National Synchrotron Light Source Seminar

Copper plays an important role in angiogenesis and tumor growth. The anti-growth action of copper chelators is mainly their induced inhibition of angiogenesis. Cu is considered as a target for novel cancer therapies that offer lower level of toxicity compared to current available chemotherapies. Although Cu oxidation state has not been directly implicated as being a characteristic of the tumor growth process, this can not be completed excluded as a potential role of Cu in tumor growth. As Cu concentration in tissue samples (prostate and breast cancer) has few parts per million. X-ray fluorescence microprobe (XFM) spectroscopy can detect very low metal concentrations with high efficiency and identify oxidation states and coordination chemistry using spectral lines that are normally unresolved by other techniques. This low metal concentration required a high flux incident beam capable to generate enough fluorescence x-rays to be detected. The main drawback in this configuration is the high intensity of the scattering signal from the supporting matrix. Measuring copper K fluorescence from tissue samples, for instance, can be critically masked by the strong scattering signal, reducing the sensitivity level and potentially saturating conventional solid-state photon-counting detectors. To overcome these limitations a high energy resolution and high efficiency compact, short focal distance Bent Crystal Laue Analyzer (BCLA) detection system has been developed for copper speciation in biological samples. The analyzer has energy resolution of 14 eV@ Cu Kα line and it has notable advantages to resolve the Cu Kα1, Kα2, and Kβ fluorescence lines while offering a very low background. The designed BCLA will be used on copper speciation studies in biological samples with specific applications to cancer biology.