Imaging of radiation-sensitive samples in transmission electron microscopes equipped with Zernike phase plates

Single particle analysis based on Zernike phase contrast transmission electron microscopy

“…Zero-loss imaging is essential in the case of cryo-tomography where the specimens are relatively thick (Grimm et al, 1997). The phase plate is expected to provide an additional boost in signal-to-noise Malac et al, 2007). The zero-loss filtration has not yet been proven to provide a worthwhile improvement for single particle analysis where the specimens are relatively thin.…”

“…The design and performance of the Zernike phase plate have been discussed in detail elsewhere Nagayama, 2001, 2006;Malac et al, 2007). It consists of a thin material film with a small hole in the center.…”

“…Most of them showed promising ''proof of concept'' results, but were eventually abandoned because of various practical problems. Recently, interest in such devices has been reborn and is growing rapidly (Nagayama, 1999;Nagayama, 2001, 2006;Nagayama and Danev, 2003;Lentzen, 2004;Hosokawa et al, 2005;Huang et al, 2006;Majorovits et al, 2007;Cambie et al, 2007;Malac et al, 2007). These devices work by modulating the phase of the electron wave at a diffraction plane.…”

“…The most obvious effect is a boost in overall image contrast as a result of the enhanced transfer of low spatial frequencies (Tosaka et al, 2005;Kaneko et al, 2006;Ohta et al, 2006). The improved phase contrast characteristics of the microscope are especially beneficial for imaging of the low-Z specimens common in cryo-EM Malac et al, 2007).…”

Methods for testing Zernike phase plates and a report on silicon-based phase plates with reduced charging and improved ageing characteristics

“…The usefulness of in-focus TEM phase-plate imaging has long been appreciated, and has recently been affirmed (Malac et al, 2008; Chang et al, 2010; Hall et al, 2011), but practical problems with its implementation for “real-world” use have hindered widespread adoption (see reviews by Nagayama and Danev, 2009; Danev et al, 2009; Danev and Nagayama, 2010; Nagayama 2011). Nevertheless, the current state of development has enabled early applications to biological problems, validating the technical advantages of phase-plate imaging (Danev and Nagayama, 2008; Fukuda and Nagayama, 2012; Rochat et al, 2011; Hosogi et al, 2011; Danev et al, 2010; Murata et al, 2010; Shigematsu et al, 2010; Yui et al, 2008; Yamaguchi et al, 2008).…”