The localisation of biologically important metals in soft and calcified tissues using a synchrotron x-ray fluorescence technique

A microbeam synchrotron x-ray fluorescence (mu-SXRF) technique has been employed in investigating the localisation of metals in two biological systems, soft and calcified tissue. Breast carcinoma is the focus of the former investigations, and osteoarthritis, that of the latter. Copper has been the metal of particular interest in breast tissue work, although 2D maps of other elements of importance have also been produced in present studies. Elemental maps were obtained at 18 gm spatial resolution and compared with light transmission images of histological sections. The comparison was successful when the sections were stained for cancer cells, revealing, in most cases, elevated metal levels in the cancer cells, with a possible exception of iron. With regard to a synovial joint in which an osteoarthritic lesion was found, the samples were taken from the equine joint allowing study of the distribution of calcium and zinc in cartilage and subchondral bone. Here, a particular question concerns the extent to which links can be established between the well-delineated contours of elemental presence that are observed within this surface and the structural deformation characteristic of the osteoarthritic lesion. mu-SXRF mappings, of depth resolution 15 mu m, have been obtained from the joint surface, up-to and just beyond the cement-line that forms the bond between subchondral bone and cartilage. Outside of the immediate area of the lesion, the presence of Ca and Zn each display a peak at the cartilage surface and also at the tidemark; within the lesion there is significant loss of surface elemental enhancement. Copyright (C) 2007 John Wiley & Sons, Ltd.