Single-particle tracking of EGF via low density labeling with 20% aminoQD–SA. A single cell is shown in the imaging field (QD605 channel). Large patches of brightness represent autofluorescence, bright spots represent clusters of QDs, movie shows fluorescence intermittency of single QDs, which migrate in a manner consistent with active transport of labeled receptors. Scale bar, 5 µm.
ⓦ A movie in AVI format is available.