Fluorescent ion-selective nanosensors for intracellular analysis with improved lifetime and size.

We describe the synthesis and characterization of sodium-selective polymeric nanosensors that improves upon the lifetime and size of previous fiberless nanosensors. Sonication is used to form the polymer nanospheres that contain all the components needed for ion sensing. Even though the size is small (approximately 120 nm), the lifetime of these sensors in solution is on the order of a week. The surface coating has also been optimized for stability, biocompatibility, and ease of chemical modification.