Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

From Microscopy to Nanoscopy

10.08.2007
Photoswitchable rhodamine amides for high-resolution optical 3D far-field microscopy

Layer-by-layer light microscopic nanoscale images of cells and without having to prepare thin sections?

A team led by Stefan Hell and Mariano Bossi at the Max Planck Intstitute for Biophysical Chemistry in Göttingen is now leading the way with a technique called optical 3D far-field microscopy—with nanoscale resolution, good signal-to-noise ratio, and relatively short exposure times.

The secret of their success lies in special photoswitchable fluorescence dyes, the researchers report to the journal Angewandte Chemie. These rhodamine amides make it possible to obtain highly resolved 3D images of transparent fluorescence-marked samples such as living cells.

... more about:
»Photon »amides »rhodamine »switched »wavelength

Until fairly recently, the resolution of light microscopes was limited by the wavelength of the light. This means that details finer than 200 nanometers (millionths of millimeters) cannot be observed. There are non-optical methods, such as electron microscopy, but light microscopy is still the only way to observe the interior of whole, or even living, cells. The use of fluorescent dyes makes it possible to selectively obtain images of individual cell components, for example, proteins. Today, the wavelength dogma is overcome.

Hell received the German Future Prize in 2006 for the first concept breaking the wavelength barrier the stimulated emission depletion (STED) microscope . Molecules are transferred from a “dark” (non-fluorescent) to a “bright” (fluorescent) excited energy state—with a spacial sharpness far beyond those 200 nanometers.

Now the german team is demonstrating the power of another concept. They use molecules that are not only transferred but can be “switched” from “fluorescent” to “non-fluorescent” and back. In contrast to the STED and other related methods of the team, only separate, isolated marker molecules are randomly switched on at the same time. Their fluorescence is registered, and then they get switched off again automatically. In this way, the simultaneously fluorescing (switched on) markers are farther apart from each other than the minimum distance that the microscope can resolve.

This is only possible using switchable molecules that emit many photons, one after the other, when switched on. If these photons are captured with a camera, the centers of the individual fluorescing dots can be distinguished. After the exposure, the molecule becomes dark again (switches off), allowing further, neighboring molecules to be photographed. This process is repeated many times, until many dots become a picture. The full distribution can be reconstructed—at a resolution not limited by the wavelength of light.

The researchers have now found a class of substances that fulfill all the requirements of this technique: rhodamine amides. At the core of these molecules lies a system of five rings. In this form, the compound is colorless and does not fluoresce. Irradiation with light induces an isomerization in which one of the rings is opened. This form of the molecule is red and can be excited several times.

Most importantly: rhodamine amides can be switched on by either a UV photon or two photons in the red part of the spectrum. This two-photon excitation can be focused onto a thin plane, which allows biological samples to be photographed layer by layer. The individual images can then be reconstructed into a single multilayer image. The resolution reached in the focal plane is far beyond the diffraction barrier (10–30 nm).

Author: Stefan W. Hell, Max-Planck-Institut für Biophysikalische Chemie, Göttingen (Germany), http://www.mpibpc.gwdg.de/abteilungen/200/

Title: Photochromic Rhodamines Provide Nanoscopy with Optical Sectioning

Angewandte Chemie International Edition 2007, 46, No. 33, 6266–6270, doi: 10.1002/anie.200702167

Stefan W. Hell | Angewandte Chemie
Further information:
http://www.mpibpc.gwdg.de/abteilungen/200/
http://pressroom.angewandte.org

Further reports about: Photon amides rhodamine switched wavelength

More articles from Life Sciences:

nachricht 'Lipid asymmetry' plays key role in activating immune cells
20.02.2018 | Biophysical Society

nachricht New printing technique uses cells and molecules to recreate biological structures
20.02.2018 | Queen Mary University of London

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

'Lipid asymmetry' plays key role in activating immune cells

20.02.2018 | Life Sciences

MRI technique differentiates benign breast lesions from malignancies

20.02.2018 | Medical Engineering

Major discovery in controlling quantum states of single atoms

20.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>