RESOLFT Optical Nanoscopy with Organic and Inorganic Dyes

A/Professor Peng Xi
Depatment of Biomedical Engineering, Peking University, China

10:30 am Friday, 11 April 2014, EN101 Lecture Theatre (EN Building), Hawthorn.

Conventional optical microscopy, although been widely applied in biological research, can only yield optical resolution approaching the Abbe diffraction limit of ~200 nm. This is still larger than many subcellular organelles whose size is in a few to tens of nanometers. These limitations have driven the development of super-resolution optical imaging methodologies over the past decade.
REversible/Saturable OpticaL Fluorescence Transitions (RESOLFT) is one of the technique that utilizes spatially designed pattern to shrink the effective fluorescence point spread function (PSF). One of the RESOLFT technique, stimulated emission depletion (STED) microscopy, uses the overlap between the excitation focus and an intense doughnut-shaped spot, to instantly de-excite markers from their fluorescent state to the ground state by stimulated emission process. Yet, since the organic dye is prone to the ON-OFF process of STED, they suffer from photobleaching severely in STED nanoscopy. The alternatives include the approach of inorganic dye which is non-photobleachable, or other means to turn the peripherial off. For example, fluorescent nano-diamond (FND) is a good candidate for its photostability.
In this work, we present the application of RESOLFT nanoscopy in subcellular organelle imaging. STED and SIM super-resolution techniques are compared with FND nanoparticles as well as bulk FNDs grown in a large diamond. Also, we present our recent advance on the application of upconversion nanoparticles on optical nanoscopy.

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