Colloids and Surfaces A: Physicochemical and Engineering Aspects, Apr 1, 2021
Polydopamine (PDA) films allow to functionalize almost all materials with a conformal and chemica... more Polydopamine (PDA) films allow to functionalize almost all materials with a conformal and chemically active coating. These coatings can react with reducible metallic cations and with all kinds of molecules carrying nucleophilic groups. Recently, our team extended PDA chemistry to a vast repertoire of oxidants and to acidic conditions. However, the influence of changes in the method of PDA deposition on the properties of the obtained coatings, in particular the antioxidant properties, have not been sufficiently explored. It is anticipated that the antioxidant properties should depend on the film preparation method. A combination of experimental techniques, atomic force microscopy, cyclic voltammetry and X ray photoelectron spectroscopy are used to relate the antioxidant properties of PDA films to their structural features and to their chemical composition. It is demonstrated that the antioxidant properties of PDA films are not only dependent on the type of the employed oxidant – which can be expected to affect a variable density of oxidizable groups on the surface of PDA - but also on the oxidant film morphology and roughness
Oxidation of 6-nitrodopamine (1) with horseradish peroxidase (HRP)/H2O2 in 0.05 M phosphate buffe... more Oxidation of 6-nitrodopamine (1) with horseradish peroxidase (HRP)/H2O2 in 0.05 M phosphate buffer, pH 7.4 afforded as main product the novel 5-[4-(2-aminoethyl)-2-hydroxy-5-nitrophenoxy]-6, 7-dihydroxy-4-nitro-2, 3-dihydroindole (4). Similar oxidation of the 4-...
A TPCA-based, three-marker analysis has been used to demonstrate that the dimeric benzothiazolylt... more A TPCA-based, three-marker analysis has been used to demonstrate that the dimeric benzothiazolylthiazinoisoquinoline units recently identi\ufb01ed in natural and synthetic pheomelanins are dominant structural building blocks of red human hair pheomelanin. This \ufb01nding would prompt a revisit of pheomelanin build-up in terms of coupling of carboxylated benzothiazine intermediates into a speci\ufb01c BT-TIQ-related dimeric building block preceding further polymerization. Thus, BT-TIQ would reproduce all of the main chemical properties and spectral features of human pheomelanin. In this sense, BTTIQ compares to none of the low molecular weight intermediates so far isolated, including the trichochromes, and should, therefore, be duly considered in future models of pheomelanin structure
Colloids and Surfaces A: Physicochemical and Engineering Aspects, Apr 1, 2021
Polydopamine (PDA) films allow to functionalize almost all materials with a conformal and chemica... more Polydopamine (PDA) films allow to functionalize almost all materials with a conformal and chemically active coating. These coatings can react with reducible metallic cations and with all kinds of molecules carrying nucleophilic groups. Recently, our team extended PDA chemistry to a vast repertoire of oxidants and to acidic conditions. However, the influence of changes in the method of PDA deposition on the properties of the obtained coatings, in particular the antioxidant properties, have not been sufficiently explored. It is anticipated that the antioxidant properties should depend on the film preparation method. A combination of experimental techniques, atomic force microscopy, cyclic voltammetry and X ray photoelectron spectroscopy are used to relate the antioxidant properties of PDA films to their structural features and to their chemical composition. It is demonstrated that the antioxidant properties of PDA films are not only dependent on the type of the employed oxidant – which can be expected to affect a variable density of oxidizable groups on the surface of PDA - but also on the oxidant film morphology and roughness
Oxidation of 6-nitrodopamine (1) with horseradish peroxidase (HRP)/H2O2 in 0.05 M phosphate buffe... more Oxidation of 6-nitrodopamine (1) with horseradish peroxidase (HRP)/H2O2 in 0.05 M phosphate buffer, pH 7.4 afforded as main product the novel 5-[4-(2-aminoethyl)-2-hydroxy-5-nitrophenoxy]-6, 7-dihydroxy-4-nitro-2, 3-dihydroindole (4). Similar oxidation of the 4-...
A TPCA-based, three-marker analysis has been used to demonstrate that the dimeric benzothiazolylt... more A TPCA-based, three-marker analysis has been used to demonstrate that the dimeric benzothiazolylthiazinoisoquinoline units recently identi\ufb01ed in natural and synthetic pheomelanins are dominant structural building blocks of red human hair pheomelanin. This \ufb01nding would prompt a revisit of pheomelanin build-up in terms of coupling of carboxylated benzothiazine intermediates into a speci\ufb01c BT-TIQ-related dimeric building block preceding further polymerization. Thus, BT-TIQ would reproduce all of the main chemical properties and spectral features of human pheomelanin. In this sense, BTTIQ compares to none of the low molecular weight intermediates so far isolated, including the trichochromes, and should, therefore, be duly considered in future models of pheomelanin structure
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Papers by Marco d'Ischia