Dresden 2003 – wissenschaftliches Programm

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O: Oberflächenphysik

O 18: Rastersondentechniken II

O 18.4: Vortrag

Dienstag, 25. März 2003, 12:00–12:15, M\"UL/ELCH

High-Resolution Near-Field Optical Imaging of Single Nuclear Pore Complexes — •Christiane Höppener, Daniel Molenda, Harald Fuchs, and Andreas Naber — Physikalisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, 48149 Münster

The nuclear envelope (NE) of a cell nucleus is perforated by macromolecular protein assemblies. These nuclear pore complexes (NPCs) regulate the exchange of all kind of molecules between the cytoplasm and the nucleus in an eukaryotic cell. For the investigation of the translocation mechanism in such pores a technique is required which has the ability to distinguish single NPCs within a fully native membrane. Scanning near-field optical microscopy (SNOM) provides a high optical resolution capability far below the diffraction limit and is therefore principally able to optically resolve single NPCs of Xenopus laevis with a nearest neighbor distance of ∼ 120 nm . A tapping mode like force distance control based on a quartz tuning fork [1] enables us to perform SNOM measurements in a liquid environment with almost the same sensitivity as under ambient conditions. By means of this technique we were able to take fluorescence images of a native NE in liquid with an optical resolution of ∼ 60 nm. These images show for the first time optically resolved single NPCs in their native environment.

[1] A. Naber, H.-J. Maas, K. Razavi, and U.C. Fischer, Rev. Sci. Instrum. 70, 3955 (1999).