Ji, B. et al. Nat. Nanotechnol. 10, 170–175 (2015).

Quantum dots (QDs) are popular probes for imaging owing to their brightness and photostability. However, their environmental sensitivity and blinking properties limit their utility. Ji et al. sought to modify QDs to overcome these limitations. They encapsulated a QD first in amorphous silica and then in a gold nanoshell. The gold nanoshell serves two major functions. The first is to shield the QD from the environment, stabilizing its photophysical properties. The second is to act as a plasmonic resonator, which effectively eliminates the nonradiative processes that cause blinking. The result is a 'golden QD' that displays remarkably stable signal in single-particle spectroscopy experiments and that has higher photostability than unmodified QDs. This new class of QDs should expand the versatility of these probes for many biological applications.