title: Axial resolution enhancement by 4Pi confocal fluorescence microscopy with two-photon excitation.
abstract: Confocal fluorescence microscopy and two-photon microscopy have become important techniques for the three-dimensional imaging of intact cells. Their lateral resolution is about 200-300 nm for visible light, whereas their axial resolution is significantly worse. By superimposing the spherical wave fronts from two opposing objective lenses in a coherent fashion in 4Pi microscopy, the axial resolution is greatly improved to approximately 100 nm. In combination with specific tagging of proteins or other cellular structures, 4Pi microscopy enables a multitude of molecular interactions in cell biology to be studied. Here, we discuss the choice of appropriate fluorescent tags for dual-color 4Pi microscopy and present applications of this technique in cellular biophysics. We employ two-color fluorescence detection of actin and tubulin networks stained with fluorescent organic dyes; mitochondrial networks are imaged using the photoactivatable fluorescent protein EosFP. A further example concerns the interaction of nanoparticles with mammalian cells.
authors: Institute of Biophysics, University of Ulm, 89069 Ulm, Germany.
authors: Sylvia
authors: S
authors: Glaschick
authors: Carlheinz
authors: C
authors: Röcker
authors: Karen
authors: K
authors: Deuschle
authors: Jörg
authors: J
authors: Wiedenmann
authors: Franz
authors: F
authors: Oswald
authors: Volker
authors: V
authors: Mailänder
authors: G Ulrich
authors: GU
authors: Nienhaus