(Previously publishing as Gelsomina De Stasio) University of Wisconsin-Madison, Department of Physics
The combination of high-spatial resolution photoelectron emission spectromicroscopy (X-PEEM)  and x-ray absorption near-edge structure (XANES) spectroscopy opened up a new way of looking at biological and medical problems. Most importantly, soft x-ray absorption spectroscopy is sensitive to both chemical composition and molecular structure of organic molecules and minerals [2,3] and is therefore ideal for studying complex systems, tissues and biominerals . We will discuss two recent discoveries, and one longer-term set of experiments. The first is the sensitivity of XANES to protein misfolding and aggregation, relevant to Alzheimer’s and prion diseases . The second discovery is the azimuthal-rotation dependence of C K-edge XANES spectra of aragonite (a CaCO3 polymorph). Such dependence was well known to occur for polar rotations but not expected for azimuthal rotations. This observation, first made in a biomineral, the aragonitic mother-of-pearl from abalone shells, was also reproduced in geologic aragonite crystals, and is due to local breaking of symmetry at the -CO3 groups in aragonite, but not in calcite (another CaCO3 polymorph). Because of this new effect, the crystal orientation of individual tablets in abalone mother-of-pearl images and C distribution maps was obtained with X-PEEM . The thisd experiment is aimed at optimizing a therapy for glioblastoma, the most malignant of brain cancers . This gadolinium synchrotron stereotactic radiotherapy (GdSSR) requires delivery of gadolinium to the nuclei of cancer cells (analyzed with X-PEEM and STXM), while sparing the normal brain, and stereotactic exposure to 51 keV photons to stimulate Auger electron emission, cleave DNA double-strands, and selectively induce cancer cell death .
 Bradley H. Frazer, Marco Girasole, Lisa M. Wiese, Torsten Franz and Gelsomina De Stasio, Spectromicroscope for the PHotoelectron Imaging of Nanostructures with X-rays (SPHINX): performance in biology, medicine and geology. Ultramicroscopy 99, 87-94 (2004).
 Matthias Labrenz, Gregory K. Druschel, Tamara Thomsen-Ebert, Benjamin Gilbert, Susan A. Welch, Kenneth M. Kemner, Graham A. Logan, Roger E. Summons, Gelsomina De Stasio, Philip L. Bond, Barry Lai, Shelly D. Kelly, and Jillian F. Banfield, Sphalerite (ZnS) deposits forming in natural biofilms of sulfate-reducing bacteria. Science 290, 1744-47, 2000.
 Clara S. Chan*, Gelsomina De Stasio*, Susan A. Welch, Marco Girasole, Bradley H. Frazer, Maria Nesterova, Sirine Fakra, and Jillian F. Banfield, Microbial polysaccharides template assembly of nanocrystal fibers, *Equal contributors. Science 303, 1656-1658 (2004).
 P.U.P.A. Gilbert, Bradley H. Frazer and M. Abrecht. The organic-mineral interface in biominerals. Reviews in Mineralogy and Geochemistry. In: Molecular Geomicrobiology. Vol 59. JF Banfield, KH Nealson, J. Cervini-Silva (eds), Mineralogical Society of America, Washington DC, p 157-185 (2005).
 Christopher J. Johnson, Ronke M. Olabisi, Rebecca A. Metzler, Benjamin Gilbert, Bradley H. Frazer, Debbie McKenzie, Judd M. Aiken, and P.U.P.A. Gilbert. X-ray spectromicroscopy captures cross-b fibril formation. Submitted 2006.
 Rebecca A. Metzler, Mike Abrecht, Ronke M. Olabisi, Daniel Ariosa, Christopher J. Johnson, Bradley H. Frazer, Susan N. Coppersmith, P.U.P.A. Gilbert. Crystallographic Order and Disorder in Nacre. Submitted 2006.
 Gelsomina De Stasio, Patrizia Casalbore, Roberto Pallini, Benjamin Gilbert, Francesca Sanita’, Maria Teresa Ciotti, Giancarlo Rosi, Armando Festinesi, Luigi Maria Larocca, Alessandro Rinelli, Didier Perret, David W. Mogk, Paolo Perfetti, Minesh P. Mehta, and Delio Mercanti, Gadolinium in Human Glioblastoma Cells for Gadolinium Neutron Capture Therapy. Cancer Research 61, 4272-4277, 2001.
 Gelsomina De Stasio, Deepika Rajesh, Judith M. Ford, Matthew J. Daniels, Robert J. Erhardt, Bradley H. Frazer, Tolek Tyliszczak, Mary K. Gilles, Robert L. Conhaim, Steven P. Howard, John F. Fowler, François Estève, and Minesh P. Mehta. Motexafin-Gadolinium Taken Up in Vitro by at Least 90% of Glioblastoma Cell Nuclei. Clinical Cancer Research 12, 206-213 (2006).
Diamond Light Source is the UK's national synchrotron science facility, located at the Harwell Science and Innovation Campus in Oxfordshire.
Copyright © 2017 Diamond Light Source
Diamond Light Source Ltd
Harwell Science & Innovation Campus