ASU researchers demonstrate new technique that improves the power of atomic force...( onents in an image he added. It mean...)

Atomic force microscopes provide images on the nanometer scale by using a highly sensitive and tiny probe that is essentially pulled across a surface. By doing this, researchers can obtain topographical images down to a nanometer scale.

To use the AFM in its new mode, the researchers attached antibodies keyed to individual proteins to the tip of an AFM's probe. When an antibody reacts with the protein it is specifically targeted for, it creates a variance in the microscope's reading compared to a reading with a bare tip, thus showing the presence of a protein or other specific material in the region being scanned.

To help ensure that the antibody tipped probe is truly sensitive, a strand of polymer connects the antibody to the tip, providing a tether that allows the antibody to wiggle into position to better connect with the protein receptors. A magnetically excited cantilever makes the tip oscillate up and down to make the antibody disconnect and reconnect and keep the probe moving.

A key capability of this technique, Lindsay said, is that it allows researchers to see how components of a cell react on a molecular scale when they experience biological processes, such as their response to a specific chemical or compound. In this mode, it could provide researchers with a molecular "time-lapsed movie" of such reactions, which could lead to greater understanding of the chemical dynamics involved in how cells react to such stimuli.

Lindsay said the new AFM method could be significant for drug discovery.

"This development opens up the AFM as a research tool," Lindsay added. "The ability to identify the specific proteins o
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Contact: Skip Derra
skip.derra@asu.edu
480-965-4823
Arizona State University
16-Aug-2004