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

Philip Yip, Jens U Sutter

Research output: Contribution to journalArticle

4 Citations (Scopus)
23 Downloads (Pure)

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.
Original languageEnglish
Article number027001
Number of pages10
JournalMethods and Applications in Fluorescence
Volume6
DOIs
Publication statusPublished - 25 Jan 2018

Keywords

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

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