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Falco W, Botero E, Falcão E, Santiago E, Bagnato V, Caires A. In vivo observation of chlorophyll fluorescence quenching induced by gold nanoparticles. J Photochem Photobiol A Chem 2011. [DOI: 10.1016/j.jphotochem.2011.09.027] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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52
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Kahnt A, Kärnbratt J, Esdaile LJ, Hutin M, Sawada K, Anderson HL, Albinsson B. Temperature dependence of charge separation and recombination in porphyrin oligomer-fullerene donor-acceptor systems. J Am Chem Soc 2011; 133:9863-71. [PMID: 21595470 PMCID: PMC3119959 DOI: 10.1021/ja2019367] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Indexed: 01/12/2023]
Abstract
Electron-transfer reactions are fundamental to many practical devices, but because of their complexity, it is often very difficult to interpret measurements done on the complete device. Therefore, studies of model systems are crucial. Here the rates of charge separation and recombination in donor-acceptor systems consisting of a series of butadiyne-linked porphyrin oligomers (n = 1-4, 6) appended to C(60) were investigated. At room temperature, excitation of the porphyrin oligomer led to fast (5-25 ps) electron transfer to C(60) followed by slower (200-650 ps) recombination. The temperature dependence of the charge-separation reaction revealed a complex process for the longer oligomers, in which a combination of (i) direct charge separation and (ii) migration of excitation energy along the oligomer followed by charge separation explained the observed fluorescence decay kinetics. The energy migration is controlled by the temperature-dependent conformational dynamics of the longer oligomers and thereby limits the quantum yield for charge separation. Charge recombination was also studied as a function of temperature through measurements of femtosecond transient absorption. The temperature dependence of the electron-transfer reactions could be successfully modeled using the Marcus equation through optimization of the electronic coupling (V) and the reorganization energy (λ). For the charge-separation rate, all of the donor-acceptor systems could be successfully described by a common electronic coupling, supporting a model in which energy migration is followed by charge separation. In this respect, the C(60)-appended porphyrin oligomers are suitable model systems for practical charge-separation devices such as bulk-heterojunction solar cells, where conformational disorder strongly influences the electron-transfer reactions and performance of the device.
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Affiliation(s)
- Axel Kahnt
- Physical Chemistry, Department of Chemical and Biological Engineering, Chalmers University of Technology, Kemivägen 3, 412 96 Göteborg, Sweden
| | - Joakim Kärnbratt
- Physical Chemistry, Department of Chemical and Biological Engineering, Chalmers University of Technology, Kemivägen 3, 412 96 Göteborg, Sweden
| | - Louisa J. Esdaile
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Marie Hutin
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Katsutoshi Sawada
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Harry L. Anderson
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Bo Albinsson
- Physical Chemistry, Department of Chemical and Biological Engineering, Chalmers University of Technology, Kemivägen 3, 412 96 Göteborg, Sweden
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53
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Matsuoka KI, Tahara H, Akiyama T, Yamada S. Effects of capping layers on the photoelectrochemical property of silver nanoparticle-modified indium–tin-oxide electrode. J Photochem Photobiol A Chem 2011. [DOI: 10.1016/j.jphotochem.2011.03.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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54
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Das RK, Bhat S, Banerjee S, Aymonier C, Loppinet-Serani A, Terech P, Maitra U, Raffy G, Desvergne JP, Del Guerzo A. Self-assembled composite nano-materials exploiting a thermo reversible n-acene fibrillar scaffold and organic-capped ZnO nanoparticles. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c0jm02603d] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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55
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Chowdhury S, Wu Z, Jaquins-Gerstl A, Liu S, Dembska A, Armitage BA, Jin R, Peteanu LA. Wavelength Dependence of the Fluorescence Quenching Efficiency of Nearby Dyes by Gold Nanoclusters and Nanoparticles: The Roles of Spectral Overlap and Particle Size. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2011; 115:20105-20112. [PMID: 22924090 PMCID: PMC3424614 DOI: 10.1021/jp204836w] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The efficiency of the glutathione monolayer-protected gold nanocluster (NC) Au(25) (1.2 nm metal core diameter (d)) in quenching the emission of dyes intercalated into DNA is compared to that of 2 and 4 nm gold nanoparticles (NPs). In all cases, the DNA/dye moieties and the gold particles are not covalently attached but rather form non-covalent ground state complexes. Under these conditions, steady-state measurements reveal that the quenching efficiency of Au(25) is a factor of 10 lower than that of plasmonic 4 nm gold NPs but comparable to that of 2 nm particles which do not show a distinct plasmon band. Nonetheless, significant emission quenching is observed even at very low (nM) concentrations of Au(25). The quenching efficiency of the 4 nm NPs is significantly higher for dyes emitting near the wavelength of the plasmon peak whereas that of the 2 nm gold NPs is well described by the nano-surface energy transfer (NSET) model proposed by the Strouse group (J. Am. Chem. Soc. 127, 3115 2005). Interestingly, for Au(25) the maximum quenching efficiency occurs for dyes emitting in the same wavelength range as that of the 2 and 4 nm NPs (490-560 nm), where it shows no discrete absorption features, rather than for wavelengths coincident with its HOMO-LUMO, intra-band or inter-band transitions. The fluorescence quenching properties of Au(25) NCs are therefore found to be distinct from those of larger NCs and NPs but do not appear to conform to theoretical predictions advanced thus far.
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56
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Lim SI, Ojea-Jiménez I, Varon M, Casals E, Arbiol J, Puntes V. Synthesis of platinum cubes, polypods, cuboctahedrons, and raspberries assisted by cobalt nanocrystals. NANO LETTERS 2010; 10:964-73. [PMID: 20143792 DOI: 10.1021/nl100032c] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The introduction of metallic traces into the synthesis of platinum nanocrystals (Pt NCs) has been investigated as a surfactant-independent means of controlling shape. Various nanocrystal morphologies have been produced without modification of the reaction conditions, composition, and concentration other than the presence of cobalt traces (<5%). In the presence of metallic cobalt (a strong reducer for Pt cations) cubic Pt NCs are obtained, while cobalt ions or gold NCs have no effect on the synthesis, and as a result, polypods are obtained. Intermediate shapes such as cemented cubes or cuboctahedron NCs are also obtained under similar conditions. Thus, various NC shapes can be obtained with subtle changes, which illustrates the high susceptibility and mutability of the NC shape to modification of the reaction kinetics during the early reduction process. Our studies help progress toward a general mechanism for nanocrystal shape control.
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Cuquerella MC, Pocoví-Martínez S, Pérez-Prieto J. Photocatalytic coalescence of functionalized gold nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:1548-1550. [PMID: 20030323 DOI: 10.1021/la9040503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A novel strategy for the synthesis of chromophore-functionalized AuNPs with a narrow size distribution is reported. It consists of increasing the size of preprepared NPs by means of a fast (second scale) and clean (light and an organic photocatalyst) method. The results agree with thiolate ligand liberation from the NP surface promoted by photogenerated radicals. This lets gold cores come together and finally coalesce.
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Affiliation(s)
- M Consuelo Cuquerella
- Department of Organic Chemistry, ICMOL, Universidad de Valencia, 46980 Paterna, Valencia, Spain
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58
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Malicki M, Hales JM, Rumi M, Barlow S, McClary L, Marder SR, Perry JW. Excited-state dynamics and dye–dye interactions in dye-coated gold nanoparticles with varying alkyl spacer lengths. Phys Chem Chem Phys 2010; 12:6267-77. [DOI: 10.1039/b926938j] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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59
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Chen Y, He B, Huang T, Liu H. Controlled synthesis of palladium icosahedra nanocrystals by reducing H2PdCl4 with tetraethylene glycol. Colloids Surf A Physicochem Eng Asp 2009. [DOI: 10.1016/j.colsurfa.2009.07.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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60
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Azzam EMS, Badawi AM, Alawady ARE, Soliman A. Synthesis and Characterization of Self-Assembling Some Thiol Surfactants on Gold Nanoparticles. J DISPER SCI TECHNOL 2009. [DOI: 10.1080/01932690802553932] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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61
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Ghosh SK, Pal T. Photophysical aspects of molecular probes near nanostructured gold surfaces. Phys Chem Chem Phys 2009; 11:3831-44. [DOI: 10.1039/b817373g] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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62
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Liang TC, Lin HC. Supramolecular assembly of H-bonded copolymers/complexes/nanocomposites and fluorescence quenching effects of surface-modified gold nanoparticles on fluorescent copolymers containing pyridyl H-acceptors and acid H-donors. ACTA ACUST UNITED AC 2009. [DOI: 10.1039/b823450g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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63
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Comparative studies on adsorption behavior of thionine on gold nanoparticles with different sizes. J Colloid Interface Sci 2008; 327:243-50. [DOI: 10.1016/j.jcis.2008.07.057] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2008] [Revised: 07/26/2008] [Accepted: 07/29/2008] [Indexed: 12/25/2022]
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64
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Chen L, Zhong Y, Zeng F, Zhao J, Wu S. Interactions Between Gold Nanoparticles and Polymer Bearing 3-Styryl Thiophene Chromophores. J Inorg Organomet Polym Mater 2008. [DOI: 10.1007/s10904-008-9226-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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65
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Richter H, McCarthy K, Nevin KP, Johnson JP, Rotello VM, Lovley DR. Electricity generation by Geobacter sulfurreducens attached to gold electrodes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:4376-4379. [PMID: 18303924 DOI: 10.1021/la703469y] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The versatility of gold for electrode manufacture suggests that it could be an ideal material for some microbial fuel cell applications. However, previous studies have suggested that microorganisms that readily transfer electrons to graphite do not transfer electrons to gold. Investigations with Geobacter sulfurreducens demonstrated that it could grow on gold anodes producing current nearly as effectively as with graphite anodes. Current production was associated with the development of G. sulfurreducens biofilms up to 40 microm thick. No current was produced if pilA, the gene for the structural protein of the conductive pili of G. sulfurreducens, was deleted. The finding that gold is a suitable anode material for microbial fuel cells offers expanded possibilities for the construction of microbial fuel cells and the electrochemical analysis of microbe-electrode interactions.
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Affiliation(s)
- Hanno Richter
- Departments of Microbiology and Chemistry, University of Massachusetts-Amherst, MA 01003, USA.
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66
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Zheng A, Chen J, Wu G, Wei H, He C, Kai X, Wu G, Chen Y. Optimization of a sensitive method for the “switch-on” determination of mercury(II) in waters using Rhodamine B capped gold nanoparticles as a fluorescence sensor. Mikrochim Acta 2008. [DOI: 10.1007/s00604-008-0023-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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67
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Ghosh SK, Pal T. Interparticle coupling effect on the surface plasmon resonance of gold nanoparticles: from theory to applications. Chem Rev 2008; 107:4797-862. [PMID: 17999554 DOI: 10.1021/cr0680282] [Citation(s) in RCA: 1447] [Impact Index Per Article: 90.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sujit Kumar Ghosh
- Department of Chemistry, Raidighi College, Raidighi-743383, South 24-Parganas, India
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68
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Kang S, Yasuda M, Miyasaka H, Hayashi H, Kawasaki M, Umeyama T, Matano Y, Yoshida K, Isoda S, Imahori H. Light harvesting and energy transfer in multiporphyrin-modified CdSe nanoparticles. CHEMSUSCHEM 2008; 1:254-261. [PMID: 18605215 DOI: 10.1002/cssc.200700138] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Multiporphyrin-modified CdSe nanoparticles (CdSe-H2P) were prepared to elucidate the interaction between chromophores and luminescent semiconducting nanoparticles in the excited and ground states. The CdSe-H2P nanoparticles were obtained by place-exchange reactions of hexadecylamine-thiophenol-modified CdSe nanoparticles with porphyrin alkanethiols in toluene. The number of porphyrin molecules on the surface of a single CdSe nanoparticle increased with increasing reaction time to reach a saturated maximum of 21. The porphyrins as well as the core in CdSe-H2P can absorb UV/Vis radiation. Steady-state emission and emission-lifetime measurements reveal efficient energy transfer from the CdSe excited state to the porphyrins in the CdSe-H2P nanoparticles. The resulting porphyrin excited singlet state is not quenched by the CdSe core. These unique properties are in sharp contrast with those of multiporphyrin-modified metal and silica nanoparticles. Thus, semiconducting nanoparticle-multiporphyrin composites are highly promising as novel artificial photosynthetic materials.
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Affiliation(s)
- Soonchul Kang
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
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69
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Kotiaho A, Lahtinen RM, Tkachenko NV, Efimov A, Kira A, Imahori H, Lemmetyinen H. Gold nanoparticle enhanced charge transfer in thin film assemblies of porphyrin-fullerene dyads. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:13117-13125. [PMID: 18004896 DOI: 10.1021/la702535a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Photoinduced vectorial electron transfer in a molecularly organized porphyrin-fullerene (PF) dyad film is enhanced by the interlayer charge transfer from the porphyrin moiety of the dyad to an octanethiol protected (dcore approximately 2 nm) gold nanoparticle (AuNP) film. By using the time-resolved Maxwell displacement charge (TRMDC) method, the charge separation distance was found to increase by 5 times in a multilayer film structure where the gold nanoparticles face the porphyrin moiety of the dyad, that is, AuNP|PF, compared to the case of the PF layer alone. Films were assembled by the Langmuir-Blodgett (LB) method using octadecylamine (ODA) as the matrix compound. Atomic force microscopy (AFM) images of the monolayers revealed that AuNPs are arranged into continuous, islandlike structures and PF dyads form clusters. The porphyrin reference layer was assembled with the AuNP layer to gain insight on the interaction mechanism between porphyrin and gold nanoparticles. Interlayer electron transfer was also observed between the AuNPs and porphyrin reference, but the efficiency is lower than that in the AuNP|PF film. Fluorescence emission of the reference porphyrin is slightly quenched, and fluorescence decay becomes faster in the presence of AuNPs. The proposed mechanism for the electron transfer in the AuNP|PF film is thus the primary electron transfer from the porphyrin to the fullerene followed by a secondary hole transfer from the porphyrin to the AuNPs, resulting in an increased charge separation distance and enhanced photovoltage.
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Affiliation(s)
- Anne Kotiaho
- Institute of Materials Chemistry, Tampere University of Technology, P.O. Box 541, 33101 Tampere, Finland.
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70
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Jebb M, Sudeep PK, Pramod P, Thomas KG, Kamat PV. Ruthenium(II) Trisbipyridine Functionalized Gold Nanorods. Morphological Changes and Excited-State Interactions. J Phys Chem B 2007; 111:6839-44. [PMID: 17477562 DOI: 10.1021/jp070701j] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Gold nanorods synthesized using cetyltrimethylammonium bromide and tetraoctylammonium bromide as stabilizers are functionalized with a thiol derivative of ruthenium(II) trisbipyridyl complex [(Ru(bpy)3(2+)-C5-SH] in dodecanethiol using a place-exchange reaction. The changes in the plasmon absorption bands and transmission electron micrographs indicate significant changes in the gold rod morphology during the place-exchange reaction. The (Ru(bpy)(3)2+-C5-SH in its excited state undergoes quick deactivation when bound to gold nanorods. More than 60% of the emission was quenched when [(Ru(bpy)3(2+)-C5-SH] was bound to gold nanorods. Emission decay analysis indicates that the energy transfer rate constant is greater than 10(10) s(-1).
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Affiliation(s)
- Meghan Jebb
- Radiation Laboratory, Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-0579, USA
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71
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Peng Z, Chen Z, Jiang J, Zhang X, Shen G, Yu R. A novel immunoassay based on the dissociation of immunocomplex and fluorescence quenching by gold nanoparticles. Anal Chim Acta 2007; 583:40-4. [PMID: 17386524 DOI: 10.1016/j.aca.2006.10.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2006] [Revised: 09/30/2006] [Accepted: 10/04/2006] [Indexed: 11/16/2022]
Abstract
This study reports a novel, simple and sensitive immunoassay using fluorescence quenching caused by gold nanoparticles coated with antibody. The method is based on a non-competitive heterogeneous immunoassay of human IgG conducted by the typical procedure of sandwich immunocomplex formation. Goat anti-human IgG was first adsorbed on polystyrene microwells, and human IgG analyte was captured by the primary antibody and then sandwiched by antibody labeled with gold nanoparticles. The sandwich-type immunocomplex was subsequently dissociated by the mixed solution of sodium hydroxide and trisodium citrate, the solution obtained, which contains gold nanoparticles coated with antibody, was used to quench fluorescence. The fluorescence intensity of fluorescein at 517 nm was inversely proportional to the logarithm of the concentration of human IgG in the dynamic range of 10-5000 ng mL(-1) with a detection limit of 4.7 ng mL(-1). The electrochemical experiments and the UV-vis measurements were applied to demonstrate whether the immunogold was dissociated completely and whether the gold nanoparticles aggregated after being dissociated, respectively. The proposed system can be extended to detect target molecules such as other kinds of antigen and DNA strands, and has broad potential applications in disease diagnosis.
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Affiliation(s)
- Zhaofeng Peng
- State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, People's Republic of China
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73
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Sakakibara K, Ifuku S, Tsujii Y, Kamitakahara H, Takano T, Nakatsubo F. Langmuir−Blodgett Films of a Novel Cellulose Derivative with Dihydrophytyl Group: The Ability to Anchor β-Carotene Molecules. Biomacromolecules 2006; 7:1960-7. [PMID: 16768420 DOI: 10.1021/bm060083x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A novel cellulose derivative, 6-O-dihydrophytylcellulose (DHPC), was first synthesized via a ring-opening polymerization and allowed to self-assemble onto an air-water interface. Langmuir-Blodgett (LB) films were characterized with atomic force microscope (AFM), UV-vis spectroscopy, and Fourier transform infrared spectroscopy. The surface pressure-area (pi-A) isotherms for DHPC and beta-carotene (betaC) mixture indicated strong interaction between these compounds to pack well. Thus, DHPC has the ability to anchor betaC in the monolayer. It was proved that a betaC-DHPC monolayer was transferred successfully onto a substrate, yielding Y-type LB films by UV spectroscopic analysis. The transmission and reflection-absorption IR spectra (RAS) indicated that the dihydrophytyl chains had almost trans-zigzag conformation and were oriented nearly perpendicular to the substrate. AFM section analysis revealed the thickness per layer to be 2.32 nm. Consequently, DHPC was found to be an appropriate matrix to fabricate the mixed LB films containing betaC.
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Affiliation(s)
- Keita Sakakibara
- Division of Forest and Biomaterials Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan.
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74
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Lim IIS, Goroleski F, Mott D, Kariuki N, Ip W, Luo J, Zhong CJ. Adsorption of Cyanine Dyes on Gold Nanoparticles and Formation of J-Aggregates in the Nanoparticle Assembly. J Phys Chem B 2006; 110:6673-82. [PMID: 16570972 DOI: 10.1021/jp057584h] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This paper describes the results of an investigation of the interparticle interactions and reactivities in the assembly of gold nanoparticles mediated by cyanine dyes. The combination of the positively charged indolenine cyanine dyes and the negatively charged gold nanoparticles is shown to form a J-aggregate bridged assembly of nanoparticles, in addition to hydrophobic interparticle and electrostatic dye-particle interactions. Such interparticle interactions and reactivities are studied by probing the absorption of J-aggregates and fluorescence from the dyes and the surface plasmon resonance absorption from the nanoparticles. The J-aggregation of the dyes adsorbed on the nanoparticles is shown to play an important role in the assembly of nanoparticles. The spectral evolution of the J-band of the dyes and the surface plasmon resonance band of the nanoparticles was found to be sensitive to the nature of the charge and the structure of the dyes. The fluorescence quenching for the dyes was shown to be quantitatively related to the surface coverage of the dyes on the nanocrystal surfaces. These findings have provided important information for assessing a two-step process involving a rapid adsorption of the dyes on the nanoparticles and a subsequent assembly of the nanoparticles involving a combination of interparticle J-aggregation and hydrophobic interactions of the adsorbed dyes. The results are discussed in terms of the structural effects of the dyes, and the interparticle molecular interactions and reactivities, which provide important physical and chemical insights into the design of dye-nanoparticle structured functional nanomaterials.
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Affiliation(s)
- I-Im S Lim
- Department of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, USA
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75
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Ding Y, Zhang X, Liu X, Guo R. Adsorption characteristics of thionine on gold nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:2292-8. [PMID: 16489820 DOI: 10.1021/la052897p] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Adsorption characteristics of thionine on gold nanoparticles have been studied by using UV-vis absorption spectroscopy, fluorescence spectroscopy, transmission electron microscopy (TEM), cyclic voltammetry and Fourier transform infrared spectroscopy. With the increasing concentration of gold nanoparticles, the absorption peak intensity of H-type dimers of thionine increases continuously, whereas that of monomers of thionine first increases and then decreases. The addition of gold nanoparticles makes the equilibrium between the monomer and H-type dimer forms of thionine move toward the dimer forms. Furthermore, the adsorption behavior of thionine on gold nanoparticles is also influenced by temperature. TEM images show that the addition of thionine results in an obvious aggregation, and further support the absorption spectral results. The fluorescence intensity of adsorbed thionine is quenched by gold nanoparticles due to the electronic interaction between thionine molecules and gold nanoparticles. Cyclic voltammetric and infrared spectroscopic studies show that the nitrogen atoms of both of the NH2 moieties of thionine strongly bind to the gold nanoparticle surfaces through the electrostatic interaction of thionine with gold nanoparticles. For 15-20 nm particles, the number of adsorbed thionine molecules per gold nanoparticle is about 7.66 x 10(4). Thionine molecules can not only bind to a particle to form a compact monolayer via both of the NH2 moieties, but they can also bind to two particles via their two NH(2) moieties, respectively.
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Affiliation(s)
- Yuanhua Ding
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
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76
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Zhang G, Zhang D, Zhao X, Ai X, Zhang J, Zhu D. Assembly of a Tetrathiafulvalene-Anthracene Dyad on the Surfaces of Gold Nanoparticles: Tuning the Excited-State Properties of the Anthracene Unit in the Dyad. Chemistry 2006; 12:1067-73. [PMID: 16240316 DOI: 10.1002/chem.200500524] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Due to the unique features of the tetrathiafulvalene (TTF) unit, such as the electron-donating ability and presence of methylthio groups, dyad 1 can be assembled on the surfaces of gold nanoparticles, as indicated by absorption, electrochemical, and fluorescent-spectral studies. Dyad 1 can also be disassembled by the addition of thiols. Assembly of dyad 1 on the surfaces of gold nanoparticles leads to the formation of a triad (A1-D-A2), which in turn modulates the photoinduced electron-transfer process within dyad 1. Accordingly, the fluorescence intensity of dyad 1, after assembly with gold nanoparticles, increases, and the fluorescence lifetime is prolonged. Furthermore, the assembly of dyad 1 on gold nanoparticles facilitates photodimerization of the anthracene units of dyad 1. Both fluorescence and photodimerization are associated with the excited-state behavior of the anthracene unit, thus it may be concluded that the excited-state properties of the anthracene unit can be tuned upon complexation with gold nanoparticles.
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Affiliation(s)
- Guanxin Zhang
- The Key Laboratory of Organic Solids, Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China
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Huang W, Masuda G, Maeda S, Tanaka H, Ogawa T. Molecular Junctions Composed of Oligothiophene Dithiol-Bridged Gold Nanoparticles Exhibiting Photoresponsive Properties. Chemistry 2006; 12:607-19. [PMID: 16193525 DOI: 10.1002/chem.200500822] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Three oligothiophene dithiols with different numbers of thiophene rings (3, 6 or 9) have been synthesized and characterized. The X-ray single crystal structures of terthiophene 2 and sexithiophene 5 are reported herein to show the exact molecular lengths, and to explain the difference between their UV-visible spectra arising from the different packing modes. These dithiols with different chain lengths were then treated with 2-dodecanethiol-protected active gold nanoparticles (Au-NPs) by means of in situ thiol-to-thiol ligand exchange in the presence of 1 microm gap Au electrodes. Thus the molecular junctions composed of self-assembled films were prepared, in which oligothiophene dithiol-bridged Au-NPs were attached to two electrodes by means of Au-S bonded contacts. The morphologies and current-voltage (I-V) characteristics of these films were studied by SEM and AFM approaches, which suggested that the thickness of the films (3-4 layers) varied within the size of one isolated Au-NP and typical distance-dependent semiconductor properties could be observed. Temperature dependent I-V measurements for these molecular junctions were performed in which the films served as active elements in the temperature range 6-300 K; classical Arrhenius plots and subsequent linear fits were carried out to give the activation energies (deltaE) of devices. Furthermore, preliminary studies on the photoresponsive properties of these devices were explored at 80, 160, and 300 K, respectively. Physical and photochemical mechanisms were used to explain the possible photocurrent generation processes. To the best of our knowledge, this is the first report in which oligothiophene dithiols act as bridging units to link Au-NPs, and also the first report about functionalized Au-NPs exhibiting photoresponse properties in the solid state.
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Affiliation(s)
- Wei Huang
- Research Center for Molecular Nanoscience, Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi, 444-8787, Japan.
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