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
2004 |
Chemical structure effect on the excited-state relaxation dynamics of the PYP chromophore Inproceedings A Espagne; P Changenet-Barret; S Charier; J -B Baudin; L Jullien; P Plaza; M M Martin Martin, M M; Hynes, J T (Ed.): VIth International Conference on Femtochemistry, p. 421-424, Elsevier, 2004. @inproceedings{RN88, title = {Chemical structure effect on the excited-state relaxation dynamics of the PYP chromophore}, author = {A Espagne and P Changenet-Barret and S Charier and J -B Baudin and L Jullien and P Plaza and M M Martin}, editor = {M M Martin and J T Hynes}, year = {2004}, date = {2004-01-01}, booktitle = {VIth International Conference on Femtochemistry}, pages = {421-424}, publisher = {Elsevier}, series = {Femtochemistry and Femtobiology: Ultrafast Events in Molecular Science}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Competition and symbiosis in a chemical world Article de journal A Lemarchand; L Jullien Journal of Physical Chemistry B, 108 (31), p. 11782–11791, 2004. @article{Lemarchand:2004, title = {Competition and symbiosis in a chemical world}, author = {A Lemarchand and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-4143134116&doi=10.1021%2fjp0379392&partnerID=40&md5=78471d67bd8e500016462d556b193707}, doi = {10.1021/jp0379392}, year = {2004}, date = {2004-01-01}, journal = {Journal of Physical Chemistry B}, volume = {108}, number = {31}, pages = {11782--11791}, abstract = {A possible road for the emergence of complexity in artificial inhomogeneous chemical systems is analyzed. We build a reaction-diffusion model inspired from a surfactant-based scheme leading to the formation of micelles and vesicles. Our model only relies on autocatalysis and the existence of a critical concentration. Depending on the parameter values of the extended dynamical system, this simple model already accounts for typical behaviors of living organisms. In particular, competition and different types of symbiotic relationships are reproduced.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A possible road for the emergence of complexity in artificial inhomogeneous chemical systems is analyzed. We build a reaction-diffusion model inspired from a surfactant-based scheme leading to the formation of micelles and vesicles. Our model only relies on autocatalysis and the existence of a critical concentration. Depending on the parameter values of the extended dynamical system, this simple model already accounts for typical behaviors of living organisms. In particular, competition and different types of symbiotic relationships are reproduced. |
Early molecular events in the photoactive yellow protein: Role of the chromophore photophysics Article de journal P Changenet-Barret; A Espagne; S Charier; J -B Baudin; L Jullien; P Plaza; K J Hellingwerf; M M Martin Photochemical and Photobiological Sciences, 3 (8), p. 823–829, 2004. @article{Changenet-Barret:2004, title = {Early molecular events in the photoactive yellow protein: Role of the chromophore photophysics}, author = {P Changenet-Barret and A Espagne and S Charier and J -B Baudin and L Jullien and P Plaza and K J Hellingwerf and M M Martin}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-4644243446&doi=10.1039%2fb400398e&partnerID=40&md5=45520bcadbdf2612c16ef874b207d73b}, doi = {10.1039/b400398e}, year = {2004}, date = {2004-01-01}, journal = {Photochemical and Photobiological Sciences}, volume = {3}, number = {8}, pages = {823--829}, abstract = {We report a comparative study of the isomerization reaction in native and denatured photoactive yellow protein (PYP) and in various chromophore analogues in their trans deprotonated form. The excited-state relaxation dynamics was followed by subpicosecond transient absorption and gain spectroscopy. The free p-hydroxycinnamate (pCA2−) and its amide analogue (pCM-) are found to display a quite different transient spectroscopy from that of PYP. The excited-state deactivation leads to the formation of the ground-state cis isomer without any detectable intermediate with a mechanism comparable to trans-stilbene photoisomerization. On the contrary, the early stage of the excited-state deactivation of the free thiophenyl-p-hydroxycinnamate (pCT-) and of the denatured PYP is similar to that of the native protein. It involves the formation of an intermediate absorbing in the spectral region located between the bleaching and gain bands in less than 2 ps. However, in these two cases, the formation of the cis isomer has not been proved yet. This difference with pCA- and pCM- might result from the fact that, in the thioester substituted chromophore, simultaneous population of two quasi-degenerate excited states occurs upon excitation. This comparative study highlights the determining role of the chromophore structure and of its intrinsic properties in the primary molecular events in native PYP. © 2004 The Royal Society of Chemistry and Owner Societies.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report a comparative study of the isomerization reaction in native and denatured photoactive yellow protein (PYP) and in various chromophore analogues in their trans deprotonated form. The excited-state relaxation dynamics was followed by subpicosecond transient absorption and gain spectroscopy. The free p-hydroxycinnamate (pCA2−) and its amide analogue (pCM-) are found to display a quite different transient spectroscopy from that of PYP. The excited-state deactivation leads to the formation of the ground-state cis isomer without any detectable intermediate with a mechanism comparable to trans-stilbene photoisomerization. On the contrary, the early stage of the excited-state deactivation of the free thiophenyl-p-hydroxycinnamate (pCT-) and of the denatured PYP is similar to that of the native protein. It involves the formation of an intermediate absorbing in the spectral region located between the bleaching and gain bands in less than 2 ps. However, in these two cases, the formation of the cis isomer has not been proved yet. This difference with pCA- and pCM- might result from the fact that, in the thioester substituted chromophore, simultaneous population of two quasi-degenerate excited states occurs upon excitation. This comparative study highlights the determining role of the chromophore structure and of its intrinsic properties in the primary molecular events in native PYP. © 2004 The Royal Society of Chemistry and Owner Societies. |
Micelles of lipid-oligonucleotide conjugates: Implications for membrane anchoring and base pairing Article de journal C Gosse; A Boutorine; I Aujard; M Chami; A Kononov; E Cogné-Laage; J -F Allemand; J Li; L Jullien Journal of Physical Chemistry B, 108 (20), p. 6485–6497, 2004. @article{Gosse:2004, title = {Micelles of lipid-oligonucleotide conjugates: Implications for membrane anchoring and base pairing}, author = {C Gosse and A Boutorine and I Aujard and M Chami and A Kononov and E Cogn\'{e}-Laage and J -F Allemand and J Li and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-2642510833&partnerID=40&md5=53c7d85ed744a277e84cbf84aeee9834}, year = {2004}, date = {2004-01-01}, journal = {Journal of Physical Chemistry B}, volume = {108}, number = {20}, pages = {6485--6497}, abstract = {This report examines the organization properties of new fluorescent DNA-lipids, either alone in water or in interaction with 1-octyl-β-D- glucopyranoside micelles or egg phosphatidylcholine vesicles. We first describe the design and the syntheses of the conjugates. Then, we use UV-Vis absorption, steady-state fluorescence emission, electron microscopy, and fluorescence correlation spectroscopy after two-photon excitation to show that these DNA-lipids form spherical micelles in aqueous solution and incorporate much better in micelles than in vesicles. We also investigate the significance of the lipophilic chains of these DNA-lipids on the melting behavior of the double-stranded hybrids: in water melting curves are broadened whereas in amphiphilic assemblies duplexes melt as the unconjugated controls. This work is expected to be useful for improving the rational design of antisense medicines.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This report examines the organization properties of new fluorescent DNA-lipids, either alone in water or in interaction with 1-octyl-β-D- glucopyranoside micelles or egg phosphatidylcholine vesicles. We first describe the design and the syntheses of the conjugates. Then, we use UV-Vis absorption, steady-state fluorescence emission, electron microscopy, and fluorescence correlation spectroscopy after two-photon excitation to show that these DNA-lipids form spherical micelles in aqueous solution and incorporate much better in micelles than in vesicles. We also investigate the significance of the lipophilic chains of these DNA-lipids on the melting behavior of the double-stranded hybrids: in water melting curves are broadened whereas in amphiphilic assemblies duplexes melt as the unconjugated controls. This work is expected to be useful for improving the rational design of antisense medicines. |
Molecular sorting by stochastic resonance Article de journal D Alcor; V Croquettet; L Jullien; A Lemarchand Proceedings of the National Academy of Sciences of the United States of America, 101 (22), p. 8276–8280, 2004. @article{Alcor:2004, title = {Molecular sorting by stochastic resonance}, author = {D Alcor and V Croquettet and L Jullien and A Lemarchand}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-2942622061&doi=10.1073%2fpnas.0400663101&partnerID=40&md5=8788f849313811632d06374bd9df174a}, doi = {10.1073/pnas.0400663101}, year = {2004}, date = {2004-01-01}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {101}, number = {22}, pages = {8276--8280}, abstract = {To sort a targeted species from a mixture, we introduce a procedure that relies on the enhancement of its effective diffusion coefficient. We use the formation of a host-guest complex between α-cyclodextrin and a dye to evidence the dye dispersion when the medium is submitted to an oscillating field. In particular, we demonstrate that the effective diffusion coefficient of the dye may be increased far beyond its intrinsic value by tuning the driving field frequency in the stochastic resonance regime. We use this effect to selectively sort from a mixture a dye that is addressed by its rate constants for association with α-cyclodextrin.}, keywords = {}, pubstate = {published}, tppubtype = {article} } To sort a targeted species from a mixture, we introduce a procedure that relies on the enhancement of its effective diffusion coefficient. We use the formation of a host-guest complex between α-cyclodextrin and a dye to evidence the dye dispersion when the medium is submitted to an oscillating field. In particular, we demonstrate that the effective diffusion coefficient of the dye may be increased far beyond its intrinsic value by tuning the driving field frequency in the stochastic resonance regime. We use this effect to selectively sort from a mixture a dye that is addressed by its rate constants for association with α-cyclodextrin. |
Tuning a reaction using two-site catalysis and far-from-equilibrium conditions Article de journal A Lemarchand; L Jullien Physical Chemistry Chemical Physics, 6 (2), p. 398–405, 2004. @article{Lemarchand:2004a, title = {Tuning a reaction using two-site catalysis and far-from-equilibrium conditions}, author = {A Lemarchand and L Jullien}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0942279538&doi=10.1039%2fb306678a&partnerID=40&md5=e3871b3d5a541f07ec447fa2ec0e8ff5}, doi = {10.1039/b306678a}, year = {2004}, date = {2004-01-01}, journal = {Physical Chemistry Chemical Physics}, volume = {6}, number = {2}, pages = {398--405}, abstract = {We show that a given kinetic mechanism, appropriate for describing the evolution of concentrations in a two-site catalysis, exhibits various properties when maintaining the system far from equilibrium and varying the order of magnitude of the rate constants: tuning of reaction yield, autocatalysis and kinetic proofreading are obtained. The model, involving molecules with two coupled reactive sites, gives some hints to design simple artificial systems possessing complex properties of living systems.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We show that a given kinetic mechanism, appropriate for describing the evolution of concentrations in a two-site catalysis, exhibits various properties when maintaining the system far from equilibrium and varying the order of magnitude of the rate constants: tuning of reaction yield, autocatalysis and kinetic proofreading are obtained. The model, involving molecules with two coupled reactive sites, gives some hints to design simple artificial systems possessing complex properties of living systems. |
2003 |
Adhesion of Arg-Gly-Asp (RGD) peptide vesicles onto an integrin surface: Visualization of the segregation of RGD ligands into the adhesion plaques by fluorescence Article de journal V Marchi-Artzner; B Lorz; C Gosse; L Jullien; R Merkel; H Kessler; E Sackmann Langmuir, 19 (3), p. 835–841, 2003. @article{Marchi-Artzner:2003, title = {Adhesion of Arg-Gly-Asp (RGD) peptide vesicles onto an integrin surface: Visualization of the segregation of RGD ligands into the adhesion plaques by fluorescence}, author = {V Marchi-Artzner and B Lorz and C Gosse and L Jullien and R Merkel and H Kessler and E Sackmann}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037418070&doi=10.1021%2fla026227k&partnerID=40&md5=a637abfe410c4e6040431b2fcd2d5843}, doi = {10.1021/la026227k}, year = {2003}, date = {2003-01-01}, journal = {Langmuir}, volume = {19}, number = {3}, pages = {835--841}, abstract = {Integrins are adhesion receptors that mediate cell adhesion and play an important function in many biological processes such as morphogenesis and tissue remodeling. These membrane proteins specifically interact with a short tripeptide sequence, RGD (Arg-Gly-Asp), present in numerous extracellular macromolecules. Model systems have been developed in order to understand how membrane adhesion is induced by this specific RGD peptide ligand/integrin recognition system. We have previously shown that RGD giant vesicles selectively adhere to endothelial cells by formation of pinning centers. Nevertheless, the nature of the lipids located in the adhesion contact zone is unknown. One hypothesis is that the lipidic ligands migrate to the contact zone where they are confined after binding to the receptor. To study the possible formation of ligand domains within the vesicle bilayer, we synthesized a fluorescently labeled RGD lipid that can be easily incorporated in giant vesicles. Adhesion of giant RGD vesicles onto an integrin-functionalized surface was followed simultaneously by reflection interference contrast microscopy and fluorescence microscopy. For the first time, it was possible to observe the microsegregation of RGD lipids in the contact zone during adhesion. Additionally, we observed interesting photosensitive properties of the chalcone chromophore that could lead to a new method of analyzing the lipid organization within the membrane during adhesion and to the design of new ligand lipids and vesicle vectors for cell targeting.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Integrins are adhesion receptors that mediate cell adhesion and play an important function in many biological processes such as morphogenesis and tissue remodeling. These membrane proteins specifically interact with a short tripeptide sequence, RGD (Arg-Gly-Asp), present in numerous extracellular macromolecules. Model systems have been developed in order to understand how membrane adhesion is induced by this specific RGD peptide ligand/integrin recognition system. We have previously shown that RGD giant vesicles selectively adhere to endothelial cells by formation of pinning centers. Nevertheless, the nature of the lipids located in the adhesion contact zone is unknown. One hypothesis is that the lipidic ligands migrate to the contact zone where they are confined after binding to the receptor. To study the possible formation of ligand domains within the vesicle bilayer, we synthesized a fluorescently labeled RGD lipid that can be easily incorporated in giant vesicles. Adhesion of giant RGD vesicles onto an integrin-functionalized surface was followed simultaneously by reflection interference contrast microscopy and fluorescence microscopy. For the first time, it was possible to observe the microsegregation of RGD lipids in the contact zone during adhesion. Additionally, we observed interesting photosensitive properties of the chalcone chromophore that could lead to a new method of analyzing the lipid organization within the membrane during adhesion and to the design of new ligand lipids and vesicle vectors for cell targeting. |
Two-Site Molecules as a Road for Engineering Complexity in Chemical Systems Article de journal L Jullien; A Lemarchand; S Charier; O Ruel; J -B Baudin Journal of Physical Chemistry B, 107 (36), p. 9905–9917, 2003. @article{Jullien:2003, title = {Two-Site Molecules as a Road for Engineering Complexity in Chemical Systems}, author = {L Jullien and A Lemarchand and S Charier and O Ruel and J -B Baudin}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0141903432&partnerID=40&md5=9979810858071b93857cd7f74f6d4365}, year = {2003}, date = {2003-01-01}, journal = {Journal of Physical Chemistry B}, volume = {107}, number = {36}, pages = {9905--9917}, abstract = {Molecules that contain two coupled reactive sites are simple chemical systems that may nevertheless already exhibit some complex behaviors when they are subjected to suitable external constraints. This report first proposes a theoretical model and an experimental illustration to demonstrate that the introduction of an auxiliary reactive site on a substrate can lead to local and continuous tuning of the thermodynamic and kinetic properties of a reaction of interest. It is then shown that a similar kinetic scheme that is appropriate for describing the evolution of concentrations in a two-site catalysis exhibits diverse properties when maintaining the system far from equilibrium and varying the order of magnitude of the rate constants: tuning of chemical yield, autocatalysis, and kinetic proofreading are obtained.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Molecules that contain two coupled reactive sites are simple chemical systems that may nevertheless already exhibit some complex behaviors when they are subjected to suitable external constraints. This report first proposes a theoretical model and an experimental illustration to demonstrate that the introduction of an auxiliary reactive site on a substrate can lead to local and continuous tuning of the thermodynamic and kinetic properties of a reaction of interest. It is then shown that a similar kinetic scheme that is appropriate for describing the evolution of concentrations in a two-site catalysis exhibits diverse properties when maintaining the system far from equilibrium and varying the order of magnitude of the rate constants: tuning of chemical yield, autocatalysis, and kinetic proofreading are obtained. |
2002 |
Excited-state relation dynamics of a PYP chromophore model in solution: Influence of the thioester group Article de journal P Changenet-Barret; A Espagne; N Katsonis; S Charier; J -B Baudin; L Jullien; P Plaza; M M Martin Chemical Physics Letters, 365 (3-4), p. 285–291, 2002. @article{Changenet-Barret:2002, title = {Excited-state relation dynamics of a PYP chromophore model in solution: Influence of the thioester group}, author = {P Changenet-Barret and A Espagne and N Katsonis and S Charier and J -B Baudin and L Jullien and P Plaza and M M Martin}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037109026&doi=10.1016%2fS0009-2614%2802%2901480-X&partnerID=40&md5=5fdfd4c614229bacad91377caee585a1}, doi = {10.1016/S0009-2614(02)01480-X}, year = {2002}, date = {2002-01-01}, journal = {Chemical Physics Letters}, volume = {365}, number = {3-4}, pages = {285--291}, abstract = {Cis-trans photoisomerization of a photoactive yellow protein chromophore model, the deprotonated trans S-phenyl thio-p-hydroxycinnamate, is studied in aqueous solution by subpicosecond transient absorption and gain spectroscopy. The excited-state deactivation is found to involve the formation, in 1.7 ps, of an intermediate state which decays in 2.8 ps. A persistent bleaching signal is observed at longer times indicating that the excited state not only relaxes to the ground state but also partly forms a stable photoproduct, possibly the cis isomer. This behavior is analogous to that of the native photoactive yellow protein. © 2002 Elsevier Science B.V. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Cis-trans photoisomerization of a photoactive yellow protein chromophore model, the deprotonated trans S-phenyl thio-p-hydroxycinnamate, is studied in aqueous solution by subpicosecond transient absorption and gain spectroscopy. The excited-state deactivation is found to involve the formation, in 1.7 ps, of an intermediate state which decays in 2.8 ps. A persistent bleaching signal is observed at longer times indicating that the excited state not only relaxes to the ground state but also partly forms a stable photoproduct, possibly the cis isomer. This behavior is analogous to that of the native photoactive yellow protein. © 2002 Elsevier Science B.V. All rights reserved. |
Hyperpolar multichromophoric nanoassembly for molecular nonlinear optics Inproceedings M Blanchard-Desce; M Ait Amer Meziane; E D Rekaï; J -B Baudin; L Jullien; I Ledoux; J Zyss Proceedings of SPIE - The International Society for Optical Engineering, p. 163–172, 2002. @inproceedings{Blanchard-Desce:2002, title = {Hyperpolar multichromophoric nanoassembly for molecular nonlinear optics}, author = {M Blanchard-Desce and M Ait Amer Meziane and E D Reka\"{i} and J -B Baudin and L Jullien and I Ledoux and J Zyss}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0038754955&doi=10.1117%2f12.452066&partnerID=40&md5=2ab898884653fe6f8f9fc785379b4d94}, doi = {10.1117/12.452066}, year = {2002}, date = {2002-01-01}, booktitle = {Proceedings of SPIE - The International Society for Optical Engineering}, volume = {4798}, pages = {163--172}, abstract = {A multichromophoric nanoassembly was designed by gathering seven push-pull chromophores on a β - cyclodextrin assembling unit via covalent linkers. Such supermolecule provides a valuable model for the investigation of confinement effects on the linear and nonlinear optical properties of push-pull chromophores in the condensed phase. Push-pull chromophores display a significant ground-state dipole, thus promoting dipolar interactions that are expected to influence both the conformation and the optical properties of the multichromophoric assembly. In this perspective, the photophysical and nonlinear optical properties of the mutichromophoric bundle were investigated and compared to those of the monomeric chromophore. The absorption, circular dichroism and fluorescence investigations provide evidence that the push-pull chromophores do not behave as isolated independent chromophores within the multichromophoric assembly. The nanoscale supermolecule is hypsochromically and significantly hypochromically shifted with respect to its monomeric analogue. In addition, the close proximity promotes excitonic coupling, as well as excimer formation phenomena. The nanoscopic assembly also shows a very large dipolar moment (μ = 38 D), and a significant molecular first-order hyperpolarizability, which reveal a spontaneous sheaf-type self-arrangement of the dipolar chromophores within the supermolecule. Such chiral hyperpolar nanoassemblies are promising candidates as model systems for nanophotonics.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } A multichromophoric nanoassembly was designed by gathering seven push-pull chromophores on a β - cyclodextrin assembling unit via covalent linkers. Such supermolecule provides a valuable model for the investigation of confinement effects on the linear and nonlinear optical properties of push-pull chromophores in the condensed phase. Push-pull chromophores display a significant ground-state dipole, thus promoting dipolar interactions that are expected to influence both the conformation and the optical properties of the multichromophoric assembly. In this perspective, the photophysical and nonlinear optical properties of the mutichromophoric bundle were investigated and compared to those of the monomeric chromophore. The absorption, circular dichroism and fluorescence investigations provide evidence that the push-pull chromophores do not behave as isolated independent chromophores within the multichromophoric assembly. The nanoscale supermolecule is hypsochromically and significantly hypochromically shifted with respect to its monomeric analogue. In addition, the close proximity promotes excitonic coupling, as well as excimer formation phenomena. The nanoscopic assembly also shows a very large dipolar moment (μ = 38 D), and a significant molecular first-order hyperpolarizability, which reveal a spontaneous sheaf-type self-arrangement of the dipolar chromophores within the supermolecule. Such chiral hyperpolar nanoassemblies are promising candidates as model systems for nanophotonics. |
Raspberry vesicles Article de journal A -L Bernard; M -A Guedeau-Boudeville; L Jullien; J -M Di Meglio Biochimica et Biophysica Acta - Biomembranes, 1567 (SUPPL.), p. 1–5, 2002. @article{Bernard:2002, title = {Raspberry vesicles}, author = {A -L Bernard and M -A Guedeau-Boudeville and L Jullien and J -M Di Meglio}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037164714&doi=10.1016%2fS0005-2736%2802%2900617-X&partnerID=40&md5=56de717378c694caa9099d109ffa604a}, doi = {10.1016/S0005-2736(02)00617-X}, year = {2002}, date = {2002-01-01}, journal = {Biochimica et Biophysica Acta - Biomembranes}, volume = {1567}, number = {SUPPL.}, pages = {1--5}, abstract = {We present a method to control the osmotic stress of giant unilamellar vesicles (GUV) and we report an original shrinkage mode of the vesicles: the volume reduction is accompanied by the formation of inverted daughter vesicles which gives the shrunk vesicles the appearance of raspberries. We analyze this peculiar shrinkage and we propose some physical origins for the observed phenomena. © 2002 Elsevier Science B.V. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We present a method to control the osmotic stress of giant unilamellar vesicles (GUV) and we report an original shrinkage mode of the vesicles: the volume reduction is accompanied by the formation of inverted daughter vesicles which gives the shrunk vesicles the appearance of raspberries. We analyze this peculiar shrinkage and we propose some physical origins for the observed phenomena. © 2002 Elsevier Science B.V. All rights reserved. |
Synthesis and properties of water-soluble gold colloids covalently derivatized with neutral polymer monolayers Article de journal C Mangeney; F Ferrage; I Aujard; V Artzner; L Jullien; O Ouari; E Djouhar Rékai; A Laschewsky; I Vikholm; J W Sadowski Journal of the American Chemical Society, 124 (20), p. 5811–5821, 2002. @article{Mangeney:2002, title = {Synthesis and properties of water-soluble gold colloids covalently derivatized with neutral polymer monolayers}, author = {C Mangeney and F Ferrage and I Aujard and V Artzner and L Jullien and O Ouari and E Djouhar R\'{e}kai and A Laschewsky and I Vikholm and J W Sadowski}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037157185&doi=10.1021%2fja010796h&partnerID=40&md5=0866a4217a986ce8c43d1a84df5645a0}, doi = {10.1021/ja010796h}, year = {2002}, date = {2002-01-01}, journal = {Journal of the American Chemical Society}, volume = {124}, number = {20}, pages = {5811--5821}, abstract = {Citrate-capped gold nanoparticles as well as planar gold surfaces can be efficiently grafted with a covalently attached polymer monolayer a few nanometers thick, by simple contact of the metal surface with dilute aqueous solutions of hydrophilic polymers that are end-capped with disulfide moieties, as shown by UV/vis absorption, dynamic light scattering, and surface plasmon resonance studies. The hydrophilic polymer-coated gold colloids can be freeze-dried and stored as powders that can be subsequently dissolved to yield stable aqueous dispersions, even at very large concentrations. They allow for applying filtrations, gel permeation chromatography, or centrifugation. They do not suffer from undesirable nonspecific adsorption of proteins while allowing the diffusion of small species within the hydrogel surface coating. In addition, specific properties of the original hydrophilic polymers are retained such as a lower critical solution temperature. The latter feature could be useful to enhance optical responses of functionalized gold surfaces toward interaction with various substrates.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Citrate-capped gold nanoparticles as well as planar gold surfaces can be efficiently grafted with a covalently attached polymer monolayer a few nanometers thick, by simple contact of the metal surface with dilute aqueous solutions of hydrophilic polymers that are end-capped with disulfide moieties, as shown by UV/vis absorption, dynamic light scattering, and surface plasmon resonance studies. The hydrophilic polymer-coated gold colloids can be freeze-dried and stored as powders that can be subsequently dissolved to yield stable aqueous dispersions, even at very large concentrations. They allow for applying filtrations, gel permeation chromatography, or centrifugation. They do not suffer from undesirable nonspecific adsorption of proteins while allowing the diffusion of small species within the hydrogel surface coating. In addition, specific properties of the original hydrophilic polymers are retained such as a lower critical solution temperature. The latter feature could be useful to enhance optical responses of functionalized gold surfaces toward interaction with various substrates. |
2001 |
A hyperpolar, multichromophoric cyclodextrin derivative: Synthesis, and linear and nonlinear optical properties Article de journal E D Rekaï; J -B Baudin; L Jullien; I Ledoux; J Zyss; M Blanchard-Desce Chemistry - A European Journal, 7 (20), p. 4395–4402, 2001. @article{Rekai:2001, title = {A hyperpolar, multichromophoric cyclodextrin derivative: Synthesis, and linear and nonlinear optical properties}, author = {E D Reka\"{i} and J -B Baudin and L Jullien and I Ledoux and J Zyss and M Blanchard-Desce}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035887434&doi=10.1002%2f1521-3765%2820011015%297%3a20%3c4395%3a%3aAID-CHEM4395%3e3.0.CO%3b2-W&partnerID=40&md5=a7139d4eee973c3a274eacb7e3bc5041}, doi = {10.1002/1521-3765(20011015)7:20<4395::AID-CHEM4395>3.0.CO;2-W}, year = {2001}, date = {2001-01-01}, journal = {Chemistry - A European Journal}, volume = {7}, number = {20}, pages = {4395--4402}, abstract = {A chiral, highly polar, multichromophoric supermolecule has been designed by gathering seven push-pull chromophores onto a β-cyclodextrin assembling unit through covalent flexible linkers. The photophysical and nonlinear optical properties of this mutichromophoric conical bundle were investigated and compared with those of the monomeric chromophore. The strongly absorbing multichromophoric system combines interesting features: it has a high molecular first-order hyperpolarisability and a very large dipolar moment (μ=38 D) which reveal a self-arrangement of the dipolar chromophores within the supermolecule. The confinement of the push-pull chromophores within the nanoscopic bundle affects their optical properties and promotes interactions: The multichromophoric supermolecule is hypochromically and hypsochromically shifted with respect to its monomeric analogue. In addition, the close proximity promotes excitonic coupling, as well as excimer formation phenomena.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A chiral, highly polar, multichromophoric supermolecule has been designed by gathering seven push-pull chromophores onto a β-cyclodextrin assembling unit through covalent flexible linkers. The photophysical and nonlinear optical properties of this mutichromophoric conical bundle were investigated and compared with those of the monomeric chromophore. The strongly absorbing multichromophoric system combines interesting features: it has a high molecular first-order hyperpolarisability and a very large dipolar moment (μ=38 D) which reveal a self-arrangement of the dipolar chromophores within the supermolecule. The confinement of the push-pull chromophores within the nanoscopic bundle affects their optical properties and promotes interactions: The multichromophoric supermolecule is hypochromically and hypsochromically shifted with respect to its monomeric analogue. In addition, the close proximity promotes excitonic coupling, as well as excimer formation phenomena. |
Evaluation of the separation efficiency of some processes based on interaction of reactive species with a static, spatially periodic potential Article de journal L Jullien; A Lemarchand Journal of Physical Chemistry B, 105 (19), p. 4415–4423, 2001. @article{Jullien:2001a, title = {Evaluation of the separation efficiency of some processes based on interaction of reactive species with a static, spatially periodic potential}, author = {L Jullien and A Lemarchand}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035902352&doi=10.1021%2fjp003532a&partnerID=40&md5=2cf0333f07c719f673415a9141d0597d}, doi = {10.1021/jp003532a}, year = {2001}, date = {2001-01-01}, journal = {Journal of Physical Chemistry B}, volume = {105}, number = {19}, pages = {4415--4423}, abstract = {A procedure is proposed to achieve the selective extraction of any given species from a mixture of closely related molecules exhibiting similar thermodynamic and kinetic properties. It is based on exposing the mixture to a reactive, out-of-equilibrium medium in the presence of a static and spatially periodic potential. Optimal results are obtained upon satisfying stochastic resonance conditions involving the rate constants, the diffusion coefficients of the chemical species, and the characteristic features of the periodic potential. In the case of an electric field, the corresponding relations are shown to be compatible with the current level of experimental achievement.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A procedure is proposed to achieve the selective extraction of any given species from a mixture of closely related molecules exhibiting similar thermodynamic and kinetic properties. It is based on exposing the mixture to a reactive, out-of-equilibrium medium in the presence of a static and spatially periodic potential. Optimal results are obtained upon satisfying stochastic resonance conditions involving the rate constants, the diffusion coefficients of the chemical species, and the characteristic features of the periodic potential. In the case of an electric field, the corresponding relations are shown to be compatible with the current level of experimental achievement. |
Evolution of a chemical system as a trajectory in a phase space. A fruitful picture of the second law Article de journal L Jullien; H Lemarchand Journal of Chemical Education, 78 (6), p. 803–810, 2001. @article{Jullien:2001, title = {Evolution of a chemical system as a trajectory in a phase space. A fruitful picture of the second law}, author = {L Jullien and H Lemarchand}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035366781&partnerID=40&md5=2b72ee0bebcbb0fe5139db918d170852}, year = {2001}, date = {2001-01-01}, journal = {Journal of Chemical Education}, volume = {78}, number = {6}, pages = {803--810}, keywords = {}, pubstate = {published}, tppubtype = {article} } |