Title: Polarization induced contrast X-ray fluorescence at submicrometer resolution reveals nanometer apatite crystal orientations across entire tooth sections

Abstract

For biomedical research, successful imaging of calcified microstructures often relies on absorption differences between features, or on employing dies with selective affinity to areas of interest. When texture is concerned, e.g. for crystal orientation studies, polarization induced contrast is of particular interest. This requires sufficient interaction of the incoming radiation with the volume of interest in the sample to produce orientation-based contrast. Here we demonstrate polarization induced contrast at the calcium K-edge using submicron sized monochromatic synchrotron X-ray beams. We exploit the orientation dependent subtle absorption differences of hydroxyl-apatite crystals in teeth, with respect to the polarization field of the beam. Interaction occurs with the fully mineralized samples, such that differences in density do not contribute to the contrast. Our results show how polarization induced contrast X-ray fluorescence mapping at specific energies of the calcium K-edge reveals the micrometer and submicrometer crystal arrangements in human tooth tissues. This facilitates combining both high spatial resolution and large fields of view, achieved in relatively short acquisition times in reflection geometry. In enamel we observe the varying crystal orientations of the micron sized prisms exposed on our prepared surface. We easily reproduce crystal orientation maps, typically observed in polished thin sections. We evenmore » reveal maps of submicrometer mineralization fronts in spherulites in intertubular dentine. This Ca K-edge polarization sensitive method (XRF-PIC) does not require thin samples for transmission nor extensive sample preparation. It can be used on both fresh, moist samples as well as fossilized samples where the information of interests lies in the crystal orientations and where the crystalline domains extend several micrometers beneath the exposed surface.« less

Authors:

Hesse, Bernhard; Stier, Deborah ;

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Cotte, Marine; Forien, Jean-Baptiste; Zaslansky, Paul

Publication Date:

Mon Dec 03 00:00:00 EST 2018

Research Org.:

Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:

1484326

Alternate Identifier(s):

OSTI ID: 1497983

Report Number(s):

LLNL-JRNL-756138
Journal ID: ISSN 2156-7085

Grant/Contract Number:  

AC52-07NA27344

Resource Type:

Published Article

Journal Name:

Biomedical Optics Express

Additional Journal Information:

Journal Name: Biomedical Optics Express Journal Volume: 10 Journal Issue: 1; Journal ID: ISSN 2156-7085

Publisher:

Optical Society of America

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; 47 OTHER INSTRUMENTATION; 59 BASIC BIOLOGICAL SCIENCES