Biological x-ray microscopy with a compact laser system

Abstract

The development of x-ray microscopy for the biological and medical sciences offers several inherent advantages over other high resolution microscopy techniques, such as confocal optical microscopy and electron microscopy [1]. Short wavelength radiation allows for much higher spatial resolution than optical techniques, while at the same time possessing sufficient depth of field to image whole-cell structures of several microns size. High image-contrast, and even elemental mapping, can be obtained by selection of the appropriate x-ray wavelength. Moreover in avoiding the need for the sample preparation procedures inherent to electron microscopy (staining, drying, sectioning etc.) x-ray imaging permits the visualization of biological specimens in their natural state. Previous developments in x-ray microscopy have mostly used synchrotron radiation sources [2]. These offer precision variability in x-ray emission but are restricted to major facilities, and require long exposure times to record an image. This latter limitation prevents the high resolution analysis of mobile living organisms [3]. Early work with laser plasma x-ray sources also required the use of major facilities (dedicated to laser fusion) [4].