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Motovilov KA, Mostert AB. Melanin: Nature's 4th bioorganic polymer. SOFT MATTER 2024; 20:5635-5651. [PMID: 39012013 DOI: 10.1039/d4sm00491d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/17/2024]
Abstract
The pigments known as the melanins are widely recognized for their responsibility in the coloration of human skin, eyes, hair, and minimising the harmful effects of solar ultraviolet radiation. But specialists are aware that the melanins are present in all living kingdoms, barring viruses, and have functionality that extends beyond neutralizing ionising radiation. The ubiquitous presence of melanin in almost all human organs, recognized in recent years, as well as the presence of melanin in organisms that are evolutionarily distant from each other, indicate the fundamental importance of this class of material for all life forms. In this review, we argue for the need to accept melanins as the fourth primordial class of biological polymers, along with nucleic acids, proteins and polysaccharides. We consistently compare the properties of these canonical biological polymers with the properties of melanin and highlight key features that fundamentally distinguish melanins, their function and its mysteries.
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Affiliation(s)
- K A Motovilov
- Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Institutsky Lane 9, Dolgoprudny 141701, Moscow Region, Russia.
| | - A B Mostert
- Department of Physics and Centre for Integrative Semiconductor Materials, Swansea University Bay Campus, Fabian Way, Swansea SA1 8EN, UK
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2
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Ball V, Hirtzel J, Leks G, Frisch B, Talon I. Experimental Methods to Get Polydopamine Films: A Comparative Review on the Synthesis Methods, the Films' Composition and Properties. Macromol Rapid Commun 2023; 44:e2200946. [PMID: 36758219 DOI: 10.1002/marc.202200946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/07/2023] [Indexed: 02/11/2023]
Abstract
In 2007, polydopamine (PDA) films were shown to be formed spontaneously on the surface of all known classes of materials by simply dipping those substrates in an aerated dopamine solution at pH = 8.5 in the presence of Tris(hydroxymethyl) amino methane buffer. This universal deposition method has raised a burst of interest in surface science, owing not only to the universality of this water based one pot deposition method but also to the ease of secondary modifications. Since then, PDA films and particles are shown to have applications in energy conversion, water remediation systems, and last but not least in bioscience. The deposition of PDA films from aerated dopamine solutions is however a slow and inefficient process at ambient temperature with most of the formed material being lost as a precipitate. This incited to explore the possibility to get PDA and related films based on other catecholamines, using other oxidants than dissolved oxygen and other deposition methods. Those alternatives to get PDA and related films are reviewed and compared in this paper. It will appear that many more investigations are required to get better insights in the relationships between the preparation method of PDA and the properties of the obtained coatings.
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Affiliation(s)
- Vincent Ball
- Faculté de Chirurgie Dentaire, Université de Strasbourg, 8 rue Sainte Elisabeth, Strasbourg, 67000, France
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 1121, 1 rue Eugène Boeckel, Strasbourg, 670000, France
| | - Jordana Hirtzel
- Faculté de Chirurgie Dentaire, Université de Strasbourg, 8 rue Sainte Elisabeth, Strasbourg, 67000, France
- 3Bio Team, Laboratoire de Conception et Application de Molécules Bioactives, UMR 7199 Université de Strasbourg/CNRS, Faculté de Pharmacie, Illkirch, Cedex, F-67401, France
| | - Guillaume Leks
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 1121, 1 rue Eugène Boeckel, Strasbourg, 670000, France
- 3Bio Team, Laboratoire de Conception et Application de Molécules Bioactives, UMR 7199 Université de Strasbourg/CNRS, Faculté de Pharmacie, Illkirch, Cedex, F-67401, France
| | - Benoît Frisch
- 3Bio Team, Laboratoire de Conception et Application de Molécules Bioactives, UMR 7199 Université de Strasbourg/CNRS, Faculté de Pharmacie, Illkirch, Cedex, F-67401, France
| | - Isabelle Talon
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 1121, 1 rue Eugène Boeckel, Strasbourg, 670000, France
- Service de Chirurgie Pédiatrique, Hôpitaux Universitaires de Strasbourg, 1 rue Molière, Strasbourg, 67200, France
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3
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Liu Y, Chen Y, Yu Z, Zhang Y. Biological control of melanin biosynthesis pathway on prolific and pleochromatic induction of Lasiodiplodia theobromae. Arch Microbiol 2023; 205:46. [PMID: 36592230 DOI: 10.1007/s00203-022-03396-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 12/12/2022] [Accepted: 12/29/2022] [Indexed: 01/03/2023]
Abstract
To obtain a kind of microbial pigment with high yield and variety coloration by regulating the pigment synthesis pathway in this experiment, Lasiodiplodia theobromae was used to induce pigment secretion by prolific inducing factors (tyrosinase, Cu2+, stilbene glycoside) and pleochromatic inducing factors (L-tyrosine, L-cysteine, tricyclazole). The results showed that through single factor and compound culture, the most reasonable inducing formula was 150 ku/L tyrosinase, while tricyclazole at 10 mg/L for 30 days had a maximum color difference of 42.92 NBS with a reddish-brown color in 10 days. The melanin content increased gradually with the extension of culture time, and the pleochromatic inducing group was up to 3.47 mg/mL, higher than that of the prolific inducing group. However, the poor solubility of purified melanin with a diameter of 100-200 nm was observed in conventional solvents. Through effective induction, it is expected that L. theobromae can secrete melanin stably and be widely used in printing, dyeing, electronics, and the chemical industry.
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Affiliation(s)
- Yuansong Liu
- College of Design and Innovation, Wenzhou Polytechnic, Wenzhou, 325035, China. .,College of Materials Science and Technology, Beijing Forestry University, Beijing, 100083, China. .,Beijing Key Laboratory of Wood Science and Engineering, Beijing Forestry University, Beijing, 100083, China.
| | - Yunyun Chen
- College of Design and Innovation, Wenzhou Polytechnic, Wenzhou, 325035, China
| | - Zhiming Yu
- College of Materials Science and Technology, Beijing Forestry University, Beijing, 100083, China.,Beijing Key Laboratory of Wood Science and Engineering, Beijing Forestry University, Beijing, 100083, China
| | - Yang Zhang
- College of Materials Science and Technology, Beijing Forestry University, Beijing, 100083, China.,Beijing Key Laboratory of Wood Science and Engineering, Beijing Forestry University, Beijing, 100083, China
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4
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Galeb HA, Wilkinson EL, Stowell AF, Lin H, Murphy ST, Martin‐Hirsch PL, Mort RL, Taylor AM, Hardy JG. Melanins as Sustainable Resources for Advanced Biotechnological Applications. GLOBAL CHALLENGES (HOBOKEN, NJ) 2021; 5:2000102. [PMID: 33552556 PMCID: PMC7857133 DOI: 10.1002/gch2.202000102] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 11/04/2020] [Indexed: 05/17/2023]
Abstract
Melanins are a class of biopolymers that are widespread in nature and have diverse origins, chemical compositions, and functions. Their chemical, electrical, optical, and paramagnetic properties offer opportunities for applications in materials science, particularly for medical and technical uses. This review focuses on the application of analytical techniques to study melanins in multidisciplinary contexts with a view to their use as sustainable resources for advanced biotechnological applications, and how these may facilitate the achievement of the United Nations Sustainable Development Goals.
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Affiliation(s)
- Hanaa A. Galeb
- Department of ChemistryLancaster UniversityLancasterLA1 4YBUK
- Department of ChemistryScience and Arts CollegeRabigh CampusKing Abdulaziz UniversityJeddah21577Saudi Arabia
| | - Emma L. Wilkinson
- Department of Biomedical and Life SciencesLancaster UniversityLancasterLA1 4YGUK
| | - Alison F. Stowell
- Department of Organisation, Work and TechnologyLancaster University Management SchoolLancaster UniversityLancasterLA1 4YXUK
| | - Hungyen Lin
- Department of EngineeringLancaster UniversityLancasterLA1 4YWUK
| | - Samuel T. Murphy
- Department of EngineeringLancaster UniversityLancasterLA1 4YWUK
- Materials Science InstituteLancaster UniversityLancasterLA1 4YBUK
| | - Pierre L. Martin‐Hirsch
- Lancashire Teaching Hospitals NHS TrustRoyal Preston HospitalSharoe Green LanePrestonPR2 9HTUK
| | - Richard L. Mort
- Department of Biomedical and Life SciencesLancaster UniversityLancasterLA1 4YGUK
| | - Adam M. Taylor
- Lancaster Medical SchoolLancaster UniversityLancasterLA1 4YWUK
| | - John G. Hardy
- Department of ChemistryLancaster UniversityLancasterLA1 4YBUK
- Materials Science InstituteLancaster UniversityLancasterLA1 4YBUK
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5
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15N NMR Shifts of Eumelanin Building Blocks in Water: A Combined Quantum Mechanics/Statistical Mechanics Approach. Molecules 2020; 25:molecules25163616. [PMID: 32784827 PMCID: PMC7465604 DOI: 10.3390/molecules25163616] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/03/2020] [Accepted: 08/04/2020] [Indexed: 02/05/2023] Open
Abstract
Theoretical results for the magnetic shielding of protonated and unprotonated nitrogens of eumelanin building blocks including monomers, dimers, and tetramers in gas phase and water are presented. The magnetic property in water was determined by carrying out Monte Carlo statistical mechanics sampling combined with quantum mechanics calculations based on the gauge-including atomic orbitals approach. The results show that the environment polarization can have a marked effect on nitrogen magnetic shieldings, especially for the unprotonated nitrogens. Large contrasts of the oligomerization effect on magnetic shielding show a clear distinction between eumelanin building blocks in solution, which could be detected in nuclear magnetic resonance experiments. Calculations for a π-stacked structure defined by the dimer of a tetrameric building block indicate that unprotonated N atoms are significantly deshielded upon π stacking, whereas protonated N atoms are slightly shielded. The results stress the interest of NMR experiments for a better understanding of the eumelanin complex structure.
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7
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Facile fabrication and biological imaging applications of salicylaldehyde based fluorescent organic nanoparticles with aggregation-induced emission and ESIPT feature. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111331] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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8
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Tissue-specific geometry and chemistry of modern and fossilized melanosomes reveal internal anatomy of extinct vertebrates. Proc Natl Acad Sci U S A 2019; 116:17880-17889. [PMID: 31427524 PMCID: PMC6731645 DOI: 10.1073/pnas.1820285116] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Recent reports of nonintegumentary melanosomes in fossils hint at functions for melanin beyond color production, but the biology and evolution of internal melanins are poorly understood. Our results show that internal melanosomes are widespread in diverse fossil and modern vertebrates and have tissue-specific geometries and metal chemistries. Tissue-specific chemical signatures can persist in fossils despite some diagenetic overprint, allowing the reconstruction of internal soft-tissue anatomy in fossil vertebrates, and suggest that links between melanin and metal regulation have deep evolutionary origins in vertebrates. Recent discoveries of nonintegumentary melanosomes in extant and fossil amphibians offer potential insights into the physiological functions of melanin not directly related to color production, but the phylogenetic distribution and evolutionary history of these internal melanosomes has not been characterized systematically. Here, we present a holistic method to discriminate among melanized tissues by analyzing the anatomical distribution, morphology, and chemistry of melanosomes in various tissues in a phylogenetically broad sample of extant and fossil vertebrates. Our results show that internal melanosomes in all extant vertebrates analyzed have tissue-specific geometries and elemental signatures. Similar distinct populations of preserved melanosomes in phylogenetically diverse vertebrate fossils often map onto specific anatomical features. This approach also reveals the presence of various melanosome-rich internal tissues in fossils, providing a mechanism for the interpretation of the internal anatomy of ancient vertebrates. Collectively, these data indicate that vertebrate melanins share fundamental physiological roles in homeostasis via the scavenging and sequestering of metals and suggest that intimate links between melanin and metal metabolism in vertebrates have deep evolutionary origins.
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9
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Motovilov KA, Grinenko V, Savinov M, Gagkaeva ZV, Kadyrov LS, Pronin AA, Bedran ZV, Zhukova ES, Mostert AB, Gorshunov BP. Redox chemistry in the pigment eumelanin as a function of temperature using broadband dielectric spectroscopy. RSC Adv 2019; 9:3857-3867. [PMID: 35518099 PMCID: PMC9060503 DOI: 10.1039/c8ra09093a] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 01/22/2019] [Indexed: 12/12/2022] Open
Abstract
We demonstrate on synthetic eumelanin that biomolecular conductivity models should account for temperature and hydration effects coherently.
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Affiliation(s)
| | - V. Grinenko
- Institute for Solid State and Materials Physics
- TU Dresden
- Dresden
- Germany
- Institute for Metallic Materials
| | - M. Savinov
- Institute of Physics AS CR
- Praha 8
- Czech Republic
| | | | | | - A. A. Pronin
- Prokhorov General Physics Institute of the Russian Academy of Sciences
- Moscow
- Russia
| | - Z. V. Bedran
- Moscow Institute of Physics and Technology
- Russia
| | - E. S. Zhukova
- Moscow Institute of Physics and Technology
- Russia
- Prokhorov General Physics Institute of the Russian Academy of Sciences
- Moscow
- Russia
| | | | - B. P. Gorshunov
- Moscow Institute of Physics and Technology
- Russia
- Prokhorov General Physics Institute of the Russian Academy of Sciences
- Moscow
- Russia
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Mondal S, Thampi A, Puranik M. Kinetics of Melanin Polymerization during Enzymatic and Nonenzymatic Oxidation. J Phys Chem B 2018; 122:2047-2063. [PMID: 29364665 DOI: 10.1021/acs.jpcb.7b07941] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Melanin is an abundant biopigment in the animal kingdom, but its structure remains poorly understood. This is a substantial impediment to understanding the mechanistic origin of its observed functions. Proposed models of melanin structure include aggregates of both linear and macrocyclic units and noncovalently held monomers. Both models are broadly in agreement with current experimental data. To constrain the structural and kinetic models of melanin, experimental data of high resolution with chemical specificity accompanied by atomistic modeling are required. We have addressed this by obtaining electronic absorption, infrared, and ultraviolet resonance Raman (RR) spectra of melanin at several wavelengths of excitation that are sensitive to small changes in structure. From these experiments, we observed kinetics of the formation of different species en route to melanin polymerization. Exclusive chemical signatures of monomer 3,4-dihydroxyphenylalanine (dopa), intermediate dopachrome (DC), and early-time polymer are established through their vibrational bands at 1292, 1670, and 1616 cm-1 respectively. Direct evidence of reduced heterogeneity of melanin oligomers in tyrosinase-induced formation is provided from experimental measurements of vibrational bandwidths. Models made with density functional theory show that the linear homopolymeric structures of 5,6-dihydroxyindole can account for experimentally observed wavenumbers and broad bandwidth in Raman spectra of dopa-melanin. We capture resonance Raman (RR) signature of DC, the intermediate stabilized by the enzyme tyrosinase, for the first time in an enzyme-assisted melanization reaction using 488 nm excitation wavelength and propose that this wavelength can be used to probe reaction intermediates of melanin formation in solution.
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Affiliation(s)
- Sayan Mondal
- Indian Institute of Science Education and Research , Pune 411008, India
| | - Arya Thampi
- Indian Institute of Science Education and Research , Pune 411008, India
| | - Mrinalini Puranik
- Indian Institute of Science Education and Research , Pune 411008, India
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11
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Zucca FA, Segura-Aguilar J, Ferrari E, Muñoz P, Paris I, Sulzer D, Sarna T, Casella L, Zecca L. Interactions of iron, dopamine and neuromelanin pathways in brain aging and Parkinson's disease. Prog Neurobiol 2017; 155:96-119. [PMID: 26455458 PMCID: PMC4826627 DOI: 10.1016/j.pneurobio.2015.09.012] [Citation(s) in RCA: 417] [Impact Index Per Article: 59.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 09/14/2015] [Accepted: 09/17/2015] [Indexed: 12/11/2022]
Abstract
There are several interrelated mechanisms involving iron, dopamine, and neuromelanin in neurons. Neuromelanin accumulates during aging and is the catecholamine-derived pigment of the dopamine neurons of the substantia nigra and norepinephrine neurons of the locus coeruleus, the two neuronal populations most targeted in Parkinson's disease. Many cellular redox reactions rely on iron, however an altered distribution of reactive iron is cytotoxic. In fact, increased levels of iron in the brain of Parkinson's disease patients are present. Dopamine accumulation can induce neuronal death; however, excess dopamine can be removed by converting it into a stable compound like neuromelanin, and this process rescues the cell. Interestingly, the main iron compound in dopamine and norepinephrine neurons is the neuromelanin-iron complex, since neuromelanin is an effective metal chelator. Neuromelanin serves to trap iron and provide neuronal protection from oxidative stress. This equilibrium between iron, dopamine, and neuromelanin is crucial for cell homeostasis and in some cellular circumstances can be disrupted. Indeed, when neuromelanin-containing organelles accumulate high load of toxins and iron during aging a neurodegenerative process can be triggered. In addition, neuromelanin released by degenerating neurons activates microglia and the latter cause neurons death with further release of neuromelanin, then starting a self-propelling mechanism of neuroinflammation and neurodegeneration. Considering the above issues, age-related accumulation of neuromelanin in dopamine neurons shows an interesting link between aging and neurodegeneration.
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Affiliation(s)
- Fabio A Zucca
- Institute of Biomedical Technologies, National Research Council of Italy, Segrate, Milan, Italy
| | - Juan Segura-Aguilar
- Faculty of Medicine, Molecular and Clinical Pharmacology, ICBM, University of Chile, Santiago, Chile
| | - Emanuele Ferrari
- Institute of Biomedical Technologies, National Research Council of Italy, Segrate, Milan, Italy
| | - Patricia Muñoz
- Faculty of Medicine, Molecular and Clinical Pharmacology, ICBM, University of Chile, Santiago, Chile
| | - Irmgard Paris
- Faculty of Medicine, Molecular and Clinical Pharmacology, ICBM, University of Chile, Santiago, Chile; Department of Basic Sciences, Faculty of Sciences, Santo Tomás University, Viña del Mar, Chile
| | - David Sulzer
- Department of Psychiatry, Columbia University Medical Center, New York, NY, USA; Department of Neurology, Columbia University Medical Center, New York, NY, USA; Department of Pharmacology, Columbia University Medical Center, New York, NY, USA
| | - Tadeusz Sarna
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Luigi Casella
- Department of Chemistry, University of Pavia, Pavia, Italy
| | - Luigi Zecca
- Institute of Biomedical Technologies, National Research Council of Italy, Segrate, Milan, Italy.
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12
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Lin B, Kong L, Hodgson PD, Mudie S, Hawley A, Dumée LF. Controlled porosity and pore size of nano-porous gold by thermally assisted chemical dealloying – a SAXS study. RSC Adv 2017. [DOI: 10.1039/c6ra28423j] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Nano-porous metals offer great potential for applications such as bio-sensors, chemical reactors, platforms for cell growth, and media for separation because of their high surface area and reactivity at the nanoscale.
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Affiliation(s)
- Bao Lin
- Deakin University
- Australia Institute for Frontier Materials
- Australia
| | - Lingxue Kong
- Deakin University
- Australia Institute for Frontier Materials
- Australia
| | - Peter D. Hodgson
- Deakin University
- Australia Institute for Frontier Materials
- Australia
| | | | | | - Ludovic F. Dumée
- Deakin University
- Australia Institute for Frontier Materials
- Australia
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13
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Jeppe KJ, Yang J, Long SM, Carew ME, Zhang X, Pettigrove V, Hoffmann AA. Detecting copper toxicity in sediments: from the subindividual level to the population level. J Appl Ecol 2016. [DOI: 10.1111/1365-2664.12840] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Katherine J. Jeppe
- Centre for Aquatic Pollution Identification and Management (CAPIM) School of BioSciences The University of Melbourne Royal Pde Parkville Vic. 3010 Australia
| | - Jianghua Yang
- State Key Laboratory of Pollution Control & Resource Reuse School of the Environment Nanjing University Nanjing 210046 China
| | - Sara M. Long
- Centre for Aquatic Pollution Identification and Management (CAPIM) School of BioSciences The University of Melbourne Royal Pde Parkville Vic. 3010 Australia
| | - Melissa E. Carew
- School of BioSciences The University of Melbourne Bio21 Molecular Science and Biotechnology Institute 30 Flemington Rd Parkville Vic. 3010 Australia
| | - Xiaowei Zhang
- State Key Laboratory of Pollution Control & Resource Reuse School of the Environment Nanjing University Nanjing 210046 China
| | - Vincent Pettigrove
- Centre for Aquatic Pollution Identification and Management (CAPIM) School of BioSciences The University of Melbourne Royal Pde Parkville Vic. 3010 Australia
| | - Ary A. Hoffmann
- School of BioSciences The University of Melbourne Bio21 Molecular Science and Biotechnology Institute 30 Flemington Rd Parkville Vic. 3010 Australia
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14
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d'Ischia M, Wakamatsu K, Cicoira F, Di Mauro E, Garcia-Borron JC, Commo S, Galván I, Ghanem G, Kenzo K, Meredith P, Pezzella A, Santato C, Sarna T, Simon JD, Zecca L, Zucca FA, Napolitano A, Ito S. Melanins and melanogenesis: from pigment cells to human health and technological applications. Pigment Cell Melanoma Res 2016; 28:520-44. [PMID: 26176788 DOI: 10.1111/pcmr.12393] [Citation(s) in RCA: 279] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 06/30/2015] [Indexed: 12/22/2022]
Abstract
During the past decade, melanins and melanogenesis have attracted growing interest for a broad range of biomedical and technological applications. The burst of polydopamine-based multifunctional coatings in materials science is just one example, and the list may be expanded to include melanin thin films for organic electronics and bioelectronics, drug delivery systems, functional nanoparticles and biointerfaces, sunscreens, environmental remediation devices. Despite considerable advances, applied research on melanins and melanogenesis is still far from being mature. A closer intersectoral interaction between research centers is essential to raise the interests and increase the awareness of the biomedical, biomaterials science and hi-tech sectors of the manifold opportunities offered by pigment cells and related metabolic pathways. Starting from a survey of biological roles and functions, the present review aims at providing an interdisciplinary perspective of melanin pigments and related pathway with a view to showing how it is possible to translate current knowledge about physical and chemical properties and control mechanisms into new bioinspired solutions for biomedical, dermocosmetic, and technological applications.
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Affiliation(s)
- Marco d'Ischia
- Department of Chemical Sciences, University of Naples Federico II, Naples, Italy
| | - Kazumasa Wakamatsu
- Department of Chemistry, Fujita Health University School of Health Sciences, Toyoake, Aichi, Japan
| | - Fabio Cicoira
- Department of Chemical Engineering, École Polytechnique de Montréal, Montréal, QC, Canada
| | - Eduardo Di Mauro
- Department of Engineering Physics, École Polytechnique de Montréal, Montréal, QC, Canada
| | | | - Stephane Commo
- L'Oréal Recherche & Innovation, Aulnay sous Bois, France
| | - Ismael Galván
- Departamento de Ecología Evolutiva, Estación Biológica de Doñana - CSIC, Sevilla, Spain
| | - Ghanem Ghanem
- LOCE, Institut J. Bordet, Université Libre de Bruxelles, Brussels, Belgium
| | - Koike Kenzo
- Development Research - Hair Care Products, KAO Corporation, Sumida, Tokyo, Japan
| | - Paul Meredith
- Centre for Organic Photonics and Electronics, School of Mathematics and Physics, University of Queensland, Brisbane, Qld, Australia
| | - Alessandro Pezzella
- Department of Chemical Sciences, University of Naples Federico II, Naples, Italy
| | - Clara Santato
- Department of Engineering Physics, École Polytechnique de Montréal, Montréal, QC, Canada
| | - Tadeusz Sarna
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - John D Simon
- Department of Chemistry, University of Virginia, Charlottesville, VA, USA
| | - Luigi Zecca
- Institute of Biomedical Technologies - National Research Council of Italy, Milan, Italy
| | - Fabio A Zucca
- Institute of Biomedical Technologies - National Research Council of Italy, Milan, Italy
| | | | - Shosuke Ito
- Department of Chemistry, Fujita Health University School of Health Sciences, Toyoake, Aichi, Japan
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15
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Kong J, Seyed Shahabadi SI, Lu X. Integration of inorganic nanostructures with polydopamine-derived carbon: tunable morphologies and versatile applications. NANOSCALE 2016; 8:1770-1788. [PMID: 26750427 DOI: 10.1039/c5nr06711a] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Polydopamine (PDA), a mussel adhesive-inspired biomimetic polymer, has attracted tremendous attention owing to its extremely versatile adhesion properties, facile aqueous coating process, capability of self-assembly to form nanostructures, and abundant surface functional groups for secondary modification. PDA is also a fantastic carbon source because it gives nitrogen (N)-doped graphite-like carbon in high yield, and the carbonized PDA (C-PDA) thin coatings have similar properties to those of N-doped multilayered graphene, i.e., they exhibit high electrical conductivity, and good electrochemical and mechanical properties. In comparison with other carbon sources, an outstanding feature of PDA lies in its ease of integration with inorganic nanostructures and capability for easy tailoring the structure and morphology of the resultant composite nanostructures. In this article, different routes for the preparation of C-PDA-based composite nanostructures, such as carbon/metal oxide and carbon/Si hollow, mesoporous, core-shell, yolk-shell nanostructures, are introduced with typical examples. The structures, morphologies and properties of the C-PDA-based composite nanostructures are also reviewed, and their potential applications in various engineering fields, such as energy storage, solar water splitting, flexible electronics, catalysis, sensing and environmental engineering, are highlighted. Finally a future outlook for this fascinating composite-nanostructure enabler is also presented.
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Affiliation(s)
- Junhua Kong
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798.
| | - Seyed Ismail Seyed Shahabadi
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798.
| | - Xuehong Lu
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798.
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16
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Analysis of pH-dependent Structure and Mass Transfer Characteristics of Polydopamine Membranes by Molecular Dynamics Simulation. Chin J Chem Eng 2014. [DOI: 10.1016/j.cjche.2014.09.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Perna G, Lasalvia M, D’Antonio P, Mallardi A, Palazzo G, Fiocco D, Gallone A, Cicero R, Capozzi V. Morphology of synthetic DOPA-eumelanin deposited on glass and mica substrates: An atomic force microscopy investigation. Micron 2014; 64:28-33. [DOI: 10.1016/j.micron.2014.03.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 03/25/2014] [Accepted: 03/30/2014] [Indexed: 11/27/2022]
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18
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He P, Xu B, Wang PP, Liu H, Wang X. A monolayer polyoxometalate superlattice. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:4339-4344. [PMID: 24782444 DOI: 10.1002/adma.201400856] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Revised: 03/19/2014] [Indexed: 06/03/2023]
Affiliation(s)
- Peilei He
- Department of Chemistry, Tsinghua University, Beijing, 100084, China
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19
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Chen CT, Chuang C, Cao J, Ball V, Ruch D, Buehler MJ. Excitonic effects from geometric order and disorder explain broadband optical absorption in eumelanin. Nat Commun 2014; 5:3859. [PMID: 24848640 DOI: 10.1038/ncomms4859] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Accepted: 04/11/2014] [Indexed: 12/21/2022] Open
Abstract
Eumelanin is a ubiquitous biological pigment, and the origin of its broadband absorption spectrum has long been a topic of scientific debate. Here, we report a first-principles computational investigation to explain its broadband absorption feature. These computations are complemented by experimental results showing a broadening of the absorption spectra of dopamine solutions upon their oxidation. We consider a variety of eumelanin molecular structures supported by experiments or theoretical studies, and calculate the absorption spectra with proper account of the excitonic couplings based on the Frenkel exciton model. The interplay of geometric order and disorder of eumelanin aggregate structures broadens the absorption spectrum and gives rise to a relative enhancement of absorption intensity at the higher-energy end, proportional to the cube of absorption energy. These findings show that the geometric disorder model is as able as the chemical disorder model, and complements this model, to describe the optical properties of eumelanin.
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Affiliation(s)
- Chun-Teh Chen
- Laboratory for Atomistic and Molecular Mechanics (LAMM), Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Room 1-235A&B, Cambridge, Massachusetts 02139, USA
| | - Chern Chuang
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
| | - Jianshu Cao
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
| | - Vincent Ball
- Faculté de Chirurgie Dentaire, Université de Strasbourg, 8 rue Sainte Elizabeth, 67000 Strasbourg, France and Unité INSERM 1121, 11 rue Humann, 67085 Strasbourg Cédex, France
| | - David Ruch
- Department for Advanced Materials and Structures, Centre de Recherche Public Henri Tudor, 5 rue Bommel, L-4940 Hautcharage, Luxembourg
| | - Markus J Buehler
- 1] Laboratory for Atomistic and Molecular Mechanics (LAMM), Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Room 1-235A&B, Cambridge, Massachusetts 02139, USA [2] Center for Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA [3] Center for Computational Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
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20
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Costa TG, Szpoganicz B, Caramori GF, de Almeida VR, Mangrich AS, Mangoni AP. Spectroscopy and theoretical studies of natural melanin (eumelanin) and its complexation by iron(III). J COORD CHEM 2014. [DOI: 10.1080/00958972.2014.905686] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Thiago G. Costa
- Laboratório de Equilíbrio Químico, Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Bruno Szpoganicz
- Laboratório de Equilíbrio Químico, Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Giovanni F. Caramori
- Grupo de Estrutura Eletrônica Molecular, Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Vicente R. de Almeida
- Laboratório de Equilíbrio Químico, Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Antônio S. Mangrich
- Laboratório de Química Inorgânica, Universidade Federal do Paraná, Curitiba, Brazil
| | - Ana P. Mangoni
- Laboratório de Química Inorgânica, Universidade Federal do Paraná, Curitiba, Brazil
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21
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Gorniak T, Haraszti T, Garamus VM, Buck AR, Senkbeil T, Priebe M, Hedberg-Buenz A, Koehn D, Salditt T, Grunze M, Anderson MG, Rosenhahn A. Nano-scale morphology of melanosomes revealed by small-angle X-ray scattering. PLoS One 2014; 9:e90884. [PMID: 24621581 PMCID: PMC3951238 DOI: 10.1371/journal.pone.0090884] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 01/27/2014] [Indexed: 12/02/2022] Open
Abstract
Melanosomes are highly specialized organelles that produce and store the pigment melanin, thereby fulfilling essential functions within their host organism. Besides having obvious cosmetic consequences – determining the color of skin, hair and the iris – they contribute to photochemical protection from ultraviolet radiation, as well as to vision (by defining how much light enters the eye). Though melanosomes can be beneficial for health, abnormalities in their structure can lead to adverse effects. Knowledge of their ultrastructure will be crucial to gaining insight into the mechanisms that ultimately lead to melanosome-related diseases. However, due to their small size and electron-dense content, physiologically intact melanosomes are recalcitrant to study by common imaging techniques such as light and transmission electron microscopy. In contrast, X-ray-based methodologies offer both high spatial resolution and powerful penetrating capabilities, and thus are well suited to study the ultrastructure of electron-dense organelles in their natural, hydrated form. Here, we report on the application of small-angle X-ray scattering – a method effective in determining the three-dimensional structures of biomolecules – to whole, hydrated murine melanosomes. The use of complementary information from the scattering signal of a large ensemble of suspended organelles and from single, vitrified specimens revealed a melanosomal sub-structure whose surface and bulk properties differ in two commonly used inbred strains of laboratory mice. Whereas melanosomes in C57BL/6J mice have a well-defined surface and are densely packed with 40-nm units, their counterparts in DBA/2J mice feature a rough surface, are more granular and consist of 60-nm building blocks. The fact that these strains have different coat colors and distinct susceptibilities to pigment-related eye disease suggest that these differences in size and packing are of biological significance.
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Affiliation(s)
- Thomas Gorniak
- Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany; Applied Physical Chemistry, Ruprecht-Karls-University Heidelberg, Heidelberg, Germany; Analytical Chemistry - Biointerfaces, Ruhr-University Bochum, Bochum, Germany
| | - Tamas Haraszti
- Applied Physical Chemistry, Ruprecht-Karls-University Heidelberg, Heidelberg, Germany; Max-Planck-Institute for Intelligent Systems, Stuttgart, Germany
| | - Vasyl M Garamus
- Helmholtz-Zentrum Geesthacht, Zentrum für Material- und Küstenforschung GmbH, Geesthacht, Germany
| | - Andreas R Buck
- Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany; Applied Physical Chemistry, Ruprecht-Karls-University Heidelberg, Heidelberg, Germany; Analytical Chemistry - Biointerfaces, Ruhr-University Bochum, Bochum, Germany
| | - Tobias Senkbeil
- Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany; Applied Physical Chemistry, Ruprecht-Karls-University Heidelberg, Heidelberg, Germany
| | - Marius Priebe
- Institute for X-Ray Physics, University of Göttingen, Göttingen, Germany
| | - Adam Hedberg-Buenz
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, Iowa, United States of America; Center for the Prevention and Treatment of Visual Loss, Iowa City Veterans Affairs (VA) Health Care System, Iowa City, Iowa, United States of America
| | - Demelza Koehn
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, Iowa, United States of America
| | - Tim Salditt
- Institute for X-Ray Physics, University of Göttingen, Göttingen, Germany
| | - Michael Grunze
- Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany; Applied Physical Chemistry, Ruprecht-Karls-University Heidelberg, Heidelberg, Germany
| | - Michael G Anderson
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, Iowa, United States of America; Center for the Prevention and Treatment of Visual Loss, Iowa City Veterans Affairs (VA) Health Care System, Iowa City, Iowa, United States of America
| | - Axel Rosenhahn
- Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany; Applied Physical Chemistry, Ruprecht-Karls-University Heidelberg, Heidelberg, Germany; Analytical Chemistry - Biointerfaces, Ruhr-University Bochum, Bochum, Germany
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22
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Ball V, Gracio J, Vila M, Singh MK, Metz-Boutigue MH, Michel M, Bour J, Toniazzo V, Ruch D, Buehler MJ. Comparison of synthetic dopamine-eumelanin formed in the presence of oxygen and Cu2+ cations as oxidants. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:12754-12761. [PMID: 24015825 DOI: 10.1021/la4029782] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
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 "polydopamine films". 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 "polydopamine films" 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-eumelanins produced from dopamine in the presence of either air (O2 being the oxidant) or Cu(2+) 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 Cu(2+) incorporation in Cu dopamine-eumelanin.
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Affiliation(s)
- Vincent Ball
- Faculté de Chirurgie Dentaire, Université de Strasbourg , 1 Place de l'Hôpital, 67000 Strasbourg, France
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23
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Kanteev M, Goldfeder M, Chojnacki M, Adir N, Fishman A. The mechanism of copper uptake by tyrosinase from Bacillus megaterium. J Biol Inorg Chem 2013; 18:895-903. [DOI: 10.1007/s00775-013-1034-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 08/12/2013] [Indexed: 10/26/2022]
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24
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Pham CLL, Kirby N, Wood K, Ryan T, Roberts B, Sokolova A, Barnham KJ, Masters CL, Knott RB, Cappai R, Curtain CC, Rekas A. Guanidine hydrochloride denaturation of dopamine-induced α-synuclein oligomers: A small-angle X-ray scattering study. Proteins 2013; 82:10-21. [DOI: 10.1002/prot.24332] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 05/10/2013] [Accepted: 05/19/2013] [Indexed: 01/18/2023]
Affiliation(s)
- Chi L. L. Pham
- Department of Pathology and Bio21 Molecular Science and Technology Institute; The University of Melbourne; Victoria 3010 Australia
| | - Nigel Kirby
- SAXS/WAXS Beamline, The Australian Synchrotron; Clayton Victoria 3168 Australia
| | - Kathleen Wood
- Australian Nuclear Science and Technology Organisation (ANSTO); Kirrawee New South Wales 2232 Australia
| | - Timothy Ryan
- The University of Melbourne, Florey Institute of Neuroscience and Mental Health; Victoria 3010 Australia
| | - Blaine Roberts
- The University of Melbourne, Florey Institute of Neuroscience and Mental Health; Victoria 3010 Australia
| | - Anna Sokolova
- Australian Nuclear Science and Technology Organisation (ANSTO); Kirrawee New South Wales 2232 Australia
| | - Kevin J. Barnham
- The University of Melbourne, Florey Institute of Neuroscience and Mental Health; Victoria 3010 Australia
| | - Colin L. Masters
- The University of Melbourne, Florey Institute of Neuroscience and Mental Health; Victoria 3010 Australia
| | - Robert B. Knott
- Australian Nuclear Science and Technology Organisation (ANSTO); Kirrawee New South Wales 2232 Australia
| | - Roberto Cappai
- Department of Pathology and Bio21 Molecular Science and Technology Institute; The University of Melbourne; Victoria 3010 Australia
| | - Cyril C. Curtain
- Department of Pathology and Bio21 Molecular Science and Technology Institute; The University of Melbourne; Victoria 3010 Australia
- The University of Melbourne, Florey Institute of Neuroscience and Mental Health; Victoria 3010 Australia
| | - Agata Rekas
- Australian Nuclear Science and Technology Organisation (ANSTO); Kirrawee New South Wales 2232 Australia
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25
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Chen CT, Ball V, de Almeida Gracio JJ, Singh MK, Toniazzo V, Ruch D, Buehler MJ. Self-assembly of tetramers of 5,6-dihydroxyindole explains the primary physical properties of eumelanin: experiment, simulation, and design. ACS NANO 2013; 7:1524-1532. [PMID: 23320483 DOI: 10.1021/nn305305d] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Eumelanin is a ubiquitous pigment in nature and has many intriguing physicochemical properties, such as broad-band and monotonous absorption spectrum, antioxidant and free radical scavenging behavior, and strong nonradiative relaxation of photoexcited electronic states. These properties are highly related to its structural and mechanical properties and make eumelanin a fascinating candidate for the design of multifunctional nanomaterials. Here we report joint experimental-computational investigation of the structural and mechanical properties of eumelanin assemblies produced from dopamine, revealing that the mass density of dry eumelanin is 1.55 g/cm³ and its Young's modulus is ≈5 GPa. We also find that wet eumelanin has a lower mass density and Young's modulus depending on the water-to-melanin ratio. Most importantly, our data show that eumelanin molecules tend to form secondary structures based on noncovalent π stacking in both dry and wet conditions, with an interlayer distance between eumelanin molecules of 3.3 Å. Corresponding transmission electron microscope images confirm the supramolecular organization predicted in our simulations. Our simulations show that eumelanin is an isotropic material at a larger scale when eumelanin molecules are randomly oriented to form secondary structures. These results are in good agreement with experimental observations, density functional theory calculations, and bridge the gap between earlier experimental and small-scale quantum mechanical studies of eumelanin. We use the knowledge acquired from the simulations to select a partner molecule, a cationic phthalocyanine, allowing us to produce layer-by-layer films containing eumelanin that display an electrical conductivity 5 orders of magnitudes higher than that of pure eumelanin films.
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Affiliation(s)
- Chun-Teh Chen
- Laboratory for Atomistic and Molecular Mechanics, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Room 1-235A&B, Cambridge, Massachusetts 02139, USA
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26
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Corani A, Huijser A, Iadonisi A, Pezzella A, Sundström V, d’Ischia M. Bottom-Up Approach to Eumelanin Photoprotection: Emission Dynamics in Parallel Sets of Water-Soluble 5,6-Dihydroxyindole-Based Model Systems. J Phys Chem B 2012; 116:13151-8. [DOI: 10.1021/jp306436f] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alice Corani
- Department of Chemical Physics, Lund University, Box 124, 221 00 Lund, Sweden
| | - Annemarie Huijser
- Department of Chemical Physics, Lund University, Box 124, 221 00 Lund, Sweden
| | - Alfonso Iadonisi
- Department of Chemical Sciences, University of Naples “Federico II”, Via
Cintia, 80126 Naples, Italy
| | - Alessandro Pezzella
- Department of Chemical Sciences, University of Naples “Federico II”, Via
Cintia, 80126 Naples, Italy
| | - Villy Sundström
- Department of Chemical Physics, Lund University, Box 124, 221 00 Lund, Sweden
| | - Marco d’Ischia
- Department of Chemical Sciences, University of Naples “Federico II”, Via
Cintia, 80126 Naples, Italy
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27
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Arzillo M, Mangiapia G, Pezzella A, Heenan RK, Radulescu A, Paduano L, d'Ischia M. Eumelanin buildup on the nanoscale: aggregate growth/assembly and visible absorption development in biomimetic 5,6-dihydroxyindole polymerization. Biomacromolecules 2012; 13:2379-90. [PMID: 22651227 DOI: 10.1021/bm3006159] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Establishing structure-property relationships in the black insoluble eumelanins, the key determinants of human pigmentation and skin photoprotective system, is a considerable conceptual and experimental challenge in the current drive for elucidation of the biological roles of these biopolymers and their application as advanced materials for organoelectronics. Herein, we report a new breakthrough toward this goal by the first detailed investigation on the nanoscale level of the oxidative polymerization of 5,6-dihydroxyindole (DHI), a model process of eumelanin synthesis. On the basis of a combined use of spectrophotometry, dynamic light scattering (DLS), and small-angle neutron scattering (SANS) investigations, it was possible to unveil the dynamics of the aggregation process before precipitation, the key relationships with visible light absorption and the shape of fundamental aggregates. The results indicated a polymerization mechanism of the type: Polymer(n) + DHI(x) = Polymer(n+x), where DHI(x) indicates monomer, dimer, or low oligomers (x ≤ 5). During polymerization, visible absorption increases rapidly, reaching a plateau. Particle growth proceeds slowly, with formation of 2-D structures ~55 nm thick, until precipitation occurs, that is, when large aggregates with a maximum hydrodynamic radius (R(h)) of ~1200 nm are formed. Notably, markedly smaller R(h) values, up to ~110 nm, were determined in the presence of poly(vinyl alcohol) (PVA) that was shown to be an efficient aggregation-preventing agent for polymerizing DHI ensuring water solubilization. Finally, it is shown that DHI monomer can be efficiently and partially irreversibly depleted from aqueous solutions by the addition of eumelanin suspensions. This behavior is suggested to reflect oxidant-independent competing pathways of polymer synthesis and buildup via monomer conversion on the active aggregate surface contributing to particle growth. Besides filling crucial gaps in DHI polymerization, these results support the attractive hypothesis that eumelanins may behave as a peculiar example of living biopolymers. The potential of PVA as a powerful tool for solution chemistry-based investigations of eumelanin supramolecular organization and for technological manipulation purposes is underscored.
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Affiliation(s)
- Marianna Arzillo
- Department of Chemical Sciences, University of Naples Federico II, Napoli (NA), Italy
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28
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Small molecule modulators of aggregation in synthetic melanin polymerizations. Bioorg Med Chem Lett 2012; 22:5503-7. [PMID: 22835871 DOI: 10.1016/j.bmcl.2012.07.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 07/06/2012] [Accepted: 07/06/2012] [Indexed: 11/23/2022]
Abstract
There are numerous potential applications for melanin-binding compounds, and new methods are of interest to identify melanin-binding agents. A portion of the polymerization to eumelanin, the black to brown pigment in humans, is thought to be supramolecular aggregation of nanoparticles derived from dihydroxyindoles. Starting with chloroquine, a known eumelanin-binding compound, the ability of small molecules to influence aggregation in synthetic eumelanin polymerizations was investigated. Twenty-eight compounds were tested, including pharmaceuticals, dyes, aromatics, and amines. Compounds that either accelerate or delay the appearance of macroscopic particles in synthetic eumelanin polymerizations were uncovered.
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29
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Mostert AB, Powell BJ, Pratt FL, Hanson GR, Sarna T, Gentle IR, Meredith P. Role of semiconductivity and ion transport in the electrical conduction of melanin. Proc Natl Acad Sci U S A 2012; 109:8943-7. [PMID: 22615355 PMCID: PMC3384144 DOI: 10.1073/pnas.1119948109] [Citation(s) in RCA: 264] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Melanins are pigmentary macromolecules found throughout the biosphere that, in the 1970s, were discovered to conduct electricity and display bistable switching. Since then, it has been widely believed that melanins are naturally occurring amorphous organic semiconductors. Here, we report electrical conductivity, muon spin relaxation, and electron paramagnetic resonance measurements of melanin as the environmental humidity is varied. We show that hydration of melanin shifts the comproportionation equilibrium so as to dope electrons and protons into the system. This equilibrium defines the relative proportions of hydroxyquinone, semiquinone, and quinone species in the macromolecule. As such, the mechanism explains why melanin at neutral pH only conducts when "wet" and suggests that both carriers play a role in the conductivity. Understanding that melanin is an electronic-ionic hybrid conductor rather than an amorphous organic semiconductor opens exciting possibilities for bioelectronic applications such as ion-to-electron transduction given its biocompatibility.
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Affiliation(s)
- Albertus B. Mostert
- Centre for Organic Photonics and Electronics, School of Mathematics and Physics, University of Queensland, Brisbane St. Lucia QLD 4072, Australia
| | - Benjamin J. Powell
- Centre for Organic Photonics and Electronics, School of Mathematics and Physics, University of Queensland, Brisbane St. Lucia QLD 4072, Australia
| | - Francis L. Pratt
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - Graeme R. Hanson
- Centre for Advanced Imaging, University of Queensland, Brisbane St. Lucia QLD 4072, Australia
| | - Tadeusz Sarna
- Department of Biophysics, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, 31-007, Krakow, Poland; and
| | - Ian R. Gentle
- Centre for Organic Photonics and Electronics, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane St. Lucia QLD 4072, Australia
| | - Paul Meredith
- Centre for Organic Photonics and Electronics, School of Mathematics and Physics, University of Queensland, Brisbane St. Lucia QLD 4072, Australia
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30
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Melanin-based coatings as lead-binding agents. Bioinorg Chem Appl 2012; 2012:361803. [PMID: 22611345 PMCID: PMC3350951 DOI: 10.1155/2012/361803] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Revised: 01/23/2012] [Accepted: 02/07/2012] [Indexed: 11/26/2022] Open
Abstract
Interactions between metal ions and different forms of melanin play significant roles in melanin biochemistry. The binding properties of natural melanin and related synthetic materials can be exploited for nonbiological applications, potentially including water purification. A method for investigating metal ion-melanin interactions on solid support is described, with lead as the initial target. 2.5 cm discs of the hydrophobic polymer PVDF were coated with synthetic eumelanin from the tyrosinase-catalyzed polymerization of L-dopa, and with melanin extracted from human hair. Lead (Pb2+) binding was quantified by atomic absorption spectroscopy (flame mode), and the data was well fit by the Langmuir model. Langmuir affinities ranged from 3.4 · 103 to 2.2 · 104 M−1. At the maximum capacity observed, the synthetic eumelanin coating bound ~9% of its mass in lead. Binding of copper (Cu2+), zinc (Zn2+), and cadmium (Cd2+) to the synthetic-eumelanin-coated discs was also investigated. Under the conditions tested, the Langmuir affinities for Zn2+, Cd2+, and Cu2+ were 35%, 53%, and 77%, respectively, of the Langmuir affinity for Pb2+. The synthetic-eumelanin-coated discs have a slightly higher capacity for Cu2+ on a per mole basis than for Pb2+, and lower capacities for Cd2+ and Zn2+. The system described can be used to address biological questions and potentially be applied toward melanin-based water purification.
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31
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Reale S, Crucianelli M, Pezzella A, d'Ischia M, De Angelis F. Exploring the frontiers of synthetic eumelanin polymers by high-resolution matrix-assisted laser/desorption ionization mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2012; 47:49-53. [PMID: 22282089 DOI: 10.1002/jms.2025] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
New trends in material science and nanotechnologies have spurred growing interest in eumelanins black insoluble biopolymers derived by tyrosinase-catalysed oxidation of tyrosine via 5,6-dihydroxyindole (DHI) and its 2-carboxylic acid (DHICA). Efficient antioxidant and photoprotective actions, associated with peculiar optoelectronic properties, are recognised as prominent functions of eumelanin macromolecules within the human and mammalian pigmentary system, making them unique candidates for the realisation of innovative bio-inspired functional soft materials, with structure-based physical-chemical properties. An unprecedented breakthrough into the mechanism of synthetic eumelanin buildup has derived from a detailed investigation of the oxidative polymerization of DHI and its N-methyl derivative (NMDHI) by linear and reflectron matrix-assisted laser/desorption ionization mass spectrometry. Regular collections of oligomers of increasing masses, spanning the entire m/z ranges up to 5000 Da (>30-mer) and 8000 Da (> 50-mer) for the two building blocks, respectively, were disclosed. It is the first time that the in vitro polymerisation of dihydroxyindoles to form synthetic eumelanins is explored up to its high mass limits, giving at the same time information on the polymerisation mode, whether it follows a stepwise pattern (being this the conclusion in our case) or a staking sequencing of small-sized entities. It also highlighted the influence of the N-methyl substituent on the polymerization process; this opens the way to the production of N-functionalized, synthetic eumelanin-inspired soft materials, for possible future technological applications.
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Affiliation(s)
- Samantha Reale
- Department of Chemistry, Chemical Engineering and Materials, University of L'Aquila, Via Vetoio, I-67100, Coppito, L'Aquila, Italy
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32
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Kong J, Yee WA, Yang L, Wei Y, Phua SL, Ong HG, Ang JM, Li X, Lu X. Highly electrically conductive layered carbon derived from polydopamine and its functions in SnO2-based lithium ion battery anodes. Chem Commun (Camb) 2012; 48:10316-8. [DOI: 10.1039/c2cc35284b] [Citation(s) in RCA: 193] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Ball V, Del Frari D, Michel M, Buehler MJ, Toniazzo V, Singh MK, Gracio J, Ruch D. Deposition Mechanism and Properties of Thin Polydopamine Films for High Added Value Applications in Surface Science at the Nanoscale. BIONANOSCIENCE 2011. [DOI: 10.1007/s12668-011-0032-3] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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34
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Hawkins DP, Ragnarsdóttir KV. The Cu, Mn and Zn concentration of sheep wool: influence of washing procedures, age and colour of matrix. THE SCIENCE OF THE TOTAL ENVIRONMENT 2009; 407:4140-4148. [PMID: 19329142 DOI: 10.1016/j.scitotenv.2009.02.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Revised: 11/14/2008] [Accepted: 02/06/2009] [Indexed: 05/27/2023]
Abstract
No standard or wholly proven method to determine the trace metal status of human or animal 'hair' yet exists. It is well known that hair-metal concentrations are highly influenced by washing procedures applied before analysis. A novel method to determine the efficiency of washing procedures at removing exogenous contaminants was devised. It was shown that suitability of washing procedures was element-specific and increased sonication time during washing progressively removed more Mn and Zn from sheep wool. The efficiency of exogenous contaminant removal by including sonication during washing was also dependent on the efficiency of procedures under study. The Cu, Mn and Zn concentration, and thus exogenous contaminant level, of sheep wool increased in tandem with its age. Additionally, Cu and Zn concentrations of black wool were significantly higher than white wool: a relationship ascribed to melanins. This investigation shows the necessity to standardise procedures used during analysis of 'hair' fibres, and to assess each washing procedure for each element before performing routine analysis.
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Affiliation(s)
- D P Hawkins
- Department of Earth Sciences, University of Bristol, Bristol, UK
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35
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Kaur G, He J, Xu J, Pingali S, Jutz G, Böker A, Niu Z, Li T, Rawlinson D, Emrick T, Lee B, Thiyagarajan P, Russell TP, Wang Q. Interfacial assembly of turnip yellow mosaic virus nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:5168-5176. [PMID: 19354217 DOI: 10.1021/la900167s] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
An extensive study of the factors that affect the interfacial assembly of bionanoparticles at the oil/water (O/W) interface is reported. Bionanoparticles, such as viruses, have distinctive structural properties due to the unique arrangement of their protein structures. The assembly process of such bionanoparticles at interfaces is governed by factors including the ionic strength and pH of the aqueous layer, concentration of the particles, and nature of the oil phase. This study highlights the impact of these factors on the interfacial assembly of bionanoparticles at the O/W interface using native turnip yellow mosaic virus (TYMV) as the prototype. Robust monolayer assemblies of TYMV were produced by self-assembly at the O/W interface using emulsions and planar interfaces. TYMV maintained its structure and integrity under different assembly conditions. For the emulsion droplets, they were fully covered with TYMV as evidenced by transmission electron microscopy (TEM) and scanning force microscopy (SFM). Tensiometry and small-angle neutron scattering (SANS) further supported this finding. Although the emulsions offered a complete coverage by TYMV particles, they lacked long-range ordering due to rapid exchange at the interface. By altering the assembly process, highly ordered, hexagonal arrays of TYMV were obtained at planar O/W interfaces. The pH, ionic strength, and viscosity of the solution played a crucial role in enhancing the lateral ordering of TYMV assembled at the planar O/W interface. This interfacial ordering of TYMV particles was further stabilized by introduction of a positively charged dehydroabietyl amine (DHAA) in the organic phase which held the assembly together by electrostatic interactions. The long-range array formation was observed using TEM and SFM. The results presented here illustrate that the interfacial assembly at the O/W interface is a versatile approach to achieve highly stable self-assembled structures.
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Affiliation(s)
- Gagandeep Kaur
- Department of Chemistry and Biochemistry and Nanocenter, University of South Carolina, 631 Sumter Street, Columbia, South Carolina 29208, USA
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36
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Gauden M, Pezzella A, Panzella L, Neves-Petersen MT, Skovsen E, Petersen SB, Mullen KM, Napolitano A, d’Ischia M, Sundström V. Role of Solvent, pH, and Molecular Size in Excited-State Deactivation of Key Eumelanin Building Blocks: Implications for Melanin Pigment Photostability. J Am Chem Soc 2008; 130:17038-43. [DOI: 10.1021/ja806345q] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M. Gauden
- Department of Chemical Physics, Lund University, Box 124, S 22100 Lund, Sweden, Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Naples, Italy, Department of Physics and Nanotechnology, Aalborg University, Denmark, and Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam
| | - A. Pezzella
- Department of Chemical Physics, Lund University, Box 124, S 22100 Lund, Sweden, Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Naples, Italy, Department of Physics and Nanotechnology, Aalborg University, Denmark, and Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam
| | - L. Panzella
- Department of Chemical Physics, Lund University, Box 124, S 22100 Lund, Sweden, Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Naples, Italy, Department of Physics and Nanotechnology, Aalborg University, Denmark, and Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam
| | - M. T. Neves-Petersen
- Department of Chemical Physics, Lund University, Box 124, S 22100 Lund, Sweden, Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Naples, Italy, Department of Physics and Nanotechnology, Aalborg University, Denmark, and Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam
| | - E. Skovsen
- Department of Chemical Physics, Lund University, Box 124, S 22100 Lund, Sweden, Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Naples, Italy, Department of Physics and Nanotechnology, Aalborg University, Denmark, and Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam
| | - S. B. Petersen
- Department of Chemical Physics, Lund University, Box 124, S 22100 Lund, Sweden, Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Naples, Italy, Department of Physics and Nanotechnology, Aalborg University, Denmark, and Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam
| | - K. M. Mullen
- Department of Chemical Physics, Lund University, Box 124, S 22100 Lund, Sweden, Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Naples, Italy, Department of Physics and Nanotechnology, Aalborg University, Denmark, and Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam
| | - A. Napolitano
- Department of Chemical Physics, Lund University, Box 124, S 22100 Lund, Sweden, Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Naples, Italy, Department of Physics and Nanotechnology, Aalborg University, Denmark, and Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam
| | - M. d’Ischia
- Department of Chemical Physics, Lund University, Box 124, S 22100 Lund, Sweden, Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Naples, Italy, Department of Physics and Nanotechnology, Aalborg University, Denmark, and Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam
| | - V. Sundström
- Department of Chemical Physics, Lund University, Box 124, S 22100 Lund, Sweden, Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Naples, Italy, Department of Physics and Nanotechnology, Aalborg University, Denmark, and Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam
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37
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Ganguly R, Aswal VK, Hassan PA. Room temperature sphere-to-rod growth and gelation of PEO–PPO–PEO triblock copolymers in aqueous salt solutions. J Colloid Interface Sci 2007; 315:693-700. [PMID: 17707391 DOI: 10.1016/j.jcis.2007.07.026] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Revised: 06/29/2007] [Accepted: 07/13/2007] [Indexed: 11/20/2022]
Abstract
The effects of NaCl and KF on the sphere-to-rod micellar growth behavior of triblock copolymers having two different compositions, (EO)20(PO)70(EO)20 (P123) and (EO)26(PO)40(EO)26 (P85), have been studied by dynamic light scattering (DLS), small angle neutron scattering (SANS) and dilute solution viscometry. NaCl can effectively tune the sphere-to-rod growth temperature of the micelles of both these copolymers and induce micellar growth down to the room temperature and below. The growth behavior is found to be dependent on the composition of the copolymer as P123 being more hydrophobic shows the room temperature growth in the presence of ethanol at significantly lesser NaCl concentration than the less hydrophobic copolymer P85. DLS studies depict for the first time the growth driven transition of the copolymer solutions from dilute to semi-dilute regime as a function of copolymer and salt concentrations. KF can also induce room temperature growth of the P123 micelles at lesser salt concentration than NaCl but it fails to induce any such growth of the P85 micelles. A pseudo-binary temperature-concentration phase diagram on 15% copolymer solutions shows the variation of the sphere-to-rod transition temperature and the cloud point of the copolymer solutions as a function of salt concentration.
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Affiliation(s)
- R Ganguly
- Chemistry Division, Bhabha Atomic Research Center, Mumbai 400 085, India.
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38
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He J, Zhang Q, Gupta S, Emrick T, Russell TP, Thiyagarajan P. Drying droplets: a window into the behavior of nanorods at interfaces. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2007; 3:1214-7. [PMID: 17546580 DOI: 10.1002/smll.200700055] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Affiliation(s)
- Jinbo He
- Department of Polymer Science & Engineering, University of Massachusetts, Amherst, MA 01003, USA
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39
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Littrell KC, Gallas JM, Zajac GW, Thiyagarajan P. Structural Studies of Bleached Melanin by Synchrotron Small-angle X-ray Scattering¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2003)0770115ssobmb2.0.co2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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40
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Sobolewski AL, Domcke W. Photophysics of Eumelanin: Ab Initio Studies on the Electronic Spectroscopy and Photochemistry of 5,6-Dihydroxyindole. Chemphyschem 2007; 8:756-62. [PMID: 17279594 DOI: 10.1002/cphc.200600768] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Excited-state reaction paths and energy profiles of 5,6-dihydroxyindole (DHI), one of the elementary building blocks of eumelanin, have been determined with the approximated singles-and-doubles coupled-cluster (CC2) method. 6-Hydroxy-4-dihydro-indol-5-one (HHI) is identified as a photochromic species, which is formed via nonadiabatic hydrogen migration from the dangling OH group of DHI to the neighboring carbon atom of the six-membered ring. It is shown that HHI is a typical excited-state hydrogen-transfer (ESIHT) system. HHI absorbs strongly in the visible range of the spectrum. A barrierless hydrogen transfer in the (1)pipi* excited state, followed by barrierless torsion of the hydroxyl group, lead to a low-lying S(1)-S(0) conical intersection and thus to ultrafast internal conversion. This very efficient mechanism of excited-state deactivation provides HHI with a high degree of intrinsic photostability. It is suggested that the metastable photochemical product HHI plays an essential role for the photoprotective biological function of eumelanin.
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41
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Abstract
In 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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Affiliation(s)
- Paul Meredith
- Soft Condensed Matter Physics Group, School of Physical Sciences, University of Queensland, Brisbane, Australia
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42
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McGraw KJ. Dietary mineral content influences the expression of melanin-based ornamental coloration. Behav Ecol 2006. [DOI: 10.1093/beheco/arl059] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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43
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Russell JT, Lin Y, Böker A, Su L, Carl P, Zettl H, He J, Sill K, Tangirala R, Emrick T, Littrell K, Thiyagarajan P, Cookson D, Fery A, Wang Q, Russell TP. Self-assembly and cross-linking of bionanoparticles at liquid-liquid interfaces. Angew Chem Int Ed Engl 2006; 44:2420-6. [PMID: 15806611 DOI: 10.1002/anie.200462653] [Citation(s) in RCA: 227] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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44
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Mackay ME, Tuteja A, Duxbury PM, Hawker CJ, Van Horn B, Guan Z, Chen G, Krishnan RS. General strategies for nanoparticle dispersion. Science 2006; 311:1740-3. [PMID: 16556836 DOI: 10.1126/science.1122225] [Citation(s) in RCA: 560] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Traditionally the dispersion of particles in polymeric materials has proven difficult and frequently results in phase separation and agglomeration. We show that thermodynamically stable dispersion of nanoparticles into a polymeric liquid is enhanced for systems where the radius of gyration of the linear polymer is greater than the radius of the nanoparticle. Dispersed nanoparticles swell the linear polymer chains, resulting in a polymer radius of gyration that grows with the nanoparticle volume fraction. It is proposed that this entropically unfavorable process is offset by an enthalpy gain due to an increase in molecular contacts at dispersed nanoparticle surfaces as compared with the surfaces of phase-separated nanoparticles. Even when the dispersed state is thermodynamically stable, it may be inaccessible unless the correct processing strategy is adopted, which is particularly important for the case of fullerene dispersion into linear polymers.
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Affiliation(s)
- Michael E Mackay
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824, USA.
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45
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Tran ML, Powell BJ, Meredith P. Chemical and structural disorder in eumelanins: a possible explanation for broadband absorbance. Biophys J 2006; 90:743-52. [PMID: 16284264 PMCID: PMC1367100 DOI: 10.1529/biophysj.105.069096] [Citation(s) in RCA: 169] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2005] [Accepted: 09/26/2005] [Indexed: 11/18/2022] Open
Abstract
We report the results of an experimental and theoretical study of the electronic and structural properties of a key eumelanin precursor-5,6,-dihydroxyindole-2-carboxylic acid (DHICA)-and its dimeric forms. We have used optical spectroscopy to follow the oxidative polymerization of DHICA to eumelanin and observe red shifting and broadening of the absorption spectrum as the reaction proceeds. First principles density functional theory calculations indicate that DHICA oligomers (possible reaction products of oxidative polymerization) have the gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital red-shifted gaps with respect to the monomer. Furthermore, different bonding configurations (leading to oligomers with different structures) produce a range of gaps. These experimental and theoretical results lend support to the chemical disorder model where the broadband monotonic absorption characteristic of all melanins is a consequence of the superposition of a large number of nonhomogeneously broadened Gaussian transitions associated with each of the components of a melanin ensemble. These results suggest that the traditional model of eumelanin as an amorphous organic semiconductor is not required to explain its optical properties and should be thoroughly reexamined. These results have significant implications for our understanding of the physics, chemistry, and biological function of these important biological macromolecules. Indeed, one may speculate that the robust functionality of melanins in vitro is a direct consequence of its heterogeneity, i.e., chemical disorder is a "low cost" natural resource in these systems.
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Affiliation(s)
- M Linh Tran
- Soft Condensed Matter Physics Group, and Theoretical Condensed Matter Physics Group, School of Physical Sciences, University of Queensland, Brisbane, QLD 4072, Australia
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46
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Nighswander-Rempel SP, Riesz J, Gilmore J, Bothma JP, Meredith P. Quantitative Fluorescence Excitation Spectra of Synthetic Eumelanin. J Phys Chem B 2005; 109:20629-35. [PMID: 16853670 DOI: 10.1021/jp053704+] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Previously reported excitation spectra for eumelanin are sparse and inconsistent. Moreover, these studies have failed to account for probe beam attenuation and emission reabsorption within the samples, making them qualitative at best. We report for the first time quantitative excitation spectra for synthetic eumelanin, acquired for a range of solution concentrations and emission wavelengths. Our data indicate that probe beam attenuation and emission reabsorption significantly affect the spectra even in low-concentration eumelanin solutions and that previously published data do not reflect the true excitation profile. We apply a correction procedure (previously applied to emission spectra) to account for these effects. Application of this procedure reconstructs the expected relationship of signal intensity with concentration, and the normalized spectra show a similarity in form to the absorption profiles. These spectra reveal valuable information regarding the photophysics and photochemistry of eumelanin. Most notably, an excitation peak at 365 nm (3.40 eV), whose position is independent of emission wavelength, is possibly attributable to a 5,6-dihydroxyindole-2-carboxylic acid (DHICA) component singly linked to a polymeric structure.
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Affiliation(s)
- Stephen P Nighswander-Rempel
- Centre for Biophotonics and Laser Science and Soft Condensed Matter Theory Group, School of Physical Sciences, University of Queensland, St. Lucia, QLD 4067, Australia.
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47
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Hamill AC, Wang SC, Lee CT. Probing Lysozyme Conformation with Light Reveals a New Folding Intermediate. Biochemistry 2005; 44:15139-49. [PMID: 16285717 DOI: 10.1021/bi051646c] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A means to control lysozyme conformation with light illumination has been developed using the interaction of the protein with a photoresponsive surfactant. Upon exposure to the appropriate wavelength of light, the azobenzene surfactant undergoes a reversible photoisomerization, with the visible-light (trans) form being more hydrophobic than the UV-light (cis) form. As a result, surfactant binding to the protein and, thus, protein unfolding, can be tuned with light. Small-angle neutron scattering (SANS) measurements were used to provide detailed information of the protein conformation in solution. Shape-reconstruction methods applied to the SANS data indicate that under visible light the protein exhibits a native-like form at low surfactant concentrations, a partially swollen form at intermediate concentrations, and a swollen/unfolded form at higher surfactant concentrations. Furthermore, the SANS data combined with FT-IR spectroscopic analysis of the protein secondary structure reveal that unfolding occurs primarily in the alpha domain of lysozyme, while the beta domain remains relatively intact. Thus, the surfactant-unfolded intermediate of lysozyme appears to be a separate structure than the well-known alpha-domain intermediate of lysozyme that contains a folded alpha domain and unfolded beta domain. Because the interactions between the photosurfactant and protein can be tuned with light, illumination with UV light returns the protein to a native-like conformation. Fluorescence emission data of the nonpolar probe Nile red indicate that hydrophobic domains become available for probe partitioning in surfactant-protein solutions under visible light, while the availability of these hydrophobic domains to the probe decrease under UV light. Dynamic light scattering and UV-vis spectroscopic measurements further confirm the shape-reconstruction findings and reveal three discrete conformations of lysozyme. The results clearly demonstrate that visible light causes a greater degree of lysozyme swelling than UV light, thus allowing for the protein conformation to be controlled with light.
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Affiliation(s)
- Andrea C Hamill
- Department of Chemical Engineering, University of Southern California, Los Angeles, California 90089-1211, USA
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48
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Sarangarajan R, Apte SP. Melanin Aggregation and Polymerization: Possible Implications in Age-Related Macular Degeneration. Ophthalmic Res 2005; 37:136-41. [PMID: 15867475 DOI: 10.1159/000085533] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2004] [Accepted: 01/18/2005] [Indexed: 11/19/2022]
Abstract
The state of aggregation of the polymer melanin may determine its propensity to act either as an antioxidant or as a pro-oxidant. Age-related alterations in its state of aggregation are suggested to alter the degree of polymerization so as to confer increased pro-oxidant propensity to the melanin polymer. Degradative processes in/of melanosomes and lysosomes in the retinal pigment epithelium (RPE) appear to be intimately connected so that they may involve exchange of contents between these two organelles. An increased pro-oxidant environment inside lysosomes has been associated with preventing the digestion of cellular components including photoreceptor outer rod segments partly by altering function of lysosomal hydrolases. It is speculated that age-related accumulation of low-molecular-weight phototoxic pro-oxidant melanin oligomers within lysosomes in the RPE may be partly responsible for decreasing the digestive rate of incorporated cellular components (including photoreceptor outer rod segments) which may lead to lipofuscin formation. More work is required to definitively refute or support such a hypothesis.
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Affiliation(s)
- Rangaprasad Sarangarajan
- Department of Phamaceutical Sciences, Massachusetts College of Pharmacy and Health Sciences, Worcester, MA, USA
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49
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Seagle BLL, Rezai KA, Kobori Y, Gasyna EM, Rezaei KA, Norris JR. Melanin photoprotection in the human retinal pigment epithelium and its correlation with light-induced cell apoptosis. Proc Natl Acad Sci U S A 2005; 102:8978-83. [PMID: 15951427 PMCID: PMC1157035 DOI: 10.1073/pnas.0501971102] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Time-resolved electron paramagnetic resonance (TREPR) spectroscopy was used to study melanin free radicals in human retinal pigment epithelium (RPE) cells and tyrosine-derived synthetic melanin. TREPR signal traces from RPE cells reveal in vivo light-induced melanin free radical photochemistry in more detail than previously known. Electron spin polarization reflecting a non-Boltzmann population within the energy levels of the spin system is observed in RPE cells as the result of the triplet state photoproduction and subsequent disappearance of free radicals in the melanin polymer. In a set of RPE cells cultured from individual sources, differences in optical absorption, continuous wave EPR spectra, and TREPR signals were correlated with apoptosis assays performed by flow cytometry. Continuous wave EPR spectra of RPE cells and TREPR of acidified synthetic melanin suggest that increased melanin aggregation provides an increase in photoprotection in the RPE cells that are relatively less susceptible to blue light-induced apoptosis.
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50
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Capozzi V, Perna G, Gallone A, Biagi P, Carmone P, Fratello A, Guida G, Zanna P, Cicero R. Raman and optical spectroscopy of eumelanin films. J Mol Struct 2005. [DOI: 10.1016/j.molstruc.2004.11.074] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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