Approximately twenty years ago,
Gerd Binnig and Heinrich Rohrer
published images from their new
invention, the scanning tunneling
microscope (STM), which was the
first scanning probe microscope
(SPM) ever developed [Binnig,
1982]. Their new instrument was
able to resolve atomic structures
by raster scanning a conductive
tip, mounted on a ceramic piezo-
electric element, over a conductive
sample. The incredible resolution
of this new microscope was met
with great enthusiasm within the
international scientific community
and laboratories throughout the
world began building similar
instruments. The implications of a
high-resolution imaging tool that
could operate under ambient con-
ditions were not lost on biologists,
who quickly teamed with physicists
to develop new STM techniques
to apply to biological samples.