Invited Paper IPF-MoM9
Intracellular Fluorescence Imaging at Nanometer Resolution

Monday, October 20, 2008, 11:00 am, Room 312

Fluorescence microscopy, is usually limited in its ability to resolve and focus on features smaller than the optical diffraction limit. However special photoactivated fluorescent proteins can be harnessed in a technique called Photo-Activated Localization Microscopy, PALM. Successive sparse subsets of these fluorescent proteins can be activated, imaged, individual molecules localized and their coordinates accumulated and rendered into a PALM image. Thereby the distribution of labeled endogenous proteins can be seen with the resolution of an electron microscope. PALM images of protein location and organization are illustrated with mitochondria, lysosomes, actin networks, focal adhesions and other cell structures. Another technique, an interferometric microscope, is described that can measure the vertical position of fluorescent molecules to nanometer precision with high photon efficiency. This can be combined with PALM to give full 3 dimensional molecular coordinates of proteins with ~ 20 nm resolution.