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Dynamics of Protein Elements of Hybrid Nanostructures - Molecular Dynamics Simulations of Light Harvesting Peridinin-Chlorophyll a-Protein Model

100%
Jasiński A., Mikulska K., Krajnik B., Mackowski S., Nowak W.
Acta Physica Polonica A
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2012
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vol. 122
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issue 2
284-288
EN
Hybrid nanostructures are often composed of inorganic parts and "biological" ones. Optimized through million years of evolution light harvesting proteins are hard to mimic synthetically. Promising strategy in search for efficient solar cells is an attachment of selected natural protein systems to inorganic quantum dots. Such experimental hybrid structures should have improved charge separation properties. Among the most promising proteins is peridinin-chlorophyll-protein from Amphidinium carterae (PCP). It has a wide absorption spectrum (420-550 nm), optimized for sunlight. The dynamics of this protein, used in modern nanotechnology has been not addressed yet. In this work we present results of PCP computer modeling using a well established molecular dynamics methodology. The CHARMM27 force field parameters were prepared for this protein and all chromophore components. The system was embedded in a box of water, with proper counter ions, and a number of 10 ns molecular dynamics simulations were run using the NAMD code. It has been found that peridinine chromophores exhibit substantial orientational flexibility but a pair Per612 and Per613 is more rigid than the remaining two carotenoids. Orientation and dynamics of absorption and emission electric dipole moments have been also analyzed. Apparently, the architecture of PCP is not optimized for efficient Per-Chl a energy transfer by the Förster mechanism. Several practical issues related to molecular dynamics simulation of similar hybrid nanostructures are discussed.
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Influence of Plasmon Resonance in Silver Island Film on the Optical Properties of Peridinin-Chlorophyll-Protein Light-Harvesting Complexes

86%
Ciszak K., Olejnik M., Strzelecki J., Krajnik B., Piątkowski D., Hofmann E., Mackowski S.
Acta Physica Polonica A
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2012
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vol. 122
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issue 2
275-278
EN
We study the effect of plasmon excitations in silver island film on the optical properties of peridinin-chlorophyll-protein light-harvesting complex using scanning fluorescence microscopy. With this technique we can unambiguously locate areas where the biomolecules are deposited on the metallic nanostructures from the areas where they stick to the glass surface. The enhancement factor of fluorescence intensity obtained for such a hybrid nanostructure is found to be 3. Plasmon excitations in the SIF layer also influence the dynamics of the emission, but in this case the interpretation of the results is more complex.
3
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Fluorescence Mapping of PCP Light-Harvesting Complexes Coupled to Silver Nanowires

86%
Krajnik B., Piatkowski D., Olejnik M., Czechowski N., Hofmann E., Heiss W., Mackowski S.
Acta Physica Polonica A
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2012
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vol. 122
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issue 2
259-262
EN
In this work we demonstrate confocal fluorescence imaging of hybrid nanostructures composed of silver nanowires and peridinin-chlorophyll-protein light-harvesting complexes. The length of silver nanowires, which reaches 10 μm, allows for determination of the nanowire position and consequently direct correlation with the fluorescence image. In this way we probe the influence of plasmon induced electromagnetic field on the fluorescence of light-harvesting complexes. When the nanowires are spaced from the light-harvesting complexes by a 10 nm thick dielectric layer, we observe a fluorescence enhancement, which depends upon the laser excitation wavelength. The measured enhancement values are 2.5 and 1.9 for 405 nm and 485 nm, respectively. Larger enhancement for the 405 nm excitation is attributed to direct creation of plasmon excitations in the silver nanowires.
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