Comparison of Synthetic Dopamine鈥揈umelanin Formed in the Presence of Oxygen and Cu2+ Cations as Oxidants

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• 作者：Vincent Ball ; Jos茅 Gracio ; Mercedes Vila ; Manoj Kumar Singh ; Marie-H茅l猫ne Metz-Boutigue ; Marc Michel ; J茅r么me Bour ; Val茅rie Toniazzo ; David Ruch ; Markus J. Buehler
• 刊名：Langmuir
• 出版年：2013
• 出版时间：October 15, 2013
• 年：2013
• 卷：29
• 期：41
• 页码：12754-12761
• 全文大小：323K
• 年卷期：v.29,no.41(October 15, 2013)
• ISSN：1520-5827

文摘

Eumelanin is not only a ubiquitous pigment among living organisms with photoprotective and antioxidant functions, but is also the subject of intense interest in materials science due to its photoconductivity and as a possible universal coating platform, known as 鈥減olydopamine films鈥? The structure of eumelanin remains largely elusive, relying either on a polymeric model or on a heterogeneous aggregate structure. The structure of eumelanin as well as that of the closely related 鈥減olydopamine films鈥?can be modified by playing on the nature of the oxidant used to oxidize dopamine or related compounds. In this investigation, we show that dopamine鈥揺umelanins produced from dopamine in the presence of either air (O₂ being the oxidant) or Cu²⁺ cations display drastically different optical and colloidal properties in relation with a different supramolecular assembly of the oligomers of 5,6 dihydroxyindole, the final oxidation product of dopamine. The possible origin of these differences is discussed on the basis of Cu²⁺ incorporation in Cu dopamine鈥揺umelanin.