Advancement in super-resolution microscopy through the use of a graphene layer.

Graphene constitutes a single layer of atoms in a two-dimensional hexagonal lattice in which one atom forms each vertex, is an allotrope of carbon. Graphene has long been studied since its initial observation by electron microscopes in 1962.

In the past, it was microscopy that taught the world about graphene and now, it is graphene which is pushing the microscopy forward to new heights. Recently, the researchers at the University of Göttingen have created a new method to take advantage of the properties of graphene to interact it with light-emitting molecules. Doing this allowed the scientists for the first time to optically measure extremely small distances, in the order of 1 ångström (one ten-billionth of a meter), with high accuracy and reproducibility, which in turn, allowed the scientists to measure the thickness of the single lipid bilayers. Lipid bilayers are the things which are responsible for making the membranes of all living cells. According to the results, the lipid bilayers which are made up of two layers of fatty acid chain molecules have a total thickness of only a few nanometers (1 billionth of a meter). All of the results were published in the journal Nature Photonics.

The team of researchers led by Professor Enderlein utilized a single sheet of graphene with a thickness of an atom (0.34 nm), to modulate the emission of fluorescent (light-emitting) molecules when they came near the graphene sheet. The superior optical transparency of graphene and its modulation capabilities make it an extremely sensitive tool for measuring the distance of single molecules from the graphene sheet. This method is so accurate that even the most slight distance changes of around 1 ångström can be resolved. The scientists were able to demonstrate this by depositing single molecules above the graphene layer, by determining their distance by monitoring and evaluating their light emission.

Arindam Ghosh, the first author of the paper said,”Our method has enormous potential for super-resolution microscopy because it allows us to localize single molecules with nanometre resolution not only laterally (as with earlier methods) but also with similar accuracy along the third direction, which enables true three-dimensional optical imaging on the length scale of macromolecules.”

“This will be a powerful tool with numerous applications to resolve distances with sub-nanometer accuracy in individual molecules, molecular complexes, or small cellular organelles,” added Professor Jörg Enderlein, the publication’s corresponding author and head of the Third Institute of Physics (Biophysics) where the work took place.

Purushottam Gaurav

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