title: Nanoscale X-ray microscopic imaging of mammalian mineralized tissue.
abstract: A novel hard transmission X-ray microscope (TXM) at the Stanford Synchrotron Radiation Lightsource operating from 5 to 15 keV X-ray energy with 14 to 30 microm2 field of view has been used for high-resolution (30-40 nm) imaging and density quantification of mineralized tissue. TXM is uniquely suited for imaging of internal cellular structures and networks in mammalian mineralized tissues using relatively thick (50 microm), untreated samples that preserve tissue micro- and nanostructure. To test this method we performed Zernike phase contrast and absorption contrast imaging of mouse cancellous bone prepared under different conditions of in vivo loading, fixation, and contrast agents. In addition, the three-dimensional structure was examined using tomography. Individual osteocytic lacunae were observed embedded within trabeculae in cancellous bone. Extensive canalicular networks were evident and included processes with diameters near the 30-40 nm instrument resolution that have not been reported previously. Trabecular density was quantified relative to rod-like crystalline apatite, and rod-like trabecular struts were found to have 51-54% of pure crystal density and plate-like areas had 44-53% of crystal density. The nanometer resolution of TXM enables future studies for visualization and quantification of ultrastructural changes in bone tissue resulting from osteoporosis, dental disease, and other pathologies.
authors.affiliation: Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA. jandrews@slac.stanford.edu
authors.forename: Joy C
authors.initials: JC
authors.lastname: Andrews
authors.forename: Eduardo
authors.initials: E
authors.lastname: Almeida
authors.forename: Marjolein C H
authors.initials: MC
authors.lastname: van der Meulen
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Alwood
authors.forename: Chialing
authors.initials: C
authors.lastname: Lee
authors.forename: Yijin
authors.initials: Y
authors.lastname: Liu
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.forename: Florian
authors.initials: F
authors.lastname: Meirer
authors.forename: Michael
authors.initials: M
authors.lastname: Feser
authors.forename: Jeff
authors.initials: J
authors.lastname: Gelb
authors.forename: Juana
authors.initials: J
authors.lastname: Rudati
authors.forename: Andrei
authors.initials: A
authors.lastname: Tkachuk
authors.forename: Wenbing
authors.initials: W
authors.lastname: Yun
authors.forename: Piero
authors.initials: P
authors.lastname: Pianetta
mesh_terms: D000818:Animals; D015519:Bone Density; D001842:Bone and Bones / Q000737:chemistry* / Q000648:ultrastructure*; D004577:Electron Probe Microanalysis / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D051379:Mice; D008810:Mice, Inbred C57BL; D014054:Tomography / Q000379:methods