51
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Demchenko AP. The future of fluorescence sensor arrays. Trends Biotechnol 2005; 23:456-60. [PMID: 15967523 DOI: 10.1016/j.tibtech.2005.06.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2005] [Revised: 05/05/2005] [Accepted: 06/08/2005] [Indexed: 11/18/2022]
Abstract
The rapid progress in sensor and biosensor array technologies needs a general strategy in the design of fluorescence reporters. Such reporters should provide a high density of sensor elements, allow analysis of targets of different affinities, and be internally calibrated, reproducible and have a rapid readout. Several criteria are introduced here for the comparative evaluation of fluorescence-sensing techniques. It is shown that only the two-band wavelength ratiometric sensing with a single reporter dye exhibiting rapid reversible excited-state reaction can satisfy all these criteria and is a prospective candidate for further development.
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Affiliation(s)
- Alexander P Demchenko
- TUBITAK Research Institute for Genetic Engineering and Biotechnology, 41470 Gebze-Kocaeli, Turkey.
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52
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Demchenko AP. Optimization of fluorescence response in the design of molecular biosensors. Anal Biochem 2005; 343:1-22. [PMID: 16018869 DOI: 10.1016/j.ab.2004.11.041] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2004] [Revised: 11/24/2004] [Accepted: 11/24/2004] [Indexed: 11/23/2022]
Affiliation(s)
- Alexander P Demchenko
- TUBITAK Research Institute for Genetic Engineering Biotechnology, 41470 Gebze-Kocaeli, Turkey.
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53
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2-[4-(Dimethylamino)phenyl]-3-hydroxy-4H-chromene-4-one: A H-bond-sensitive fluorescent probe for investigating binary mixtures of organic solvents. Anal Chim Acta 2005. [DOI: 10.1016/j.aca.2005.04.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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54
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Turkmen Z, Klymchenko AS, Oncul S, Duportail G, Topcu G, Demchenko AP. A triterpene oleanolic acid conjugate with 3-hydroxyflavone derivative as a new membrane probe with two-color ratiometric response. ACTA ACUST UNITED AC 2005; 64:1-18. [PMID: 16019078 DOI: 10.1016/j.jbbm.2005.03.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2004] [Revised: 02/22/2005] [Accepted: 03/16/2005] [Indexed: 10/25/2022]
Abstract
We report on the synthesis by coupling of a triterpenoid oleanolic acid with 4'-diethylamino-3-hydroxyflavone (FE) to produce an environment-sensitive biomembrane probe with two-band ratiometric response in fluorescence emission. The synthesized compound (probe FOT) was tested in a series of model solvents and demonstrated the response to solvent polarity and intermolecular hydrogen bonding very similar to that of parent probe FE. Meantime when incorporated into lipid bilayer membranes, it showed new features differing in response between lipids of different surface charges as well as between glycerophospholipids and sphingomyelin. We observed that in the conditions of coexistence of rafts and non-raft structures the probe is excluded from the rafts.
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Affiliation(s)
- Zeynep Turkmen
- TUBITAK Research Institute for Genetic Engineering and Biotechnology, 41470 Gebze-Kocaeli, Turkey
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55
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Pereira RV, Garcia Ferreira AP, Gehlen MH. Excited-State Intramolecular Charge Transfer in 9-Aminoacridine Derivative. J Phys Chem A 2005; 109:5978-83. [PMID: 16833932 DOI: 10.1021/jp044704x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new fluorochromic dye was obtained from the reaction of 9-aminoacridine with ethyl-2-cyano-3-ethoxyacrylate. It displays complex fluorescence that is ascribed to normal emission from the acridine chromophore in addition to excited-state intramolecular charge transfer (ESICT) formed upon light excitation. The analysis of the fluorescence decays in different solvents reveals two short-lived components in the range of 80-450 ps and 0.7-3.2 ns, ascribed to the formation and decay of the intramolecular charge transfer (ICT) state, in addition to a third component of about 9.0 ns, which is related to the normal emission from the acridine singlet excited state, probably in an enol-imine tautomeric form. The ICT emission is readily quenched by water addition to polar solvents, and this effect is ascribed to changes in the keto-amine/enol-imine equilibrium of this fluorochromic dye.
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Affiliation(s)
- Robson Valentim Pereira
- Instituto de Química de São Carlos, Universidade de São Paulo, 13560-590, São Carlos SP, Brazil
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56
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Pivovarenko VG, Wróblewska A, Błazejowski J. The effect of hydrogen bonding interactions between 2-[4-(dimethylamino)phenyl]-3-hydroxy-4H-chromene-4-one in the ground and excited states and dimethylsulfoxide or methanol on electronic absorption and emission transitions. J Mol Struct 2004. [DOI: 10.1016/j.molstruc.2004.05.035] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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57
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Klymchenko AS, Duportail G, Demchenko AP, Mély Y. Bimodal distribution and fluorescence response of environment-sensitive probes in lipid bilayers. Biophys J 2004; 86:2929-41. [PMID: 15111409 PMCID: PMC1304161 DOI: 10.1016/s0006-3495(04)74344-1] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
A remarkable heterogeneity is often observed in the spectroscopic properties of environment-sensitive fluorescence probes in phospholipid bilayers. To explain its origin, we provided a detailed investigation of the fluorescence excitation and emission spectra of 4'-dimethylamino-3-hydroxyflavone (probe F) in bilayer vesicles with the variations of fatty acid composition, polar heads, temperature, and cholesterol content. Probe F, due to excited-state intramolecular proton transfer, exhibits two bands in emission that are differently sensitive to intermolecular interactions-thereby allowing us to distinguish universal (dipole-dipole) and specific (H-bonding) interactions within the bilayer. Spectroscopic, quenching, and anisotropy data suggest the presence of two forms of probe F at different locations in the bilayer: an H-bond free form located below sn(1)-carbonyls and an H-bonded form located at the polar membrane interface. We provide a quantitative analysis of the distribution of the probe between these two locations as well as the polarity of these locations, and show that both the distribution and the polarity contribute to the probe response. Moreover, analysis of literature data on other environment-sensitive probes (Prodan, Laurdan, Nile Red, NBD lipids, etc.) in lipid bilayers allows us to suggest that the bimodal distribution in the lipid bilayer is probably a general feature of low-polar molecules with polar groups capable of H-bonding interactions.
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Affiliation(s)
- Andrey S Klymchenko
- Laboratoire de Pharmacologie et Physicochimie, Unité Mixte de Recherche 7034 du Centre National de la Recherche Scientifique, Faculté de Pharmacie, Université Louis Pasteur, Illkirch, France.
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58
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Klymchenko AS, Mély Y. 7-(2-Methoxycarbonylvinyl)-3-hydroxychromones: new dyes with red shifted dual emission. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2004.09.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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59
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Klymchenko AS, Mély Y, Demchenko AP, Duportail G. Simultaneous probing of hydration and polarity of lipid bilayers with 3-hydroxyflavone fluorescent dyes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2004; 1665:6-19. [PMID: 15471566 DOI: 10.1016/j.bbamem.2004.06.004] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2004] [Revised: 06/15/2004] [Accepted: 06/15/2004] [Indexed: 11/24/2022]
Abstract
The penetration of water into the hydrophobic interior leads to polarity and hydration profiles across lipid membranes which are fundamental in the maintenance of membrane architecture as well as in transport and insertion processes into the membrane. The present paper is an original attempt to evaluate simultaneously polarity and hydration properties of lipid bilayers by a fluorescence approach. We applied two 3-hydroxyflavone probes anchored in lipid bilayers at a relatively precise depth through their attached ammonium groups. They are present in two forms: either in H-bond-free form displaying a two-band emission due to an excited state intramolecular proton transfer reaction (ESIPT), or in H-bonded form displaying a single-band emission with no ESIPT. The individual emission profiles of these forms were obtained by deconvolution of the probes' fluorescence spectra. The polarity of the probe surrounding the bilayer was estimated from the two-band spectra of the H-bond-free form, while the local hydration was estimated from the relative contribution of the two forms. Our results confirm that by increasing the lipid order (phase transition from fluid to gel phase, addition of cholesterol or decrease in the lipid unsaturation), the polarity and to a lesser extent, the hydration of the bilayers decrease simultaneously. In contrast, when fluidity (i.e. lipid order) is kept invariant, increase of temperature and of bilayer curvature leads to a higher bilayer hydration with no effect on the polarity. Furthermore, no correlation was found between dipole potential and the hydration of the bilayers.
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Affiliation(s)
- Andrey S Klymchenko
- Laboratoire de Pharmacologie et Physicochimie, UMR 7034 du CNRS, Faculté de Pharmacie, Université Louis Pasteur, BP 60024, 67401 Illkirch, France.
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60
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Tran R, Ho S, Dea P. Effects of ethanol on lipid bilayers with and without cholesterol: the distearoylphosphatidylcholine system. Biophys Chem 2004; 110:39-47. [PMID: 15223142 DOI: 10.1016/j.bpc.2004.01.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2003] [Revised: 01/06/2004] [Accepted: 01/06/2004] [Indexed: 11/25/2022]
Abstract
Differential scanning calorimetry (DSC) and fluorescence spectroscopy are useful techniques for investigating the phase transitions of phospholipid bilayers. In this study, these methods have been extended to determine the effects of ethanol on DSPC and DSPC/2 mol.% cholesterol bilayers. The biphasic effect of the main transition was observed on the DSC heating scans above 0.60 M ethanol. In addition, the concentration at which the biphasic effect occurs is not significantly changed in the presence of 2 mol.% cholesterol. For the fluorescence studies, 1,6-diphenyl-1,3,5-hexatriene (DPH) has been incorporated into the bilayer to monitor the phase transitions through the displacement of DPH. This fluorescent probe is used to directly determine the onset of interdigitation in the bilayer systems as indicated by a large decrease in the DPH fluorescence intensity. The addition of cholesterol lowered and broadened the transition temperatures of the phosphatidylcholine (PC) system. However, 2 mol.% cholesterol did not have a significant effect on the induction of the interdigitated phase in DSPC as observed from the small difference in ethanol threshold concentration for the two systems. This suggests that DSPC forms a more stable interdigitated gel phase than other PCs with shorter acyl chains.
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Affiliation(s)
- Rosalie Tran
- Department of Chemistry, Occidental College, 1600 Campus Road, Los Angeles, CA 90041, USA
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61
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Klymchenko AS, Duportail G, Mély Y, Demchenko AP. Ultrasensitive two-color fluorescence probes for dipole potential in phospholipid membranes. Proc Natl Acad Sci U S A 2003; 100:11219-24. [PMID: 12972636 PMCID: PMC208738 DOI: 10.1073/pnas.1934603100] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The principle of electrochromic modulation of excited-state intramolecular proton-transfer reaction was applied for the design of fluorescence probes with high two-color sensitivity to dipole potential, Psid, in phospholipid bilayers. We report on the effect of Psid variation on excitation and fluorescence spectra of two new 3-hydroxyflavone probes, which possess opposite orientations of the fluorescent moiety in the lipid bilayer. The dipole potential in the bilayer was modulated by the addition of 6-ketocholestanol or phloretin and by substitution of dimyristoyl phosphatidylcholine lipid with its ether analog 1,2-di-o-tetradecyl-sn-glycero-3-phosphocholine, and its value was estimated by the reference styryl dye 1-(3-sulfonatopropyl)-4-[beta[2-(di-n-octylamino)-6-naphthyl]vinyl]pyridinium betaine. We demonstrate that after Psid changes, the probe orienting in the bilayer similarly to the reference dye shows similar shifts in the excitation spectra, whereas the probe with the opposite orientation shows the opposite shifts. The new observation is that the response of 3-hydroxyflavone probes to Psid in excitation spectra is accompanied by and quantitatively correlated with dramatic changes of relative intensities of the two well separated emission bands that belong to the initial normal and the product tautomer forms of the excited-state intramolecular proton-transfer reaction. This provides a strong response to Psid by change in emission color.
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Affiliation(s)
- Andrey S Klymchenko
- TUBITAK Research Institute for Genetic Engineering and Biotechnology, Gebze-Kocaeli 41470, Turkey
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62
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Roshal AD, Moroz VI, Pivovarenko VG, Wróblewska A, Błazejowski J. Spectral and acid-base features of 3,7-dihydroxy-2,8-diphenyl-4H,6H-pyrano[3,2-g]chromene-4,6-dione (diflavonol)--a potential probe for monitoring the properties of liquid phases. J Org Chem 2003; 68:5860-9. [PMID: 12868918 DOI: 10.1021/jo034200f] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Diflavonol is a molecule that can exist in neutral or anionic form and in several tautomeric forms in ground and excited states. Absorption and emission spectroscopy combined with theoretical calculations have shown that only one tautomer of neutral diflavonol exists in the ground state, but two exist in the excited state. In the latter case, one is the tautomer originating from the ground state tautomer, which exists in strongly protic solvents, the other is the phototautomer occurring in weakly protic or aprotic solvents as a result of the intramolecular transfer of one proton. The OH groups present in diflavonol and involved in weak intramolecular hydrogen bonds exhibit a proton-donating ability reflected by the experimental values of acidity constants or theoretical enthalpies and free energies of proton detachment. The electronically excited molecule is a relatively strong acid when it loses one proton. With increasing basicity of the medium, monoanionic and dianionic forms occur which exhibit spectral characteristics and an emission ability different from those of neutral diflavonol. These interesting features of diflavonol open up possibilities for the analytical use of the compound and its application as a spectral probe sensitive to the properties of liquid phases.
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Affiliation(s)
- A D Roshal
- Institute of Chemistry, Kharkiv V.N. Karazin National University, Svoboda 4, 61077 Kharkiv, Ukraine
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63
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Bader AN, Pivovarenko V, Demchenko AP, Ariese F, Gooijer C. Solvent influence on excited-state intramolecular proton transfer in 3-hydroxychromone derivatives studied by cryogenic high-resolution fluorescence spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2003; 59:1593-1603. [PMID: 12714082 DOI: 10.1016/s1386-1425(02)00361-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
High-resolution Shpol'skii spectra (recorded at 10 K in n-octane) of 3-hydroxychromone (3HC) substituted at the 2-position with a furan (3HC-F), a benzofuran (3HC-BF) or a naphthofuran group (3HC-NF) are presented. Being close analogues of 3-hydroxyflavone (3HF), these compounds can undergo excited-state intramolecular proton transfer (ESIPT). Luminescence can occur from the normal N* state (blue) or from the tautomeric T* state (green). Whether blue or green emission is observed is strongly dependent on hydrogen-bonding interactions with the environment. For all three chromones studied, high-resolution emission spectra in the green region (T*-->T) were obtained in pure n-octane, showing four sites with distinct emission bands and detailed vibrational structures, whereas no blue emission was detected. Contrary to the spectra published for 3HF, the emission lines were very narrow (line-broadening effects beyond detection) which implies that the ESIPT rate constants are >10(12) s(-1), at least 25 times lower than for 3HF. In order to study the effects of hydrogen-bonding solvents, four isomers of octanol (1-, 2-, 3- and 4-octanol) were added, forming 1:1 complexes with the 3HC derivatives. For all the combinations considered both blue and additional green emission was observed and in some cases narrow-banded spectra were obtained, mostly in the green. Only for the 3HC-NF/2-octanol complex, narrow-banded emission was found both in the blue and in the green region. It is demonstrated that these emissions come from different configurations of the complex. Possible structures for the two complex species are proposed, supported by semi-empirical calculations on complex formation enthalpies.
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Affiliation(s)
- Arjen N Bader
- Department of Analytical Chemistry and Applied Spectroscopy, Laser Centre, Vrije Universiteit, De Boelelaan 1083, 1081 HV, Amsterdam, The Netherlands
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64
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Klymchenko AS, Pivovarenko VG, Demchenko AP. Elimination of the Hydrogen Bonding Effect on the Solvatochromism of 3-Hydroxyflavones. J Phys Chem A 2003. [DOI: 10.1021/jp027315g] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andrey S. Klymchenko
- TUBITAK Research Institute for Genetic Engineering and Biotechnology, 41470 Gebze-Kocaeli, Turkey, Department of Chemistry, Kyiv National Taras Shevchenko University, 01033 Kyiv, Ukraine, and A. V. Palladin Institute of Biochemistry, 9 Leontovicha str., 01030 Kyiv, Ukraine
| | - Vasyl G. Pivovarenko
- TUBITAK Research Institute for Genetic Engineering and Biotechnology, 41470 Gebze-Kocaeli, Turkey, Department of Chemistry, Kyiv National Taras Shevchenko University, 01033 Kyiv, Ukraine, and A. V. Palladin Institute of Biochemistry, 9 Leontovicha str., 01030 Kyiv, Ukraine
| | - Alexander P. Demchenko
- TUBITAK Research Institute for Genetic Engineering and Biotechnology, 41470 Gebze-Kocaeli, Turkey, Department of Chemistry, Kyiv National Taras Shevchenko University, 01033 Kyiv, Ukraine, and A. V. Palladin Institute of Biochemistry, 9 Leontovicha str., 01030 Kyiv, Ukraine
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65
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Klymchenko AS, Pivovarenko VG, Demchenko AP. Perturbation of planarity as the possible mechanism of solvent-dependent variations of fluorescence quantum yield in 2-aryl-3-hydroxychromones. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2003; 59:787-792. [PMID: 12609629 DOI: 10.1016/s1386-1425(02)00233-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In order to understand the unexpectedly low quantum yields of 3-hydroxyflavones (3-HFs) in certain solvents, such as acetonitrile or ethyl acetate, the comparative study of solvent-dependent properties of parent 3-HF, 2-furyl-3-hydroxychromone and 2-benzofuryl-3-hydroxychromone derivatives have been performed. The results suggest that the formation of intermolecular hydrogen bond of 3-hydroxy group with the solvent favors non-planar conformations of phenyl group with respect to chromone system. This steric hindrance is not observed in the case of furan- and benzofuran-substituted 3-hydroxychromones (3-HCs). These results suggesting a new strategy for dramatic improvement of fluorescence properties of 3-HCs as two-wavelength ratiometric fluorescence probes.
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Affiliation(s)
- Andrey S Klymchenko
- Research Institute for Genetic Engineering and Biotechnology, TUBITAK Marmara Research Center, Gebze-Kocaeli 41470, Turkey
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66
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Klymchenko AS, Duportail G, Ozturk T, Pivovarenko VG, Mély Y, Demchenko AP. Novel two-band ratiometric fluorescence probes with different location and orientation in phospholipid membranes. CHEMISTRY & BIOLOGY 2002; 9:1199-208. [PMID: 12445770 DOI: 10.1016/s1074-5521(02)00244-2] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
3-hydroxyflavone (3-HF) derivatives are very attractive fluorescence sensors due to their ability to respond to small changes in their microenvironment via a dramatic alteration of the relative intensities of their two well-separated emission bands. We developed fluorescence probes with locations at different depths and orientations of 3-HF moiety in the phospholipid bilayer, which determine their fluorescence behavior. While the spectral shifts of the probes correlate with their binding site polarity, the intensity ratio is a complex parameter that is also sensitive to the local hydration. We demonstrate that even the deeply located probes sense this hydration effect, which can be modulated by the charge of the lipid heads and is anisotropic with respect to the bilayer plane. Thus the two-band ratiometric fluorescence probes can provide multiparametric information on the properties of lipid membranes at different depths.
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Affiliation(s)
- Andrey S Klymchenko
- TUBITAK Research Institute for Genetic Engineering and Biotechnology, Gebze-Kocaeli 41470, Turkey
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67
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Dipole moments of 4′-aminoflavonols determined using electro-optical absorption measurements or molecular Stark-effect spectroscopy. J Photochem Photobiol A Chem 2002. [DOI: 10.1016/s1010-6030(02)00270-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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68
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69
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Ercelen S, Klymchenko AS, Demchenko AP. Ultrasensitive fluorescent probe for the hydrophobic range of solvent polarities. Anal Chim Acta 2002. [DOI: 10.1016/s0003-2670(02)00493-2] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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70
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Bach D, Borochov N, Wachtel E. Phase separation of cholesterol and the interaction of ethanol with phosphatidylserine-cholesterol bilayer membranes. Chem Phys Lipids 2002; 114:123-30. [PMID: 11934393 DOI: 10.1016/s0009-3084(01)00189-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Thermotropic and structural effects of ethanol on phosphatidylserine (PS) membranes containing up to 0.4 mol fraction cholesterol were investigated by differential scanning calorimetry, X-ray diffraction and fluorescence spectroscopy. It was found that in the presence of cholesterol, 10% (v/v) added ethanol depresses the melting temperature of the phospholipid by approximately 2 degrees C, similar to what was observed in the absence of cholesterol. Below the melting temperature the progressive disordering effect of added cholesterol is weakly enhanced by the presence of ethanol. In the liquid crystalline state, the marked decrease in the thickness of the bilayer which ethanol causes in the absence of cholesterol (Chem. Phys. Lipids 92 (1998) 127), is also observed in its presence. We conclude that, in contrast to what has been observed for zwitterionic phospholipids, high concentrations of cholesterol do not diminish the interaction of ethanol with PS membranes. With addition of 10% (v/v) ethanol, crystalline cholesterol diffraction, an indication of phase separation of the sterol, appears at mol fraction cholesterol 0.34, as compared to 0.3 in the absence of ethanol (Chem. Phys. Lipids 92 (1998) 71).
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Affiliation(s)
- D Bach
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel.
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71
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72
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Duportail G, Klymchenko A, Mely Y, Demchenko A. Neutral fluorescence probe with strong ratiometric response to surface charge of phospholipid membranes. FEBS Lett 2001; 508:196-200. [PMID: 11718715 DOI: 10.1016/s0014-5793(01)03055-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We report on dramatic differences in fluorescence spectra of 4'-dimethylamino-3-hydroxyflavone (probe F) studied in phospholipid membranes of different charge (phosphatidyl glycerol, phosphatidylcholine (PC), their mixture and the mixture of PC with a cationic lipid). The effect consists in variations of relative intensities at two well-separated band maxima at 520 and 570 nm belonging to normal (N*) and tautomer (T*) excited states of flavone chromophore. Based on these studies we propose a new approach to measure electrostatic potential at the surface layer of phospholipid membranes, which is based on potential-dependent changes of bilayer hydration and involves very sensitive and convenient ratiometric measurements in fluorescence emission.
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Affiliation(s)
- G Duportail
- Laboratoire de Pharmacologie et Physicochimie, UMR 7034 du CNRS, Faculté de Pharmacie, Université Louis Pasteur, Illkirch, France
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73
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Klymchenko AS, Ozturk T, Pivovarenko VG, Demchenko AP. A 3-hydroxychromone with dramatically improved fluorescence properties. Tetrahedron Lett 2001. [DOI: 10.1016/s0040-4039(01)01723-3] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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74
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Pappayee N, Mishra AK. Evaluation of 1-naphthol as a convenient fluorescent probe for monitoring ethanol-induced interdigitation in lipid bilayer membrane. Photochem Photobiol 2001; 73:573-8. [PMID: 11421061 DOI: 10.1562/0031-8655(2001)073<0573:eonaac>2.0.co;2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In this work we have tried to evaluate the usefulness of 1-naphthol as an excited state proton transfer fluorescent probe for studying the ethanol-induced interdigitation in lipid bilayer membranes. When ethanol concentration in lipisome is progressively increased, the neutral form fluorescence of 1-naphthol is found to decrease with corresponding increase in the anionic form intensity. This behavior is in contrast to that observed in the absence of lipid where a reverse effect is noticed. Modification of lipid bilayer is known to occur in the presence of ethanol, which increases the packing density of the membrane. Due to this induction of interdigitated gel phase, redistribution of naphthol between the inner core and interfacial region of the lipid bilayer takes places, accounting for the reduction in neutral form fluorescence intensity. The partition coefficient values and the quenching studies also support the redistribution of 1-naphthol in the liposome membrane. The neutral form fluorescence of 1-naphthol successfully monitors the shift in phase transition temperature due to ethanol-induced interdigitation. It also explains the prevention of interdigitation in lipid bilayer at high cholesterol concentration.
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Affiliation(s)
- N Pappayee
- Department of Chemistry, Indian Institute of Technology, Madras, Chennai 600036, India
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Klymchenko AS, Ozturk T, Pivovarenko VG, Demchenko AP. Synthesis and spectroscopic properties of benzo- and naphthofuryl-3-hydroxychromones. CAN J CHEM 2001. [DOI: 10.1139/v01-066] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
With the focus of designing new fluorescent probes, four new 3-hydroxy-chromone derivatives bearing benzofuran and naphthofuran groups were synthesized. They show bathochromic absorption shifts relative to 3-hydroxyflavone with the ability of retention to display the excited-state proton transfer. Disruption of the planarity by the methyl group in the furan ring leads to a decrease of both the extinction coefficient and the contribution of long wavelength absorption band, while molecules without a methyl group showed two distinct absorption bands. Shifts to longer wavelengths are also observed in fluorescent spectra, and the absence of the methyl group results in a dramatic increase of fluorescence quantum yield and lifetime. Of the extended 3-hydroxychromone derivatives, 3-hydroxy-2-naphtho[2,1-b]furan-2-yl-chromone has shown comparable, and in some cases better, absorption and fluorescence properties than the 3-hydroxychromones synthesized so far, which make it a highly promising candidate as molecular probe for analytical chemistry, biophysics, and cellular biology.Key words: benzo- and naphthofuryl-3-hydroxyflavone, synthesis, electronic spectra, fluorescence, excited state proton transfer.
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Roshal A, Grigorovich A, Doroshenko A, Pivovarenko V, Demchenko A. Flavonols as metal-ion chelators: complex formation with Mg2+ and Ba2+ cations in the excited state. J Photochem Photobiol A Chem 1999. [DOI: 10.1016/s1010-6030(99)00105-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Abstract
The fluorescent probe Prodan has been widely used as a probe of model and biological membranes. Its fluorescent maxima in phospholipid bilayers vary as a function of phase state, with maxima at 485 for the liquid crystal Lalpha, 435 nm for the gel L'beta, and 507 nm for the interdigitated gel LbetaI phase, with excitation at 359 nm. These spectral changes have been used for the detection of phase changes among these phases. In the present study, the fluorescent properties and partition coefficients of Prodan in model membranes of phosphatidylcholines and phosphatidylethanols have been studied as a function of lipid phase state and cholesterol content. It is shown that the Prodan spectrum in the presence of cholesterol no longer reflects the known phase state of the lipid; in each phase state, the presence of cholesterol leads to a spectrum with the maximum at 435 nm, characteristic of the noninterdigitated gel phase. The partition coefficient of Prodan into these lipids also varies with the phase state, giving values of 0.35 x 10(4) in the interdigitated gel, 1.8 x 10(4) in the noninterdigitated gel, and 7. 6 x 10(4) in the liquid crystal phase. In the presence of cholesterol these partition coefficients are increased to 13 x 10(4) for the liquid crystal and the gel phase, and 5.1 x 10(4) in the presence of 100 mg/ml ethanol. These results suggest that Prodan has preferential interactions with cholesterol, and is thus not a randomly distributed fluorescent reporter probe in membranes containing cholesterol. These results suggest that Prodan should be used only with great caution in complex lipid mixtures, particularly biological membranes.
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Affiliation(s)
- O P Bondar
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas 66103, and Veterans Administration Medical Center, Kansas City, Missouri 64128 USA
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