Probing Cellular Uptake of Nanoparticles, One at a Time

Advanced fluorescence microscopy is the method of choice to study cellular uptake of nanoparticles with molecular specificity and nanoscale resolution; yet, direct visualization of nanoparticles entry into cells poses severe technical challenges. Here, we have combined super-resolution photoactivation localization microscopy (PALM) with single particle tracking (SPT) to visualize clathrin-mediated endocytosis (CME) of polystyrene nanoparticles at very high spatial and temporal resolution.