The imaging performance of today's generation of Transmission Electron Microscopes
(TEMs) is improved dramatically through the use of a novel technique, the thin
film phase plate.
JEOL is the only electron
microscope supplier to offer commercially-available thin film phase plate technology
to its Life Sciences customers, in particular those involved in cryo-electron
microscopy and cryo-electron tomography. The phase contrast imaging capability
of a phase-plate outfitted JEOL TEM increases specimen contrast by orders of
While phase plate technology - invented by Frits Zernike and awarded the Physic
Nobel prize in 1953 - is an accepted tool for live-cell imaging with the light
microscope (LM), it is a novel approach to imaging with the TEM. Similar to
the LM application, the TEM application employs a -phase plate that shifts the
phase of only the scattered electrons, resulting in amplitude contrast rather
than phase contrast as these electrons interfere with the unscattered electrons
in the image plane (See Fig. 1).
“Nearly perfect phase-contrast specimens, like frozen-hydrated samples,
can now be imaged with superior contrast, which greatly benefits studies where
the image contrast is a limiting factor, such as single-particle imaging and
tomography.” says Dr. Jaap Brink, JEOL's TEM Product Manager. Thus,
the phase plate imaging technique stands to have a huge impact in not just the
academic field, but also in the field of applied sciences, R&D, or every
field where cryo-imaging is being used.
Extensive research has led to the further development of phase plate technology
at the laboratory of Prof. Kuniaki Nagayama, Director & Professor of Okazaki
Institute for Integrative Bioscience in Japan. Prof. Nagayama and his colleagues
have illustrated the potential for routine phase contrast TEM imaging of frozen-hydrated
macromolecules. Using custom software they have applied the phase plate imaging
successfully to cryo-tomography (See Fig. 2).
JEOL's TEM columns are optimally designed for phase contrast cryo-electron
tomography, as they are unsurpassed in the ability to customize the imaging
parameters without sacrificing ease of use. Furthermore, developments have led
to continuously heated phase plate holders with piezo drives and software for
precise positioning of the phase plate and zero loss energy filtering through
an in-column Omega filter.
Within the past few months, JEOL USA has seen an increase in orders for its
biological TEMs, especially its 200 and 300 keV models. Collaborative partnerships
between these researchers and JEOL USA are aimed at maximizing the efficacy
of the phase plate technology.