Photodynamics of Melanin Radicals: Contribution to Photoprotection by Melanin†.

Tadeusz Sarna

Photochemistry and photobiology 2023 Mar

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The mechanism of very efficient relaxation of the melanin-photoexcited states, responsible for the photoprotective action of the pigment, remains a subject for intense investigation. The most recent study by C. Grieco, F. Kohl, and B. Kohler, entitled "Ultrafast radical photogeneration pathways in eumelanin," addresses key issues of melanin photophysics and photochemistry. By using femtosecond broad-band pump probe-transient absorption measurements, the researchers were able to identify the absorption spectrum of DOPA melanin radicals for the first time and proposed two distinct mechanisms of radical formation-photoionization and photoinduced charge separation. The observed photodynamic of melanin radicals suggests a new paradigm in which the ultrafast excited state deactivation is due to the efficient recombination of melanin radicals created promptly by photoexcitation. © 2022 American Society for Photobiology.

Citation

Tadeusz Sarna. Photodynamics of Melanin Radicals: Contribution to Photoprotection by Melanin†. Photochemistry and photobiology. 2023 Mar;99(2):866-868