Eumelanin fibrils

Ross McQueenie; Jens Sutter; Jan Karolin; David J. Birch

doi:10.1117/1.JBO.17.7.075001

9 July 2012 Eumelanin fibrils

Ross McQueenie, Jens Sutter, Jan Karolin, David J. Birch

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Journal of Biomedical Optics, Vol. 17, Issue 7, 075001 (July 2012). https://doi.org/10.1117/1.JBO.17.7.075001

Abstract

We describe the auto-oxidation of 3, 4-dihydroxy-L-phenylalanine (L-DOPA) in the synthesis of eumelanin to spontaneously produce fibrils upon drying. The self-assembled fibrils are of characteristic diameter ~ 1 to 2 μm, composed of filaments, and are unidirectional, apart from branches that are formed at typically an angle of 20 to 22 deg. The fibrils are characterized using fluorescence spectroscopy, fluorescence decay times, scanning electron microscopy, atomic force microscopy, and fluorescence lifetime imaging microscopy. The fibrils mimic natural melanin in consisting of core eumelanin with efficient nonradiative properties, but they also display pockets of electronically isolated species with higher radiative rates on the nanosecond timescale. Eumelanin fibrils formed occasionally in solution are tentatively attributed to a scaffold of bacteria or fungus. Fabricating and characterizing novel synthetic eumelanin structures such as fibrils are of interest in helping to reveal a functional structure for eumelanin, in understanding its photophysics, in learning more about L-DOPA as it is used in the treatment of Parkinson's disease, and in producing novel materials which might embody some of the diverse properties of eumelanin.

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Ross McQueenie, Jens Sutter, Jan Karolin, and David J. Birch "Eumelanin fibrils," Journal of Biomedical Optics 17(7), 075001 (9 July 2012). https://doi.org/10.1117/1.JBO.17.7.075001

Published: 9 July 2012

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