High resolution X-ray micrography of live Candida albicans using laser plasma pulsed point X-ray sources.

Abstract

Electron microscopy is still the most frequently used method for visualization of subcellular structures in spite of limitations due to the preparation required to visualize the specimen, High resolution X-ray microscopy is a relatively new technique, still under development and restricted to a few large synchrotron X-ray sources. We utilized a single-shot laser (nanosecond) plasma to generate X-rays similar to synchrotron facilities to image live cells of Candida albicans. The emission spectrum was tuned for optimal absorption by carbon-rich material. The photoresist was then scanned by an atomic force microscope to give a differential X-ray absorption pattern. Using this technique, with a sample image time of 90 min, we have visualized a distinct 152.24 nm thick consistent ring structure around cells of C albicans representing the cell wall, and distinct 'craters' inside, one of 570-90 nm diameter and three smaller ones, each 400 nm in diameter. This technique deserves further exploration concerning its application in the ultrastructural study of live, hydrated microbiological samples and of macromolecules.