Correlative Chemical Element Imaging in Cells Using Fluorescence Microscopy and Synchrotron X-ray Fluorescence

Synchrotron radiation X-ray fluorescence (SXRF) microscopy holds the potential for fundamental breakthroughs in the understanding of biological systems because chemical element distributions can be evidenced at the sub-cellular level (<100 nm) with low detection limits (<100 ng/g). In addition to SXRF, it is also possible to perform X-ray Absorption Spectroscopy (XAS) which is based on the photoelectric effect. X-ray absorption near edge structure (XANES) provides information about oxidation state and molecular geometry of the elements. What is the distribution of trace metals in cells? Do some elements accumulate within sub-cellular organelles? What are the chemical species of the elements in these organelles? These are some of the fundamental questions that can be addressed using X-ray chemical element imaging and speciation with synchrotron radiation beams [1].