Stefan Vogt's Virtual Home

Research Interests: Soft X-ray microscopy

In soft X-ray microscopy (XRM) different proteins are not readily distinguishable. However, in cell biology it is often desirable to localize single proteins, e.g., inside the cell nucleus. In visible light microscopy this is achieved by immuno-fluorescence labeling. Fluorochrome conjugated antibodies are used to tag the investigated protein with a fluorescent dye, which is detected in the microscope. Towards the same purpose immuno-gold labeling is used in electron microscopy. Instead of a fluorochrome colloidal gold is used as a label, which becomes visible due to its high electron density. In XRM the contrast mechanism is due to the X-ray absorption of the sample. The strong absorption of gold allows one to use the same immuno-gold labeling approach as above

In my Ph.D. Thesis on Investigations of Immunolabelled Structures in the Cell Nucleus by X-Ray and Light Microscopy, which I did in the Institute for X-Ray Physics at the Georg-August-Universität Göttingen, I worked to look at a few aspects of immunolabelling for soft X-ray Microscopy.

In my Master's Thesis (which I did while I was with the X-ray microscopy group at the State University of New York at Stony Brook) I worked on 'Dark Field X-Ray Microscopy: Theoretical Calculations and Biological Cell Labeling'.  It's available for download.
  Among other things, I made some numerical simulations of the effect a limited detector aperture would have on the image in a scanning transmission x-ray microscope (STXM). As an object I used 20 nm thick protein rods, to which 10-30 nm thick gold rods are attached. .

last update 21 October, 2009