AFM investigations of self-assembled DOPA–melanin nano-aggregates

Jastrzębska, Maria; Mróz, Iwona; Barwiński, Bogdan; Wrzalik, R.; Boryczka, Stanisław

doi:10.1007/s10853-010-4575-4

Cited by 12 publications

(7 citation statements)

References 34 publications

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“…Although the optical microscope images might suggest fractal behavior, the AFM and SEM images clearly show the structures are not fractal. Previously, smaller filaments of ∼250 nm width have been reported using AFM, but these were obtained immediately after 72 h aeration 7 and not the 48 h aeration and two weeks incubation we have employed. Hence it seems possible the longer incubation time we are working with allows smaller filaments time to combine to produce the larger fibrils that we observe; although we cannot rule out we are simply observing the aggregation of larger structures.…”

Section: Resultsmentioning

confidence: 96%

“…Recent AFM studies have revealed morphological details on L-DOPA-eumelanin fibrils of width ∼250 nm and depth ∼50 nm that are formed upon drying shortly after aeration. 7 Here we present results on the spectroscopy and microscopy of L-DOPA-eumelanin fibrils and discuss them in the context of more commonly studied morphologies for eumelanin.…”

Section: Introductionmentioning

confidence: 98%

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Eumelanin fibrils

et al. 2012

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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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Section: Resultsmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 98%

Eumelanin fibrils

et al. 2012

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“…The self-assembly of these aggregates is owned by the interactions between particles. [39] Figure 4 (b) displays the topography of FMNPs-1, where few NPs can be observed along with disperse fragments of FMNPs-1, which suggests that the size of the particles is much superior to the radius of curvature of the AFM tip, ca. 10 nm.…”

Section: Preparation and Functionalization Of Melanin Nanoparticlesmentioning

confidence: 99%

Electro-responsive controlled drug delivery from melanin nanoparticles

Caldas

Santos

Rebelo

et al. 2020

International Journal of Pharmaceutics

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A n a Cl á u d i a S a n t o s , a p r e s e n t a d o s à F a c u l d a d e d e F a r má c i a d a Un i v e r s i d a d e d e Co i mb r a , p a r a a p r e c i a ç ã o n a p r e s t a ç ã o d e p r o v a s p ú b l i c a s d e Me s t r a d o I n t e g r a d o e m Ci ê n c i a s F a r ma c ê u t i c a s. s e t e mb r o 2 0 1 8 Eu, Mariana Elisabete Rodrigues Caldas, estudante do Mestrado Integrado em Ciências Farmacêuticas, com o nº 2012133041, declaro assumir toda a responsabilidade pelo conteúdo do Documento Relatório de Estágio e Monografia intitulada "Electro-responsive controlled drug delivery from melanin nanoparticles" apresentados à Faculdade de Farmácia da Universidade de Coimbra, no âmbito da unidade curricular de Estágio Curricular. Mais declaro que este Documento é um trabalho original e que toda e qualquer afirmação ou expressão, por mim utilizada, está referenciada na Bibliografia, segundo os critérios bibliográficos legalmente estabelecidos, salvaguardando sempre os Direitos de Autor, à exceção das minhas opiniões pessoais. Coimbra, 07 de setembro de 2018 (Mariana Elisabete Rodrigues Caldas) Palavras-chave: melanina; biopolímeros; material natural; nanopartícula; libertação de fármaco; libertação de fármaco sensível a estímulos elétricos.

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“…Melanin is ubiquitous natural pigment which is found in many organisms like skin, hair, brain, and eyes ,. This heterogeneous pigment is one of the polycyclic biopolymers with specific and functional properties that has attracted considerable attention in biological applications, including photoprotection, antioxidation, metal ion chelation, and free radical scavenging . Melanin plays a vital role in living organism due to its natural chelating ability for metal ions and regulation their amount in bio‐systems .…”

Section: Introductionmentioning

confidence: 99%

“…[24,25] This heterogeneous pigment is one of the polycyclic biopolymers with specific and functional properties that has attracted considerable attention in biological applications, including photoprotection, antioxidation, metal ion chelation, and free radical scavenging. [25][26][27][28] Melanin plays a vital role in living organism due to its natural chelating ability for metal ions and regulation their amount in bio-systems. [29] It should be mentioned that the chelating ability of melanin to metal ions in nanoscale increases owing to high surface to volume ratio of melanin NPs.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Naturally Active Melanin Nano‐Platforms Chelated with Barium Ions as a Potential X‐Ray‐Computed Tomography Contrast Agent

Nedaei

Delavari

2018

ChemistrySelect

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Facile preparation of biocompatible nano‐platforms for computed tomography (CT) is demanding. In this work, PEGylated melanin nanoparticles (MNPs) are prepared and reacted with barium ions as CT imaging contrast agent (Ba‐MNPs‐mPEG). It is found that the hydrodynamic size of MNPs is in accordance with size of MNPs measured by electron microscopy (4±1 nm). The zeta potential of MNPs reduces by PEGylation and chelating with Ba2+ ions. Fourier transformed infrared (FTIR) analysis proposed that OH and NH groups of MNPs are possible binding sites for Ba2+ ions. The prepared Ba‐MNPs‐mPEG shows no significant cytotoxicity at concentration up to 100 ppm of barium concentration after 24 h. Finally, our results indicated that the X‐ray attenuation of Ba‐MNPs‐mPEG is similar and slightly higher than Iohexol as the commercially available iodinated contrasting agent at the same concentrations.

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AFM investigations of self-assembled DOPA–melanin nano-aggregates

Cited by 12 publications

References 34 publications

Eumelanin fibrils

Eumelanin fibrils

Electro-responsive controlled drug delivery from melanin nanoparticles

Preparation of Naturally Active Melanin Nano‐Platforms Chelated with Barium Ions as a Potential X‐Ray‐Computed Tomography Contrast Agent

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