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High Resolution Fluorescence Microscopy Wins Nobel Prize and a Place in the Central Microscopy Research Facility

Date: Friday, October 24, 2014


The new STED system attains resolution below the diffraction limit of regular fluorescence microscopy by using using a depletion laser to shrink the fluorescing area of a specimen. Tom Moninger of the CMRF says “The Leica SP8 STED 3x system is a super-resolution microscope is based on the STED (STimulated Emission Depletion) principle developed by Nobel Prize laureate Stefan Hell. It is a purely optical technique that is not dependent on post-processing to general sub-diffraction resolution. The SP8 STED microscope, recently installed in the University of Iowa’s Central Microscopy Research Facility, is equipped with a 660 nm depletion laser. The system has a guaranteed resolution of 50 nm though investigators have been routinely achieving 40 nm. Both STED and standard confocal imaging modes are available.”

STED diagram

The SP8 STED is equipped with multiple excitation lasers including a continuum fiber laser that can deliver up to 8 simultaneous lines of any wavelengths between 470 and 670 nm. A 405 nm diode laser efficiently excites DAPI and other short wavelength fluorophores. A high-power argon ion laser is also available for rapid bleaching in support of FRAP and other dynamic experiments.

The SP8 STED light path is based on Acousto-Optic Modulators and contains no traditional fixed filter elements. Excitation wavelengths and emission bands are freely tunable. The microscope has 4 detectors, two PMTs and two high-sensitivity Hybrid detectors.

[STED System in CMRF] All visible light fluorophores can be optimally imaged in confocal mode. Alexa 532 and tetramethylrhodamine are ideal STED fluorophores. YFP, Venus and mStrawberry are excellent STED fluorescent proteins. Please contact Tom Moninger if you have any questions about the Leica SP8 STED system or would like a demonstration.