement ratio upon click reaction (IAC/IBC) of tetrazine-functionalized fluorogenic probes, influences of molecular aggregation on emission properties have been overlooked. In this study, we reveal that ultrahigh IAC/IBC can be realized in aggregate systems when tetrazine is paired with aggregation-induced emission (AIE) luminogens. Tetrazine increases its quenching efficiency upon aggregation and drastically reduces background emissions. Subsequent click reactions trigger 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 term "Matthew Effect" in Aggregate Emission to describe this unique fluorogenicity, potentially providing a universal approach to attain ultrahigh emission enhancements in diverse fluorogenic systems.

Keywords: Aggregation-induced emission, Nanomaterial, bioorthogonal chemistry, Click Chemistry, Tetrazine, Fluorescence Imaging