Compiled by BioPhotonics staff
PASADENA, Calif. – Extending the technology of the three-dimensional
microscope, scientists have added a dimension that promises sweeping applications
in biological research, medicine and the development of new electronic devices.
The four-dimensional scanning ultrafast electron microscope was
developed by chemistry Nobel laureate Ahmed H. Zewail and his colleagues at California
Institute of Technology. They discovered a way to integrate time into traditional
electron microscopy observations, which resulted in the creation of high-resolution
images of vanishingly small nanoscale objects in four dimensions rather than three.
Their laser-driven technology enabled researchers to visualize
3-D structures such as a ring-shaped carbon nanotube as it wiggled in response to
heating, over a femtosecond timescale. Although they obtained 3-D information from
the approach, it was limited in that it showed the object as stationary rather than
undergoing its natural movements.
The scientists overcame the limitations using their 4-D scanning
ultrafast electron microscopy technique, which allowed deeper insights into the
innermost structure of materials. Their work, which appeared in two papers from
the Journal of the American Chemical Society (doi: 10.1021/ ja203821y and doi: 10.1021/ja2031322),
describes how the technique could be used to investigate atomic-scale dynamics on
metal surfaces, and to watch the vibrations of a single silver nanowire and a gold
The scientists said the new techniques hold promise for a variety
of applications, including single-particle biological imaging and materials science.
Funding for the work came from the National Science Foundation,
the US Air Force Office of Scientific Research, the Gordon & Betty Moore Physical
Biology Center at Caltech, and the Arab Fund for Economic and Social Development.