Ion-Switchable Quantum Dot Förster Resonance Energy Transfer Rates in Ratiometric Potassium Sensors.
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 Förster 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.
['Ruckh|Timothy T|TT|', 'Skipwith|Christopher G|CG|', 'Chang|Wendi|W|', 'Senko|Alexander W|AW|', 'Bulovic|Vladimir|V|', 'Anikeeva|Polina O|PO|', 'Clark|Heather A|HA|']
D015374:Biosensing Techniques D005453:Fluorescence D031541:Fluorescence Resonance Energy Transfer D005456:Fluorescent Dyes D057809:HEK293 Cells D006801:Humans D007477:Ions D007700:Kinetics D018613:Microscopy, Confocal D061848:Optical Imaging D010316:Particle Size D011188:Potassium D045663:Quantum Dots D013499:Surface Properties
quantum dot nanosensor FRET ion sensing optode