Improved Detail in Biological Soft X-ray Microscopy: Study of Blood Platelets

Abstract

Improved image quality in soft x-ray contact microscopy can be obtained by examining the resist with transmission rather than scanning electron microscopy. Application of the new technique to air-dried preparations of human blood platelets reveals structures not visible in the same cells with transmission electron microscopy or when the resist is examined by scanning electron microscopy. As seen by the new technique, platelet pseudopods contain a central structure connected to a network in the platelet and dense bodies exhibit a lamellar structure.

Flash X‐ray microscopy with a gas jet plasma source

“…The ultrastructure and elemental composition of these preparations have been characterized extensively in the electron microscope, and the observable detail has been reported to correlate well with that seen 8) 1984 The Royal Microscopical Society in freeze-and critical point-dried specimens (Skaer et al, 1976;Costa et al, 1977). Furthermore, contact X-ray images of these cells utilizing an electron-gun source have already been produced (Feder et al, 1981), and are thus available for comparison with images produced with the flash source.…”

“…The cylinder is imploded by magnetic forces onto the gas jet axis, resulting in a high temperature plasma. of the developed resist during observation in the scanning electron microscope (SEM), it was coated with a thin layer (-10 nm) of gold palladium and studied in the SEM at 20 kV as described previously (Feder et al, 1981).…”

X‐ray microscopy

“…The development of contact microscopy by Feder and collaborators a decade ago (42) brought the modern technology of X-ray resists and electron microscopy to the the oldest form of X-ray imaging. This form of microscopy is compatible with, and is practised with a wide variety of sources, including X-ray lasers, conventional microfocus X-ray generators, laser-plasma sources, as well as synchrotron radiation (43,44).…”

Contact microscopy with synchrotron radiation

“…Recently by making silicon nicride windows supported by a silicon wafer frame, Feder et al (10) has developed a way to mount the photoresist and sample on SiN3 so that the final metal-coated x-ray replica can be viewed by transmission electron microscopy (TEM). This offers not only higher resolution imaging of the replica, but in future will permit, the digitization of the replica image using scanning transmission electron microscopy (STEM) and direct high resolution image analysis using the state-of-the-art computer assisted software now available on analytical electron microscopes.…”