Nanotechnology researchers at UC
Davis have shown that they can use a red blood cell to
calibrate a sensitive instrument, an atomic force microscope.
"It turns around the rules of nanotechnology, by using biology
to calibrate an instrument," said Volkmar Heinrich, assistant professor
in the Department of Biomedical Engineering at UC Davis and co-author
of the paper with graduate student Chawin Ounkomol.
An atomic force microscope uses a tiny lever that runs over
the surface of an object. Small deflections of the tip are read and
translated to produce an image of the object's surface. However,
accurate calibration of the springiness of the tip is difficult.
Heinrich and Ounkomol used individual red blood cells sucked
onto the end of a pipette to push the lever. The lab has previously
developed a model that calculates the exact forces needed to squeeze a
red blood cell by a certain amount. They could therefore use the red
blood cell to very accurately calibrate the springiness of the atomic
force microscope cantilever.
Heinrich does not see the technique as a new way to calibrate
these instruments, but it does show that the red blood cell can be used
as an accurate force transducer, he said, and could be used as a tool
to measure forces between individual molecules and cells or between
molecules. Those measurements can advance our understanding of cell
biology, for example how cancers spread or how immune cells enter
tissues to fight infection.
Posted 16th May 2008
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