Adv. Funct. Mater. 24, 4796–4803 (2014)

Fluorescent semiconductor quantum dots are potentially useful as labelling and tracking agents within cells due to the broad range of available emission colours, their photostability and high photoluminescence efficiency. However, the temporal 'blinking' of their emission limits the duration of the tracking. Now, Aaron Keller and co-workers from Los Alamos National Laboratory, the US Naval Research Laboratory and the University of New Mexico Health Services Center have used giant non-blinking dots to get around the problem. The team used thick-shell dots made from a 4 nm core of CdSe surrounded by a shell of 16 monolayers of CdS. The resulting giant quantum dots were approximately 15 nm in size. The dots were then used as an optical label for three-dimensional tracking of single proteins in live cells, in particular the IgE-FcεRI receptor. Results showed a sevenfold increase in the probability of observing IgE-FcεRI for longer than one minute when using the giant dots rather than their conventional counterparts.