Professeur des Universités, Sorbonne Université
Responsable du pôle de Chimie Physique et Biologique de la Matière Vivante
PASTEUR, Département de chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS
24 rue Lhomond, 75005 Paris, France
Email: Ludovic.Jullien@ens.psl.eu or Ludovic.Jullien@sorbonne-universite.fr
Phone: +33 144323333
Office: E142c
Home page: https://ludovicjullien.org/
Publications
2009 |
Thermal modulation and filtered video acquisition to image reactive species among non reactive ones Inproceedings K Zrelli; T Barilero; T Le Saux; L Jullien; H Berthoumieux; A Lemarchand; C Gosse Proceedings of Conference, MicroTAS 2009 - The 13th International Conference on Miniaturized Systems for Chemistry and Life Sciences, p. 958–960, 2009. @inproceedings{Zrelli:2009, title = {Thermal modulation and filtered video acquisition to image reactive species among non reactive ones}, author = {K Zrelli and T Barilero and T Le Saux and L Jullien and H Berthoumieux and A Lemarchand and C Gosse}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84901796758&partnerID=40&md5=4d1969e49d590169bf74d7e23b252ed9}, year = {2009}, date = {2009-01-01}, booktitle = {Proceedings of Conference, MicroTAS 2009 - The 13th International Conference on Miniaturized Systems for Chemistry and Life Sciences}, pages = {958--960}, abstract = {Periodic temperature excitation allows for modulating the concentration of a reagent with given amplitude and phase shift, both related of its characteristic chemical dynamics [1]. Therefore, we rely on thermal oscillations, associated with appropriate detection in fluorescence microscopy and data filtering, to selectively image a duplex forming oligonucleotide in a sample that contains non-hybridizing sequences in similar amount. © 2009 CBMS.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } Periodic temperature excitation allows for modulating the concentration of a reagent with given amplitude and phase shift, both related of its characteristic chemical dynamics [1]. Therefore, we rely on thermal oscillations, associated with appropriate detection in fluorescence microscopy and data filtering, to selectively image a duplex forming oligonucleotide in a sample that contains non-hybridizing sequences in similar amount. © 2009 CBMS. |
2008 |
A caged retinoic acid for one- and two-photon excitation in zebrafish embryos Article de journal P Neveu; I Aujard; C Benbrahim; T Le Saux; J -F Allemand; S Vriz; D Bensimon; L Jullien Angewandte Chemie - International Edition, 47 (20), p. 3744–3746, 2008. @article{Neveu:2008, title = {A caged retinoic acid for one- and two-photon excitation in zebrafish embryos}, author = {P Neveu and I Aujard and C Benbrahim and T Le Saux and J -F Allemand and S Vriz and D Bensimon and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-45549089482&doi=10.1002%2fanie.200800037&partnerID=40&md5=320b837fbef96180278af6d16a13797a}, doi = {10.1002/anie.200800037}, year = {2008}, date = {2008-01-01}, journal = {Angewandte Chemie - International Edition}, volume = {47}, number = {20}, pages = {3744--3746}, abstract = {(Chemical Equation Presented) Escaping the cage: Retinoic acid (RA), a crucial signaling molecule for the embryogenesis of vertebrates, can be photoreleased from a simple caged derivative (cRA) upon illumination. In zebrafish embryos, cRA causes RA-induced phenotypes with one- and two-photon excitation (see picture), which opens a route to the noninvasive generation of controlled RA concentration patterns in vivo. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.}, keywords = {}, pubstate = {published}, tppubtype = {article} } (Chemical Equation Presented) Escaping the cage: Retinoic acid (RA), a crucial signaling molecule for the embryogenesis of vertebrates, can be photoreleased from a simple caged derivative (cRA) upon illumination. In zebrafish embryos, cRA causes RA-induced phenotypes with one- and two-photon excitation (see picture), which opens a route to the noninvasive generation of controlled RA concentration patterns in vivo. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA. |
Alcohol uncaging with fluorescence reporting: Evaluation of o-acetoxyphenyl methyloxazolone precursors Article de journal N Gagey; M Emond; P Neveu; C Benbrahim; B Goetz; I Aujard; J -B Baudin; L Jullien Organic Letters, 10 (12), p. 2341–2344, 2008. @article{Gagey:2008, title = {Alcohol uncaging with fluorescence reporting: Evaluation of o-acetoxyphenyl methyloxazolone precursors}, author = {N Gagey and M Emond and P Neveu and C Benbrahim and B Goetz and I Aujard and J -B Baudin and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-48849106962&doi=10.1021%2fol800284g&partnerID=40&md5=ea3b7c88c69385542890143aea72f28a}, doi = {10.1021/ol800284g}, year = {2008}, date = {2008-01-01}, journal = {Organic Letters}, volume = {10}, number = {12}, pages = {2341--2344}, abstract = {(Chemical Equation Presented) This paper evaluates a series of photolabile protecting groups with built-in fluorescence reporting. They rely on readily available o-acetoxyphenyl methyloxazolones as activated precursors. Alcohol substrates are easily caged. The resulting photoactivable esters exhibit large one- and two-photon uncaging cross sections. The alcohol substrates are quantitatively released in a 1:1 molar ratio with a strongly fluorescent coumarin coproduct that serves as a reporter to quantify substrate delivery. © 2008 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } (Chemical Equation Presented) This paper evaluates a series of photolabile protecting groups with built-in fluorescence reporting. They rely on readily available o-acetoxyphenyl methyloxazolones as activated precursors. Alcohol substrates are easily caged. The resulting photoactivable esters exhibit large one- and two-photon uncaging cross sections. The alcohol substrates are quantitatively released in a 1:1 molar ratio with a strongly fluorescent coumarin coproduct that serves as a reporter to quantify substrate delivery. © 2008 American Chemical Society. |
Fourier transform to analyse reaction-diffusion dynamics in a microsystem Article de journal A Estévez-Torres; T Le Saux; C Gosse; A Lemarchand; A Bourdoncle; L Jullien Lab on a Chip, 8 (7), p. 1205–1209, 2008. @article{Estevez-Torres:2008, title = {Fourier transform to analyse reaction-diffusion dynamics in a microsystem}, author = {A Est\'{e}vez-Torres and T Le Saux and C Gosse and A Lemarchand and A Bourdoncle and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-46149125030&doi=10.1039%2fb805412f&partnerID=40&md5=61edf13ed55e8879919bd89b45ba779a}, doi = {10.1039/b805412f}, year = {2008}, date = {2008-01-01}, journal = {Lab on a Chip}, volume = {8}, number = {7}, pages = {1205--1209}, abstract = {An integrated approach relying on a microsystem is introduced to easily extract, from a single experiment and with a global robust bi-exponential fit, an extensive set of thermodynamic, kinetic, and diffusion parameters governing associations in solution. © The Royal Society of Chemistry.}, keywords = {}, pubstate = {published}, tppubtype = {article} } An integrated approach relying on a microsystem is introduced to easily extract, from a single experiment and with a global robust bi-exponential fit, an extensive set of thermodynamic, kinetic, and diffusion parameters governing associations in solution. © The Royal Society of Chemistry. |
2007 |
Changes in the Morphology of Giant Vesicles Under Various Physico-Chemical Stresses incollection M -A Guedeau-Boudeville; A -L Bernard; J Bradley; A Singh; L Jullien Giant Vesicles: Perspectives in Supramolecular Chemistry, 6 , p. 341–349, 2007. @incollection{Guedeau-Boudeville:2007, title = {Changes in the Morphology of Giant Vesicles Under Various Physico-Chemical Stresses}, author = {M -A Guedeau-Boudeville and A -L Bernard and J Bradley and A Singh and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84955368046&doi=10.1002%2f9780470511534.ch26&partnerID=40&md5=630542a3e134f9fe44a60c1a944d2643}, doi = {10.1002/9780470511534.ch26}, year = {2007}, date = {2007-01-01}, booktitle = {Giant Vesicles: Perspectives in Supramolecular Chemistry}, volume = {6}, pages = {341--349}, keywords = {}, pubstate = {published}, tppubtype = {incollection} } |
Fourier analysis to measure diffusion coefficients and resolve mixtures on a continuous electrophoresis chip Article de journal A Estévez-Torres; C Gosse; T Le Saux; J -F Allemand; V Croquette; H Berthoumieux; A Lemarchand; L Jullien Analytical Chemistry, 79 (21), p. 8222–8231, 2007. @article{Estevez-Torres:2007, title = {Fourier analysis to measure diffusion coefficients and resolve mixtures on a continuous electrophoresis chip}, author = {A Est\'{e}vez-Torres and C Gosse and T Le Saux and J -F Allemand and V Croquette and H Berthoumieux and A Lemarchand and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35848961243&doi=10.1021%2fac070532z&partnerID=40&md5=a7d83124bd11f49b053fcdce6e8e4fcf}, doi = {10.1021/ac070532z}, year = {2007}, date = {2007-01-01}, journal = {Analytical Chemistry}, volume = {79}, number = {21}, pages = {8222--8231}, abstract = {We report a method to measure diffusion coefficients of fluorescent solutes in the 102-106 Da molecular mass range in a glass-PDMS chip. Upon applying a permanent electric field, the solute is introduced through a narrow channel into a wide analysis chamber where it migrates along the injection axis and diffuses in two dimensions. The diffusion coefficient is extracted after 1D Fourier transform of the resulting stationary concentration pattern. Analysis is straightforward, requiring no numerical integration or velocity field simulation. The diffusion coefficients measured for fluorescein, rhodamine green-labeled oligonucleotides, and YOYO-1-stained dsDNA fragments agree with the literature values and with our own fluorescence correlation spectroscopy measurements. As shown for 151 and 1257 base pair dsDNA mixtures, the present method allows us to rely on diffusion to quantitatively characterize the nature and the composition of binary mixtures. In particular, we implement a DNA hybridization assay to illustrate the efficiency of the proposed protocol for library screening. © 2007 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report a method to measure diffusion coefficients of fluorescent solutes in the 102-106 Da molecular mass range in a glass-PDMS chip. Upon applying a permanent electric field, the solute is introduced through a narrow channel into a wide analysis chamber where it migrates along the injection axis and diffuses in two dimensions. The diffusion coefficient is extracted after 1D Fourier transform of the resulting stationary concentration pattern. Analysis is straightforward, requiring no numerical integration or velocity field simulation. The diffusion coefficients measured for fluorescein, rhodamine green-labeled oligonucleotides, and YOYO-1-stained dsDNA fragments agree with the literature values and with our own fluorescence correlation spectroscopy measurements. As shown for 151 and 1257 base pair dsDNA mixtures, the present method allows us to rely on diffusion to quantitatively characterize the nature and the composition of binary mixtures. In particular, we implement a DNA hybridization assay to illustrate the efficiency of the proposed protocol for library screening. © 2007 American Chemical Society. |
Temporal modulation of a spatially periodic potential for kinetically governed oriented motion Article de journal H Berthoumieux; L Jullien; A Lemarchand Journal of Physical Chemistry B, 111 (8), p. 2045–2051, 2007. @article{Berthoumieux:2007, title = {Temporal modulation of a spatially periodic potential for kinetically governed oriented motion}, author = {H Berthoumieux and L Jullien and A Lemarchand}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33947412367&doi=10.1021%2fjp0669714&partnerID=40&md5=7fe1c3e7a7d426370505fe7f621596d3}, doi = {10.1021/jp0669714}, year = {2007}, date = {2007-01-01}, journal = {Journal of Physical Chemistry B}, volume = {111}, number = {8}, pages = {2045--2051}, abstract = {This theoretical paper introduces an experimental protocol derived from the concept of Brownian motors in order to selectively confer an oriented motion to given charged reactants. Instead of maintaining permanently the system in nonequilibrium conditions, we propose a simple experimental trick to restore periodically a transient out-of-equilibrium regime: the reactive medium is alternately submitted to a sawtooth potential and to a potential ramp. The model provides approximate analytical expressions for the operating conditions allowing us to design the extraction from a mixture of any desired reactant characterized by its rate constants. The orders of magnitude suggest a possible implementation in microsystems where the present approach could be used for separation and analysis. © 2007 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This theoretical paper introduces an experimental protocol derived from the concept of Brownian motors in order to selectively confer an oriented motion to given charged reactants. Instead of maintaining permanently the system in nonequilibrium conditions, we propose a simple experimental trick to restore periodically a transient out-of-equilibrium regime: the reactive medium is alternately submitted to a sawtooth potential and to a potential ramp. The model provides approximate analytical expressions for the operating conditions allowing us to design the extraction from a mixture of any desired reactant characterized by its rate constants. The orders of magnitude suggest a possible implementation in microsystems where the present approach could be used for separation and analysis. © 2007 American Chemical Society. |
Thermal characterization of a microfluidic cell using the 3ωmethod Inproceedings T Barilero; P -O Chapuis; D Pujade; S Guilet; V Croquette; L Jullien; S Volz; C Gosse TRANSDUCERS and EUROSENSORS '07 - 4th International Conference on Solid-State Sensors, Actuators and Microsystems, p. 1849–1852, 2007. @inproceedings{Barilero:2007, title = {Thermal characterization of a microfluidic cell using the 3ωmethod}, author = {T Barilero and P -O Chapuis and D Pujade and S Guilet and V Croquette and L Jullien and S Volz and C Gosse}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-50049116299&doi=10.1109%2fSENSOR.2007.4300516&partnerID=40&md5=79f1cc20e9e80b3a75700b59074ba356}, doi = {10.1109/SENSOR.2007.4300516}, year = {2007}, date = {2007-01-01}, booktitle = {TRANSDUCERS and EUROSENSORS '07 - 4th International Conference on Solid-State Sensors, Actuators and Microsystems}, pages = {1849--1852}, abstract = {Resistive heaters, 36 μm to 2 mm side, were microfabricated in indium-tin-oxide (ITO) using ion beam etching (IBE). A microfluidic cell was subsequently assembled and its thermal behavior was studied by the 3ω method. Experiments and finite element model (FEM) simulations both satisfactorily agreed with a simple one-dimensional model for heat diffusion. ©2007 IEEE.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } Resistive heaters, 36 μm to 2 mm side, were microfabricated in indium-tin-oxide (ITO) using ion beam etching (IBE). A microfluidic cell was subsequently assembled and its thermal behavior was studied by the 3ω method. Experiments and finite element model (FEM) simulations both satisfactorily agreed with a simple one-dimensional model for heat diffusion. ©2007 IEEE. |
Two-photon uncaging with fluorescence reporting: Evaluation of the o-hydroxycinnamic platform Article de journal N Gagey; P Neveu; C Benbrahim; B Goetz; I Aujard; J -B Baudin; L Jullien Journal of the American Chemical Society, 129 (32), p. 9986–9998, 2007. @article{Gagey:2007, title = {Two-photon uncaging with fluorescence reporting: Evaluation of the o-hydroxycinnamic platform}, author = {N Gagey and P Neveu and C Benbrahim and B Goetz and I Aujard and J -B Baudin and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547870514&doi=10.1021%2fja0722022&partnerID=40&md5=680a2519805e064c0d94072f36b1e534}, doi = {10.1021/ja0722022}, year = {2007}, date = {2007-01-01}, journal = {Journal of the American Chemical Society}, volume = {129}, number = {32}, pages = {9986--9998}, abstract = {This paper evaluates the ohydroxycinnamic platform for designing efficient caging groups with fluorescence reporting upon one- and two-photon excitation. The model cinnamates are easily prepared in one step by coupling commercial or readily available synthons. They exhibit a large one-photon absorption that can be tuned in the near-UV range. Uncaging after one-photon excitation was investigated by 1H NMR, UV-vis absorption, and steady-state fluorescence emission. In the whole investigated series, the caged substrate is quantitatively released upon photolysis. At the same time, uncaging releases a strongly fluorescent coproduct that can be used as a reporter for quantitative substrate delivery. The quantum yield of double bond photoisomerization leading to uncaging after one-photon absorption mostly lies in the 10% range. Taking advantage of the favorable photophysical properties of the uncaging coproduct, we use a series of techniques based on fluorescence emission to measure the action uncaging cross sections with two-photon excitation of the present cinnamates. Exhibiting values in the 1-10 GM range at 750 nm, they satisfactorily compare with the most efficient caging groups reported to date. Noticeably, the uncaging behavior with two-photon excitation is retained in vivo as suggested by the results observed in living zebrafish embryos. Reliable structure property relationships were extracted from analysis of the present collected data. In particular, the careful kinetic analysis allows us to discuss the relevance of the ohydroxycinnamic platform for diverse caging applications with one- and two-photon excitation. © 2007 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This paper evaluates the ohydroxycinnamic platform for designing efficient caging groups with fluorescence reporting upon one- and two-photon excitation. The model cinnamates are easily prepared in one step by coupling commercial or readily available synthons. They exhibit a large one-photon absorption that can be tuned in the near-UV range. Uncaging after one-photon excitation was investigated by 1H NMR, UV-vis absorption, and steady-state fluorescence emission. In the whole investigated series, the caged substrate is quantitatively released upon photolysis. At the same time, uncaging releases a strongly fluorescent coproduct that can be used as a reporter for quantitative substrate delivery. The quantum yield of double bond photoisomerization leading to uncaging after one-photon absorption mostly lies in the 10% range. Taking advantage of the favorable photophysical properties of the uncaging coproduct, we use a series of techniques based on fluorescence emission to measure the action uncaging cross sections with two-photon excitation of the present cinnamates. Exhibiting values in the 1-10 GM range at 750 nm, they satisfactorily compare with the most efficient caging groups reported to date. Noticeably, the uncaging behavior with two-photon excitation is retained in vivo as suggested by the results observed in living zebrafish embryos. Reliable structure property relationships were extracted from analysis of the present collected data. In particular, the careful kinetic analysis allows us to discuss the relevance of the ohydroxycinnamic platform for diverse caging applications with one- and two-photon excitation. © 2007 American Chemical Society. |
Two-photon uncaging with the efficient 3,5-dibromo-2,4-dihydroxycinnamic caging group Article de journal N Gagey; P Neveu; L Jullien Angewandte Chemie - International Edition, 46 (14), p. 2467–2469, 2007. @article{Gagey:2007a, title = {Two-photon uncaging with the efficient 3,5-dibromo-2,4-dihydroxycinnamic caging group}, author = {N Gagey and P Neveu and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250818700&doi=10.1002%2fanie.200604598&partnerID=40&md5=8e8a20b5554d394654aed024d24583b4}, doi = {10.1002/anie.200604598}, year = {2007}, date = {2007-01-01}, journal = {Angewandte Chemie - International Edition}, volume = {46}, number = {14}, pages = {2467--2469}, abstract = {(Chemical Equation Presented) An optical syringe for targeted delivery of a substrate in vivo has been developed on the basis of the 3,5-dibromo-2,4- dihydroxycinnamic caging group. Two-photon excitation of the caged compound uncages the substrate (ethanol in the scheme) and forms a coumarin whose fluorescence allows the concentration of released substrate to be quantified. Single-cell release can be achieved with a focused laser (shown schematically for a zebrafish embryo). © 2007 Wiley-VCH Verlag GmbH & Co. KGaA.}, keywords = {}, pubstate = {published}, tppubtype = {article} } (Chemical Equation Presented) An optical syringe for targeted delivery of a substrate in vivo has been developed on the basis of the 3,5-dibromo-2,4- dihydroxycinnamic caging group. Two-photon excitation of the caged compound uncages the substrate (ethanol in the scheme) and forms a coumarin whose fluorescence allows the concentration of released substrate to be quantified. Single-cell release can be achieved with a focused laser (shown schematically for a zebrafish embryo). © 2007 Wiley-VCH Verlag GmbH & Co. KGaA. |
2006 |
O-nitrobenzyl photolabile protecting groups with red-shifted absorption: Syntheses and uncaging cross-sections for one- And two-photon excitation Article de journal I Aujard; C Benbrahim; M Gouget; O Ruel; J -B Baudin; P Neveu; L Jullien Chemistry - A European Journal, 12 (26), p. 6865–6879, 2006. @article{Aujard:2006, title = {O-nitrobenzyl photolabile protecting groups with red-shifted absorption: Syntheses and uncaging cross-sections for one- And two-photon excitation}, author = {I Aujard and C Benbrahim and M Gouget and O Ruel and J -B Baudin and P Neveu and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33748546615&doi=10.1002%2fchem.200501393&partnerID=40&md5=d3011a8b9ba16aa9a425b2fd309a5fac}, doi = {10.1002/chem.200501393}, year = {2006}, date = {2006-01-01}, journal = {Chemistry - A European Journal}, volume = {12}, number = {26}, pages = {6865--6879}, abstract = {We evaluated the o-nitrobenzyl platform for designing photolabile protecting groups with red-shifted absorption that could be photolyzed upon one- and two-photon excitation. Several synthetic pathways to build different conjugated o-nitrobenzyl backbones, as well as to vary the benzylic position, are reported. Relative to the reference 4,5-dimethoxy-2-nitrobenzyl group, several o-nitrobenzyl derivatives exhibit a large and red-shifted one-photon absorption within the near-UV range. Uncaging after one-photon excitation was studied by measuring UV-visible absorption and steady-state fluorescence emission on model caged ethers and esters. In the whole series investi gated, the caged substrates were released cleanly upon photolysis. Quantum yields of uncaging after one-photon absorption lie within the 0.11% range. We observed that these drop as the maximum wavelength absorption of the o-nitrobenzyl protecting group is increased. A new method based on fluorescence correlation spectroscopy (PCS) after two-photon excitation was used to measure the action uncaging cross section for two-photon excitation. The series of o-nitrobenzyl caged fluorescent coumarins investigated exhibit values within the 0.10.01 Goeppert-Mayer (GM) range. Such results are in line with the low quantum yields of uncaging associated with cross-sections of 1-50 GM for two-photon absorption. Although the cross-sections for one- and two-photon absorption of o-nitrobenzyl photolabile protecting groups can be readily improved, we emphasize the difficulty in enlarging the corresponding action uncaging cross-sections in view of the observed trend of their quantum yield of uncaging. © 2006 Wiley-VCH Verlag GmbH & Co, KGaA.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We evaluated the o-nitrobenzyl platform for designing photolabile protecting groups with red-shifted absorption that could be photolyzed upon one- and two-photon excitation. Several synthetic pathways to build different conjugated o-nitrobenzyl backbones, as well as to vary the benzylic position, are reported. Relative to the reference 4,5-dimethoxy-2-nitrobenzyl group, several o-nitrobenzyl derivatives exhibit a large and red-shifted one-photon absorption within the near-UV range. Uncaging after one-photon excitation was studied by measuring UV-visible absorption and steady-state fluorescence emission on model caged ethers and esters. In the whole series investi gated, the caged substrates were released cleanly upon photolysis. Quantum yields of uncaging after one-photon absorption lie within the 0.11% range. We observed that these drop as the maximum wavelength absorption of the o-nitrobenzyl protecting group is increased. A new method based on fluorescence correlation spectroscopy (PCS) after two-photon excitation was used to measure the action uncaging cross section for two-photon excitation. The series of o-nitrobenzyl caged fluorescent coumarins investigated exhibit values within the 0.10.01 Goeppert-Mayer (GM) range. Such results are in line with the low quantum yields of uncaging associated with cross-sections of 1-50 GM for two-photon absorption. Although the cross-sections for one- and two-photon absorption of o-nitrobenzyl photolabile protecting groups can be readily improved, we emphasize the difficulty in enlarging the corresponding action uncaging cross-sections in view of the observed trend of their quantum yield of uncaging. © 2006 Wiley-VCH Verlag GmbH & Co, KGaA. |
Photophysics of a series of efficient fluorescent pH probes for dual-emission-wavelength measurements in aqueous solutions Article de journal S Charier; O Ruel; J -B Baudin; D Alcor; J -F Allemand; A Meglio; L Jullien; B Valeur Chemistry - A European Journal, 12 (4), p. 1097–1113, 2006. @article{Charier:2006, title = {Photophysics of a series of efficient fluorescent pH probes for dual-emission-wavelength measurements in aqueous solutions}, author = {S Charier and O Ruel and J -B Baudin and D Alcor and J -F Allemand and A Meglio and L Jullien and B Valeur}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-31344460620&doi=10.1002%2fchem.200500619&partnerID=40&md5=ba45e0a9ace96d749f8d4a985ed8a55c}, doi = {10.1002/chem.200500619}, year = {2006}, date = {2006-01-01}, journal = {Chemistry - A European Journal}, volume = {12}, number = {4}, pages = {1097--1113}, abstract = {This paper evaluates the 5-aryl-2-pyridyloxazole backbone to engineer donor-acceptor fluorescent pH probes after one- or two-photon absorption. Parent fluorophores, as well as derivatives that can be used to label biomolecules, can be easily obtained in good yields. These molecules exhibit a large one-photon absorption in the near-UV range, and a strong fluorescence emission that covers the whole visible domain. The 5-aryl-2-pyridyloxazole derivatives also possess significant cross sections for two-photon absorption. Upon pyridine protonation, large shifts were observed in the absorption spectra after one- and two-photon excitation, as well as in the emission spectra. This feature was used to measure the pKa of the investigated compounds that range between 2 and 8. In most of the investigated derivatives, the pKa increased upon light excitation and protonation exchanges took place during the lifetime of the excited state, as shown by phase-modulation fluorometry analysis. Several 5-aryl-2-pyridyloxazole derivatives are suggested as efficient probes to reliably measure the pH of aqueous solutions by means of ratiometric methods that are dependent on fluorescence emission. © 2006 Wiley-VCH Verlag GmbH & Co. KGaA.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This paper evaluates the 5-aryl-2-pyridyloxazole backbone to engineer donor-acceptor fluorescent pH probes after one- or two-photon absorption. Parent fluorophores, as well as derivatives that can be used to label biomolecules, can be easily obtained in good yields. These molecules exhibit a large one-photon absorption in the near-UV range, and a strong fluorescence emission that covers the whole visible domain. The 5-aryl-2-pyridyloxazole derivatives also possess significant cross sections for two-photon absorption. Upon pyridine protonation, large shifts were observed in the absorption spectra after one- and two-photon excitation, as well as in the emission spectra. This feature was used to measure the pKa of the investigated compounds that range between 2 and 8. In most of the investigated derivatives, the pKa increased upon light excitation and protonation exchanges took place during the lifetime of the excited state, as shown by phase-modulation fluorometry analysis. Several 5-aryl-2-pyridyloxazole derivatives are suggested as efficient probes to reliably measure the pH of aqueous solutions by means of ratiometric methods that are dependent on fluorescence emission. © 2006 Wiley-VCH Verlag GmbH & Co. KGaA. |
Quadruplex-based molecular beacons as tunable DNA probes Article de journal A Bourdoncle; A E Torres; C Gosse; L Lacroix; P Vekhoff; T Le Saux; L Jullien; J -L Mergny Journal of the American Chemical Society, 128 (34), p. 11094–11105, 2006. @article{Bourdoncle:2006, title = {Quadruplex-based molecular beacons as tunable DNA probes}, author = {A Bourdoncle and A E Torres and C Gosse and L Lacroix and P Vekhoff and T Le Saux and L Jullien and J -L Mergny}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33748052721&doi=10.1021%2fja0608040&partnerID=40&md5=68c9f7b0a980f51035c5a06b54023673}, doi = {10.1021/ja0608040}, year = {2006}, date = {2006-01-01}, journal = {Journal of the American Chemical Society}, volume = {128}, number = {34}, pages = {11094--11105}, abstract = {Molecular beacons (MBs) are fluorescent nucleic acid probes with a hairpin-shaped structure in which the 5′ and 3′ ends are self-complementary. Due to a change in their emissive properties upon recognition with complementary sequences, MBs allow the diagnosis of single-stranded DNA or RNA with high mismatch discrimination, in vitro and in vivo. Whereas the stems of MB hairpins usually rely on the formation of a Watson-Crick duplex, we demonstrate in this report that the preceding structure can be replaced by a G-quadruplex motif (G4). Intramolecular quadruplexes may still be formed with a central loop composed of 12 to 21 bases, therefore extending the sequence repertoire of quadruplex formation. G4-MB can efficiently be used for oligonucleotide discrimination: in the presence of a complementary sequence, the central loop hybridizes and forms a duplex that causes opening of the quadruplex stem. The corresponding G4-MB unfolding can be detected by a change in its fluorescence emission. We discuss the thermodynamic and kinetic opportunities that are provided by using G4-MB instead of traditional MB. In particular, the intrinsic feature of the quadruplex motif facilitates the design of functional molecular beacons by independently varying the concentration of monovalent or divalent cations in the medium. © 2006 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Molecular beacons (MBs) are fluorescent nucleic acid probes with a hairpin-shaped structure in which the 5′ and 3′ ends are self-complementary. Due to a change in their emissive properties upon recognition with complementary sequences, MBs allow the diagnosis of single-stranded DNA or RNA with high mismatch discrimination, in vitro and in vivo. Whereas the stems of MB hairpins usually rely on the formation of a Watson-Crick duplex, we demonstrate in this report that the preceding structure can be replaced by a G-quadruplex motif (G4). Intramolecular quadruplexes may still be formed with a central loop composed of 12 to 21 bases, therefore extending the sequence repertoire of quadruplex formation. G4-MB can efficiently be used for oligonucleotide discrimination: in the presence of a complementary sequence, the central loop hybridizes and forms a duplex that causes opening of the quadruplex stem. The corresponding G4-MB unfolding can be detected by a change in its fluorescence emission. We discuss the thermodynamic and kinetic opportunities that are provided by using G4-MB instead of traditional MB. In particular, the intrinsic feature of the quadruplex motif facilitates the design of functional molecular beacons by independently varying the concentration of monovalent or divalent cations in the medium. © 2006 American Chemical Society. |
2005 |
An approach to extract rate constants from reaction-diffusion dynamics in a microchannel Article de journal J -B Salmon; C Dubrocq; P Tabeling; S Charier; D Alcor; L Jullien; F Ferrage Analytical Chemistry, 77 (11), p. 3417–3424, 2005. @article{Salmon:2005, title = {An approach to extract rate constants from reaction-diffusion dynamics in a microchannel}, author = {J -B Salmon and C Dubrocq and P Tabeling and S Charier and D Alcor and L Jullien and F Ferrage}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-20444391378&doi=10.1021%2fac0500838&partnerID=40&md5=069b35f666f1edab8f021528a9616794}, doi = {10.1021/ac0500838}, year = {2005}, date = {2005-01-01}, journal = {Analytical Chemistry}, volume = {77}, number = {11}, pages = {3417--3424}, abstract = {A theoretical model is proposed to extract rate constants of second-order chemical reactions down to the millisecond time scale from the observation of reaction-diffusion processes in a microchannel. We validate this theoretical approach by examining an appropriate model reaction. The measured rate constant is in excellent agreement with this obtained from nuclear magnetic resonance experiments. © 2005 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A theoretical model is proposed to extract rate constants of second-order chemical reactions down to the millisecond time scale from the observation of reaction-diffusion processes in a microchannel. We validate this theoretical approach by examining an appropriate model reaction. The measured rate constant is in excellent agreement with this obtained from nuclear magnetic resonance experiments. © 2005 American Chemical Society. |
Reactant concentrations from fluorescence correlation spectroscopy with tailored fluorescent probes. An example of local calibration-free pH measurement Article de journal S Charier; A Meglio; D Alcor; E Cogné-Laage; J -F Allemand; L Jullien; A Lemarchand Journal of the American Chemical Society, 127 (44), p. 15491–15505, 2005. @article{Charier:2005, title = {Reactant concentrations from fluorescence correlation spectroscopy with tailored fluorescent probes. An example of local calibration-free pH measurement}, author = {S Charier and A Meglio and D Alcor and E Cogn\'{e}-Laage and J -F Allemand and L Jullien and A Lemarchand}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-27644487200&doi=10.1021%2fja053909w&partnerID=40&md5=63004e877da68d3e2aa7472577479c8d}, doi = {10.1021/ja053909w}, year = {2005}, date = {2005-01-01}, journal = {Journal of the American Chemical Society}, volume = {127}, number = {44}, pages = {15491--15505}, abstract = {The present account is concerned with the measurement of local reactant concentrations by observing specific fluorescent probes in fluorescence correlation spectroscopy (FCS). The Theoretical Analysis section revisits the photophysical, thermodynamic, and kinetic information that is contained in the corresponding FCS correlation curves. In particular, we examine the conditions under which FCS is revealed as a superior tool to measure concentrations of reactive species. Careful molecular engineering of the specific fluorescent probes that simultaneously integrates photophysical, thermodynamic, and kinetic constraints will be required to benefit most from FCS. We illustrate the FCS titration approach with a series of fluorescent probes that we tailored to measure pH at around 4-6 by FCS after two-photon excitation. We show that an optimal design allows one to access pH without any preliminary calibrations such as the determination of the protonation constant or the photophysical properties of the fluorescent probe. © 2005 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The present account is concerned with the measurement of local reactant concentrations by observing specific fluorescent probes in fluorescence correlation spectroscopy (FCS). The Theoretical Analysis section revisits the photophysical, thermodynamic, and kinetic information that is contained in the corresponding FCS correlation curves. In particular, we examine the conditions under which FCS is revealed as a superior tool to measure concentrations of reactive species. Careful molecular engineering of the specific fluorescent probes that simultaneously integrates photophysical, thermodynamic, and kinetic constraints will be required to benefit most from FCS. We illustrate the FCS titration approach with a series of fluorescent probes that we tailored to measure pH at around 4-6 by FCS after two-photon excitation. We show that an optimal design allows one to access pH without any preliminary calibrations such as the determination of the protonation constant or the photophysical properties of the fluorescent probe. © 2005 American Chemical Society. |