Selective and sensitive determination of real-time Butyrylcholinesterase activity via Phenoxy 1,2-dioxetane-based chemiluminescent probe

Butyrylcholinesterase (BChE), or pseudo-cholinesterase, is one of the significant cholinesterases in the human body with a diverse substrate range and function area. It plays crucial roles in numerous physiological and pathological processes, including regulation of acetylcholine, detoxification of poisons, metabolism of drugs, regulation of fat metabolism, and beyond. Accordingly, it is an essential yet challenging target for bioimaging studies. Several methods and small molecule probes have been proposed for BChE activity detection and measurement so far. However, they suffered from either low detection limits, inadequate selectivity or method-intrinsic drawbacks. Herein, we have presented a BChE-responsive chemiluminescent probe, BCC, based on a phenoxy 1,2-dioxetane core with an electron-withdrawing acrylic group for monitoring BChE activity in native biological contexts; thus, we have introduced the first-ever example of a chemiluminescence-based bioimaging technic for the visualization of BChE activity. BCC generated a selective and sensitive turn-on response with BChE but not with competitive analytes in aqueous solutions. BCC was successfully utilized to measure and visualize endogenous BChE activity in normal and cancerous cell lines without showing any toxicity. Inhibition studies have proven that BCC can detect fluctuations in BChE levels precisely. BChE in healthy mice models has been visualized in distinct body regions, from the liver to the brain, as BCC could pass through the blood-brain barrier. Likewise, tumours grown on mouse models derived from neuroblastoma cells have been pictured with a very high signal-to-noise ratio. Hence, BCC stood out as a promising chemiluminescent probe for selective and sensitive detection of BChE, which can be used to further understand its contribution to regular biological processes and the formation of diseases.