| 1. |
- Bergström, Fredrik, et al.
(författare)
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Dimers of dipyrrometheneboron difluoride (BODIPY) with light spectroscopic applications in chemistry and biology.
- 2002
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Ingår i: Journal of the American Chemical Society. - 0002-7863 .- 1520-5126. ; 124:2, s. 196-204
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Tidskriftsartikel (refereegranskat)abstract
- A ground-state dimer (denoted D(I)) exhibiting a strong absorption maximum at 477 nm (epsilon = 97 000 M(-1)cm(-1)) can form between adjacent BODIPY groups attached to mutant forms of the protein, plasminogen activator inhibitor type 1 (PAI-1). No fluorescence from excited D(I) was detected. A locally high concentration of BODIPY groups was also achieved by doping lipid phases (micelles, vesicles) with BODIPY-labeled lipids. In addition to an absorption band located at about 480 nm, a new weak absorption band is also observed at ca. 570 nm. Both bands are ascribed to the formation of BODIPY dimers of different conformation (D(I) and D(II)). Contrary to D(I) in PAI-1, the D(II) aggregates absorbing at 570 nm are emitting light observed as a broad band centered at about 630 nm. The integrated absorption band of D(I) is about twice that of the monomer, which is compatible with exciton coupling within a dimer. The Förster radius of electronic energy transfer between a BODIPY excited monomer and the ground-state dimer (D(I)()) is 57 +/- 2 A. A simple model of exciton coupling suggests that in D(I) two BODIPY groups are stacked on top of each other in a sandwich-like configuration with parallel electronic transition dipoles. For D(II) the model suggests that the S(0) --> S(1) transition dipoles are colinear. An explanation for the previously reported (J. Am. Chem. Soc. 1994, 116, 7801) exceptional light spectroscopic properties of BODIPY is also presented. These are ascribed to the extraordinary electric properties of the BODIPY chromophore. First, changes of the permanent electric dipole moment (Delta(mu) approximately -0.05 D) and polarizability (-26 x 10(-40) C m(2) V(-1)) between the ground and the first excited states are small. Second, the S(0) <--> S(1) electronic transition dipole moments are perpendicular to Delta(mu).
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| 2. |
- Bergström, Fredrik, et al.
(författare)
-
Dimers of Dipyrrometheneboron Difluoride (BODIPY) with Light Spectroscopic Applications in Chemistry and Biology
- 2002
-
Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 124:2, s. 196-204
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Tidskriftsartikel (refereegranskat)abstract
- A ground-state dimer (denoted DI) exhibiting a strong absorption maximum at 477 nm ( = 97 000 M-1cm-1) can form between adjacent BODIPY groups attached to mutant forms of the protein, plasminogen activator inhibitor type 1 (PAI-1). No fluorescence from excited DI was detected. A locally high concentration of BODIPY groups was also achieved by doping lipid phases (micelles, vesicles) with BODIPY-labeled lipids. In addition to an absorption band located at about 480 nm, a new weak absorption band is also observed at ca. 570 nm. Both bands are ascribed to the formation of BODIPY dimers of different conformation (DI and DII). Contrary to DI in PAI-1, the DII aggregates absorbing at 570 nm are emitting light observed as a broad band centered at about 630 nm. The integrated absorption band of DI is about twice that of the monomer, which is compatible with exciton coupling within a dimer. The Förster radius of electronic energy transfer between a BODIPY excited monomer and the ground-state dimer (DI) is 57 ± 2 Å. A simple model of exciton coupling suggests that in DI two BODIPY groups are stacked on top of each other in a sandwich-like configuration with parallel electronic transition dipoles. For DII the model suggests that the S0 S1 transition dipoles are collinear. An explanation for the previously reported (J. Am. Chem. Soc. 1994, 116, 7801) exceptional light spectroscopic properties of BODIPY is also presented. These are ascribed to the extraordinary electric properties of the BODIPY chromophore. First, changes of the permanent electric dipole moment ( -0.05 D) and polarizability (-26 × 10-40 C m2 V-1) between the ground and the first excited states are small. Second, the S0 S1 electronic transition dipole moments are perpendicular to .
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| 3. |
- Habenicht, Anja, et al.
(författare)
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Two-photon excitation and time-resolved fluorescence: I. The proper response function for analysing single-photon counting experiments
- 2002
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Ingår i: Chemical Physics Letters. ; 354:5-6, s. 367-75
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Tidskriftsartikel (refereegranskat)abstract
- An accurate instrumental response function is needed to deconvolute fluorescence data obtained by time-correlated single-photon counting (TCSPC) upon multi-photon excitation. Hitherto the response function was obtained by measuring Rayleigh scattering (RS) from colloidal solutions, as is also used in one-photon excited fluorescence. We show that hyper Rayleigh scattering (HRS) provides a better choice for deconvolution of fluorescence decays, as obtained by TCSPC and two-photon excitation (TPE). The one- and two-photon response functions were monitored as RS and HRS from colloidal gold particles at 800 and 400 nm, respectively.
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| 4. |
- Mikhalyov, Ilya, et al.
(författare)
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Electronic ground and excited state properties of dipyrrometheneboron difluoride (BODIPY): Dimers with application to biosciences
- 2002
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Ingår i: PCCP Physical Chemistry, Chemical Physics and Biophysical Chemistry. - : Royal Society of Chemistry (RSC). ; 4:5663-70
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Tidskriftsartikel (refereegranskat)abstract
- Numerous derivatives of BODIPY (4,4-difluoro-4-borata-3a-azonia-4a-aza-s-indacene) are frequently used as fluorescent probes in modern protein and lipid research. Present studies of purpose-synthesised molecules show that the BODIPY chromophore can form two different ground state dimers, denoted DI and DII. In practise DI exhibits negligible fluorescence emission, but a strong absorption band {(477 nm)=102000 mol–1 dm3 cm–1}, while DII is fluorescent with the radiative lifetime 20 ns, and red-shifted absorption {(577 nm)}=26000 mol–1 dm3 cm–1} relative to that of the monomer. Energy transfer is demonstrated from monomeric BODIPY to DI, as well as to DII. Donor–donor energy migration is also shown to occur between excited and ground state DII. Both DI and DII are of potential interest in examining structure-function of proteins and lipid membrane systems.
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| 5. |
- Mukhtar, Emad, et al.
(författare)
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Hyper Rayleigh Scattering Yields Improved Response Function in Analysing 2-Photon Excited Fluorescence
- 2002
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Ingår i: Journal of Fluorescence. - 1053-0509 .- 1573-4994. ; 12:3-4, s. 481-4
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Tidskriftsartikel (refereegranskat)abstract
- An accurate instrumental response function is needed to conclusively deconvolute fluorescence data based on time-correlated single-photon counting (TCSPC) and multiphoton excitation. Routinely the response function is measured as Rayleigh scattering (RS) from a colloidal solution, even if the excitation is a multiphoton event. Present work demonstrates that a response function obtained as hyper Rayleigh scattering (HRS) provides a better choice for deconvolution of 2-photon excited fluorescence decays. The 1- and 2-photon response functions were monitored as RS and HRS from colloidal gold particles at 800 and 400 nm, respectively.
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