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DeMarco M, Ballard M, Grage E, Nourigheimasi F, Getter L, Shafiee A, Ghadiri E. Enhanced photochemical activity and ultrafast photocarrier dynamics in sustainable synthetic melanin nanoparticle-based donor-acceptor inkjet-printed molecular junctions. NANOSCALE 2023; 15:14346-14364. [PMID: 37602764 DOI: 10.1039/d3nr02387g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/22/2023]
Abstract
Melanin is a stable, widely light-absorbing, photoactive, and biocompatible material viable for energy conversion, photocatalysis, and bioelectronic applications. To achieve multifunctional nanostructures, we synthesized melanin nanoparticles of uniform size and controlled chemical composition (dopamelanin and eumelanin) and used them with titanium dioxide to fabricate donor-acceptor bilayers. Their size enhances the surface-to-volume ratio important for any surface-mediated functionality, such as photocatalysis, sensing, and drug loading and release, while controlling their chemical composition enables to control the film's functionality and reproducibility. Inkjet printing uniquely allowed us to control the deposited amount of materials with minimum ink waste suitable for reproducible materials deposition. We studied the photochemical characteristics of the donor-acceptor melanin-TiO2 nanostructured films via photocatalytic degradation of methylene blue dye under selective UV-NIR and Vis-NIR irradiation conditions. Under both irradiation conditions, they exhibited photocatalytic characteristics superior to pure melanin and, under UV-NIR irradiation, superior to TiO2 alone; TiO2 is photoactive only under UV irradiation. The enhanced photocatalytic characteristics of the melanin-TiO2 nanostructured bilayer films, particularly when excited by visible light, point to charge separation at the melanin-TiO2 interface as a possible mechanism. We performed ultrafast laser spectroscopy to investigate the photochemical characteristics of pure melanin and the melanin-TiO2 constructs and found that their time-resolved photoexcited spectral patterns differ. We performed singular value decomposition analysis to quantitatively deconvolute and compare the dynamics of photochemical processes for melanin and melanin-TiO2 heterostructures. This observation supports electronic interactions, namely, interfacial charge separation at the melanin and TiO2 interface. The excited-state relaxation in melanin-TiO2 increases markedly from 5 ps to 400 ps. The results are remarkable for the future intriguing application of melanin-based constructs for bioelectronics and energy conversion.
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Affiliation(s)
- Max DeMarco
- Chemistry Department, Wake Forest University, USA.
- Center for Functional Materials, Wake Forest University, USA
| | - Matthew Ballard
- Chemistry Department, Wake Forest University, USA.
- Center for Functional Materials, Wake Forest University, USA
| | - Elinor Grage
- Chemistry Department, Wake Forest University, USA.
- Center for Functional Materials, Wake Forest University, USA
| | - Farnoush Nourigheimasi
- Chemistry Department, Wake Forest University, USA.
- Center for Functional Materials, Wake Forest University, USA
| | - Lillian Getter
- Chemistry Department, Wake Forest University, USA.
- Center for Functional Materials, Wake Forest University, USA
| | - Ashkan Shafiee
- Wake Forest School of Medicine, Wake Forest University, USA
- Center for Functional Materials, Wake Forest University, USA
| | - Elham Ghadiri
- Chemistry Department, Wake Forest University, USA.
- Wake Forest School of Medicine, Wake Forest University, USA
- Center for Functional Materials, Wake Forest University, USA
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2
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Pinelli R, Ferrucci M, Biagioni F, Berti C, Bumah VV, Busceti CL, Puglisi-Allegra S, Lazzeri G, Frati A, Fornai F. Autophagy Activation Promoted by Pulses of Light and Phytochemicals Counteracting Oxidative Stress during Age-Related Macular Degeneration. Antioxidants (Basel) 2023; 12:1183. [PMID: 37371913 DOI: 10.3390/antiox12061183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/15/2023] [Accepted: 05/27/2023] [Indexed: 06/29/2023] Open
Abstract
The seminal role of autophagy during age-related macular degeneration (AMD) lies in the clearance of a number of reactive oxidative species that generate dysfunctional mitochondria. In fact, reactive oxygen species (ROS) in the retina generate misfolded proteins, alter lipids and sugars composition, disrupt DNA integrity, damage cell organelles and produce retinal inclusions while causing AMD. This explains why autophagy in the retinal pigment epithelium (RPE), mostly at the macular level, is essential in AMD and even in baseline conditions to provide a powerful and fast replacement of oxidized molecules and ROS-damaged mitochondria. When autophagy is impaired within RPE, the deleterious effects of ROS, which are produced in excess also during baseline conditions, are no longer counteracted, and retinal degeneration may occur. Within RPE, autophagy can be induced by various stimuli, such as light and naturally occurring phytochemicals. Light and phytochemicals, in turn, may synergize to enhance autophagy. This may explain the beneficial effects of light pulses combined with phytochemicals both in improving retinal structure and visual acuity. The ability of light to activate some phytochemicals may further extend such a synergism during retinal degeneration. In this way, photosensitive natural compounds may produce light-dependent beneficial antioxidant effects in AMD.
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Affiliation(s)
- Roberto Pinelli
- SERI, Switzerland Eye Research Institute, 6900 Lugano, Switzerland
| | - Michela Ferrucci
- Human Anatomy, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy
| | - Francesca Biagioni
- IRCCS, Istituto di Ricovero e Cura a Carattere Scientifico, Neuromed, 86077 Pozzili, Italy
| | - Caterina Berti
- SERI, Switzerland Eye Research Institute, 6900 Lugano, Switzerland
| | - Violet Vakunseth Bumah
- Department of Chemistry and Biochemistry, College of Sciences, San Diego State University, San Diego, CA 92182, USA
- Department of Chemistry and Physics, University of Tennessee, Martin, TN 38237, USA
| | - Carla Letizia Busceti
- IRCCS, Istituto di Ricovero e Cura a Carattere Scientifico, Neuromed, 86077 Pozzili, Italy
| | | | - Gloria Lazzeri
- Human Anatomy, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy
| | - Alessandro Frati
- IRCCS, Istituto di Ricovero e Cura a Carattere Scientifico, Neuromed, 86077 Pozzili, Italy
| | - Francesco Fornai
- Human Anatomy, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy
- IRCCS, Istituto di Ricovero e Cura a Carattere Scientifico, Neuromed, 86077 Pozzili, Italy
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3
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Zhang S, Wang L, Kang Y, Wu J, Zhang Z. Nanomaterial-based Reactive Oxygen Species Scavengers for Osteoarthritis Therapy. Acta Biomater 2023; 162:1-19. [PMID: 36967052 DOI: 10.1016/j.actbio.2023.03.030] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 02/17/2023] [Accepted: 03/20/2023] [Indexed: 03/29/2023]
Abstract
Reactive oxygen species (ROS) play distinct but important roles in physiological and pathophysiological processes. Recent studies on osteoarthritis (OA) have suggested that ROS plays a crucial role in its development and progression, serving as key mediators in the degradation of the extracellular matrix, mitochondrial dysfunction, chondrocyte apoptosis, and OA progression. With the continuous development of nanomaterial technology, the ROS-scavenging ability and antioxidant effects of nanomaterials are being explored, with promising results already achieved in OA treatment. However, current research on nanomaterials as ROS scavengers for OA is relatively non-uniform and includes both inorganic and functionalized organic nanomaterials. Although the therapeutic efficacy of nanomaterials has been reported to be conclusive, there is still no uniformity in the timing and potential of their use in clinical practice. This paper reviews the nanomaterials currently used as ROS scavengers for OA treatment, along with their mechanisms of action, with the aim of providing a reference and direction for similar studies, and ultimately promoting the early clinical use of nanomaterials for OA treatment. STATEMENT OF SIGNIFICANCE: Reactive oxygen species (ROS) play an important role in the pathogenesis of osteoarthritis (OA). Nanomaterials serving as promising ROS scavengers have gained increasing attention in recent years. This review provides a comprehensive overview of ROS production and regulation, as well as their role in OA pathogenesis. Furthermore, this review highlights the applications of various types of nanomaterials as ROS scavengers in OA treatment and their mechanisms of action. Finally, the challenges and future prospects of nanomaterial-based ROS scavengers in OA therapy are discussed.
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Sarna T. Photodynamics of Melanin Radicals: Contribution to Photoprotection by Melanin †. Photochem Photobiol 2022; 99:866-868. [PMID: 36453981 DOI: 10.1111/php.13753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 11/14/2022] [Indexed: 12/05/2022]
Abstract
The mechanism of very efficient relaxation of the melanin-photoexcited states, responsible for the photoprotective action of the pigment, remains a subject for intense investigation. The most recent study by C. Grieco, F. Kohl, and B. Kohler, entitled "Ultrafast radical photogeneration pathways in eumelanin," addresses key issues of melanin photophysics and photochemistry. By using femtosecond broad-band pump probe-transient absorption measurements, the researchers were able to identify the absorption spectrum of DOPA melanin radicals for the first time and proposed two distinct mechanisms of radical formation-photoionization and photoinduced charge separation. The observed photodynamic of melanin radicals suggests a new paradigm in which the ultrafast excited state deactivation is due to the efficient recombination of melanin radicals created promptly by photoexcitation.
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Affiliation(s)
- Tadeusz Sarna
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
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Sasikumar D, Vinod K, Sunny J, Hariharan M. Exciton interactions in helical crystals of a hydrogen-bonded eumelanin monomer. Chem Sci 2022; 13:2331-2338. [PMID: 35310511 PMCID: PMC8864807 DOI: 10.1039/d1sc06755a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 01/19/2022] [Indexed: 12/04/2022] Open
Abstract
Eumelanin, a naturally occurring group of heterogeneous polymers/aggregates providing photoprotection to living organisms, consist of 5,6-dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic acid (DHICA) building blocks. Despite their prevalence in the animal world, the structure and therefore the mechanism behind the photoprotective broadband absorption and non-radiative decay of eumelanin remain largely unknown. As a small step towards solving the incessant mystery, DHI is crystallized in a non-protic solvent environment to obtain DHI crystals having a helical packing motif. The present approach reflects the solitary directional effect of hydrogen bonds between the DHI chromophores for generating the crystalline assembly and filters out any involvement of the surrounding solvent environment. The DHI single crystals having an atypical chiral packing motif (P212121 Sohncke space group) incorporate enantiomeric zig-zag helical stacks arranged in a herringbone fashion with respect to each other. Each of the zig-zag helical stacks originates from a bifurcated hydrogen bonding interaction between the hydroxyl substituents in adjacent DHI chromophores which act as the backbone structure for the helical assembly. Fragment-based excited state analysis performed on the DHI crystalline assembly demonstrates exciton delocalization along the DHI units that connect each enantiomeric helical stack while, within each stack, the excitons remain localized. Fascinatingly, over the time evolution for generation of single-crystals of the DHI-monomer, mesoscopic double-helical crystals are formed, possibly attributed to the presence of covalently connected DHI trimers in chloroform solution. The oligomeric DHI (in line with the chemical disorder model) along with the characteristic crystalline packing observed for DHI provides insights into the broadband absorption feature exhibited by the chromophore. Single crystals of DHI monomer, a eumelanin precursor, adopt an atypical chiral packing arrangement incorporating enantiomeric zig-zag helical stacks while its covalently connected DHI trimer forms double-helical crystals in the mesoscopic scale.![]()
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Affiliation(s)
- Devika Sasikumar
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram Maruthamala P.O., Vithura Thiruvananthapuram Kerala 695551 India
| | - Kavya Vinod
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram Maruthamala P.O., Vithura Thiruvananthapuram Kerala 695551 India
| | - Jeswin Sunny
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram Maruthamala P.O., Vithura Thiruvananthapuram Kerala 695551 India
| | - Mahesh Hariharan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram Maruthamala P.O., Vithura Thiruvananthapuram Kerala 695551 India
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6
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Zhou X, Gong X, Cao W, Forman CJ, Oktawiec J, D'Alba L, Sun H, Thompson MP, Hu Z, Kapoor U, McCallum NC, Malliakas CD, Farha OK, Jayaraman A, Shawkey MD, Gianneschi NC. Anisotropic Synthetic Allomelanin Materials via Solid-State Polymerization of Self-Assembled 1,8-Dihydroxynaphthalene Dimers. Angew Chem Int Ed Engl 2021; 60:17464-17471. [PMID: 33913253 DOI: 10.1002/anie.202103447] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/13/2021] [Indexed: 01/15/2023]
Abstract
Melanosomes in nature have diverse morphologies, including spheres, rods, and platelets. By contrast, shapes of synthetic melanins have been almost entirely limited to spherical nanoparticles with few exceptions produced by complex templated synthetic methods. Here, we report a non-templated method to access synthetic melanins with a variety of architectures including spheres, sheets, and platelets. Three 1,8-dihydroxynaphthalene dimers (4-4', 2-4' and 2-2') were used as self-assembling synthons. These dimers pack to form well-defined structures of varying morphologies depending on the isomer. Specifically, distinctive ellipsoidal platelets can be obtained using 4-4' dimers. Solid-state polymerization of the preorganized dimers generates polymeric synthetic melanins while maintaining the initial particle morphologies. This work provides a new route to anisotropic synthetic melanins, where the building blocks are preorganized into specific shapes, followed by solid-state polymerization.
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Affiliation(s)
- Xuhao Zhou
- Department of Chemistry, International Institute of Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University, Evanston, IL, 60208, USA
| | - Xinyi Gong
- Department of Chemistry, International Institute of Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University, Evanston, IL, 60208, USA
| | - Wei Cao
- Department of Chemistry, International Institute of Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University, Evanston, IL, 60208, USA
| | - Christopher J Forman
- Department of Chemistry, International Institute of Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University, Evanston, IL, 60208, USA
| | - Julia Oktawiec
- Department of Chemistry, International Institute of Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University, Evanston, IL, 60208, USA
| | - Liliana D'Alba
- Department of Biology, Evolution and Optics of Nanostructures Group, University of Ghent, 9000, Ghent, Belgium
| | - Hao Sun
- Department of Chemistry, International Institute of Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University, Evanston, IL, 60208, USA
| | - Matthew P Thompson
- Department of Chemistry, International Institute of Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University, Evanston, IL, 60208, USA
| | - Ziying Hu
- Department of Chemistry, International Institute of Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University, Evanston, IL, 60208, USA
| | - Utkarsh Kapoor
- Department of Chemical and Biomolecular Engineering, Colburn Laboratory, University of Delaware, Newark, DE, 19716, USA
| | - Naneki C McCallum
- Department of Chemistry, International Institute of Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University, Evanston, IL, 60208, USA
| | - Christos D Malliakas
- Department of Chemistry, International Institute of Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University, Evanston, IL, 60208, USA
| | - Omar K Farha
- Department of Chemistry, International Institute of Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University, Evanston, IL, 60208, USA
| | - Arthi Jayaraman
- Department of Chemical and Biomolecular Engineering, Colburn Laboratory, Department of Materials Science and Engineering, University of Delaware, Newark, DE, 19716, USA
| | - Matthew D Shawkey
- Department of Biology, Evolution and Optics of Nanostructures Group, University of Ghent, 9000, Ghent, Belgium
| | - Nathan C Gianneschi
- Department of Chemistry, International Institute of Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University, Evanston, IL, 60208, USA.,Department of Materials Science and Engineering, and Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
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7
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Zhou X, Gong X, Cao W, Forman CJ, Oktawiec J, D'Alba L, Sun H, Thompson MP, Hu Z, Kapoor U, McCallum NC, Malliakas CD, Farha OK, Jayaraman A, Shawkey MD, Gianneschi NC. Anisotropic Synthetic Allomelanin Materials via Solid‐State Polymerization of Self‐Assembled 1,8‐Dihydroxynaphthalene Dimers. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202103447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Xuhao Zhou
- Department of Chemistry International Institute of Nanotechnology Simpson-Querrey Institute Chemistry of Life Processes Institute Lurie Cancer Center Northwestern University Evanston IL 60208 USA
| | - Xinyi Gong
- Department of Chemistry International Institute of Nanotechnology Simpson-Querrey Institute Chemistry of Life Processes Institute Lurie Cancer Center Northwestern University Evanston IL 60208 USA
| | - Wei Cao
- Department of Chemistry International Institute of Nanotechnology Simpson-Querrey Institute Chemistry of Life Processes Institute Lurie Cancer Center Northwestern University Evanston IL 60208 USA
| | - Christopher J. Forman
- Department of Chemistry International Institute of Nanotechnology Simpson-Querrey Institute Chemistry of Life Processes Institute Lurie Cancer Center Northwestern University Evanston IL 60208 USA
| | - Julia Oktawiec
- Department of Chemistry International Institute of Nanotechnology Simpson-Querrey Institute Chemistry of Life Processes Institute Lurie Cancer Center Northwestern University Evanston IL 60208 USA
| | - Liliana D'Alba
- Department of Biology Evolution and Optics of Nanostructures Group University of Ghent 9000 Ghent Belgium
| | - Hao Sun
- Department of Chemistry International Institute of Nanotechnology Simpson-Querrey Institute Chemistry of Life Processes Institute Lurie Cancer Center Northwestern University Evanston IL 60208 USA
| | - Matthew P. Thompson
- Department of Chemistry International Institute of Nanotechnology Simpson-Querrey Institute Chemistry of Life Processes Institute Lurie Cancer Center Northwestern University Evanston IL 60208 USA
| | - Ziying Hu
- Department of Chemistry International Institute of Nanotechnology Simpson-Querrey Institute Chemistry of Life Processes Institute Lurie Cancer Center Northwestern University Evanston IL 60208 USA
| | - Utkarsh Kapoor
- Department of Chemical and Biomolecular Engineering Colburn Laboratory University of Delaware Newark DE 19716 USA
| | - Naneki C. McCallum
- Department of Chemistry International Institute of Nanotechnology Simpson-Querrey Institute Chemistry of Life Processes Institute Lurie Cancer Center Northwestern University Evanston IL 60208 USA
| | - Christos D. Malliakas
- Department of Chemistry International Institute of Nanotechnology Simpson-Querrey Institute Chemistry of Life Processes Institute Lurie Cancer Center Northwestern University Evanston IL 60208 USA
| | - Omar K. Farha
- Department of Chemistry International Institute of Nanotechnology Simpson-Querrey Institute Chemistry of Life Processes Institute Lurie Cancer Center Northwestern University Evanston IL 60208 USA
| | - Arthi Jayaraman
- Department of Chemical and Biomolecular Engineering Colburn Laboratory Department of Materials Science and Engineering University of Delaware Newark DE 19716 USA
| | - Matthew D. Shawkey
- Department of Biology Evolution and Optics of Nanostructures Group University of Ghent 9000 Ghent Belgium
| | - Nathan C. Gianneschi
- Department of Chemistry International Institute of Nanotechnology Simpson-Querrey Institute Chemistry of Life Processes Institute Lurie Cancer Center Northwestern University Evanston IL 60208 USA
- Department of Materials Science and Engineering, and Department of Biomedical Engineering Northwestern University Evanston IL 60208 USA
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9
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Cao W, McCallum NC, Ni QZ, Li W, Boyce H, Mao H, Zhou X, Sun H, Thompson MP, Battistella C, Wasielewski MR, Dhinojwala A, Shawkey MD, Burkart MD, Wang Z, Gianneschi NC. Selenomelanin: An Abiotic Selenium Analogue of Pheomelanin. J Am Chem Soc 2020; 142:12802-12810. [DOI: 10.1021/jacs.0c05573] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Wei Cao
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States of America
- Department of Materials Science and Engineering, Department of Biomedical Engineering, Department of Pharmacology, International Institute for Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University, Evanston, Illinois 60208, United States of America
| | - Naneki C. McCallum
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States of America
| | - Qing Zhe Ni
- Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, California 92093, United States of America
| | - Weiyao Li
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325, United States of America
| | - Hannah Boyce
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States of America
| | - Haochuan Mao
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States of America
- Institute for Sustainability and Energy, Northwestern University, Evanston, Illinois 60208, United States of America
| | - Xuhao Zhou
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States of America
| | - Hao Sun
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States of America
- Department of Materials Science and Engineering, Department of Biomedical Engineering, Department of Pharmacology, International Institute for Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University, Evanston, Illinois 60208, United States of America
| | - Matthew P. Thompson
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States of America
- Department of Materials Science and Engineering, Department of Biomedical Engineering, Department of Pharmacology, International Institute for Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University, Evanston, Illinois 60208, United States of America
| | - Claudia Battistella
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States of America
- Department of Materials Science and Engineering, Department of Biomedical Engineering, Department of Pharmacology, International Institute for Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University, Evanston, Illinois 60208, United States of America
| | - Michael R. Wasielewski
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States of America
- Institute for Sustainability and Energy, Northwestern University, Evanston, Illinois 60208, United States of America
| | - Ali Dhinojwala
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325, United States of America
| | - Matthew D. Shawkey
- Evolution and Optics of Nanostructures Group, Department of Biology, The University of Ghent, 9000 Ghent, Belgium
| | - Michael D. Burkart
- Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, California 92093, United States of America
| | - Zheng Wang
- Center for Bio/Molecular Science and Engineering, US Naval Research Laboratory, Washington, D.C. 20375, United States of America
| | - Nathan C. Gianneschi
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States of America
- Department of Materials Science and Engineering, Department of Biomedical Engineering, Department of Pharmacology, International Institute for Nanotechnology, Simpson-Querrey Institute, Chemistry of Life Processes Institute, Lurie Cancer Center, Northwestern University, Evanston, Illinois 60208, United States of America
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Maher S, Mahmoud M, Rizk M, Kalil H. Synthetic melanin nanoparticles as peroxynitrite scavengers, photothermal anticancer and heavy metals removal platforms. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:19115-19126. [PMID: 30982188 DOI: 10.1007/s11356-019-05111-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 04/04/2019] [Indexed: 06/09/2023]
Abstract
Melanin is a ubiquitous natural polyphenolic pigment with versatile applications including physiological functions. This polymeric material is found in a diversity of living organisms from bacteria to mammals. The biocompatibility and thermal stability of melanin nanoparticles make them good candidates to work as free radical scavengers and photothermal anticancer substrates. Research studies have identified melanin as an antioxidative therapeutic agent and/or reactive oxygen species (ROS) scavenger that includes neutralization of peroxynitrite. In addition, melanin nanoparticles have emerged as an anticancer photothermal platform that has the capability to kill cancer cells. Recently, melanin nanoparticles have been successfully used as chelating agents to purify water from heavy metals, such as hexavalent chromium. This review article highlights some selected aspects of cutting-edge melanin applications. Herein, we will refer to the recent literature that addresses melanin nanoparticles and its useful physicochemical properties as a hot topic in biomaterial science. It is expected that the techniques of Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), and time-resolved Electron Paramagnetic Resonance (EPR) will have a strong impact on the full characterization of melanin nanoparticles and the subsequent exploration of their physiological and chemical mechanisms.
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Affiliation(s)
- Shaimaa Maher
- Department of Chemistry, College of Science, Cleveland State University, Cleveland, OH, 44115, USA
| | - Marwa Mahmoud
- Department of Science and Mathematics, Faculty of Petroleum and Mining Engineering, Suez University, Suez, Egypt
| | - Moustafa Rizk
- Department of Chemistry, Faculty of Science and Arts, Najran University, Sharourah, Najran, Saudi Arabia
- Department of Chemistry, Faculty of Science, Suez Canal University, Ismailia, Egypt
| | - Haitham Kalil
- Department of Chemistry, College of Science, Cleveland State University, Cleveland, OH, 44115, USA.
- Department of Chemistry, Faculty of Science, Suez Canal University, Ismailia, Egypt.
- Department of Chemistry and Biochemistry, University of Mount Union, Alliance, OH, 44601, USA.
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11
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Markitantova YV, Simirskii VN. Role of the Redox System in Initiation of a Regenerative Response of Neural Eye Tissues in Vertebrates. Russ J Dev Biol 2020. [DOI: 10.1134/s106236042001004x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Kapoor U, Jayaraman A. Self-Assembly of Allomelanin Dimers and the Impact of Poly(ethylene glycol) on the Assembly: A Molecular Dynamics Simulation Study. J Phys Chem B 2020; 124:2702-2714. [DOI: 10.1021/acs.jpcb.0c00226] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Utkarsh Kapoor
- Department of Chemical and Biomolecular Engineering, Colburn Laboratory, University of Delaware, 150 Academy Street, Newark, Delaware 19716, United States
| | - Arthi Jayaraman
- Department of Chemical and Biomolecular Engineering, Colburn Laboratory, University of Delaware, 150 Academy Street, Newark, Delaware 19716, United States
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States
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14
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Zhou X, McCallum NC, Hu Z, Cao W, Gnanasekaran K, Feng Y, Stoddart JF, Wang Z, Gianneschi NC. Artificial Allomelanin Nanoparticles. ACS NANO 2019; 13:10980-10990. [PMID: 31524373 DOI: 10.1021/acsnano.9b02160] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Allomelanin is a type of nitrogen-free melanin most commonly found in fungi. Its existence enhances resistance of the organisms to environmental damage and helps fungi survive harsh radiation conditions such as those found on spacecraft and inside contaminated nuclear power plants. We report the preparation and characterization of artificial allomelanin nanoparticles (AMNPs) via oxidative oligomerization of 1,8-dihydroxynaphthalene (1,8-DHN). We describe the resulting morphological and size control of AMNPs and demonstrate that they are radical scavengers. Finally, we show that AMNPs are taken up by neonatal human epidermal keratinocytes and packaged into perinuclear caps where they quench reactive oxygen species generated following UV exposure.
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Affiliation(s)
| | | | | | | | | | | | | | - Zhao Wang
- Department of Chemistry & Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
| | - Nathan C Gianneschi
- Department of Chemistry & Biochemistry , University of California, San Diego , La Jolla , California 92093 , United States
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15
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Lemaster JE, Jeevarathinam AS, Kumar A, Chandrasekar B, Chen F, Jokerst JV. Synthesis of Ultrasmall Synthetic Melanin Nanoparticles by UV Irradiation in Acidic and Neutral Conditions. ACS APPLIED BIO MATERIALS 2019; 2:4667-4674. [PMID: 31930189 PMCID: PMC6953903 DOI: 10.1021/acsabm.9b00747] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Synthetic melanin nanoparticles have value in metal chelation, photoprotection, and biocompatibility. Applications of these materials have been reported in optics, biomedicine, and electronics. However, precise size control has remained relatively difficult-especially for materials below 1000 nm. In this paper we describe the synthesis of ultrasmall synthetic nanoparticles with size of 9.4-31.4 nm in weakly acidic and neutral conditions via UV-irradiation. Size control of these particles was possible by varying the pH from 6.4-10.0. We then used UV-vis, FTIR, and nuclear magnetic resonance to investigate the mechanism of UV-induced polymerization. The data show that reactive oxygen species from UV irradiation oxidizes intermediates of the reaction and accelerates the formation of these synthetic melanin structures.
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Affiliation(s)
- Jeanne E. Lemaster
- Department of NanoEngineering, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | | | - Ajay Kumar
- Department of NanoEngineering, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Bhargavi Chandrasekar
- Department of NanoEngineering, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Fang Chen
- Department of NanoEngineering, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
- Department of Radiology, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Jesse V. Jokerst
- Department of NanoEngineering, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
- Materials Science and Engineering Program, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
- Department of Radiology, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
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16
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Tao JX, Zhou WC, Zhu XG. Mitochondria as Potential Targets and Initiators of the Blue Light Hazard to the Retina. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:6435364. [PMID: 31531186 PMCID: PMC6721470 DOI: 10.1155/2019/6435364] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 06/18/2019] [Accepted: 07/25/2019] [Indexed: 12/20/2022]
Abstract
Commercially available white light-emitting diodes (LEDs) have an intense emission in the range of blue light, which has raised a range of public concerns about their potential risks as retinal hazards. Distinct from other visible light components, blue light is characterized by short wavelength, high energy, and strong penetration that can reach the retina with relatively little loss in damage potential. Mitochondria are abundant in retinal tissues, giving them relatively high access to blue light, and chromophores, which are enriched in the retina, have many mitochondria able to absorb blue light and induce photochemical effects. Therefore, excessive exposure of the retina to blue light tends to cause ROS accumulation and oxidative stress, which affect the structure and function of the retinal mitochondria and trigger mitochondria-involved death signaling pathways. In this review, we highlight the essential roles of mitochondria in blue light-induced photochemical damage and programmed cell death in the retina, indicate directions for future research and preventive targets in terms of the blue light hazard to the retina, and suggest applying LED devices in a rational way to prevent the blue light hazard.
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Affiliation(s)
- Jin-Xin Tao
- Department of Neurosurgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
- Department of Clinical Medicine, The Second Clinical Medical College, Nanchang University, Nanchang 330006, China
| | - Wen-Chuan Zhou
- Department of Neurosurgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
- Department of Clinical Medicine, The Second Clinical Medical College, Nanchang University, Nanchang 330006, China
| | - Xin-Gen Zhu
- Department of Neurosurgery, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
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17
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Kim E, Kang M, Liu H, Cao C, Liu C, Bentley WE, Qu X, Payne GF. Pro- and Anti-oxidant Properties of Redox-Active Catechol-Chitosan Films. Front Chem 2019; 7:541. [PMID: 31417897 PMCID: PMC6682675 DOI: 10.3389/fchem.2019.00541] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 07/15/2019] [Indexed: 11/17/2022] Open
Abstract
Catechols are abundant in nature and are believed to perform diverse biological functions that include photoprotection (e.g., melanins), molecular signaling (e.g., catecholamine neurotransmitters), and mechanical adhesion (e.g., mussel glue). Currently, the structure-property-function relationships for catechols remain poorly resolved, and this is especially true for redox-based properties (e.g., antioxidant, pro-oxidant, and radical scavenging activities). Importantly, there are few characterization methods available to probe the redox properties of materials. In this review, we focus on recent studies with redox-active catechol-chitosan films. First, we describe film fabrication methods to oxidatively-graft catechols to chitosan through chemical, enzymatic, or electrochemical methods. Second, we discuss a new experimental characterization method to probe the redox properties of catechol-functionalized materials. This mediated electrochemical probing (MEP) method probes the redox-activities of catechol-chitosan films by: (i) employing diffusible mediators to shuttle electrons between the electrode and grafted catechols; (ii) imposing tailored sequences of input voltages to “tune” redox probing; and (iii) analyzing the output current response characteristics to infer properties. Finally, we demonstrate that the redox properties of catechol-chitosan films enable them to perform antioxidant radical scavenging functions, as well as a pro-oxidant (reactive oxygen-generation) antimicrobial functions. In summary, our increasing knowledge of catechol-chitosan films is enabling us to better-understand the functions of catechols in biology as well as enhancing our capabilities to create advanced functional materials.
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Affiliation(s)
- Eunkyoung Kim
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD, United States
| | - Mijeong Kang
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD, United States
| | - Huan Liu
- Key Laboratory for Ultrafine Materials of Ministry of Education, The State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Chunhua Cao
- Key Laboratory of Optoelectronic Chemical Materials and Devices, Ministry of Education, School of Chemical and Environmental Engineering, Jianghan University, Wuhan, China
| | - Changsheng Liu
- Key Laboratory for Ultrafine Materials of Ministry of Education, The State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - William E Bentley
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD, United States
| | - Xue Qu
- Key Laboratory for Ultrafine Materials of Ministry of Education, The State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Gregory F Payne
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD, United States
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18
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Ju KY, Degan S, Fischer MC, Zhou KC, Jia X, Yu J, Warren WS. Unraveling the molecular nature of melanin changes in metastatic cancer. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-13. [PMID: 30977334 PMCID: PMC6460485 DOI: 10.1117/1.jbo.24.5.051414] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 03/11/2019] [Indexed: 05/27/2023]
Abstract
More people die from melanoma after a stage I diagnosis than after a stage IV diagnosis, because the tools available to clinicians do not readily identify which early-stage cancers will be aggressive. Near-infrared pump-probe microscopy detects fundamental differences in melanin structure between benign human moles and melanoma and also correlates with metastatic potential. However, the biological mechanisms of these changes have been difficult to quantify, as many different mechanisms can contribute to the pump-probe signal. We use model systems (sepia, squid, and synthetic eumelanin), cellular uptake studies, and a range of pump and probe wavelengths to demonstrate that the clinically observed effects come from alterations of the aggregated mode from "thick oligomer stacks" to "thin oligomer stacks" (due to changes in monomer composition) and (predominantly) deaggregation of the assembled melanin structure. This provides the opportunity to use pump-probe microscopy for the detection and study of melanin-associated diseases.
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Affiliation(s)
- Kuk-Youn Ju
- Duke University, Department of Chemistry, Durham, North Carolina, United States
| | - Simone Degan
- Duke University, Department of Chemistry, Durham, North Carolina, United States
- Duke University, Department of Radiology, Durham, North Carolina, United States
| | - Martin C. Fischer
- Duke University, Department of Chemistry, Durham, North Carolina, United States
- Duke University, Department of Physics, Durham, North Carolina, United States
| | - Kevin C. Zhou
- Duke University, Department of Biomedical Engineering, Durham, North Carolina, United States
| | - Xiaomeng Jia
- Duke University, Department of Physics, Durham, North Carolina, United States
| | - Jin Yu
- Duke University, Department of Chemistry, Durham, North Carolina, United States
| | - Warren S. Warren
- Duke University, Department of Chemistry, Durham, North Carolina, United States
- Duke University, Department of Radiology, Durham, North Carolina, United States
- Duke University, Department of Physics, Durham, North Carolina, United States
- Duke University, Department of Biomedical Engineering, Durham, North Carolina, United States
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19
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Ribera J, Panzarasa G, Stobbe A, Osypova A, Rupper P, Klose D, Schwarze FWMR. Scalable Biosynthesis of Melanin by the Basidiomycete Armillaria cepistipes. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:132-139. [PMID: 30541276 DOI: 10.1021/acs.jafc.8b05071] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Natural melanin features many interesting properties, including the ability to shield electromagnetic radiation, the ability to act as scavenger for radical and reactive oxygen species and the capacity to chelate different metal ions. For these reasons, melanin is becoming increasingly relevant for the development of functional materials with potential applications in cosmetics, drug delivery, and water purification. However, the extraction and purification of melanin from conventional sources (e.g., sepia ink, hair, and wool) is inefficient and not easily scalable, hence diverting its technological applications. Some fungal species, especially wood-decay basidiomycetes, can be regarded as promising sources of melanin. In the present study, we screened different fungi in regard to their melanin-biosynthesis abilities using l-tyrosine as a precursor, and we found that an Armillaria cepistipes strain (Empa 655) produced the highest yield of melanin (27.98 g L-1). Physicochemical characterization of the obtained fungal melanin revealed a typical eumelanin structure. The method for the biosynthesis of fungal melanin we propose is efficient, scalable, and sustainable and has the potential to provide support for further technological exploitation.
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Affiliation(s)
- Javier Ribera
- Laboratory for Applied Wood Materials , Empa , Lerchenfeldstrasse 5 , St. Gallen 9014 , Switzerland
| | - Guido Panzarasa
- Laboratory for Soft and Living Materials, Department of Materials , ETH Zürich , Vladimir-Prelog-Weg 5 , Zürich 8093 , Switzerland
| | - Annika Stobbe
- Laboratory for Applied Wood Materials , Empa , Lerchenfeldstrasse 5 , St. Gallen 9014 , Switzerland
| | - Alina Osypova
- Innovative Sensor Technology, IST AG , Stegrütistrasse 14 , Ebnat-Kappel 9642 , Switzerland
| | - Patrick Rupper
- Laboratory for Advanced Fibers , Empa , Lerchenfeldstrase 5 , St. Gallen 9014 , Switzerland
| | - Daniel Klose
- Laboratory for Physical Chemistry, Department of Chemistry and Applied Biosciences , ETH Zürich , Vladimir-Prelog-Weg 5 , Zürich 8093 , Switzerland
| | - Francis W M R Schwarze
- Laboratory for Applied Wood Materials , Empa , Lerchenfeldstrasse 5 , St. Gallen 9014 , Switzerland
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20
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Cao C, Kim E, Liu Y, Kang M, Li J, Yin JJ, Liu H, Qu X, Liu C, Bentley WE, Payne GF. Radical Scavenging Activities of Biomimetic Catechol-Chitosan Films. Biomacromolecules 2018; 19:3502-3514. [DOI: 10.1021/acs.biomac.8b00809] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Chunhua Cao
- Key Laboratory of Optoelectronic Chemical Materials and Devices, Ministry of Education, School of Chemical and Environmental Engineering, Jianghan University, Wuhan, 430056, P R China
| | - Eunkyoung Kim
- Institute for Bioscience and Biotechnology Research, University of Maryland, 4291 Fieldhouse Drive, Plant Sciences Building, College Park, Maryland 20742, United States
- Fischell Department of Bioengineering, University of Maryland, 8228 Paint Branch Drive, 2330 Jeong H. Kim Engineering Building, College Park, Maryland 20742, United States
| | - Yi Liu
- Institute for Bioscience and Biotechnology Research, University of Maryland, 4291 Fieldhouse Drive, Plant Sciences Building, College Park, Maryland 20742, United States
- Fischell Department of Bioengineering, University of Maryland, 8228 Paint Branch Drive, 2330 Jeong H. Kim Engineering Building, College Park, Maryland 20742, United States
| | - Mijeong Kang
- Institute for Bioscience and Biotechnology Research, University of Maryland, 4291 Fieldhouse Drive, Plant Sciences Building, College Park, Maryland 20742, United States
- Fischell Department of Bioengineering, University of Maryland, 8228 Paint Branch Drive, 2330 Jeong H. Kim Engineering Building, College Park, Maryland 20742, United States
| | - Jinyang Li
- Institute for Bioscience and Biotechnology Research, University of Maryland, 4291 Fieldhouse Drive, Plant Sciences Building, College Park, Maryland 20742, United States
- Fischell Department of Bioengineering, University of Maryland, 8228 Paint Branch Drive, 2330 Jeong H. Kim Engineering Building, College Park, Maryland 20742, United States
| | - Jun-Jie Yin
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, College Park, Maryland 20740, United States
| | - Huan Liu
- Key Laboratory for Ultrafine Materials of Ministry of Education, The State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, P R China
| | - Xue Qu
- Key Laboratory for Ultrafine Materials of Ministry of Education, The State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, P R China
| | - Changsheng Liu
- Key Laboratory for Ultrafine Materials of Ministry of Education, The State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, P R China
| | - William E. Bentley
- Institute for Bioscience and Biotechnology Research, University of Maryland, 4291 Fieldhouse Drive, Plant Sciences Building, College Park, Maryland 20742, United States
- Fischell Department of Bioengineering, University of Maryland, 8228 Paint Branch Drive, 2330 Jeong H. Kim Engineering Building, College Park, Maryland 20742, United States
| | - Gregory F. Payne
- Institute for Bioscience and Biotechnology Research, University of Maryland, 4291 Fieldhouse Drive, Plant Sciences Building, College Park, Maryland 20742, United States
- Fischell Department of Bioengineering, University of Maryland, 8228 Paint Branch Drive, 2330 Jeong H. Kim Engineering Building, College Park, Maryland 20742, United States
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21
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Belemets N, Kobyliak N, Virchenko O, Falalyeyeva T, Olena T, Bodnar P, Savchuk O, Galenova T, Caprnda M, Rodrigo L, Skladany L, Delev D, Opatrilova R, Kruzliak P, Beregova T, Ostapchenko L. Effects of polyphenol compounds melanin on NAFLD/NASH prevention. Biomed Pharmacother 2017; 88:267-276. [DOI: 10.1016/j.biopha.2017.01.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/25/2016] [Accepted: 01/04/2017] [Indexed: 12/17/2022] Open
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22
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Miller DJ, Dreyer DR, Bielawski CW, Paul DR, Freeman BD. Surface Modification of Water Purification Membranes. Angew Chem Int Ed Engl 2017; 56:4662-4711. [DOI: 10.1002/anie.201601509] [Citation(s) in RCA: 441] [Impact Index Per Article: 63.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Indexed: 12/17/2022]
Affiliation(s)
- Daniel J. Miller
- McKetta Department of Chemical Engineering and Texas Materials Institute, Center for Energy and Environmental Resources The University of Texas at Austin 10100 Burnet Road, Building 133 Austin TX 78758 USA
- Joint Center for Artificial Photosynthesis Lawrence Berkeley National Laboratory 1 Cyclotron Road, 30-210C Berkeley CA 94702 USA
| | - Daniel R. Dreyer
- Nalco Champion 3200 Southwest Freeway, Ste. 2700 Houston TX 77027 USA
| | - Christopher W. Bielawski
- Center for Multidimensional Carbon Materials (CMCM) Institute for Basic Science (IBS), Ulsan National Institute of Science and Technology (UNIST) Ulsan 44919 Republic of Korea
- Department of Chemistry and Department of Energy Engineering Ulsan National Institute of Science and Technology (UNIST) Ulsan 44919 Republic of Korea
| | - Donald R. Paul
- McKetta Department of Chemical Engineering and Texas Materials Institute, Center for Energy and Environmental Resources The University of Texas at Austin 10100 Burnet Road, Building 133 Austin TX 78758 USA
| | - Benny D. Freeman
- McKetta Department of Chemical Engineering and Texas Materials Institute, Center for Energy and Environmental Resources The University of Texas at Austin 10100 Burnet Road, Building 133 Austin TX 78758 USA
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23
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Miller DJ, Dreyer DR, Bielawski CW, Paul DR, Freeman BD. Oberflächenmodifizierung von Wasseraufbereitungsmembranen. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201601509] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Daniel J. Miller
- McKetta Department of Chemical Engineering and Texas Materials Institute, Center for Energy and Environmental Resources The University of Texas, Austin 10100 Burnet Road, Building 133 Austin TX 78758 USA
- Joint Center for Artificial Photosynthesis Lawrence Berkeley National Laboratory 1 Cyclotron Road, 30-210C Berkeley CA 94702 USA
| | - Daniel R. Dreyer
- Nalco Champion 3200 Southwest Freeway, Ste. 2700 Houston TX 77027 USA
| | - Christopher W. Bielawski
- Center for Multidimensional Carbon Materials (CMCM) Institute for Basic Science (IBS), Ulsan National Institute of Science and Technology (UNIST) Ulsan 44919 Republik Korea
- Department of Chemistry and Department of Energy Engineering Ulsan National Institute of Science and Technology (UNIST) Ulsan 44919 Republik Korea
| | - Donald R. Paul
- McKetta Department of Chemical Engineering and Texas Materials Institute, Center for Energy and Environmental Resources The University of Texas, Austin 10100 Burnet Road, Building 133 Austin TX 78758 USA
| | - Benny D. Freeman
- McKetta Department of Chemical Engineering and Texas Materials Institute, Center for Energy and Environmental Resources The University of Texas, Austin 10100 Burnet Road, Building 133 Austin TX 78758 USA
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24
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Morina F, Takahama U, Mojović M, Popović-Bijelić A, Veljović-Jovanović S. Formation of stable radicals in catechin/nitrous acid systems: Participation of dinitrosocatechin. Food Chem 2016; 194:1116-22. [DOI: 10.1016/j.foodchem.2015.08.081] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 07/27/2015] [Accepted: 08/20/2015] [Indexed: 12/27/2022]
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25
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Naklua W, Mahesh K, Aundorn P, Tanmanee N, Aenukulpong K, Sutto S, Chen YZ, Chen S, Suedee R. An imprinted dopamine receptor for discovery of highly potent and selective D 3 analogues with neuroprotective effects. Process Biochem 2015. [DOI: 10.1016/j.procbio.2015.06.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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26
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Beltrán-García MJ, Prado FM, Oliveira MS, Ortiz-Mendoza D, Scalfo AC, Pessoa A, Medeiros MHG, White JF, Di Mascio P. Singlet molecular oxygen generation by light-activated DHN-melanin of the fungal pathogen Mycosphaerella fijiensis in black Sigatoka disease of bananas. PLoS One 2014; 9:e91616. [PMID: 24646830 PMCID: PMC3960117 DOI: 10.1371/journal.pone.0091616] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Accepted: 02/13/2014] [Indexed: 02/03/2023] Open
Abstract
In pathogenic fungi, melanin contributes to virulence, allowing tissue invasion and inactivation of the plant defence system, but has never been implicated as a factor for host cell death, or as a light-activated phytotoxin. Our research shows that melanin synthesized by the fungal banana pathogen Mycosphaerella fijiensis acts as a virulence factor through the photogeneration of singlet molecular oxygen O2 (1Δg). Using analytical tools, including elemental analysis, ultraviolet/infrared absorption spectrophometry and MALDI-TOF mass spectrometry analysis, we characterized both pigment content in mycelia and secreted to the culture media as 1,8-dihydroxynaphthalene (DHN)-melanin type compound. This is sole melanin-type in M. fijiensis. Isolated melanins irradiated with a Nd:YAG laser at 532 nm produced monomol light emission at 1270 nm, confirming generation of O2 (1Δg), a highly reactive oxygen specie (ROS) that causes cellular death by reacting with all cellular macromolecules. Intermediary polyketides accumulated in culture media by using tricyclazole and pyroquilon (two inhibitors of DHN-melanin synthesis) were identified by ESI-HPLC-MS/MS. Additionally, irradiation at 532 nm of that mixture of compounds and whole melanized mycelium also generated O2 (1Δg). A pigmented-strain generated more O2 (1Δg) than a strain with low melanin content. Banana leaves of cultivar Cavendish, naturally infected with different stages of black Sigatoka disease, were collected from field. Direct staining of the naturally infected leaf tissues showed the presence of melanin that was positively correlated to the disease stage. We also found hydrogen peroxide (H2O2) but we cannot distinguish the source. Our results suggest that O2 (1Δg) photogenerated by DHN-melanin may be involved in the destructive effects of Mycosphaerella fijiensis on banana leaf tissues. Further studies are needed to fully evaluate contributions of melanin-mediated ROS to microbial pathogenesis.
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Affiliation(s)
- Miguel J. Beltrán-García
- Departamento de Química-ICET, Universidad Autónoma de Guadalajara, Zapopan Jalisco, Mexico
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Fernanda M. Prado
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Marilene S. Oliveira
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - David Ortiz-Mendoza
- Departamento de Química-ICET, Universidad Autónoma de Guadalajara, Zapopan Jalisco, Mexico
- Instituto de Ingeniería, Universidad Autónoma de Baja California, Mexicali Baja California, Mexico
| | - Alexsandra C. Scalfo
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Adalberto Pessoa
- Faculdade de Ciências Farmacêuticas, Departamento de Tecnologia Bioquímico-Farmacêutica, Universidade de São Paulo, São Paulo, Brazil
| | - Marisa H. G. Medeiros
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - James F. White
- Department of Plant Biology and Pathology, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, New Jersey, United States of America
| | - Paolo Di Mascio
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
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27
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Klotho regulates retinal pigment epithelial functions and protects against oxidative stress. J Neurosci 2013; 33:16346-59. [PMID: 24107965 DOI: 10.1523/jneurosci.0402-13.2013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The retinal pigment epithelium (RPE) is a highly specialized CNS tissue that plays crucial roles in retinal homeostasis. Age-related morphological changes in the RPE have been associated with retinal degenerative disorders; our understanding of the underlying molecular mechanisms, however, remains incomplete. Here we report on a key role of Klotho (Kl), an aging-suppressor gene, in retinal health and RPE physiology. Kl(-/-) mice show RPE and photoreceptor degeneration, reduced pigment synthesis in the RPE, and impaired phagocytosis of the outer segment of the photoreceptors. Klotho protein (KL) is expressed in primary cultured human RPE, and regulates pigment synthesis by increasing the expression of MITF (microphthalmia transcription factor) and TYR (tyrosinase), two pivotal genes in melanogenesis. Importantly, KL increases phagocytosis in cultured RPE by inducing gene expression of MERTK/AXL/TYRO3. These effects of KL are mediated through cAMP-PKA-dependent phosphorylation of transcription factor CREB. In cultured human RPE, KL increases the l-3,4-dihydroxyphenylalanine synthesis and inhibits vascular endothelial growth factor (VEGF) secretion from basal membrane by inhibiting IGF-1 signaling and VEGF receptor 2 phosphorylation. KL also regulates the expression of stress-related genes in RPE, lowers the production of reactive oxygen species, and thereby, protects RPE from oxidative stress. Together, our results demonstrate a critical function for KL in mouse retinal health in vivo, and a protective role toward human RPE cells in vitro. We conclude that KL is an important regulator of RPE homeostasis, and propose that an age-dependent decline of KL expression may contribute to RPE degeneration and retinal pathology.
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28
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Chen YM, Liu ZQ, Feng ZH, Xu F, Liu JK. Adhesive protein-free synthetic hydrogels for retinal pigment epithelium cell culture with low ROS level. J Biomed Mater Res A 2013; 102:2258-67. [DOI: 10.1002/jbm.a.34904] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Accepted: 07/24/2013] [Indexed: 01/02/2023]
Affiliation(s)
- Yong Mei Chen
- Department of Chemistry; School of Science; MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter; Xi'an Jiaotong University; Xi'an 710049 People's Republic of China
- Biomedical Engineering and Biomechanics Center; Xi'an Jiaotong University; Xi'an 710049 People's Republic of China
| | - Zhen Qi Liu
- Department of Chemistry; School of Science; MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter; Xi'an Jiaotong University; Xi'an 710049 People's Republic of China
- Biomedical Engineering and Biomechanics Center; Xi'an Jiaotong University; Xi'an 710049 People's Republic of China
| | - Zhi Hui Feng
- Center for Mitochondrial Biology and Medicine; The Key Laboratory of Biomedical Information Engineering of Ministry of Education; School of Life Science and Technology and Frontier Institute of Life Science, FIST, Xi'an Jiaotong University; Xi'an 710049 People's Republic of China
| | - Feng Xu
- Biomedical Engineering and Biomechanics Center; Xi'an Jiaotong University; Xi'an 710049 People's Republic of China
- Center for Mitochondrial Biology and Medicine; The Key Laboratory of Biomedical Information Engineering of Ministry of Education; School of Life Science and Technology and Frontier Institute of Life Science, FIST, Xi'an Jiaotong University; Xi'an 710049 People's Republic of China
| | - Jian Kang Liu
- Center for Mitochondrial Biology and Medicine; The Key Laboratory of Biomedical Information Engineering of Ministry of Education; School of Life Science and Technology and Frontier Institute of Life Science, FIST, Xi'an Jiaotong University; Xi'an 710049 People's Republic of China
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Dreyer DR, Miller DJ, Freeman BD, Paul DR, Bielawski CW. Elucidating the structure of poly(dopamine). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:6428-35. [PMID: 22475082 DOI: 10.1021/la204831b] [Citation(s) in RCA: 647] [Impact Index Per Article: 53.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Herein we propose a new structure for poly(dopamine), a synthetic eumelanin that has found broad utility as an antifouling agent. Commercially available 3-hydroxytyramine hydrochloride (dopamine HCl) was polymerized under aerobic, aqueous conditions using tris(hydroxymethyl)aminomethane (TRIS) as a basic polymerization initiator, affording a darkly colored powder product upon isolation. The polymer was analyzed using a variety of solid state spectroscopic and crystallographic techniques. Collectively, the data showed that in contrast to previously proposed models, poly(dopamine) is not a covalent polymer but instead a supramolecular aggregate of monomers (consisting primarily of 5,6-dihydroxyindoline and its dione derivative) that are held together through a combination of charge transfer, π-stacking, and hydrogen bonding interactions.
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Affiliation(s)
- Daniel R Dreyer
- Department of Chemistry and Biochemistry, The University of Texas at Austin, 1 University Station, A1590 Austin, Texas, USA
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Page S, Chandhoke V, Baranova A. Melanin and melanogenesis in adipose tissue: possible mechanisms for abating oxidative stress and inflammation? Obes Rev 2011; 12:e21-31. [PMID: 20576005 DOI: 10.1111/j.1467-789x.2010.00773.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Obesity has become a worldwide epidemic and can lead to multiple chronic diseases. Adipose tissue is increasingly thought to play an active role in obesity-related pathologies such as insulin resistance and non-alcoholic fatty liver disease. Obesity has been strongly associated with systemic inflammation and, to a lesser degree, with oxidative stress, although the causal relationships among these factors are unclear. A recent study demonstrating an expression of the components of the melanogenic pathway and the presence of melanin in visceral adipose has raised questions regarding the possible role of melanogenesis in adipose tissue. As this study also found larger amounts of melanin in the adipose tissue of obese patients relative to lean ones, we hypothesize that melanin, a pigment known for its antioxidant and anti-inflammatory properties, may scavenge reactive oxygen species and abate oxidative stress and inflammation in adipose tissue. This review considers the evidence to support such a hypothesis, and speculates on the role of melanin within adipocytes. Furthermore, we consider whether the α-melanocyte-stimulating hormone or its synthetic analogues could be used to stimulate melanin production in adipocytes, should the hypothesis be supported in future experiments.
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Affiliation(s)
- S Page
- Department of Molecular and Microbiology, College of Science, George Mason University, Fairfax Center for Liver Diseases, Inova Fairfax Hospital, Falls Church, VA, USA
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31
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Huijser A, Pezzella A, Sundström V. Functionality of epidermal melanin pigments: current knowledge on UV-dissipative mechanisms and research perspectives. Phys Chem Chem Phys 2011; 13:9119-27. [DOI: 10.1039/c1cp20131j] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Greco G, Panzella L, Gentile G, Errico ME, Carfagna C, Napolitano A, d'Ischia M. A melanin-inspired pro-oxidant system for dopa(mine) polymerization: mimicking the natural casing process. Chem Commun (Camb) 2011; 47:10308-10. [DOI: 10.1039/c1cc13731j] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wang A, Marino AR, Gasyna EM, Sarna T, Norris JR. Investigation of photoexcited states in porcine eumelanin through their transient radical products. J Phys Chem B 2009; 113:10480-2. [PMID: 19572671 DOI: 10.1021/jp905417w] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Time-resolved electron paramagnetic resonance was used to monitor the photochemistry of radical pairs from melanin in porcine retinal pigment epithelial cells on the sub-microsecond time scale. Two distinct signals were found: one of enhanced absorption/emission at early times and one mostly emissive at later times. The emissive character of the longer lived feature suggests participation of an excited triplet precursor, something not generally thought to exist in melanins. The radicals in the early time signal were separated by about 21 A and those in the later time signal were separated by about 22-24 A.
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Affiliation(s)
- Alice Wang
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, USA
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35
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Murillo-Cuesta S, Contreras J, Zurita E, Cediel R, Cantero M, Varela-Nieto I, Montoliu L. Melanin precursors prevent premature age-related and noise-induced hearing loss in albino mice. Pigment Cell Melanoma Res 2009; 23:72-83. [PMID: 19843244 DOI: 10.1111/j.1755-148x.2009.00646.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Strial melanocytes are required for normal development and correct functioning of the cochlea. Hearing deficits have been reported in albino individuals from different species, although melanin appears to be not essential for normal auditory function. We have analyzed the auditory brainstem responses (ABR) of two transgenic mice: YRT2, carrying the entire mouse tyrosinase (Tyr) gene expression-domain and undistinguishable from wild-type pigmented animals; and TyrTH, non-pigmented but ectopically expressing tyrosine hydroxylase (Th) in melanocytes, which generate the precursor metabolite, L-DOPA, but not melanin. We show that young albino mice present a higher prevalence of profound sensorineural deafness and a poorer recovery of auditory thresholds after noise-exposure than transgenic mice. Hearing loss was associated with absence of cochlear melanin or its precursor metabolites and latencies of the central auditory pathway were unaltered. In summary, albino mice show impaired hearing responses during ageing and after noise damage when compared to YRT2 and TyrTH transgenic mice, which do not show the albino-associated ABR alterations. These results demonstrate that melanin precursors, such as L-DOPA, have a protective role in the mammalian cochlea in age-related and noise-induced hearing loss.
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Affiliation(s)
- Silvia Murillo-Cuesta
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), Madrid, Spain
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36
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Gauden M, Pezzella A, Panzella L, Napolitano A, d’Ischia M, Sundström V. Ultrafast Excited State Dynamics of 5,6-Dihydroxyindole, A Key Eumelanin Building Block: Nonradiative Decay Mechanism. J Phys Chem B 2009; 113:12575-80. [DOI: 10.1021/jp903190k] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Magdalena Gauden
- Department of Chemical Physics, Lund University, Box 124, S 22100 Lund, Sweden, and Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Naples, Italy
| | - Alessandro Pezzella
- Department of Chemical Physics, Lund University, Box 124, S 22100 Lund, Sweden, and Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Naples, Italy
| | - Lucia Panzella
- Department of Chemical Physics, Lund University, Box 124, S 22100 Lund, Sweden, and Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Naples, Italy
| | - Alessandra Napolitano
- Department of Chemical Physics, Lund University, Box 124, S 22100 Lund, Sweden, and Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Naples, Italy
| | - Marco d’Ischia
- Department of Chemical Physics, Lund University, Box 124, S 22100 Lund, Sweden, and Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Naples, Italy
| | - Villy Sundström
- Department of Chemical Physics, Lund University, Box 124, S 22100 Lund, Sweden, and Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Naples, Italy
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37
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d'Ischia M, Napolitano A, Pezzella A, Meredith P, Sarna T. Chemische und strukturelle Vielfalt der Eumelanine - ein kaum erforschtes optoelektronisches Biopolymer. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200803786] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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38
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Pezzella A, Panzella L, Crescenzi O, Napolitano A, Navaratnam S, Edge R, Land EJ, Barone V, d’Ischia M. Lack of Visible Chromophore Development in the Pulse Radiolysis Oxidation of 5,6-Dihydroxyindole-2-carboxylic Acid Oligomers: DFT Investigation and Implications for Eumelanin Absorption Properties. J Org Chem 2009; 74:3727-34. [DOI: 10.1021/jo900250v] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alessandro Pezzella
- Department of Organic Chemistry and Biochemistry and “Paolo Corradini” Department of Chemistry, University of Naples Federico II, Via Cinthia 4, I-80126 Naples, Italy, STFC Daresbury Laboratory, Daresbury, WA4 4AD, United Kingdom, BioScience Research Institute, Peel Building, University of Salford, Salford M5 4WT, United Kingdom, Chemistry Section, School of Physical and Geographical Sciences, Keele University, Staffs ST5 5BG, United Kingdom, School of Chemistry, University of Manchester, Oxford Road,
| | - Lucia Panzella
- Department of Organic Chemistry and Biochemistry and “Paolo Corradini” Department of Chemistry, University of Naples Federico II, Via Cinthia 4, I-80126 Naples, Italy, STFC Daresbury Laboratory, Daresbury, WA4 4AD, United Kingdom, BioScience Research Institute, Peel Building, University of Salford, Salford M5 4WT, United Kingdom, Chemistry Section, School of Physical and Geographical Sciences, Keele University, Staffs ST5 5BG, United Kingdom, School of Chemistry, University of Manchester, Oxford Road,
| | - Orlando Crescenzi
- Department of Organic Chemistry and Biochemistry and “Paolo Corradini” Department of Chemistry, University of Naples Federico II, Via Cinthia 4, I-80126 Naples, Italy, STFC Daresbury Laboratory, Daresbury, WA4 4AD, United Kingdom, BioScience Research Institute, Peel Building, University of Salford, Salford M5 4WT, United Kingdom, Chemistry Section, School of Physical and Geographical Sciences, Keele University, Staffs ST5 5BG, United Kingdom, School of Chemistry, University of Manchester, Oxford Road,
| | - Alessandra Napolitano
- Department of Organic Chemistry and Biochemistry and “Paolo Corradini” Department of Chemistry, University of Naples Federico II, Via Cinthia 4, I-80126 Naples, Italy, STFC Daresbury Laboratory, Daresbury, WA4 4AD, United Kingdom, BioScience Research Institute, Peel Building, University of Salford, Salford M5 4WT, United Kingdom, Chemistry Section, School of Physical and Geographical Sciences, Keele University, Staffs ST5 5BG, United Kingdom, School of Chemistry, University of Manchester, Oxford Road,
| | - Suppiah Navaratnam
- Department of Organic Chemistry and Biochemistry and “Paolo Corradini” Department of Chemistry, University of Naples Federico II, Via Cinthia 4, I-80126 Naples, Italy, STFC Daresbury Laboratory, Daresbury, WA4 4AD, United Kingdom, BioScience Research Institute, Peel Building, University of Salford, Salford M5 4WT, United Kingdom, Chemistry Section, School of Physical and Geographical Sciences, Keele University, Staffs ST5 5BG, United Kingdom, School of Chemistry, University of Manchester, Oxford Road,
| | - Ruth Edge
- Department of Organic Chemistry and Biochemistry and “Paolo Corradini” Department of Chemistry, University of Naples Federico II, Via Cinthia 4, I-80126 Naples, Italy, STFC Daresbury Laboratory, Daresbury, WA4 4AD, United Kingdom, BioScience Research Institute, Peel Building, University of Salford, Salford M5 4WT, United Kingdom, Chemistry Section, School of Physical and Geographical Sciences, Keele University, Staffs ST5 5BG, United Kingdom, School of Chemistry, University of Manchester, Oxford Road,
| | - Edward J. Land
- Department of Organic Chemistry and Biochemistry and “Paolo Corradini” Department of Chemistry, University of Naples Federico II, Via Cinthia 4, I-80126 Naples, Italy, STFC Daresbury Laboratory, Daresbury, WA4 4AD, United Kingdom, BioScience Research Institute, Peel Building, University of Salford, Salford M5 4WT, United Kingdom, Chemistry Section, School of Physical and Geographical Sciences, Keele University, Staffs ST5 5BG, United Kingdom, School of Chemistry, University of Manchester, Oxford Road,
| | - Vincenzo Barone
- Department of Organic Chemistry and Biochemistry and “Paolo Corradini” Department of Chemistry, University of Naples Federico II, Via Cinthia 4, I-80126 Naples, Italy, STFC Daresbury Laboratory, Daresbury, WA4 4AD, United Kingdom, BioScience Research Institute, Peel Building, University of Salford, Salford M5 4WT, United Kingdom, Chemistry Section, School of Physical and Geographical Sciences, Keele University, Staffs ST5 5BG, United Kingdom, School of Chemistry, University of Manchester, Oxford Road,
| | - Marco d’Ischia
- Department of Organic Chemistry and Biochemistry and “Paolo Corradini” Department of Chemistry, University of Naples Federico II, Via Cinthia 4, I-80126 Naples, Italy, STFC Daresbury Laboratory, Daresbury, WA4 4AD, United Kingdom, BioScience Research Institute, Peel Building, University of Salford, Salford M5 4WT, United Kingdom, Chemistry Section, School of Physical and Geographical Sciences, Keele University, Staffs ST5 5BG, United Kingdom, School of Chemistry, University of Manchester, Oxford Road,
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39
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Toffoletti A, Conti F, Sandron T, Napolitano A, Panzella L, D’Ischia M. Time-resolved EPR observation of synthetic eumelanin–superoxide radical pairs. Chem Commun (Camb) 2009:4977-9. [DOI: 10.1039/b909568c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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40
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d'Ischia M, Napolitano A, Pezzella A, Meredith P, Sarna T. Chemical and structural diversity in eumelanins: unexplored bio-optoelectronic materials. Angew Chem Int Ed Engl 2009; 48:3914-21. [PMID: 19294706 PMCID: PMC2799031 DOI: 10.1002/anie.200803786] [Citation(s) in RCA: 373] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Eumelanins, the characteristic black, insoluble, and heterogeneous biopolymers of human skin, hair, and eyes, have intrigued and challenged generations of chemists, physicists, and biologists because of their unique structural and optoelectronic properties. Recently, the methods of organic chemistry have been combined with advanced spectroscopic and imaging techniques, theoretical calculations, and methods of condensed-matter physics to gradually force these materials to reveal their secrets. Herein we review the latest advances in the field with a view to showing how the emerging knowledge is not only helping to explain eumelanin functionality, but may also be translated into effective strategies for exploiting their properties to create a new class of biologically inspired high-tech materials.
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Affiliation(s)
- Marco d'Ischia
- Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Complesso Universitario Monte S. Angelo, Via Cintia 4, I-80126, Naples, Italy.
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41
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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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Randhawa M, Huff T, Valencia JC, Younossi Z, Chandhoke V, Hearing VJ, Baranova A. Evidence for the ectopic synthesis of melanin in human adipose tissue. FASEB J 2008; 23:835-43. [PMID: 18971261 DOI: 10.1096/fj.08-116327] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Melanin is a common pigment in animals. In humans, melanin is produced in melanocytes, in retinal pigment epithelium (RPE) cells, in the inner ear, and in the central nervous system. Previously, we noted that human adipose tissue expresses several melanogenesis-related genes. In the current study, we confirmed the expression of melanogenesis-related mRNAs and proteins in human adipose tissue using real-time polymerase chain reaction and immunohistochemical staining. TYR mRNA signals were also detected by in situ hybridization in visceral adipocytes. The presence of melanin in human adipose tissue was revealed both by Fontana-Masson staining and by permanganate degradation of melanin coupled with liquid chromatography/ultraviolet/mass spectrometry determination of the pyrrole-2,3,5-tricarboxylic acid (PTCA) derivative of melanin. We also compared melanogenic activities in adipose tissues and in other human tissues using the L-[U-(14)C] tyrosine assay. A marked heterogeneity in the melanogenic activities of individual adipose tissue extracts was noted. We hypothesize that the ectopic synthesis of melanin in obese adipose may serve as a compensatory mechanism that uses its anti-inflammatory and its oxidative damage-absorbing properties. In conclusion, our study demonstrates for the first time that the melanin biosynthesis pathway is functional in adipose tissue.
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Affiliation(s)
- Manpreet Randhawa
- Molecular Biology and Microbiology Department and Center for the Study of Genomics in Liver Diseases, College of Science, George Mason University, Manassas, VA, USA
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43
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Rezai KA, Gasyna E, Seagle BLL, Norris JR, Rezaei KA. AcrySof Natural filter decreases blue light-induced apoptosis in human retinal pigment epithelium. Graefes Arch Clin Exp Ophthalmol 2008; 246:671-6. [PMID: 18299878 DOI: 10.1007/s00417-006-0484-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Revised: 10/01/2006] [Accepted: 10/19/2006] [Indexed: 11/26/2022] Open
Abstract
PURPOSE The effect of AcrySof filter (UV light-filtering chromophore; Alcon) and AcrySof Natural filter (UV- and blue light-filtering chromophores) on blue light-induced apoptosis in human retinal pigment epithelial (RPE) cells was evaluated. DESIGN Laboratory investigation CLINICAL RELEVANCE Acrysof Natural filter reduces the blue-light toxicity in RPE cells and may have a positive impact on age-related macular degeneration (AMD). METHODS RPE cells were exposed to blue light (430-450 nm) in the presence of either the AcrySof (UV only) filter or Acrysof Natural (UV and blue light) filter for 10 days. The rate of apoptosis was analyzed. RESULTS Blue light induced significant apoptosis in RPE cells. AcrySof Natural filter significantly reduced the blue light-induced apoptosis when compared to AcrySof filter. The amount of blue-light energy reaching the cells with the AcrySof filter was 4.25 mW/cm(2) and with the AcrySof Natural filter was 2.5 mW/cm(2). CONCLUSIONS AcrySof Natural filter significantly reduced blue light-induced apoptosis. This was most likely due to its filtering effect on blue wavelength light, which reduces the energy that reaches the cells. In patients with cataract who are at a high risk for AMD, the implantation of a blue light-filtering intraocular lens may be considered.
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Affiliation(s)
- Kourous A Rezai
- Department of Ophthalmology, Rush University Medical Center, Chicago, IL, USA.
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Pezzella A, Panzella L, Natangelo A, Arzillo M, Napolitano A, d'Ischia M. 5,6-dihydroxyindole tetramers with "anomalous" interunit bonding patterns by oxidative coupling of 5,5',6,6'-tetrahydroxy-2,7'-biindolyl: emerging complexities on the way toward an improved model of eumelanin buildup. J Org Chem 2007; 72:9225-30. [PMID: 17975929 DOI: 10.1021/jo701652y] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chemical or enzymatic oxidation of 5,6-dihydroxyindole (1) leads to the rapid deposition of a black solid resembling eumelanin pigments by way of a complex oligomerization/polymerization process that proceeds in the early stages via dimers 2-3 and trimers 5-6 characterized by 2,4'- and 2,7'-couplings. Despite extensive efforts, the structures of the higher oligomers, which define the structural architecture and physicochemical properties of the eumelanin particles, have so far defied elucidation. Using a dimer-dimer coupling strategy that has recently allowed the first successful entry to a tetramer of 1, we report now three additional tetramers obtained by oxidation of 5,5',6,6'-tetrahydroxy-2,7'-biindolyl (3) with the peroxidase/H2O2 system. On the basis of extensive 2D NMR and mass spectrometric analysis, the products were identified as 5,5',5'',5''',6,6',6'',6'''-octaacetoxy-7,2':3',3'':2'',7'''-tetraindolyl (acetylated 8, 3%), 5,5',5'',5''',6,6',6'',6' ''-octaacetoxy-2,7':4',4'':7'',2'''-tetraindolyl (acetylated 9, 4%), and 5,5',5'',5''',6,6',6'',6'''-octaacetoxy-2,7':2',3'':2'',7'''-tetraindolyl (acetylated 10, 5%), in which the inner units are linked through unexpected 3,3'-, 4,4'-, and 2,3'-linkages. If verified in further studies, the newly uncovered coupling patterns would entail important consequences for current models of eumelanin structure based on one-dimensional structural chains with extended pi-electron conjugation or pi-stacked flat oligomer aggregates.
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Affiliation(s)
- Alessandro Pezzella
- Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Via Cinthia 4, I-80126, Naples, Italy.
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45
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Panzella L, Pezzella A, Napolitano A, d'Ischia M. The first 5,6-dihydroxyindole tetramer by oxidation of 5,5',6,6'-tetrahydroxy- 2,4'-biindolyl and an unexpected issue of positional reactivity en route to eumelanin-related polymers. Org Lett 2007; 9:1411-4. [PMID: 17346057 DOI: 10.1021/ol070268w] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[structure: see text]. The first tetramer of the eumelanin precursor 5,6-dihydroxyindole has been obtained, as the acetyl derivative, by peroxidase/H2O2-induced oxidative coupling of 5,5',6,6'-tetrahydroxy-2,4'-biindolyl (2) in the presence of Zn2+ ions. The tetramer, 5,5',5'',5''',6,6',6'',6'''-octaacetoxy-2,4':2',3'':2'',4'''-tetraindolyl (acetylated 7), incorporates an unprecedented 2,3'-biindolyl substructure suggestive of a different positional reactivity of the 5,6-dihydroxyindole system when framed into a dimeric scaffold.
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Affiliation(s)
- Lucia Panzella
- Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Via Cinthia, I-80126 Naples, Italy
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46
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Payne GF. Biopolymer-based materials: the nanoscale components and their hierarchical assembly. Curr Opin Chem Biol 2007; 11:214-9. [PMID: 17293158 DOI: 10.1016/j.cbpa.2007.01.677] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2006] [Accepted: 01/10/2007] [Indexed: 11/22/2022]
Abstract
Protein and nucleic acid biopolymers are well appreciated for their high-performance capabilities for molecular recognition, catalysis and information storage. Increasingly, these biopolymers are being examined for materials applications. Less tractable are polysaccharides and polymers of phenols, which, despite being nature's most abundant macromolecules, remain largely ignored for advanced materials applications. In our opinion, it seems certain that biology will contribute two major capabilities for materials biofabrication - the means to generate biopolymeric components with nanoscale precision, and the mechanisms for the hierarchical assembly of nanocomponents. These capabilities will enable unprecedented control of materials structure and provide exciting opportunities at the convergence of molecular biology and macromolecular science.
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Affiliation(s)
- Gregory F Payne
- Center for Biosystems Research, University of Maryland Biotechnology Institute, 5115 Plant Sciences Building, College Park, MD 20742, USA.
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Pezzella A, Crescenzi O, Natangelo A, Panzella L, Napolitano A, Navaratnam S, Edge R, Land EJ, Barone V, d'Ischia M. Chemical, Pulse Radiolysis and Density Functional Studies of a New, Labile 5,6-Indolequinone and Its Semiquinone. J Org Chem 2007; 72:1595-603. [PMID: 17266371 DOI: 10.1021/jo0615807] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The chemical and spectroscopic characterization of 5,6-indolequinones and their semiquinones, key transient intermediates in the oxidative conversion of 5,6-dihydroxyindoles to eumelanin biopolymers, is a most challenging task. In the present paper, we report the characterization of a novel, relatively long-lived 5,6-indolequinone along with its semiquinone using an integrated chemical, pulse radiolytic, and computational approach. The quinone was obtained by oxidation of 5,6-dihydroxy-3-iodoindole (1a) with o-chloranil in cold ethyl acetate or aqueous buffer: it displayed electronic absorption bands around 400 and 600 nm, was reduced to 1a with Na2S2O4, and reacted with o-phenylenediamine to give small amounts of 3-iodo-1H-pyrrolo[2,3-b]phenazine (2). The semiquinone exhibited absorption maxima at 380 nm (sh) and 520 nm and was detected as the initial species produced by pulse radiolytic oxidation of 1a at pH 7.0. DFT investigations indicated the 6-phenoxyl radical and the N-protonated radical anion as the most stable tautomers for the neutral and anion forms of the semiquinone, respectively. Calculated absorption spectra in water gave bands at 350 (sh) and 500 nm for the neutral form and at 310 and 360 (sh) nm for the anion. Disproportionation of the semiquinone with fast second-order kinetics (2k = 1.1 x 1010 M-1 s-1) gave a chromophore with absorption bands resembling those of chemically generated 1a quinone. Computational analysis predicted 1a quinone to exist in vacuo as the quinone-methide tautomer, displaying low energy transitions at 380 and 710 nm, and in water as the o-quinone, with calculated absorption bands around 400 and 820 nm. A strong participation of a p orbital on the iodine atom in the 360-380 nm electronic transitions of the o-quinone and quinone-methide was highlighted. The satisfactory agreement between computational and experimental electronic absorption data would suggest partitioning of 1a quinone between the o-quinone and quinone-methide tautomers depending on the medium.
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Affiliation(s)
- Alessandro Pezzella
- Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Via Cintia, I-80126 Naples, Italy.
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Zadlo A, Rozanowska MB, Burke JM, Sarna TJ. Photobleaching of retinal pigment epithelium melanosomes reduces their ability to inhibit iron-induced peroxidation of lipids. ACTA ACUST UNITED AC 2007; 20:52-60. [PMID: 17250548 DOI: 10.1111/j.1600-0749.2006.00350.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Melanin in the human retinal pigment epithelium (RPE) is believed to play an important photoprotective role. However, unlike in skin, melanosomes in the RPE are rather long-lived organelles, which increases their risk of modifications resulting from significant fluxes of light and high oxygen tension. In this work, we subjected purified bovine RPE melanosomes to prolonged aerobic exposure with intense visible and near ultraviolet radiation and studied the effects of irradiation on the melanosome's capacity to inhibit peroxidation of lipids induced by iron/ascorbate. We found that control, untreated melanosomes show a concentration-dependent inhibition of the accumulation of lipid hydroperoxides and the accompanying consumption of oxygen, but photolysed melanosomes lose their antioxidant efficiency and even became prooxidant. The prooxidant action of partially photobleached melanosomes was observed for pigment granules with a melanin content reduced by about 50% compared with untreated melanosomes, as determined by electron spin resonance spectroscopy. We have previously shown that a similar loss in the content of the RPE melanin occurs during human lifetime, which may suggest that the normal antioxidant properties of human RPE melanin become compromised with aging.
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Affiliation(s)
- Andrzej Zadlo
- Department of Biophysics, Jagiellonian University, Krakow, Poland
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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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Pezzella A, Panzella L, Crescenzi O, Napolitano A, Navaratman S, Edge R, Land EJ, Barone V, d'Ischia M. Short-Lived Quinonoid Species from 5,6-Dihydroxyindole Dimers en Route to Eumelanin Polymers: Integrated Chemical, Pulse Radiolytic, and Quantum Mechanical Investigation. J Am Chem Soc 2006; 128:15490-8. [PMID: 17132016 DOI: 10.1021/ja0650246] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The transient species formed by oxidation of three dimers of 5,6-dihydroxyindole (1), a major building block of the natural biopolymer eumelanin, have been investigated. Pulse radiolytic oxidation of 5,5',6,6'-tetrahydroxy-2,4'-biindolyl (3) and 5,5',6,6'-tetrahydroxy-2,7'-biindolyl (4) led to semiquinones absorbing around 450 nm, which decayed with second-order kinetics (2k=2.8x10(9) and 1.4x10(9) M-1 s-1, respectively) to give the corresponding quinones (500-550 nm). 5,5',6, 6'-Tetrahydroxy-2,2'-biindolyl (2), on the other hand, furnished a semiquinone (lamdamax=480 nm) which disproportionated at a comparable rate (2k=3x10(9) M-1 s-1) to give a relatively stable quinone (lamdamax=570 nm). A quantum mechanical investigation of o-quinone, quinonimine, and quinone methide structures of 2-4 suggested that oxidized 2-4 exist mainly as 2-substituted extended quinone methide tautomers. Finally, an oxidation product of 3 was isolated for the first time and was formulated as the hydroxylated derivative 5 arising conceivably by the addition of water to the quinone methide intermediate predicted by theoretical analysis. Overall, these results suggest that the oxidation chemistry of biindolyls 2-4 differs significantly from that of the parent 1, whereby caution must be exercised before concepts that apply strictly to the mode of coupling of 1 are extended to higher oligomers.
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Affiliation(s)
- Alessandro Pezzella
- Department of Organic Chemistry, University of Naples Federico II, Via Cintia, I-80126 Naples, Italy
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