The gratings themselves were so small that the dimensions had to be confirmed with atomic force microscopy.

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The team, which included French and Spanish collaborators, used a variant of a technique called atomic force microscopy, or AFM.

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To do this, the researchers adapted a device known as an atomic-force microscope.

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These are intended for use in flat-panel displays (in which the tips of the nanotubes are used to spray electrons on to individual phosphor elements of the screen) and atomic-force microscopes.

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Dr Hinterdorfer and his team tested this idea by applying a coating of an antigen (an enzyme called lysozyme) to a mica sheet, and suspending an appropriate antibody from the tip of an atomic-force microscope with a flexible polymer tether.

ECONOMIST: Microscopy