Scientific reports 2015-01-01

RESOLFT nanoscopy with photoswitchable organic fluorophores.

Jiwoong Kwon, Jihee Hwang, Jaewan Park, Gi Rim Han, Kyu Young Han, Seong Keun Kim

Index: Sci. Rep. 5 , 17804, (2015)

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Abstract

Far-field optical nanoscopy has been widely used to image small objects with sub-diffraction-limit spatial resolution. Particularly, reversible saturable optical fluorescence transition (RESOLFT) nanoscopy with photoswitchable fluorescent proteins is a powerful method for super-resolution imaging of living cells with low light intensity. Here we demonstrate for the first time the implementation of RESOLFT nanoscopy for a biological system using organic fluorophores, which are smaller in size and easier to be chemically modified. With a covalently-linked dye pair of Cy3 and Alexa647 to label subcellular structures in fixed cells and by optimizing the imaging buffer and optical parameters, our RESOLFT nanoscopy achieved a spatial resolution of ~74 nm in the focal plane. This method provides a powerful alternative for low light intensity RESOLFT nanoscopy, which enables biological imaging with small organic probes at nanoscale resolution.