PMID- 16853670
OWN - NLM
STAT- MEDLINE
DCOM- 20070912
LR  - 20060720
IS  - 1520-6106 (Print)
IS  - 1520-5207 (Linking)
VI  - 109
IP  - 43
DP  - 2005 Nov 3
TI  - Quantitative fluorescence excitation spectra of synthetic eumelanin.
PG  - 20629-35
AB  - Previously reported excitation spectra for eumelanin are sparse and inconsistent. 
      Moreover, these studies have failed to account for probe beam attenuation and 
      emission reabsorption within the samples, making them qualitative at best. We 
      report for the first time quantitative excitation spectra for synthetic 
      eumelanin, acquired for a range of solution concentrations and emission 
      wavelengths. Our data indicate that probe beam attenuation and emission 
      reabsorption significantly affect the spectra even in low-concentration eumelanin 
      solutions and that previously published data do not reflect the true excitation 
      profile. We apply a correction procedure (previously applied to emission spectra) 
      to account for these effects. Application of this procedure reconstructs the 
      expected relationship of signal intensity with concentration, and the normalized 
      spectra show a similarity in form to the absorption profiles. These spectra 
      reveal valuable information regarding the photophysics and photochemistry of 
      eumelanin. Most notably, an excitation peak at 365 nm (3.40 eV), whose position 
      is independent of emission wavelength, is possibly attributable to a 
      5,6-dihydroxyindole-2-carboxylic acid (DHICA) component singly linked to a 
      polymeric structure.
FAU - Nighswander-Rempel, Stephen P
AU  - Nighswander-Rempel SP
AD  - Centre for Biophotonics and Laser Science and Soft Condensed Matter Theory Group, 
      School of Physical Sciences, University of Queensland, St. Lucia, QLD 4067, 
      Australia. snighrem@physics.uq.edu.au
FAU - Riesz, Jennifer
AU  - Riesz J
FAU - Gilmore, Joel
AU  - Gilmore J
FAU - Bothma, Jacques P
AU  - Bothma JP
FAU - Meredith, Paul
AU  - Meredith P
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Phys Chem B
JT  - The journal of physical chemistry. B
JID - 101157530
RN  - 0 (Melanins)
RN  - 12627-86-0 (eumelanin)
SB  - IM
MH  - Animals
MH  - Hair/chemistry
MH  - Humans
MH  - Kinetics
MH  - Melanins/chemical synthesis/*chemistry
MH  - Retina/chemistry
MH  - Spectrometry, Fluorescence/*methods
MH  - Spectrophotometry
EDAT- 2006/07/21 09:00
MHDA- 2007/09/13 09:00
CRDT- 2006/07/21 09:00
PHST- 2006/07/21 09:00 [pubmed]
PHST- 2007/09/13 09:00 [medline]
PHST- 2006/07/21 09:00 [entrez]
AID - 10.1021/jp053704+ [doi]
PST - ppublish
SO  - J Phys Chem B. 2005 Nov 3;109(43):20629-35. doi: 10.1021/jp053704+.