Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Novel High-Resolution Methods in Fluorescence Microscopy

03.03.2011
Heidelberg scientists employ chemical reaction for light-independent switching of fluorescent probes

Physical limits in high-resolution light microscopy can be overcome with the aid of chemical reactions. Scientists at Heidelberg University’s Institute of Physical Chemistry and members of the Cluster of Excellence “CellNetworks” have devised a new method in which light-dependent processes are replaced by chemical reactions to mark cellular structures for high-resolution optical microscopy. This method opens up new application vistas for fluorescence microscopy. The findings have been published online in the journal “Angewandte Chemie International Edition”.



The fluorescent signals from two nearby objects are superimposed by diffraction and imaged as a single feature. The ability to image individual probes separately means that their positions can be determined much more accurately to reconstruct the whole structure.

Fluorescence microscopy is a widely used method for studying cellular structures. However, the so-called diffraction limit prevents detailed examination of these structures. Objects separated by less than 0.3 μm from one another cannot be resolved. Recently, different methods have been reported to overcome this limit, among them stochastic optical reconstruction microscopy (STORM). Here the cell structures are labelled with fluorescent dyes that respond with fluorescence emission upon stimulation by light of a certain wavelength. High resolution of approx. 0.02 μm can be achieved by switching off the majority of the dyes and leaving only a small number of them on. In this way, the light emitted by neighbouring dyes is no longer superimposed. This dye-switching is also controlled by light. The dyes left on can now be individually resolved and their positions can be determined by mathematical analysis to a very high accuracy of approx. 0.003 μm. Multiple repetition of this procedure supplies precise information about the location of all the dyes, thus permitting high-resolution reconstruction of the cell structures under investigation.

This method puts several demands on the microscope and the light sources used. Switching the respective dyes requires either different laser lines (excitation wavelength) or high light intensities or both. This can lead to problems in the investigation of living cells. Accordingly, the team headed by Heidelberg chemist Dr. Dirk-Peter Herten has replaced the switching of dyes via laser light with a light-independent process. To this end, the scientists adjusted a chemical probe for the detection of copper ions in such a way that the probe and its fluorescent properties can be used to mark cellular structures. If copper(II) binds to the probe, its fluorescence is suppressed. This binding of the copper(II) ion is reversible, thus restoring the fluorescence of the probe. The microscopic investigation of cell structures is therefore controlled by a reversible chemical reaction.

The scientists have called this method CHIRON – chemically improved resolution for optical nanoscopy. According to Dr. Herten, it means that microscopy methods like STORM can be simplified to such an extent that additional laser lines and high light intensities become superfluous. All that is required is for the probe to be located in a cellular environment to which minimal amounts of copper sulphate can be added, e.g. fixed cells. “This opens up new applications for high-resolution microscopy that were formerly impracticable due to technical restrictions,” says Dr. Herten. “Our probes can be used on many microscopes.”

For more information, go to
http://www.bioquant.uni-heidelberg.de/research/groups/single_molecule_spectroscopy.html.
Note for news desks:
Digital photo material is available from the Press Office.
Original publication
M. Schwering, A. Kiel, A. Kurz, K. Lymperopoulos, A. Sprödefeld, R. Krämer, D.-P. Herten: Far-Field Nanoscopy with Reversible Chemical Reactions / Hochauflösende Mikroskopie mit reversiblen chemischen Reaktionen. Angewandte Chemie International Edition, 15 February 2011, doi: 10.1002/anie.201006013
Contact:
Dr. Dirk-Peter Herten
Cluster of Excellence “CellNetworks”
Institute of Physical Chemistry
phone: +49 6221 5451220
dirk-peter.herten@urz.uni-hd.de
Communications and Marketing
Press Office, phone: +49 6221 542311
presse@rektorat.uni-heidelberg.de

Marietta Fuhrmann-Koch | idw
Further information:
http://www.uni-heidelberg.de
http://www.bioquant.uni-heidelberg.de/research/groups/single_molecule_spectroscopy.html

More articles from Physics and Astronomy:

nachricht From Hannover around the world and to the Mars: LZH delivers laser for ExoMars 2020
21.11.2017 | Laser Zentrum Hannover e.V.

nachricht Taking a spin on plasma space tornadoes with NASA observations
20.11.2017 | NASA/Goddard Space Flight Center

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Antarctic landscape insights keep ice loss forecasts on the radar

20.11.2017 | Earth Sciences

Filling the gap: High-latitude volcanic eruptions also have global impact

20.11.2017 | Earth Sciences

Water world

20.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>