Cell-compatible Nanoprobes for Imaging Intracellular Phosphatase Activities.

Phosphatases play an important role in cell biology, but there are few suitable probes for selectively imaging phosphatase activity of live cells because the current probes require cell fixation or exhibit considerable cytotoxicity. Here we show that conjugating a D-peptide to a quinazolinone derivative generates cell-compatible, biostable probes for imaging phosphatase activities inside live cells. Moreover, our results show that inhibiting ectophosphatases is a critical factor for imaging intracellular phosphatases. As the first example of using selective inhibitors to ensure intracellular function of molecular probes, this work illustrates a facile approach to design molecular probes for profiling the activities of enzymes in spatial selective manner in a complicated environment.