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Cardia R, Dardenne N, Mula G, Pinna E, Rignanese GM, Charlier JC, Cappellini G. First-Principles Investigation of the Optical Properties of Eumelanin Protomolecules. J Phys Chem A 2023; 127:10797-10806. [PMID: 38109190 DOI: 10.1021/acs.jpca.3c04898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Using first-principles calculations, we investigate the absorption spectra (in the near-infrared, visible, and first UV range) of the two most probable eumelanin tetrameric molecules exhibiting either a linear open-chain or a cyclic porphyrine-like configuration. In order to simulate a realistic molecular system, an implicit solvent model is used in our calculations to mimic the effect of the solvated environment around the eumelanin molecule. Although the presence of solvent is found not to significantly affect the absorption pattern of both molecules, the onset of the spectra are shifted toward higher energies, especially for the linear tetramer. Interestingly, the absorption spectra and optical onsets of the two molecules differ significantly both in a vacuum and in ethanol. However, the two predicted spectra do not allow us to definitely discriminate between the two configurations when comparing the theoretical predictions with the available experimental spectrum. In addition, a mix of the two eumelanin configurations (close to fifty-fifty) leads to a maximum overlap between theoretical and experimental spectra. Consequently, this theoretical research shows that deeper insight can be gained using beyond DFT techniques on the real form of eumelanin protomolecules present in living systems as well as on their possible use in hybrid solar cells.
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Affiliation(s)
- Roberto Cardia
- Department of Physics, Università degli Studi di Cagliari, Cittadella Universitaria I-09042 Monserrato, Cagliari, Italy
| | - Nicolas Dardenne
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain (UCLouvain), B-1348 Louvain-la-Neuve, Belgium
| | - Guido Mula
- Department of Physics, Università degli Studi di Cagliari, Cittadella Universitaria I-09042 Monserrato, Cagliari, Italy
| | - Elisa Pinna
- Department of Physics, Università degli Studi di Cagliari, Cittadella Universitaria I-09042 Monserrato, Cagliari, Italy
| | - Gian-Marco Rignanese
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain (UCLouvain), B-1348 Louvain-la-Neuve, Belgium
- European Theoretical Spectroscopy Facility (ETSF)
| | - Jean-Christophe Charlier
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain (UCLouvain), B-1348 Louvain-la-Neuve, Belgium
- European Theoretical Spectroscopy Facility (ETSF)
| | - Giancarlo Cappellini
- Department of Physics, Università degli Studi di Cagliari, Cittadella Universitaria I-09042 Monserrato, Cagliari, Italy
- European Theoretical Spectroscopy Facility (ETSF)
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Cao W, Zhou X, McCallum NC, Hu Z, Ni QZ, Kapoor U, Heil CM, Cay KS, Zand T, Mantanona AJ, Jayaraman A, Dhinojwala A, Deheyn DD, Shawkey MD, Burkart MD, Rinehart JD, Gianneschi NC. Unraveling the Structure and Function of Melanin through Synthesis. J Am Chem Soc 2021; 143:2622-2637. [PMID: 33560127 DOI: 10.1021/jacs.0c12322] [Citation(s) in RCA: 131] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Melanin is ubiquitous in living organisms across different biological kingdoms of life, making it an important, natural biomaterial. Its presence in nature from microorganisms to higher animals and plants is attributed to the many functions of melanin, including pigmentation, radical scavenging, radiation protection, and thermal regulation. Generally, melanin is classified into five types-eumelanin, pheomelanin, neuromelanin, allomelanin, and pyomelanin-based on the various chemical precursors used in their biosynthesis. Despite its long history of study, the exact chemical makeup of melanin remains unclear, and it moreover has an inherent diversity and complexity of chemical structure, likely including many functions and properties that remain to be identified. Synthetic mimics have begun to play a broader role in unraveling structure and function relationships of natural melanins. In the past decade, polydopamine, which has served as the conventional form of synthetic eumelanin, has dominated the literature on melanin-based materials, while the synthetic analogues of other melanins have received far less attention. In this perspective, we will discuss the synthesis of melanin materials with a special focus beyond polydopamine. We will emphasize efforts to elucidate biosynthetic pathways and structural characterization approaches that can be harnessed to interrogate specific structure-function relationships, including electron paramagnetic resonance (EPR) and solid-state nuclear magnetic resonance (ssNMR) spectroscopy. We believe that this timely Perspective will introduce this class of biopolymer to the broader chemistry community, where we hope to stimulate new opportunities in novel, melanin-based poly-functional synthetic materials.
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Affiliation(s)
| | | | | | | | - Qing Zhe Ni
- Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Utkarsh Kapoor
- Department of Chemical and Biomolecular Engineering, Colburn Laboratory, University of Delaware, Newark, Delaware 19716, United States
| | - Christian M Heil
- Department of Chemical and Biomolecular Engineering, Colburn Laboratory, University of Delaware, Newark, Delaware 19716, United States
| | - Kristine S Cay
- Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Tara Zand
- Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Alex J Mantanona
- Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Arthi Jayaraman
- Department of Chemical and Biomolecular Engineering, Colburn Laboratory, Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Ali Dhinojwala
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325, United States
| | - Dimitri D Deheyn
- Marine Biology Research Division, Scripps Institution of Oceanography, La Jolla, California 92093-0202, United States
| | - 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
| | - Jeffrey D Rinehart
- 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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