Effect of stacking and redox state on optical absorption spectra of melanins -- comparison of theoretical and experimental results.
In this work the effect of aggregation and oxidation on the optical absorption of eumelanin oligomeric sheets is investigated by applying quantum mechanics and atomistic simulation studies to a simplified eumelanin structural model that includes 1-3 sheets of hexameric oligomer sheets. The oligomeric hypothesis is supported by AFM characterizations of synthetic eumelanins, formed by auto-oxidation or electrochemical oxidation of dihydroxyindole (DHI). Comparison of calculated absorption spectra to experimental spectra demonstrates a red shift in absorption with oxidation and stacking of the eumelanin and validates the theoretical results.
Stark
Klaus B
KB
Accelrys Incorporated, 1042 Kress Street, Houston, Texas 77020, USA. kstark@accelrys.com
Gallas
James M
JM
Zajac
Gerry W
GW
Golab
Joseph T
JT
Gidanian
Shirley
S
McIntire
Theresa
T
Farmer
Patrick J
PJ
D002627:Chemistry, Physical / Q000379:methods*; D004563:Electrochemistry; D006860:Hydrogen Bonding; D007211:Indoles / Q000737:chemistry; D008543:Melanins / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D013053:Spectrophotometry / Q000379:methods
D007211:Indoles; D008543:Melanins; C041877:eumelanin; D010100:Oxygen