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Title: Spontaneous fibril formation in eumelanin synthesised from 3,4-dihydroxyphenylalanine
Author: McQueenie, Ross
ISNI:       0000 0004 2739 8514
Awarding Body: University of Strathclyde
Current Institution: University of Strathclyde
Date of Award: 2012
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This thesis concerns synthetic melanin formation using 3,4-dihydroxyphenylalanine (DOPA), with respect to its possible fibril formation. This study aims to bridge the gap between the understanding of L-DOPA as a precursor molecule and its formation into melanin. Thus, an overview of L-DOPA is presented in three distinct stages: its fluorescence properties as a precursor, the formation of melanin from L-DOPA, and the dependence of melanin’s eventual structure based on environmental properties. Throughout this study, the aim is to directly correlate fluorescence properties with the morphology of melanin and its precursors. In particular, there is an examination of the absorption, fluorescence and lifetime properties of L-DOPA correlated with well-studied naturally fluorescent amino acids – namely tryptophan, tyrosine and phenylalanine – thus allowing examination of the effect of its molecular structural characteristics on fluorescent properties. Next, the role of environmental conditions on the formation of melanin from L-DOPA is examined, and in particular study two systems: one at pH 10 with the addition of ammonia; the other during heating to 37oC . Lastly, research is reported on novel fibril structures observed during synthetic eumelanin formation. To allow direct comparisons of structure and photophysical properties, formations were measured using multiphoton fluorescence lifetime imaging, atomic force microscopy and electron microscopy, thus finally proposing an explanation for melanin fibril synthesis. These studies reveal the continuing importance of the study of L-DOPA and melanin’s chemical and structural properties in the battle against both Parkinson’s disease and malignant melanomas.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available