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Characterisation of mineralised tissues with raman spectroscopy

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Title: Characterisation of mineralised tissues with raman spectroscopy
Authors: You, Amanda
Item Type: Thesis or dissertation
Abstract: Raman spectroscopy imaging presents a sensitive and versatile method to collect biochemical information from biomineralised tissues. The goal of this thesis was to comprehensively investigate biomineralised tissues by developing chemometrics analysis methods. Raman spectroscopy imaging was utilised to compare pathological and physiological calcifications of various biomineralised tissues. The relationship between atherosclerosis and aging on aortic medial and intimal/plaque calcification was interrogated. Cross-sectional concentration profiles of biochemical components were characterised using vertex component analysis (VCA). Significant increases were found in apatite and lipids not only in the atherosclerotic plaque but also in the directly underlying aortic media, where increased whitlockite was also observed. This study revealed a new correlation between atherosclerosis and medial calcification. An investigation into alterations due to bisphosphonate treatment in osteoporotic trabecular bone was done. Results on the composition of mineral and collagen crosslinks suggest that long term bisphosphonate treatment might lead to abnormal bone tissue, which may shed light on the reason for the association with atypical fractures. Healing capacities of different growth plate zones were compared in an organotypic embryonic chick femur model. Immunohistochemistry showed that defects introduced to the resting and proliferative zones demonstrated superior healing to pre-hypertrophic and hypertrophic zones, which show perichondrial-like tissue in the defect site. A method to spatially quantify collagen crosslinks was developed using time-of-flight secondary ion mass spectrometry (ToF-SIMS) mapping. Neonatal rat femurs were mapped, followed by partial least squares-discriminant analysis (PLS-DA). Presence of putative ionic fragments in the growth plate and epiphyseal tissue was observed. These results suggest ToF-SIMS could be a useful technique to identify collagen crosslink molecules in bioengineered systems. Various tissues were successfully characterised using chemometrics methods that were developed throughout the thesis. These methods are easily transferable for future studies of other native and bioengineered tissues or clinical diagnosis using Raman spectroscopy probes.
Content Version: Open Access
Issue Date: Sep-2016
Date Awarded: Jan-2017
URI: http://hdl.handle.net/10044/1/68024
DOI: https://doi.org/10.25560/68024
Supervisor: Stevens, Molly
Payne, David
Sponsor/Funder: Imperial College London
Rosetrees Trust
Department: Materials and Bioengineering
Publisher: Imperial College London
Qualification Level: Doctoral
Qualification Name: Doctor of Philosophy (PhD)
Appears in Collections:Materials PhD theses



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