Turyanskaya, A. (2022). Elemental analysis of bone tissue by laboratory- and synchrotron- based μXRF, including approaches to combining μXRF with other imaging techniques [Dissertation, Technische Universität Wien]. reposiTUm. https://doi.org/10.34726/hss.2022.27909
In the frame of this thesis, physical methods of analysis were used to investigate the chemical composition of biological samples, with a view to 1) further advance currently available analytical methods and techniques, and 2) solve questions of bio-/medical relevance.The first set of aims was initiated by and realized within the TU Wien doctoral program “Molecular and Elemental Imaging in Biosciences” (MEIBio). Successful combination of the existing analytical methods was achieved for the following pairs of techniques: laboratory μXRF – MALDI-MSI and laboratory μXRF – LA-ICP-MS.• The combination of modalities laboratory μXRF – MALDI-MSI was performed on chicken phalangeal cuts. This choice of a test sample allowed measurements of various types of tissues and histological structures. Since the technical aspects of the combination were primarily within the focus of the project, specific attention was paid to the sample preparation, choice of the supporting materials and to the order in which the techniques can be used. Several pipelines were tested out, providing us with both elemental and molecular information for the very same slices, so that the obtained maps could be finally superimposed producing correlated images.• The pair laboratory μXRF – LA-ICP-MS has also been fruitful. Both modalities yield elemental information, and the lateral (spatial) resolution of the techniques is in the same range. Therefore, such a combination is a promising tool in overcoming the limitations of a single technique and for cross-validation of the results. Thin sections of a rather complex sample, human femoral head cuts, were scanned first with μXRF and then with LA-ICP-MS. The main achievement of this coupling is the qualitative and quantitative information (images) provided by both methods.• The third conceived pairing was planned for the synchrotron-based μXRF and ToF-SIMS. Having an outstanding sub-μm lateral resolution, ToF-SIMS can only be compared and combined with synchrotron-based μXRF analysis. The lesson learnt from the attempted testing: a careful design of such an experiment is needed, with the emphasis on sample preparation and area selection fitting for both techniques.The second part of work comprises several projects which were mainly devoted to the investigations of the sample composition – qualitative (and, if possible, also quantitative) analysis of major, minor, and trace elements in bone tissue.• The investigation of rat bone samples carrying biodegradable Mg-based implants at different degradation timepoints was performed using the laboratory μXRF. Whereas Mg seemed to be incorporated into the bone tissue/organism at a steady pace without leaving visible clusters or aggregations; the tendency for Y was found to migrate deeper into the bone.• A set of human samples was studied using synchrotron-based μXRF in order to test out the link between osteoporosis and Mn content. It appears that human bone samples (transiliac bone biopsy samples) from male patients with idiopathic osteoporosis tend to contain less Mn globally in bone tissue as compared to healthy controls.• Another project was devoted to the investigation of Gd accumulation in human bone tissue. One of the potential sources of Gd in the human organism can be administration of gadolinium-based contrast agents for magnetic resonance imaging procedure. The measurements of samples with known and suspected administration of gadolinium-based contrast agents were conducted at the synchrotron, yielding detailed elemental maps, furthermore, for one of the samples Gd concentration could have been estimated.viOnly the work directly related to this thesis is listed here. For a complete list of publications and conference contributions produced over the duration of my doctoral work, please refer to the end of the thesis.
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