Fluorescence Quenchingof Quantum Dots by Gold Nanoparticles:A Potential Long Range Spectroscopic Ruler.

Thedependence of quantum dot (QD) fluorescence emission on theproximity of 30 nm gold nanoparticles (AuNPs) was studied with controlledinterparticle distances ranging from 15 to 70 nm. This was achievedby coassembling DNA-conjugated QDs and AuNPs in a 1:1 ratio at precisepositions on a triangular-shaped DNA origami platform. A profound,long-range quenching of the photoluminescence intensity of the QDswas observed. A combination of static and time-resolved fluorescencemeasurements suggests that the quenching is due to an increase inthe nonradiative decay rate of QD emission. Unlike FRET, the energytransfer is inversely proportional to the 2.7th power of the distancebetween nanoparticles with half quenching at ∼28 nm. This long-rangequenching phenomena may be useful for developing extended spectroscopicrulers in the future. [ABSTRACT FROM AUTHOR]