A polydiacetylenes-based sensor for the efficient detection of phospholipase D activity

Phospholipase D (PLD), as an enzyme that catalyses the hydrolysis of L-α-phosphatidylcholine to produce phosphatidic acid, plays an important role in regulating biological processes. In this work, polydiacetylenes (PDAs) bearing imidazolium as head group are reported for the efficient detection of PLD activity. Owing to the strong interaction between negatively charged phosphatidic acid and positively charged imidazolium moieties of PDAs, the PDAs were found to produce a colour transition from blue to red, and an increase in fluorescence. No obvious changes to PDAs were observed when PLD was absent in the reaction, or when the activity of PLD was inhibited by halopemide. The colour and fluorescence changes of PDAs are attributed to the generation of phosphatidic acid in the PLD-catalysed reaction. Furthermore, a paper sensor based on PDAs was constructed and exhibited convenient and sensitive detection of PLD activity.