LAUSR

Activatable chemiluminescent probes that showed enhanced chemiluminescence upon interaction with a molecular target of interest have offered promising tools for sensing and bioimaging in terms of low background, high sensitivity and im-proved penetration depth in biological tissues. Here, we reported a γ-Glutamyl transpeptidase (GGT) activatable chemilumi-nescent probe for real-time detection of GGT activity in vitro and in living mice. The probe was designed by caging an elec-tron-withdrawing acrylic group-substituted Schaap's phenoxy-dioxetane with a GGT-recognitive substrate (γ-Glu) and a self-immolative linker (p-aminobenzyl alcohol, PABA), which was initially chemiluminescence off. Upon interaction with GGT, strong chemiluminescence with a more than 800-fold turn-on ratio could be achieved in aqueous solution, allowing to spe-cifically detect GGT activity with ultrahigh signal-to-background ratio and sensitivity in vitro and in live cells. We demon-strated that the probe was reliable to quantify the GGT in serum, permitting to accurately report the elevated levels of GGT in lipopolysaccharide (LPS)-treated mice serum. Moreover, through real-time chemiluminescence imaging of GGT activity, the designed probe was feasible to detect GGT-positive tumors in living mice after intravenous (i.v.) systemic administration. This study demonstrates the high potential of GGT-activatable chemiluminescent probe for serum assays and molecular imaging, which might find wide applications in diagnosis of GGT-related diseases.