Chemistry and morphology of bone maintenance and repair in extant and extinct organisms through synchrotron and X-ray imaging

Abstract

This research focuses on the mapping and quantification of trace elements that are crucial to the processes that maintain and repair bone of both extant and extinct organisms. Chemical analyses used in this study include Synchrotron Rapid Scanning-X-Ray Fluorescence (SRS-XRF), microfocus elemental mapping, X-ray Absorption Spectroscopy (XAS), K-Edge Subtraction tomography (KES), Fourier Transform Infrared spectroscopy (FTIR), Liquid Chromatography/tandem Mass Spectroscopy (LC/MS/MS) and Proton Induced X-ray Emission (PIXE). Mapped chemistry was compared with morphological data obtained from thin section (2D) or X-ray tomography (3D) analysis to allow the correlation and comparison of different bone tissue types. SRS-XRF and microfocus elemental mapping revealed both chemical variations within different bone tissues and previously unobserved histological structures not seen using conventional histological techniques. Zinc has been found for the first time to be differentially distributed within both extant and fossil tissues in discrete sites of actively remodelling or ossifying bone at the time of death. Quantifications of trace elements were comparable using both synchrotron-based and PIXE imaging techniques, which supports the former methodology for obtaining quantitative data. Correlation between trace elements and proteins/pathways was supported by protein speciation via proteomics.FTIR was proven to be unsuccessful in mapping the distribution of organics within fossil bone due to the varying topography of the samples including both thin sectioned and polished. The use of KES has also proven to be difficult with bone tissues due to the high concentration required for this technique to be successful (1-2 weight %). X-Ray computed Tomography (XRT) analysis has proven to be of sufficient resolution to diagnose the extent of pathological tissue and in some cases, even the fine scale histology such as lamellae in both extant and fossil bone.

Date of Award	31 Dec 2015
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Roy Wogelius (Supervisor), Phillip Manning (Supervisor) & Bart Van Dongen (Supervisor)