A Fluorescent Probe for Pyrophosphate Based on Tetraphenylethylene Derivative with Aggregation-Induced Emission Characteristics

In this work, a fluorescent probe (TPE-DPA) with aggregationinduced emission (AIE) characteristics was prepared for detecting pyrophosphate (PPi) by attaching a dipicolylamine (DPA) unit into tetraphenylethylene (TPE) group. TPE-DPA exhibits intense green emission in aqueous media because of the formation of the nanoaggregates. In the presence of Cu2+, the emission of TPE-DPA can be effectively quenched due to the formation of complex TPE-DPA/Cu2+. However, upon addition of PPi, the fluorescence can be selectively recovered because of the higher affinity between Cu2+ and PPi, and thus release of TPE-DPA. The detection limit for PPi by using TPE-DPA/Cu2+ is as low as 56 nM. Importantly, this strategy can be utilized for real-time monitoring the alkaline phosphatase (ALP) activity and for imaging of PPi in living cells.