Rebecca Medda

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We introduce far-field fluorescence nanoscopy with ordinary fluorophores based on switching the majority of them to a metastable dark state, such as the triplet, and calculating the position of those left or those that spontaneously returned to the ground state. Continuous widefield illumination by a single laser and a continuously operating camera yielded(More)
Cholesterol-mediated lipid interactions are thought to have a functional role in many membrane-associated processes such as signalling events. Although several experiments indicate their existence, lipid nanodomains ('rafts') remain controversial owing to the lack of suitable detection techniques in living cells. The controversy is reflected in their(More)
We report stimulated emission depletion (STED) fluorescence microscopy with continuous wave (CW) laser beams. Lateral fluorescence confinement from the scanning focal spot delivered a resolution of 29-60 nm in the focal plane, corresponding to a 5-8-fold improvement over the diffraction barrier. Axial spot confinement increased the axial resolution by(More)
The use of high numerical aperture immersion lenses in optical microscopy is compromised by spherical aberrations induced by the refractive index mismatch between the immersion system and the embedding medium of the sample. Especially when imaging >10 micro m deep into the specimen, the refractive index mismatch results in a noticeable loss of image(More)
We report attainment of subdiffraction resolution using stimulated emission depletion (STED) microscopy with GFP-labeled samples. The approximately 70 nm lateral resolution attained in this study is demonstrated by imaging GFP-labeled viruses and the endoplasmic reticulum (ER) of a mammalian cell. Our results mark the advent of nanoscale biological(More)
We demonstrate far-field fluorescence microscopy with a focal-plane resolution of 15-20 nm in biological samples. The 10- to 12-fold multilateral increase in resolution below the diffraction barrier has been enabled by the elimination of molecular triplet state excitation as a major source of photobleaching of a number of dyes in stimulated emission(More)
Details about molecular membrane dynamics in living cells, such as lipid-protein interactions, are often hidden from the observer because of the limited spatial resolution of conventional far-field optical microscopy. The superior spatial resolution of stimulated emission depletion (STED) nanoscopy can provide new insights into this process. The application(More)
We demonstrate nanoscale resolution in far-field fluorescence microscopy using reversible photoswitching and localization of individual fluorophores at comparatively fast recording speeds and from the interior of intact cells. These advancements have become possible by asynchronously recording the photon bursts of individual molecular switching cycles. We(More)
Current far-field fluorescence nanoscopes provide subdiffraction resolution by exploiting a mechanism of fluorescence inhibition. This mechanism is implemented such that features closer than the diffraction limit emit separately when simultaneously exposed to excitation light. A basic mechanism for such transient fluorescence inhibition is the depletion of(More)
We report on fast beam-scanning stimulated-emission-depletion (STED) microscopy in the visible range using for resolution enhancement compact, low cost and turn-key continuous wave (CW) fiber lasers emitting at 592 nm. Spatial resolutions of 35 to 65 nm in the focal plane are shown for various samples including fluorescent nanoparticles, immuno-stained(More)