IBM Research (NYSE:
IBM) scientists, in collaboration with the Center for Probing the Nanoscale
at Stanford University, have demonstrated magnetic resonance imaging (MRI) with
volume resolution 100 million times finer than conventional MRI. VIDEO
This result, published in the Proceedings of the National Academy of Sciences
(PNAS), signals a significant step forward in tools for molecular biology and
nanotechnology by offering the ability to study complex 3D structures at the
By extending MRI to such fine resolution, the scientists have created a microscope
that, with further development, may ultimately be powerful enough to unravel
the structure and interactions of proteins, paving the way for new advances
in personalized healthcare and targeted medicine. This achievement stands to
impact the study of materials -- from proteins to integrated circuits -- for
which a detailed understanding of atomic structure is essential.
"This technology stands to revolutionize the way we look at viruses, bacteria,
proteins, and other biological elements," said IBM Fellow Mark Dean, vice
president of strategy and operations for IBM Research.
This advancement was enabled by a technique called magnetic resonance force
microscopy (MRFM), which relies on detecting ultrasmall magnetic forces. In
addition to its high resolution, the imaging technique has the further advantages
that it is chemically specific, can "see" below surfaces and, unlike
electron microscopy, is non-destructive to sensitive biological materials.
For more than a decade, IBM scientists have been making pioneering advances
in MRFM. Now, the IBM-led team has dramatically boosted the sensitivity of MRFM
and combined it with an advanced 3D image reconstruction technique. This allowed
them to demonstrate, for the first time, MRI on nanometer-scale biological objects.
The technique was applied to a sample of tobacco mosaic virus and achieved resolution
down to four nanometers. (One nanometer is one billionth of a meter; a tobacco
mosaic virus is 18 nanometers across.)
"MRI is well known as a powerful tool for medical imaging, but its capability
for microscopy has always been very limited," said Dan Rugar, manager of
nanoscale studies, IBM Research. "Our hope is that nano MRI will eventually
allow us to directly image the internal structure of individual protein molecules
and molecular complexes, which is key to understanding biological function."
The new device does not work like a conventional MRI scanner, which uses gradient
and imaging coils. Instead, the researchers use MRFM to detect tiny magnetic
forces as the sample sits on a microscopic cantilever -- essentially a tiny
sliver of silicon shaped like a diving board. Laser interferometry tracks the
motion of the cantilever, which vibrates slightly as magnetic spins in the hydrogen
atoms of the sample interact with a nearby nanoscopic magnetic tip. The tip
is scanned in three dimensions and the cantilever vibrations are analyzed to
create a 3D image.
IBM Research has a distinguished history in developing microscopes for nanoscale
imaging and science. IBM researchers Gerd Binnig and Heinrich Rohrer received
the 1986 Nobel Prize in Physics for their invention of the scanning tunneling
microscope, which can image individual atoms on electrically conducting surfaces.
Additionally, IBM has a track record dating back to the 1950s of improving
healthcare through scientific achievements and collaboration with healthcare
companies. In the last decade, IBM has developed a national digital mammography
archive with the University of Pennsylvania; developed a clinical trial participant
system with the Mayo Clinic; collaborated with Scripps to understand how influenza
viruses mutate and proactively develop treatments; collaborated with European
universities to develop better methods to decide on antiretroviral therapies
for HIV; launched the World Community Grid, which has done projects on cancer,
aids, dengue fever; and much more.