Micro-PIXE and histochemical studies of Zn and Ca distribution in normal bone

To better understand the role of zinc in bone mineralization we studied the distribution of Ca and Zn by microbeam particle-induced X-ray emission (µ-PIXE) profiling and mapping, and of Zn by histochemical mapping and profiling in cortical bovine bone. For µ-PIXE, measurements were carried out at the Rossendorf nuclear microprobe with a 3.1 MeV proton beam focused to a spot of ca. 3 µm, at ca. 4-8 µm effective resolution. Maps, unique scans and side-to-side scan sequences were done for Ca and Zn. The noise in Zn profiles was filtered by Fast Fourier Transform (FFT). For histochemistry, Zn was stained in thick sections by the sulphide-silver reaction. Both µ-PIXE and histochemistry showed that Zn was localized mainly at the surfaces of various structures in bone tissue.