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The graphene layer enables advances in high-resolution microscopy



  Graphene layer enables advances in high-resolution microscopy
Left: Illustration of individual molecules on the graphene layer. With such images, scientists can determine the position and orientation for each molecule. The comparison with the expected image (right) shows an excellent match. Picture credits: University of Göttingen

Researchers at the University of Göttingen have developed a new method that uses the unusual properties of graphene to interact electromagnetically with fluorescent (light-emitting) molecules. For the first time, this method allows scientists to optically measure extremely small distances of the order of 1

angstrom (one ten-billionth of a meter) with high accuracy and reproducibility. This allowed researchers to visually measure the thickness of lipid bilayers that make up the membranes of all living cells. The results were published in Nature Photonics .

Researchers at the University of Göttingen, led by Professor Enderlein, used a single graphene layer as thin as one atom (0.34 nm) thick to modulate the emission of light-emitting (fluorescent) molecules as they approached the graphene layer. The excellent optical transparency of graphene and its ability to modulate the emission of molecules across space made it an extremely sensitive tool for measuring the distance of individual molecules from the graphene layer. The accuracy of this method is so good that even the smallest changes in the distance of 1 angstrom can be resolved. The scientists were able to demonstrate this by depositing individual molecules over a graphene layer. They could then determine their distance by monitoring and evaluating their light emission. This graphene-induced modulation of molecular light emission provides an extremely sensitive and precise "ruler" for determining single-molecule positions in space. Using this method, they measured the thickness of individual lipid bilayers, which consist of two layers of fatty acid chain molecules and have a total thickness of only a few nanometers.

"Our method therefore has tremendous potential for high-resolution microscopy, allowing us to locate single molecules with nanometer resolution not only laterally (as in previous methods), but also with similar accuracy along the third direction, giving a true three-dimensional optical Figure on the length scale of macromolecules allows, "says Arindam Ghosh, the first author of the work.

"This will be a powerful tool with numerous applications to resolve distances with subnanometer accuracy in single molecules, molecular complexes, or small cellular organelles," adds Professor Jörg Enderlein, the corresponding author and director of publication, of the Third Institute for Physics (biophysics), on which the work took place.

  Graphene layer allows progress in high-resolution micrometers oscopy
A dye-labeled membrane in polarized light (arrow). This shows that molecules are aligned along the circumference of the membrane. Picture credits: University of Göttingen


Synthesis of monocrystalline hexagonal graphene quantum dots


Further information:
Arindam Ghosh et al., Graphene-based metal-induced energy transfer for optical localization in the subnanometer range, Nature Photonics (2019). DOI: 10.1038 / s41566-019-0510-7

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University of Göttingen




Quote :
Graphene Layer Enables Progress in High-Resolution Microscopy (2019, 3 September)
retrieved on 4 September 2019
from https://phys.org/news/2019-09-graphene-layer-enables-advance-super-resolution.html

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