Real-time and in-situ intracellular ATP assay with polyimidazolium brush-modified nanopipette

The level and dynamics of adenosine 5'-triphosphate (ATP) in single living cells are closely related to many kinds of important physiological and pathological processes. Herein, we report a nanosensor based on polyimidazolium brush (PimB)-modified nanopipette for intracellular ATP assay, which shows good selectivity, high spatiotemporal resolution and excellent stability. Both the specific supramolecular interaction between polyimidazolium and ATP, and the rationally tunable property of the ion transport at a confined nanopipette enable the selective assay of ATP even in complex intracellular environment. Moreover, the tiny tip (ca.300 nm) and the low polarized current (e.g., 1 nA) essentially make the as-prepared nanosensor safe to the living cells. The nanosensor is demonstrated to be useful for in-situ monitoring the basal ATP levels of chromaffin cells from wild-type mice and DJ-1 knockout mice, and for real-time monitoring the metabolism process of intracellular ATP.