Visualization of plasma membrane compartmentalization by high-speed quantum dot tracking.

In this study, we have imaged plasma membrane molecules labeled with quantum dots in live cells using a conventional wide-field microscope with high spatial precision at sampling frequencies of 1.75 kHz. Many of the resulting single molecule trajectories are sufficiently long (up to several thousand steps) to allow for robust single trajectory analysis. This analysis indicates that a majority of the investigated molecules are transiently confined in nanoscopic compartments with a mean size of (100–150 nm)(2) for a mean duration of 50–100 ms.