Tracking the formation of eumelanin from L-Dopa using coupled measurements

Philip Yip, Jens U Sutter

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Melanin plays a crucial role as a pigment all through the animal kingdom. Being a macromolecule just on the divide between an ordered crystalline or a purely amorphous form melanin has proven a challenge to structure-function analysis. Melanin assembles from small molecules much like a jigsaw and much like in a jigsaw the fine detail quickly vanishes in the overall picture. With melanin being first and foremost a photo-active molecule we focus on spectral properties for the characterisation of its structure. We use absorption measurements to illustrate the complex nature of the formation process. To gain a better hold on the formation pathway we use coupled measurements of excitation and emission to identify 'areas of interest' in the excitation-emission matrix (EEM). We then probe one area for characteristic fluorescence lifetimes to track one melanin building block through the formation process. Comparison of the EEMs of L-Dopa derived melanin with natural Sepia melanin shows characteristic differences. We show how the presence of copper ions creates a melanin closer to its natural form.
LanguageEnglish
Article number027001
Number of pages10
JournalMethods and Applications in Fluorescence
Volume6
DOIs
Publication statusPublished - 25 Jan 2018

Fingerprint

dopa
Melanin
melanin
Melanins
Levodopa
Molecules
eumelanin
pigments
Macromolecules
macromolecules
Pigments
excitation
animals
Copper
molecules
Animals
Fluorescence
Ions
Crystalline materials
copper

Keywords

  • eumelanin
  • fluorescence lifetime
  • 5,6-dihydroxyindole (DHI)
  • excitation-emission-matrix (EEM)
  • time-correlated-single-photon-counting (TCSPC)

Cite this

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title = "Tracking the formation of eumelanin from L-Dopa using coupled measurements",
abstract = "Melanin plays a crucial role as a pigment all through the animal kingdom. Being a macromolecule just on the divide between an ordered crystalline or a purely amorphous form melanin has proven a challenge to structure-function analysis. Melanin assembles from small molecules much like a jigsaw and much like in a jigsaw the fine detail quickly vanishes in the overall picture. With melanin being first and foremost a photo-active molecule we focus on spectral properties for the characterisation of its structure. We use absorption measurements to illustrate the complex nature of the formation process. To gain a better hold on the formation pathway we use coupled measurements of excitation and emission to identify 'areas of interest' in the excitation-emission matrix (EEM). We then probe one area for characteristic fluorescence lifetimes to track one melanin building block through the formation process. Comparison of the EEMs of L-Dopa derived melanin with natural Sepia melanin shows characteristic differences. We show how the presence of copper ions creates a melanin closer to its natural form.",
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Tracking the formation of eumelanin from L-Dopa using coupled measurements. / Yip, Philip; Sutter, Jens U.

In: Methods and Applications in Fluorescence , Vol. 6, 027001, 25.01.2018.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Tracking the formation of eumelanin from L-Dopa using coupled measurements

AU - Yip, Philip

AU - Sutter, Jens U

PY - 2018/1/25

Y1 - 2018/1/25

N2 - Melanin plays a crucial role as a pigment all through the animal kingdom. Being a macromolecule just on the divide between an ordered crystalline or a purely amorphous form melanin has proven a challenge to structure-function analysis. Melanin assembles from small molecules much like a jigsaw and much like in a jigsaw the fine detail quickly vanishes in the overall picture. With melanin being first and foremost a photo-active molecule we focus on spectral properties for the characterisation of its structure. We use absorption measurements to illustrate the complex nature of the formation process. To gain a better hold on the formation pathway we use coupled measurements of excitation and emission to identify 'areas of interest' in the excitation-emission matrix (EEM). We then probe one area for characteristic fluorescence lifetimes to track one melanin building block through the formation process. Comparison of the EEMs of L-Dopa derived melanin with natural Sepia melanin shows characteristic differences. We show how the presence of copper ions creates a melanin closer to its natural form.

AB - Melanin plays a crucial role as a pigment all through the animal kingdom. Being a macromolecule just on the divide between an ordered crystalline or a purely amorphous form melanin has proven a challenge to structure-function analysis. Melanin assembles from small molecules much like a jigsaw and much like in a jigsaw the fine detail quickly vanishes in the overall picture. With melanin being first and foremost a photo-active molecule we focus on spectral properties for the characterisation of its structure. We use absorption measurements to illustrate the complex nature of the formation process. To gain a better hold on the formation pathway we use coupled measurements of excitation and emission to identify 'areas of interest' in the excitation-emission matrix (EEM). We then probe one area for characteristic fluorescence lifetimes to track one melanin building block through the formation process. Comparison of the EEMs of L-Dopa derived melanin with natural Sepia melanin shows characteristic differences. We show how the presence of copper ions creates a melanin closer to its natural form.

KW - eumelanin

KW - fluorescence lifetime

KW - 5,6-dihydroxyindole (DHI)

KW - excitation-emission-matrix (EEM)

KW - time-correlated-single-photon-counting (TCSPC)

UR - http://iopscience.iop.org/journal/2050-6120

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DO - 10.1088/2050-6120/aa9724

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JO - Methods and Applications in Fluorescence

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SN - 2050-6120

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