Quantitative analysis of biological specimens by X-ray scanning analytical microscopy

X-ray scanning analytical microscopy (XSAM) can be used to visualize the elemental distribution in biological specimens. In this study, the authors prepared standard specimens for XSAM and performed quantitative analysis of various elements dissolved in soft tissues. Two different types of standard specimens were prepared. Methylmethacrylate (MMA) resin-based standard specimens were prepared with organic compounds of elements for lowconcentration standards and lithium borate glass-based standard specimens were prepared with oxides of elements for higher concentration standards. Using these standard specimens, the P and Ca concentrations in normal rat tissue and dissolved Ni, Fe and Ni concentrations around metal implanted tissues were quantitatively analyzed. The estimated concentrations of dissolved Fe, Cu and Ni from the implants were 1000, 40 and 20mM, respectively. From the concentration levels causing inflammation around these implants, the high toxicity for soft tissue of Ni and Cu at low concentrations, e.g., 10mM was confirmed. The toxicity of Cu was estimated as next to that of Ni. In contrast, Fe had low toxicity in spite of high concentrations of dissolved Fe of as much as 1000mM. In this study, it was possible to estimate the non-metallic elements and low-concentration metallic elements dispersed in soft tissue by XSAM.