Microscope gains a fourth dimension

Compiled by BioPhotonics staff

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 nanoparticle.

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.