Wednesday, October 13, 2010

‘Dead simple’ way to see atomic structure

Recently, I read an articel entitled, "‘Dead simple’ way to see atomic structure". It explained how scientists used a sheet of carbon, or one atom thick, researchers devised a new technique to have a more visual picture of the structure of molecules. What they were going for was to obtain the first direct pictures of how water coats surfaces are at room temperature and how they can be used to come up with some kind of image of a potentially unlimited number of other molecules. They wanted the image to include antibodies and other biomolecules.

James Heath, a professor of chemistry at the California Institute of Technology said, “Almost all surfaces have a coating of water on them, and that water dominates interfacial properties” and “in constant flux, and don’t sit still long enough to allow measurements.” Professor James Heath really was only explaining how hard it was to study because interfacial properties affect the wear and tear the surface and also the water molecules don't stay still enough for them to actually sit there and study them.

Amazingly, Professor Heath and his colleages ACCIDENTALY came down with a technique to pin down the moving molecules. Heath and colleagues captured and trapped the water, after they thought the anomalies might be water, under the graphene. He said, “It was a happy accident—one that we were smart enough to recognize the significance of. We were studying graphene on an atomically flat surface of mica and found some nanoscale island-shaped structures trapped between the graphene and the mica that we didn’t expect to see.”

The researchers did experiments where they deposited the graphene sheets at varying humidity levels. At higher hjmidity the odd structures became more prevalent but disappeared when in completely dry conditions. This lead the researchers to believe that they were water molecules covered by the graphene. They realized that the graphene sheet was “atomically conformal” which meant it warpped around the water molecules tightly enough to reveal their detailed atomic structure. All of this was examined with atomic force microscopy though.

Still continuing with the technique researchers have learned new details about how water coats surfaces. They found out that the first layer of water on mica is really two water molecules thick, and has the structure of ice. Once that layer is fully formed two molecule thick layer of ice forms. On top of that you get droplets. Now, the  researchers are working on improving the resolution of the technique. By doing this it could be used to send out a better picture of the atomic structure of biomolecules like antibodies and other proteins.

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