First electrochemical investigation of the redox properties of DOPA–melanins by means of a carbon paste electrode

Serpentini, Charles-Louis; Gauchet, Cécile; Montauzon, Dominique de; Comtat, Maurice; Ginestar, José; Paillous, Nicole

doi:10.1016/s0013-4686(99)00388-6

Cited by 44 publications

(35 citation statements)

References 13 publications

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“…An electrochemical investigation of redox properties of an enzymically prepared eumelanin was reported by Serpentini et al (2000). A two-electron oxidation process was observed with the corresponding potentials being +460 and +525 mV versus SCE.…”

Section: Electron Exchange Propertiesmentioning

confidence: 99%

The physical and chemical properties of eumelanin

Meredith

Sarna

2006

Pigment Cell Research

905

1,045

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SummaryIn this article, we review the current state of knowledge concerning the physical and chemical properties of the eumelanin pigment. We examine properties related to its photoprotective functionality, and draw the crucial link between fundamental molecular structure and observable macroscopic behaviour. Where necessary, we also briefly review certain aspects of the pheomelanin literature to draw relevant comparison. A full understanding of melanin function, and indeed its role in retarding or promoting the disease state, can only be obtained through a full mapping of key structure-property relationships in the main pigment types. We are engaged in such an endeavor for the case of eumelanin.

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Section: Electron Exchange Propertiesmentioning

confidence: 99%

The physical and chemical properties of eumelanin

Meredith

Sarna

2006

Pigment Cell Research

905

1,045

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“…Figure 1 shows a first redox pair in +217 and +386 mV and one shoulder in +628 mV and one reduction signal in -69 mV versus Ag/AgCl. This difference between oxidation and reduction peaks (386 -217 mV) of 169 mV suggests that redox system is irreversible 12 . Some authors 8 described that anodic peaks presented on the cyclic voltammogram cannot be assigned totally to L-dopa oxidation.…”

Section: Resultsmentioning

confidence: 97%

“…Many studies have been done about the melanins polymerization mechanism to understand its biosynthesis 9 . Some chromatographic, electrochemical and spectro-electrochemical studies [10][11][12] , besides capillary electrophoresis 13 and photoelectron spectroscopy (XPS) studies 14 have been employed to determine the melanin formation mechanism. The L-dopa (3, 4-dihydroxiphenilalanine) was used as a model compound because its structure is similar to monomers found into natural melanin structure 15 allowing the biomimetic studies about it 8,16 .…”

Section: Introductionmentioning

confidence: 99%

Optical (DRUV-VIS) and magnetic (EPR) behavior of synthetic melanins

et al. 2012

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The properties of melanins prepared from L-dopa oxidation by both chemical and electrochemical methods are reported, searching for a material with more intense optical absorption in the visible region. The characterization of the samples have been done by cyclic voltammetry (CV), cronoamperometry (CA), Fourier transformed infrared spectroscopy (FTIR), electron paramagnetic resonance spectroscopy (EPR) and diffuse reflectance ultraviolet-visible spectroscopy (DRUV-VIS) techniques. The electrochemical method enhanced the organic free radical (spin) concentration and the absorption intensity in the visible region of the spectrum. The DRUV-VIS technique along with mathematical tools, such as the Kubelka-Munk remission function, were good options for the characterization of the final products.

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“…In this work we utilized the carbon paste (CP) electrode, which was previously used for studying melanin electrochemistry [6,15]. Dry melanin ghosts were crushed lightly to a powder with a clean glass rod and mixed by weight with CP (Bioanalytical Systems, BAS, West Lafayette, IN) at melanin /CP ratios of 10:90, 20:80 and 30:70.…”

Section: Electrodesmentioning

confidence: 99%

“…Dry melanin ghosts were crushed lightly to a powder with a clean glass rod and mixed by weight with CP (Bioanalytical Systems, BAS, West Lafayette, IN) at melanin /CP ratios of 10:90, 20:80 and 30:70. The melanin/CP mixtures were packed into electrode housings (BAS) as previously described [6,15]. The packed electrodes were stored in sterile, pH 7, 50 mM/L, phosphate buffered saline (PBS) at 25°C for at least one week to allow the melanin to hydrate.…”

Section: Electrodesmentioning

confidence: 99%

Gamma radiation interacts with melanin to alter its oxidation–reduction potential and results in electric current production

Turick

Ekechukwu²,

Milliken³

et al. 2011

Bioelectrochemistry

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The presence of melanin pigments in organisms is implicated in radioprotection and in some cases, enhanced growth in the presence of high levels of ionizing radiation. An understanding of this phenomenon will be useful in the design of radioprotective materials. However, the protective mechanism of microbial melanin in ionizing radiation fields has not yet been elucidated. Here we demonstrate through the electrochemical techniques of chronoamperometry, chronopotentiometry and cyclic voltammetry that microbial melanin is continuously oxidized in the presence of gamma radiation. Our findings establish that ionizing radiation interacts with melanin to alter its oxidationreduction potential. Sustained oxidation resulted in electric current production and was most pronounced in the presence of a reductant, which extended the redox cycling capacity of melanin. This work is the first to establish that gamma radiation alters the oxidation-reduction behavior of melanin, resulting in electric current production. The significance of the work is that it provides the first step in understanding the initial interactions between melanin and ionizing radiation taking place and offers some insight for production of biomimetic radioprotective materials.

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First electrochemical investigation of the redox properties of DOPA–melanins by means of a carbon paste electrode

Cited by 44 publications

References 13 publications

The physical and chemical properties of eumelanin

The physical and chemical properties of eumelanin

Optical (DRUV-VIS) and magnetic (EPR) behavior of synthetic melanins

Gamma radiation interacts with melanin to alter its oxidation–reduction potential and results in electric current production

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