The effect of copper on eumelanin photophysics and morphology

David J S Birch; Jens Sutter

doi:10.1117/12.999948

The effect of copper on eumelanin photophysics and morphology

David J S Birch, Jens Sutter

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution book

6 Citations (Scopus)

Abstract

Despite being an important pigment in skin, hair, the eye and the brain, melanin remains one of the most enigmatic of pigments. Although the main constituents of melanin are known to be dihydroxyindoles, its photophysics is complex and
its detailed structure remains unknown. In this work we have arrested prior to completion the usual synthesis of eumelanin formed via auto-oxidation of 3, 4-dihydroxy-L-phenylalanine (L-DOPA), by the addition of copper ions. Using fluorescence techniques we report how copper modifies the self assembly of eumelanin by reducing the time to the onset of aggregation at pH 10 and yet produces simplified photophysics in terms of a clearly-defined fluorescence
spectrum and a fluorescence decay that is described well by a dominant single lifetime of ~ 6ns. This behavior isconsistent with copper inducing an enhanced abundance of 5,5-dihydroxyindole-2-carboxylic acid (DHICA). Metal ion
binding to melanin is of particular importance to neurology and has potential applications in optoelectronics.

Original language	English
Title of host publication	Imaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues XI
Editors	Daniel L. Farkas, Dan V Nicolau, Robert C Leif
Place of Publication	San Francisco, California
Number of pages	6
Volume	8587
DOIs	https://doi.org/10.1117/12.999948
Publication status	Published - 2013

Publication series

Name	Progress in biomedical optics and imaging
Publisher	SPIE
Number	23
Volume	14

Keywords

thioflavin T
aggregation
fluorescence
L-DOPA
copper ions
4-dihydroxy-L-phenylalanine

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10.1117/12.999948

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title = "The effect of copper on eumelanin photophysics and morphology",

abstract = "Despite being an important pigment in skin, hair, the eye and the brain, melanin remains one of the most enigmatic of pigments. Although the main constituents of melanin are known to be dihydroxyindoles, its photophysics is complex andits detailed structure remains unknown. In this work we have arrested prior to completion the usual synthesis of eumelanin formed via auto-oxidation of 3, 4-dihydroxy-L-phenylalanine (L-DOPA), by the addition of copper ions. Using fluorescence techniques we report how copper modifies the self assembly of eumelanin by reducing the time to the onset of aggregation at pH 10 and yet produces simplified photophysics in terms of a clearly-defined fluorescencespectrum and a fluorescence decay that is described well by a dominant single lifetime of ~ 6ns. This behavior isconsistent with copper inducing an enhanced abundance of 5,5-dihydroxyindole-2-carboxylic acid (DHICA). Metal ionbinding to melanin is of particular importance to neurology and has potential applications in optoelectronics.",

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The effect of copper on eumelanin photophysics and morphology. / Birch, David J S ; Sutter, Jens.
Imaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues XI. ed. / Daniel L. Farkas; Dan V Nicolau; Robert C Leif. Vol. 8587 San Francisco, California, 2013. (Progress in biomedical optics and imaging; Vol. 14, No. 23).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution book

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N2 - Despite being an important pigment in skin, hair, the eye and the brain, melanin remains one of the most enigmatic of pigments. Although the main constituents of melanin are known to be dihydroxyindoles, its photophysics is complex andits detailed structure remains unknown. In this work we have arrested prior to completion the usual synthesis of eumelanin formed via auto-oxidation of 3, 4-dihydroxy-L-phenylalanine (L-DOPA), by the addition of copper ions. Using fluorescence techniques we report how copper modifies the self assembly of eumelanin by reducing the time to the onset of aggregation at pH 10 and yet produces simplified photophysics in terms of a clearly-defined fluorescencespectrum and a fluorescence decay that is described well by a dominant single lifetime of ~ 6ns. This behavior isconsistent with copper inducing an enhanced abundance of 5,5-dihydroxyindole-2-carboxylic acid (DHICA). Metal ionbinding to melanin is of particular importance to neurology and has potential applications in optoelectronics.

AB - Despite being an important pigment in skin, hair, the eye and the brain, melanin remains one of the most enigmatic of pigments. Although the main constituents of melanin are known to be dihydroxyindoles, its photophysics is complex andits detailed structure remains unknown. In this work we have arrested prior to completion the usual synthesis of eumelanin formed via auto-oxidation of 3, 4-dihydroxy-L-phenylalanine (L-DOPA), by the addition of copper ions. Using fluorescence techniques we report how copper modifies the self assembly of eumelanin by reducing the time to the onset of aggregation at pH 10 and yet produces simplified photophysics in terms of a clearly-defined fluorescencespectrum and a fluorescence decay that is described well by a dominant single lifetime of ~ 6ns. This behavior isconsistent with copper inducing an enhanced abundance of 5,5-dihydroxyindole-2-carboxylic acid (DHICA). Metal ionbinding to melanin is of particular importance to neurology and has potential applications in optoelectronics.

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The effect of copper on eumelanin photophysics and morphology

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Keywords

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