Optical Absorption Spectra of Melanins - a Comparison of Theoretical and Experimental Results

Researchers at Innovene, the University of San Antonio, and the University of California, Irvine, and Accelrys have used MS Modeling’s DMol, VAMP, and Discover codes to study the effect of aggregation and oxidation on the optical absorption of eumelanin oligomeric sheets. The oligomeric hypothesis is supported by Atomic Force Microscopy (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. The work will lead to the development of better sun screen-based products, aiding the protection against, and the prevention of, skin cancer.