Ion-Switchable Quantum Dot Forster Resonance Energy Transfer Rates in Ratiometric Potassium Sensors

TitleIon-Switchable Quantum Dot Forster Resonance Energy Transfer Rates in Ratiometric Potassium Sensors
Publication TypeJournal Article
Year of Publication2016
AuthorsRuckh, TT, Skipwith, CG, Chang, W, Senko, AW, Bulovic, V, Anikeeva, PO, Clark, HA
JournalAcs Nano
Pagination4020 - 4030
Date Published2016/04//
ISBN Number1936-0851
Keywordsbulk optodes, chemical-analysis, fluorescent indicator, fret, gcamp calcium indicator, ion sensing, nanosensor, optical nanosensors, optode, pebble sensors, purkinje-cells, quantum dot, selective electrodes, single living cells, sodium

The tools for optically imaging cellular potassium concentrations in real-time are currently limited to a small set of molecular indicator dyes. Quantum dot-based nanosensors are more photostable and tunable than organic indicators, but previous designs have fallen short in size, sensitivity, and selectivity. Here, we introduce a small, sensitive, and selective nanosensor for potassium measurements. A dynamic quencher modulates the fluorescence emitted by two different quantum dot species to produce a ratiometric signal. We characterized the potassium-modulated sensor properties and investigated the photonic interactions-within the sensors. The quencher's protonation changes in response to potassium, which modulates its Forster radiative energy transfer rate and the corresponding interaction radii with each quantum dot species. The nanosensors respond to changes in potassium concentrations typical of the cellular environment and thus provide a promising tool for imaging potassium fluxes during biological events.

Short TitleACS Nano