2011 |
Savage, Rebecca C; Mativetsky, Jeffrey M; Orgiu, Emanuele ; Palma, Matteo ; Gbabode, Gabin ; Geerts, Yves H; Samori, P Integration of self-assembled discotic-based fibres into field-effect transistors: a comparison of preparation approaches Article de journal Dans: JOURNAL OF MATERIALS CHEMISTRY, 21 (1), p. 206–213, 2011, ISSN: 0959-9428. @article{savage_integration_2011, title = {Integration of self-assembled discotic-based fibres into field-effect transistors: a comparison of preparation approaches}, author = {Savage, Rebecca C. and Mativetsky, Jeffrey M. and Orgiu, Emanuele and Palma, Matteo and Gbabode, Gabin and Geerts, Yves H. and Samori, P.}, doi = {10.1039/c0jm01754j}, issn = {0959-9428}, year = {2011}, date = {2011-01-01}, journal = {JOURNAL OF MATERIALS CHEMISTRY}, volume = {21}, number = {1}, pages = {206--213}, abstract = {The role played by the preparation method upon the morphological and electrical properties of alkyl substituted thio-triphenylene-based self-assembled fibres is explored by comparing two processing approaches, termed solvent vapour annealing (SVA) and solvent induced precipitation (SIP). Both approaches led to fibres having widths of several hundred nanometres and lengths of tens of micrometres. SVA formed isolated fibres which were tens of nanometres high, flat, and tapered at the ends. Conversely, SIP fibres exhibited nearly matching heights and widths, but organized into bundles. Despite these morphological differences, the same intermolecular packing is found by XRD in each type of structure, albeit with differing degrees of long-range order. The fibres were integrated into bottom-gate bottom-contact field-effect transistors. The density and configuration of the fibres with respect to the electrodes and gate dielectric were found to play an important role in the transport properties. SIP devices yielded the highest mobilities compared to SVA and spin-coated devices, largely owing to their high degree of internal order and the possibility to achieve high fibre densities within the transistor channel.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The role played by the preparation method upon the morphological and electrical properties of alkyl substituted thio-triphenylene-based self-assembled fibres is explored by comparing two processing approaches, termed solvent vapour annealing (SVA) and solvent induced precipitation (SIP). Both approaches led to fibres having widths of several hundred nanometres and lengths of tens of micrometres. SVA formed isolated fibres which were tens of nanometres high, flat, and tapered at the ends. Conversely, SIP fibres exhibited nearly matching heights and widths, but organized into bundles. Despite these morphological differences, the same intermolecular packing is found by XRD in each type of structure, albeit with differing degrees of long-range order. The fibres were integrated into bottom-gate bottom-contact field-effect transistors. The density and configuration of the fibres with respect to the electrodes and gate dielectric were found to play an important role in the transport properties. SIP devices yielded the highest mobilities compared to SVA and spin-coated devices, largely owing to their high degree of internal order and the possibility to achieve high fibre densities within the transistor channel. |
Liscio, Andrea ; Veronese, Giulio Paolo ; Treossi, Emanuele ; Suriano, Francesco ; Rossella, Francesco ; Bellani, Vittorio ; Rizzoli, Rita ; Samori, Paolo ; Palermo, Vincenzo Charge transport in graphene-polythiophene blends as studied by Kelvin Probe Force Microscopy and transistor characterization Article de journal Dans: JOURNAL OF MATERIALS CHEMISTRY, 21 (9), p. 2924–2931, 2011, ISSN: 0959-9428. @article{liscio_charge_2011, title = {Charge transport in graphene-polythiophene blends as studied by Kelvin Probe Force Microscopy and transistor characterization}, author = {Liscio, Andrea and Veronese, Giulio Paolo and Treossi, Emanuele and Suriano, Francesco and Rossella, Francesco and Bellani, Vittorio and Rizzoli, Rita and Samori, Paolo and Palermo, Vincenzo}, doi = {10.1039/c0jm02940h}, issn = {0959-9428}, year = {2011}, date = {2011-01-01}, journal = {JOURNAL OF MATERIALS CHEMISTRY}, volume = {21}, number = {9}, pages = {2924--2931}, abstract = {Blends of reduced graphene oxide (RGO) and poly(3-hexylthiophene) (P3HT) are used as the active layer of field-effect transistors (FETs). By using sequential deposition of the two components, the density of RGO sheets can be tuned linearly, thereby modulating their contribution to the charge transport in the transistors, and the onset of charge percolation. The surface potential of RGO, P3HT and source-drain contacts is measured on the nanometric scale with Kelvin Probe Force Microscopy (KPFM), and correlated with the macroscopic performance of the FETs. KPFM is also used to monitor the potential decay along the channel in the working FETs.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Blends of reduced graphene oxide (RGO) and poly(3-hexylthiophene) (P3HT) are used as the active layer of field-effect transistors (FETs). By using sequential deposition of the two components, the density of RGO sheets can be tuned linearly, thereby modulating their contribution to the charge transport in the transistors, and the onset of charge percolation. The surface potential of RGO, P3HT and source-drain contacts is measured on the nanometric scale with Kelvin Probe Force Microscopy (KPFM), and correlated with the macroscopic performance of the FETs. KPFM is also used to monitor the potential decay along the channel in the working FETs. |
Singh, Prabhpreet ; Samori, Cristian ; Toma, Francesca Maria ; Bussy, Cyrill ; Nunes, Antonio ; Al-Jamal, Khuloud T; Menard-Moyon, Cecilia ; Prato, Maurizio ; Kostarelos, Kostas ; Bianco, Alberto Polyamine functionalized carbon nanotubes: synthesis, characterization, cytotoxicity and siRNA binding Article de journal Dans: JOURNAL OF MATERIALS CHEMISTRY, 21 (13), p. 4850–4860, 2011, ISSN: 0959-9428. @article{singh_polyamine_2011, title = {Polyamine functionalized carbon nanotubes: synthesis, characterization, cytotoxicity and siRNA binding}, author = {Singh, Prabhpreet and Samori, Cristian and Toma, Francesca Maria and Bussy, Cyrill and Nunes, Antonio and Al-Jamal, Khuloud T. and Menard-Moyon, Cecilia and Prato, Maurizio and Kostarelos, Kostas and Bianco, Alberto}, doi = {10.1039/c0jm04064a}, issn = {0959-9428}, year = {2011}, date = {2011-01-01}, journal = {JOURNAL OF MATERIALS CHEMISTRY}, volume = {21}, number = {13}, pages = {4850--4860}, abstract = {In this work we have synthesized a new series of cationic carbon nanotubes (CNTs) for siRNA binding. Both single- and multi-walled CNTs have been modified by addition or amidation reaction with short linear polyamine chains including putrescine, spermidine and spermine. All the new conjugates have been characterized with several spectroscopic and microscopic techniques. Their cytotoxic effects have been assessed on human lung carcinoma cell line. Finally, we have analyzed their capacity to bind siRNA towards the development of new carriers for gene silencing applications. The dispersibility properties and the capacity to complex siRNA of the different conjugates were found to be strongly dependent on the position of the functional groups on CNTs (i.e. mainly at the tips following the amidation reaction or on the sidewalls by direct C-C addition).}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this work we have synthesized a new series of cationic carbon nanotubes (CNTs) for siRNA binding. Both single- and multi-walled CNTs have been modified by addition or amidation reaction with short linear polyamine chains including putrescine, spermidine and spermine. All the new conjugates have been characterized with several spectroscopic and microscopic techniques. Their cytotoxic effects have been assessed on human lung carcinoma cell line. Finally, we have analyzed their capacity to bind siRNA towards the development of new carriers for gene silencing applications. The dispersibility properties and the capacity to complex siRNA of the different conjugates were found to be strongly dependent on the position of the functional groups on CNTs (i.e. mainly at the tips following the amidation reaction or on the sidewalls by direct C-C addition). |
Ciesielski, Artur ; Samori, Paolo Supramolecular assembly/reassembly processes: molecular motors and dynamers operating at surfaces Article de journal Dans: NANOSCALE, 3 (4), p. 1397–1410, 2011, ISSN: 2040-3364. @article{ciesielski_supramolecular_2011, title = {Supramolecular assembly/reassembly processes: molecular motors and dynamers operating at surfaces}, author = {Ciesielski, Artur and Samori, Paolo}, doi = {10.1039/c0nr00914h}, issn = {2040-3364}, year = {2011}, date = {2011-01-01}, journal = {NANOSCALE}, volume = {3}, number = {4}, pages = {1397--1410}, abstract = {Among the many significant advances within the field of supramolecular chemistry over the past decades, the development of the so-called “dynamers” features a direct relevance to materials science. Defined as “combinatorial dynamic polymers”, dynamers are constitutional dynamic systems and materials resulting from the application of the principles of supramolecular chemistry to polymer science. Like supramolecular materials in general, dynamers are reversible dynamic multifunctional architectures, capable of modifying their constitution by exchanging, recombining, incorporating components. They may exhibit a variety of novel properties and behave as adaptive materials. In this review we focus on the design of responsive switchable monolayers, i.e. monolayers capable to undergo significant changes in their physical or chemical properties as a result of external stimuli. Scanning tunneling microscopy studies provide direct evidence with a sub-nanometre resolution, on the formation and dynamic response of these self-assembled systems featuring controlled geometries and properties.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Among the many significant advances within the field of supramolecular chemistry over the past decades, the development of the so-called “dynamers” features a direct relevance to materials science. Defined as “combinatorial dynamic polymers”, dynamers are constitutional dynamic systems and materials resulting from the application of the principles of supramolecular chemistry to polymer science. Like supramolecular materials in general, dynamers are reversible dynamic multifunctional architectures, capable of modifying their constitution by exchanging, recombining, incorporating components. They may exhibit a variety of novel properties and behave as adaptive materials. In this review we focus on the design of responsive switchable monolayers, i.e. monolayers capable to undergo significant changes in their physical or chemical properties as a result of external stimuli. Scanning tunneling microscopy studies provide direct evidence with a sub-nanometre resolution, on the formation and dynamic response of these self-assembled systems featuring controlled geometries and properties. |
Ciesielski, Artur ; Cadeddu, Andrea ; Palma, Carlos-Andres ; Gorczynski, Adam ; Patroniak, Violetta ; Cecchini, Marco ; Samori, Paolo Self-templating 2D supramolecular networks: a new avenue to reach control over a bilayer formation Article de journal Dans: NANOSCALE, 3 (10), p. 4125–4129, 2011, ISSN: 2040-3364. @article{ciesielski_self-templating_2011, title = {Self-templating 2D supramolecular networks: a new avenue to reach control over a bilayer formation}, author = {Ciesielski, Artur and Cadeddu, Andrea and Palma, Carlos-Andres and Gorczynski, Adam and Patroniak, Violetta and Cecchini, Marco and Samori, Paolo}, doi = {10.1039/c1nr10485c}, issn = {2040-3364}, year = {2011}, date = {2011-01-01}, journal = {NANOSCALE}, volume = {3}, number = {10}, pages = {4125--4129}, abstract = {One of the greatest challenges in 2D self-assembly at interfaces is the ability to grow spatially controlled supramolecular motifs in the third dimension, exploiting the surface as a template. In this manuscript a concentration-dependent study by scanning tunneling microscopy at the solid-liquid interface, corroborated by Molecular Dynamics (MD) simulations, reveals the controlled generation of mono- or bilayer self-assembled Kagome networks based on a fully planar tetracarboxylic acid derivative. By programming the backbone of the molecular building blocks, we present a strategy to gain spatial control over the adlayer structure by conferring self-templating capacity to the 2D self-assembled network.}, keywords = {}, pubstate = {published}, tppubtype = {article} } One of the greatest challenges in 2D self-assembly at interfaces is the ability to grow spatially controlled supramolecular motifs in the third dimension, exploiting the surface as a template. In this manuscript a concentration-dependent study by scanning tunneling microscopy at the solid-liquid interface, corroborated by Molecular Dynamics (MD) simulations, reveals the controlled generation of mono- or bilayer self-assembled Kagome networks based on a fully planar tetracarboxylic acid derivative. By programming the backbone of the molecular building blocks, we present a strategy to gain spatial control over the adlayer structure by conferring self-templating capacity to the 2D self-assembled network. |
Crivillers, N; Liscio, A; Di Stasio, F; Van Dyck, C; Osella, S; Cornil, D; Mian, S; Lazzerini, G M; Fenwick, O; Orgiu, E; Reinders, F; Braun, S; Fahlman, M; Mayor, M; Cornil, J; Palermo, V; Cacialli, F; Samori, P Photoinduced work function changes by isomerization of a densely packed azobenzene-based SAM on Au: a joint experimental and theoretical study Article de journal Dans: PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 13 (32), p. 14302–14310, 2011, ISSN: 1463-9076. @article{crivillers_photoinduced_2011, title = {Photoinduced work function changes by isomerization of a densely packed azobenzene-based SAM on Au: a joint experimental and theoretical study}, author = {Crivillers, N. and Liscio, A. and Di Stasio, F. and Van Dyck, C. and Osella, S. and Cornil, D. and Mian, S. and Lazzerini, G. M. and Fenwick, O. and Orgiu, E. and Reinders, F. and Braun, S. and Fahlman, M. and Mayor, M. and Cornil, J. and Palermo, V. and Cacialli, F. and Samori, P.}, doi = {10.1039/c1cp20851a}, issn = {1463-9076}, year = {2011}, date = {2011-01-01}, journal = {PHYSICAL CHEMISTRY CHEMICAL PHYSICS}, volume = {13}, number = {32}, pages = {14302--14310}, abstract = {Responsive monolayers are key building blocks for future applications in organic and molecular electronics in particular because they hold potential for tuning the physico-chemical properties of interfaces, including their energetics. Here we study a photochromic SAM based on a conjugated azobenzene derivative and its influence on the gold work function (Phi(Au)) when chemisorbed on its surface. In particular we show that the Phi(Au) can be modulated with external stimuli by controlling the azobenzene trans/cis isomerization process. This phenomenon is characterized experimentally by four different techniques, kelvin probe, kelvin probe force microscopy, electroabsorption spectroscopy and ultraviolet photoelectron spectroscopy. The use of different techniques implies exposing the SAM to different measurement conditions and different preparation methods, which, remarkably, do not alter the observed work function change (Phi(trans)-Phi(cis)). Theoretical calculations provided a complementary insight crucial to attain a deeper knowledge on the origin of the work function photo-modulation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Responsive monolayers are key building blocks for future applications in organic and molecular electronics in particular because they hold potential for tuning the physico-chemical properties of interfaces, including their energetics. Here we study a photochromic SAM based on a conjugated azobenzene derivative and its influence on the gold work function (Phi(Au)) when chemisorbed on its surface. In particular we show that the Phi(Au) can be modulated with external stimuli by controlling the azobenzene trans/cis isomerization process. This phenomenon is characterized experimentally by four different techniques, kelvin probe, kelvin probe force microscopy, electroabsorption spectroscopy and ultraviolet photoelectron spectroscopy. The use of different techniques implies exposing the SAM to different measurement conditions and different preparation methods, which, remarkably, do not alter the observed work function change (Phi(trans)-Phi(cis)). Theoretical calculations provided a complementary insight crucial to attain a deeper knowledge on the origin of the work function photo-modulation. |
Fylaktakidou, Konstantina C; Duarte, Carolina D; Koumbis, Alexandros E; Nicolau, Claude ; Lehn, Jean-Marie Polyphosphates and Pyrophosphates of Hexopyranoses as Allosteric Effectors of Human Hemoglobin: Synthesis, Molecular Recognition, and Effect on Oxygen Release Article de journal Dans: CHEMMEDCHEM, 6 (1), p. 153–168, 2011, ISSN: 1860-7179. @article{fylaktakidou_polyphosphates_2011-1, title = {Polyphosphates and Pyrophosphates of Hexopyranoses as Allosteric Effectors of Human Hemoglobin: Synthesis, Molecular Recognition, and Effect on Oxygen Release}, author = {Fylaktakidou, Konstantina C. and Duarte, Carolina D. and Koumbis, Alexandros E. and Nicolau, Claude and Lehn, Jean-Marie}, doi = {10.1002/cmdc.201000366}, issn = {1860-7179}, year = {2011}, date = {2011-01-01}, journal = {CHEMMEDCHEM}, volume = {6}, number = {1}, pages = {153--168}, abstract = {Polyphosphorylated and perphosphorylated hexopyranose monosaccharides and disaccharides were synthesized from parent or partially protected carbohydrates as potential allosteric effectors of hemoglobin. A study toward the construction of seven- and eight-membered cyclic pyrophosphates was also performed on the sugars which had the proper orientation, protection, and number of phosphates. All final compounds were tested for their efficiency on oxygen release from human hemoglobin. Several compounds presented higher potency than myo-inositol hexakisphosphate, which is the most efficient of the known allosteric effectors of hemoglobin. Structure-activity relationships were analyzed. The affinity and efficiency depend on the number of phosphates attached to the carbohydrate skeleton and are related primarily to the number of negative charges present. Other effects operate, but play a lesser role.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Polyphosphorylated and perphosphorylated hexopyranose monosaccharides and disaccharides were synthesized from parent or partially protected carbohydrates as potential allosteric effectors of hemoglobin. A study toward the construction of seven- and eight-membered cyclic pyrophosphates was also performed on the sugars which had the proper orientation, protection, and number of phosphates. All final compounds were tested for their efficiency on oxygen release from human hemoglobin. Several compounds presented higher potency than myo-inositol hexakisphosphate, which is the most efficient of the known allosteric effectors of hemoglobin. Structure-activity relationships were analyzed. The affinity and efficiency depend on the number of phosphates attached to the carbohydrate skeleton and are related primarily to the number of negative charges present. Other effects operate, but play a lesser role. |
Koumbis, Alexandros E; Duarte, Carolina D; Nicolau, Claude ; Lehn, Jean-Marie Tetrakisphosphates and Bispyrophosphates of myo-Inositol Derivatives as Allosteric Effectors of Human Hemoglobin: Synthesis, Molecular Recognition, and Oxygen Release Article de journal Dans: CHEMMEDCHEM, 6 (1), p. 169–180, 2011, ISSN: 1860-7179. @article{koumbis_tetrakisphosphates_2011, title = {Tetrakisphosphates and Bispyrophosphates of myo-Inositol Derivatives as Allosteric Effectors of Human Hemoglobin: Synthesis, Molecular Recognition, and Oxygen Release}, author = {Koumbis, Alexandros E. and Duarte, Carolina D. and Nicolau, Claude and Lehn, Jean-Marie}, doi = {10.1002/cmdc.201000421}, issn = {1860-7179}, year = {2011}, date = {2011-01-01}, journal = {CHEMMEDCHEM}, volume = {6}, number = {1}, pages = {169--180}, abstract = {Various 2,5- and 1,4-substituted and unsubstituted myo-inositol tetrakisphosphates and bispyrophosphates were prepared following a general synthetic pathway. All final compounds were tested for their capability to induce oxygen release from human hemoglobin. Most of these proved to be efficient allosteric effectors, with similar affinities for hemoglobin to that of myo-inositol hexakisphosphate, which is one of the best known allosteric effectors of hemoglobin. The efficacy was found to be higher for free phosphates than pyrophosphates. As allosteric Hb effectors, these compounds enable enhanced oxygen release. These effects increase with the strength of Hb binding and correspond primarily to electrostatic interactions. Stereochemical and steric factors also play a significant but secondary role in molecular recognition. In view of the central role played by hypoxia in numerous types of diseases, the exploration of myo-inositol phosphate derivatives represents an important avenue in the search for substances which act on the oxygenation status of tissues and may have significant potential in the discovery and development of novel drug candidates.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Various 2,5- and 1,4-substituted and unsubstituted myo-inositol tetrakisphosphates and bispyrophosphates were prepared following a general synthetic pathway. All final compounds were tested for their capability to induce oxygen release from human hemoglobin. Most of these proved to be efficient allosteric effectors, with similar affinities for hemoglobin to that of myo-inositol hexakisphosphate, which is one of the best known allosteric effectors of hemoglobin. The efficacy was found to be higher for free phosphates than pyrophosphates. As allosteric Hb effectors, these compounds enable enhanced oxygen release. These effects increase with the strength of Hb binding and correspond primarily to electrostatic interactions. Stereochemical and steric factors also play a significant but secondary role in molecular recognition. In view of the central role played by hypoxia in numerous types of diseases, the exploration of myo-inositol phosphate derivatives represents an important avenue in the search for substances which act on the oxygenation status of tissues and may have significant potential in the discovery and development of novel drug candidates. |
Parizel, Nathalie ; Ramirez, Juan ; Burg, Christophe ; Choua, Sylvie ; Bernard, Maxime ; Gambarelli, Serge ; Maurel, Vincent ; Brelot, Lydia ; Lehn, Jean-Marie ; Turek, Philippe ; Stadler, Adrian-Mihail Modulation of self-assembly and magnetism of Cu(II) grids in solution Article de journal Dans: CHEMICAL COMMUNICATIONS, 47 (39), p. 10951–10953, 2011, ISSN: 1359-7345. @article{parizel_modulation_2011, title = {Modulation of self-assembly and magnetism of Cu(II) grids in solution}, author = {Parizel, Nathalie and Ramirez, Juan and Burg, Christophe and Choua, Sylvie and Bernard, Maxime and Gambarelli, Serge and Maurel, Vincent and Brelot, Lydia and Lehn, Jean-Marie and Turek, Philippe and Stadler, Adrian-Mihail}, doi = {10.1039/c0cc01612h}, issn = {1359-7345}, year = {2011}, date = {2011-01-01}, journal = {CHEMICAL COMMUNICATIONS}, volume = {47}, number = {39}, pages = {10951--10953}, abstract = {Depending on the Cu(II)/ligand molar ratio, a pyrimidine-based ligand generates a tetranuclear grid (1/1) or a dinuclear stick (2/1). EPR, MS and visible spectroscopy studies suggest that dilution produces partial dissociation of the grid in solution. Replacement of 2-H-pyrimidine by a 2-phenyl-triazine unit prevents the dissociation of the grid. All these factors influence the magnetic properties of the architectures herein involved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Depending on the Cu(II)/ligand molar ratio, a pyrimidine-based ligand generates a tetranuclear grid (1/1) or a dinuclear stick (2/1). EPR, MS and visible spectroscopy studies suggest that dilution produces partial dissociation of the grid in solution. Replacement of 2-H-pyrimidine by a 2-phenyl-triazine unit prevents the dissociation of the grid. All these factors influence the magnetic properties of the architectures herein involved. |
Chaur, Manuel N; Collado, Daniel ; Lehn, Jean-Marie Configurational and Constitutional Information Storage: Multiple Dynamics in Systems Based on Pyridyl and Acyl Hydrazones Article de journal Dans: CHEMISTRY-A EUROPEAN JOURNAL, 17 (1), p. 248–258, 2011, ISSN: 0947-6539. @article{chaur_configurational_2011, title = {Configurational and Constitutional Information Storage: Multiple Dynamics in Systems Based on Pyridyl and Acyl Hydrazones}, author = {Chaur, Manuel N. and Collado, Daniel and Lehn, Jean-Marie}, doi = {10.1002/chem.201002308}, issn = {0947-6539}, year = {2011}, date = {2011-01-01}, journal = {CHEMISTRY-A EUROPEAN JOURNAL}, volume = {17}, number = {1}, pages = {248--258}, abstract = {The C=N group of hydrazones can undergo E/Z isomerization both photochemically and thermally, allowing the generation of a closed process that can be tuned by either of these two physical stimuli. On the other hand, hydrazine-exchange reactions enable a constitutional change in a given hydrazone. The two classes of processes: 1) configurational (physically stimulated) and 2) constitutional (chemically stimulated) give access to short-term and long-term information storage, respectively. Such transformations are reported herein for two hydrazones (bis-pyridyl hydrazone and 2-pyridinecarboxaldehyde phenylhydrazone) that undergo a closed, chemically or physically driven process, and, in addition, can be locked or unlocked at will by metal-ion coordination or removal. These features also extend to acyl hydrazones derived from 2-pyridinecarboxaldehyde. Similarly to the terpydine-like hydrazones, such acyl hydrazones can undergo both constitutional and configurational changes, as well as metal-ion coordination. All these types of hydrazones represent dynamic systems capable of acting as multiple state molecular devices, in which the presence of coordination sites furthermore allows the metal ion-controlled locking and unlocking of the interconversion of the different states.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The C=N group of hydrazones can undergo E/Z isomerization both photochemically and thermally, allowing the generation of a closed process that can be tuned by either of these two physical stimuli. On the other hand, hydrazine-exchange reactions enable a constitutional change in a given hydrazone. The two classes of processes: 1) configurational (physically stimulated) and 2) constitutional (chemically stimulated) give access to short-term and long-term information storage, respectively. Such transformations are reported herein for two hydrazones (bis-pyridyl hydrazone and 2-pyridinecarboxaldehyde phenylhydrazone) that undergo a closed, chemically or physically driven process, and, in addition, can be locked or unlocked at will by metal-ion coordination or removal. These features also extend to acyl hydrazones derived from 2-pyridinecarboxaldehyde. Similarly to the terpydine-like hydrazones, such acyl hydrazones can undergo both constitutional and configurational changes, as well as metal-ion coordination. All these types of hydrazones represent dynamic systems capable of acting as multiple state molecular devices, in which the presence of coordination sites furthermore allows the metal ion-controlled locking and unlocking of the interconversion of the different states. |
Brelot, Lydia ; Cao, Xiao-yu ; Harrowfield, Jack ; Lehn, Jean-Marie ; Rissanen, Kari ; Russo, Luca A new hydrogen bonding motif involved in self-recognition in the solid state by functionalised macrocycles Article de journal Dans: CRYSTENGCOMM, 13 (7), p. 2346–2349, 2011, ISSN: 1466-8033. @article{brelot_new_2011, title = {A new hydrogen bonding motif involved in self-recognition in the solid state by functionalised macrocycles}, author = {Brelot, Lydia and Cao, Xiao-yu and Harrowfield, Jack and Lehn, Jean-Marie and Rissanen, Kari and Russo, Luca}, doi = {10.1039/c0ce00814a}, issn = {1466-8033}, year = {2011}, date = {2011-01-01}, journal = {CRYSTENGCOMM}, volume = {13}, number = {7}, pages = {2346--2349}, abstract = {Self-recognition within the crystal lattices of three functionalised macrocycles results in the formation of arrays of remarkably similar hermaphroditic pairs of macrocycles. In the case of two of the macrocycles containing acylhydrazine substituents, a hitherto unknown recognition pattern is found in the interaction of the hydrazine moiety with crown-ether oxygen atoms.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Self-recognition within the crystal lattices of three functionalised macrocycles results in the formation of arrays of remarkably similar hermaphroditic pairs of macrocycles. In the case of two of the macrocycles containing acylhydrazine substituents, a hitherto unknown recognition pattern is found in the interaction of the hydrazine moiety with crown-ether oxygen atoms. |
Stefankiewicz, Artur R; Harrowfield, Jack ; Madalan, Augustin ; Rissanen, Kari ; Sobolev, Alexandre N; Lehn, Jean-Marie Structural and metallo selectivity in the assembly of [2 x 2] grid-type metallosupramolecular species: Mechanisms and kinetic control Article de journal Dans: DALTON TRANSACTIONS, 40 (45), p. 12320–12332, 2011, ISSN: 1477-9226. @article{stefankiewicz_structural_2011, title = {Structural and metallo selectivity in the assembly of [2 x 2] grid-type metallosupramolecular species: Mechanisms and kinetic control}, author = {Stefankiewicz, Artur R. and Harrowfield, Jack and Madalan, Augustin and Rissanen, Kari and Sobolev, Alexandre N. and Lehn, Jean-Marie}, doi = {10.1039/c1dt11226k}, issn = {1477-9226}, year = {2011}, date = {2011-01-01}, journal = {DALTON TRANSACTIONS}, volume = {40}, number = {45}, pages = {12320--12332}, abstract = {An unsymmetrical bis(tridentate) ligand LH in which one binding site can be readily deprotonated forms a kinetically inert [Co(III)L-2](+) complex which can be used as a “corner” species for the “Coupe du Roi” assembly of trans, trans-[Co2M2L4](6+) metallogrids (M = Fe(II), Co(II), Cu(II), Zn(II)). In the mixed Co(III)/Co(II) species, the oxidation states appear to be localised. In solution, the ligand LH forms octacationic, homometallic [2 x 2] grids with the individual labile metal ions Fe(II), Co(II), Cu(II), Zn(II), seemingly as mixtures of all possible isomers arising from the unsymmetrical nature of the ligand. In the solid state, however, [Zn4L4](CF3SO3)(8)center dot 4CH(3)CN crystallises as a single species where the cation has S-4 symmetry. This stereoselectivity in the crystalline lattice is associated with interactions between the cation and triflate anions which can again be analysed in terms of the Coupe du Roi concept.}, keywords = {}, pubstate = {published}, tppubtype = {article} } An unsymmetrical bis(tridentate) ligand LH in which one binding site can be readily deprotonated forms a kinetically inert [Co(III)L-2](+) complex which can be used as a “corner” species for the “Coupe du Roi” assembly of trans, trans-[Co2M2L4](6+) metallogrids (M = Fe(II), Co(II), Cu(II), Zn(II)). In the mixed Co(III)/Co(II) species, the oxidation states appear to be localised. In solution, the ligand LH forms octacationic, homometallic [2 x 2] grids with the individual labile metal ions Fe(II), Co(II), Cu(II), Zn(II), seemingly as mixtures of all possible isomers arising from the unsymmetrical nature of the ligand. In the solid state, however, [Zn4L4](CF3SO3)(8)center dot 4CH(3)CN crystallises as a single species where the cation has S-4 symmetry. This stereoselectivity in the crystalline lattice is associated with interactions between the cation and triflate anions which can again be analysed in terms of the Coupe du Roi concept. |
Buchs (Nee Levrand), Barbara ; Fieber, Wolfgang ; Vigouroux-Elie, Florence ; Sreenivasachary, Nampally ; Lehn, Jean-Marie ; Herrmann, Andreas Release of bioactive volatiles from supramolecular hydrogels: influence of reversible acylhydrazone formation on gel stability and volatile compound evaporation Article de journal Dans: ORGANIC & BIOMOLECULAR CHEMISTRY, 9 (8), p. 2906–2919, 2011, ISSN: 1477-0520. @article{buchs_nee_levrand_release_2011, title = {Release of bioactive volatiles from supramolecular hydrogels: influence of reversible acylhydrazone formation on gel stability and volatile compound evaporation}, author = {Buchs (Nee Levrand), Barbara and Fieber, Wolfgang and Vigouroux-Elie, Florence and Sreenivasachary, Nampally and Lehn, Jean-Marie and Herrmann, Andreas}, doi = {10.1039/c0ob01139h}, issn = {1477-0520}, year = {2011}, date = {2011-01-01}, journal = {ORGANIC & BIOMOLECULAR CHEMISTRY}, volume = {9}, number = {8}, pages = {2906--2919}, abstract = {In the presence of alkali metal cations, guanosine-5'-hydrazide (1) forms stable supramolecular hydrogels by selective self-assembly into a G-quartet structure. Besides being physically trapped inside the gel structure, biologically active aldehydes or ketones can also reversibly react with the free hydrazide functions at the periphery of the G-quartet to form acylhydrazones. This particularity makes the hydrogels interesting as delivery systems for the slow release of bioactive carbonyl derivatives. Hydrogels formed from 1 were found to be significantly more stable than those obtained from guanosine. Both physical inclusion of bioactive volatiles and reversible hydrazone formation could be demonstrated by indirect methods. Gel stabilities were measured by oscillating disk rheology measurements, which showed that thermodynamic equilibration of the gel is slow and requires several cooling and heating cycles. Furthermore, combining the rheology data with dynamic headspace analysis of fragrance evaporation suggested that reversible hydrazone formation of some carbonyl compounds influences the release of volatiles, whereas the absolute stability of the gel seemed to have no influence on the evaporation rates.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In the presence of alkali metal cations, guanosine-5'-hydrazide (1) forms stable supramolecular hydrogels by selective self-assembly into a G-quartet structure. Besides being physically trapped inside the gel structure, biologically active aldehydes or ketones can also reversibly react with the free hydrazide functions at the periphery of the G-quartet to form acylhydrazones. This particularity makes the hydrogels interesting as delivery systems for the slow release of bioactive carbonyl derivatives. Hydrogels formed from 1 were found to be significantly more stable than those obtained from guanosine. Both physical inclusion of bioactive volatiles and reversible hydrazone formation could be demonstrated by indirect methods. Gel stabilities were measured by oscillating disk rheology measurements, which showed that thermodynamic equilibration of the gel is slow and requires several cooling and heating cycles. Furthermore, combining the rheology data with dynamic headspace analysis of fragrance evaporation suggested that reversible hydrazone formation of some carbonyl compounds influences the release of volatiles, whereas the absolute stability of the gel seemed to have no influence on the evaporation rates. |
Delanoe-Ayari, Helene ; Brevier, Julien ; Riveline, Daniel Scaling concepts in cell physics: paradigms for cell adhesion Article de journal Dans: SOFT MATTER, 7 (3), p. 824–829, 2011, ISSN: 1744-683X. @article{delanoe-ayari_scaling_2011, title = {Scaling concepts in cell physics: paradigms for cell adhesion}, author = {Delanoe-Ayari, Helene and Brevier, Julien and Riveline, Daniel}, doi = {10.1039/c0sm00293c}, issn = {1744-683X}, year = {2011}, date = {2011-01-01}, journal = {SOFT MATTER}, volume = {7}, number = {3}, pages = {824--829}, abstract = {Shapes and lengths are treated differently in cell biology and in physics. In cell biology, morphology is considered a powerful read-out for estimating protein activities and for classifying pathways. Spatial features are often viewed as binary signals, on or off, active or non-active. In contrast, in condensed matter physics, spatial dimensions are generally derived quantitatively with scaling relations using the mechanical properties of matter. This powerful approach allows predicting scales in new experiments. Here, we applied such a type of scaling method for specific organelles in cells: the cell adhesion structures. We show that simple relations allow one to derive measured lengths in a variety of situations and proteic complexes; if the molecular detail is not at play in such an approach, the mesoscopic equations allow one to quantitatively match the experimental observations. Based on these relations, we also predict simple rules for varying lengths of contacts and distances between contacts in future experiments.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Shapes and lengths are treated differently in cell biology and in physics. In cell biology, morphology is considered a powerful read-out for estimating protein activities and for classifying pathways. Spatial features are often viewed as binary signals, on or off, active or non-active. In contrast, in condensed matter physics, spatial dimensions are generally derived quantitatively with scaling relations using the mechanical properties of matter. This powerful approach allows predicting scales in new experiments. Here, we applied such a type of scaling method for specific organelles in cells: the cell adhesion structures. We show that simple relations allow one to derive measured lengths in a variety of situations and proteic complexes; if the molecular detail is not at play in such an approach, the mesoscopic equations allow one to quantitatively match the experimental observations. Based on these relations, we also predict simple rules for varying lengths of contacts and distances between contacts in future experiments. |
Kruse, Karsten ; Riveline, Daniel SPONTANEOUS MECHANICAL OSCILLATIONS: IMPLICATIONS FOR DEVELOPING ORGANISMS incollection Dans: {Labouesse, M} (Ed.): FORCES AND TENSION IN DEVELOPMENT, 95 , p. 67–91, 2011, ISBN: 978-0-12-385065-2. @incollection{kruse_spontaneous_2011, title = {SPONTANEOUS MECHANICAL OSCILLATIONS: IMPLICATIONS FOR DEVELOPING ORGANISMS}, author = {Kruse, Karsten and Riveline, Daniel}, editor = {{Labouesse, M}}, doi = {10.1016/B978-0-12-385065-2.00003-7}, isbn = {978-0-12-385065-2}, year = {2011}, date = {2011-01-01}, booktitle = {FORCES AND TENSION IN DEVELOPMENT}, volume = {95}, pages = {67--91}, series = {Current Topics in Developmental Biology}, abstract = {Major transformations of cells during embryonic development are traditionally associated with the activation or inhibition of genes and with protein modifications. The contributions of mechanical properties intrinsic to the matter an organism is made of, however, are often overlooked. The emerging field “physics of living matter” is addressing active material properties of the cytoskeleton and tissues like the spontaneous generation of stress, which may lead to shape changes and tissue flows, and their implications for embryonic development. Here, we discuss spontaneous mechanical oscillations to present some basic elements for understanding this physics, and we illustrate its application to developing embryos. We highlight the role of state diagrams to quantitatively probe the significance of the corresponding physical concepts for understanding development.}, keywords = {}, pubstate = {published}, tppubtype = {incollection} } Major transformations of cells during embryonic development are traditionally associated with the activation or inhibition of genes and with protein modifications. The contributions of mechanical properties intrinsic to the matter an organism is made of, however, are often overlooked. The emerging field “physics of living matter” is addressing active material properties of the cytoskeleton and tissues like the spontaneous generation of stress, which may lead to shape changes and tissue flows, and their implications for embryonic development. Here, we discuss spontaneous mechanical oscillations to present some basic elements for understanding this physics, and we illustrate its application to developing embryos. We highlight the role of state diagrams to quantitatively probe the significance of the corresponding physical concepts for understanding development. |
Beyler, Maryline ; Heitz, Valerie ; Sauvage, Jean-Pierre A noncovalently assembled porphyrinic catenane consisting of two interlocking [43]-membered rings Article de journal Dans: NEW JOURNAL OF CHEMISTRY, 35 (8), p. 1751–1757, 2011, ISSN: 1144-0546. @article{beyler_noncovalently_2011, title = {A noncovalently assembled porphyrinic catenane consisting of two interlocking [43]-membered rings}, author = {Beyler, Maryline and Heitz, Valerie and Sauvage, Jean-Pierre}, doi = {10.1039/c1nj20294d}, issn = {1144-0546}, year = {2011}, date = {2011-01-01}, journal = {NEW JOURNAL OF CHEMISTRY}, volume = {35}, number = {8}, pages = {1751--1757}, abstract = {A new macrocycle and the corresponding [2]catenane were prepared quantitatively from relatively large organic fragments using coordination chemistry bonds only (Zn-N bonds for the ring and Cu-N bonds for the catenane). The two constitutive macrorings of the [2]catenane are 43-membered rings. The organic components consist of a bis-Zn porphyrin and a 1,10-phenanthroline derivative, both fragments being significantly larger than those previously used for making related compounds. The catenane was assembled in two steps from a bis-Zn porphyrin and a 2,9-di(4 `'-pyridyl-4'-phenyl)-1,10-phenanthroline. In a first step the entwined copper(I) complex of the phenanthroline derivative was formed via Cu(I)-N interactions. Subsequently, a double ring closing reaction was performed by coordination of two equivalents of bis-Zn porphyrin to the entwined copper(I) complex. The tetraporphyrinic [2]catenane was thus obtained thanks to the formation of four Zn(II)-pyridine bonds. It has a high association constant, 4 x 10(10) M-2, due to the good geometrical fit between the constituents.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A new macrocycle and the corresponding [2]catenane were prepared quantitatively from relatively large organic fragments using coordination chemistry bonds only (Zn-N bonds for the ring and Cu-N bonds for the catenane). The two constitutive macrorings of the [2]catenane are 43-membered rings. The organic components consist of a bis-Zn porphyrin and a 1,10-phenanthroline derivative, both fragments being significantly larger than those previously used for making related compounds. The catenane was assembled in two steps from a bis-Zn porphyrin and a 2,9-di(4 `'-pyridyl-4'-phenyl)-1,10-phenanthroline. In a first step the entwined copper(I) complex of the phenanthroline derivative was formed via Cu(I)-N interactions. Subsequently, a double ring closing reaction was performed by coordination of two equivalents of bis-Zn porphyrin to the entwined copper(I) complex. The tetraporphyrinic [2]catenane was thus obtained thanks to the formation of four Zn(II)-pyridine bonds. It has a high association constant, 4 x 10(10) M-2, due to the good geometrical fit between the constituents. |
Durola, Fabien ; Lux, Jacques ; Sauvage, Jean-Pierre ; Wenger, Oliver S Bigger, better, faster: molecular shuttles with sterically non-hindering biisoquinoline chelates Article de journal Dans: SUPRAMOLECULAR CHEMISTRY, 23 (1-2, SI), p. 42–52, 2011, ISSN: 1061-0278. @article{durola_bigger_2011, title = {Bigger, better, faster: molecular shuttles with sterically non-hindering biisoquinoline chelates}, author = {Durola, Fabien and Lux, Jacques and Sauvage, Jean-Pierre and Wenger, Oliver S.}, doi = {10.1080/10610278.2010.510189}, issn = {1061-0278}, year = {2011}, date = {2011-01-01}, journal = {SUPRAMOLECULAR CHEMISTRY}, volume = {23}, number = {1-2, SI}, pages = {42--52}, abstract = {In the past, a variety of mechanically interlocked systems such as catenanes and rotaxanes were constructed on the basis of Cu(I) coordination chemistry and endocyclic 1,10-phenanthroline ligands. This review reports on the coordination chemistry of a new family of endocyclic bidentate chelators that are sterically non-hindering, namely 8,8'-diaryl-substituted 3,3'-biisoquinolines. These ligands allow the construction of new multi-component assemblies that are inaccessible with the previously investigated 1,10-phenanthrolines. On the one hand, the sterically non-hindering nature of the new endocyclic chelators makes three-component entanglements around octahedral metal centres such as iron(II), cobalt(II) and ruthenium(II) readily possible. On the other hand, it permits the construction of copper-based molecular shuttles that exhibit shuttling kinetics that excels over those of previously investigated analogous systems with 1,10-phenanthrolines. Thus, within this class of molecular machines, a bigger chelator leads to faster molecular movement, i.e. to a better performance of the molecular machine.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In the past, a variety of mechanically interlocked systems such as catenanes and rotaxanes were constructed on the basis of Cu(I) coordination chemistry and endocyclic 1,10-phenanthroline ligands. This review reports on the coordination chemistry of a new family of endocyclic bidentate chelators that are sterically non-hindering, namely 8,8'-diaryl-substituted 3,3'-biisoquinolines. These ligands allow the construction of new multi-component assemblies that are inaccessible with the previously investigated 1,10-phenanthrolines. On the one hand, the sterically non-hindering nature of the new endocyclic chelators makes three-component entanglements around octahedral metal centres such as iron(II), cobalt(II) and ruthenium(II) readily possible. On the other hand, it permits the construction of copper-based molecular shuttles that exhibit shuttling kinetics that excels over those of previously investigated analogous systems with 1,10-phenanthrolines. Thus, within this class of molecular machines, a bigger chelator leads to faster molecular movement, i.e. to a better performance of the molecular machine. |
Boyle, Megan M; Forgan, Ross S; Friedman, Douglas C; Gassensmith, Jeremiah J; Smaldone, Ronald A; Stoddart, Fraser J; Sauvage, Jean-Pierre Donor-acceptor molecular figures-of-eight Article de journal Dans: CHEMICAL COMMUNICATIONS, 47 (43), p. 11870–11872, 2011, ISSN: 1359-7345. @article{boyle_donor-acceptor_2011, title = {Donor-acceptor molecular figures-of-eight}, author = {Boyle, Megan M. and Forgan, Ross S. and Friedman, Douglas C. and Gassensmith, Jeremiah J. and Smaldone, Ronald A. and Stoddart, J. Fraser and Sauvage, Jean-Pierre}, doi = {10.1039/c1cc15333a}, issn = {1359-7345}, year = {2011}, date = {2011-01-01}, journal = {CHEMICAL COMMUNICATIONS}, volume = {47}, number = {43}, pages = {11870--11872}, abstract = {The intermolecular template-directed synthesis, separation and characterisation of two constitutional isomers that are self-complexing donor-acceptor [1] rotaxanes has been achieved by click chemistry, starting from a pi-electron deficient tetracationic cyclophane containing two azide functions and a pi-electron rich 1,5-dioxynaphthalene-containing polyether chain terminated by propargyl groups.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The intermolecular template-directed synthesis, separation and characterisation of two constitutional isomers that are self-complexing donor-acceptor [1] rotaxanes has been achieved by click chemistry, starting from a pi-electron deficient tetracationic cyclophane containing two azide functions and a pi-electron rich 1,5-dioxynaphthalene-containing polyether chain terminated by propargyl groups. |
Huang, Kuo-Ting ; Gorska, Katarzyna ; Alvarez, Susana ; Barluenga, Sofia ; Winssinger, Nicolas Combinatorial Self-Assembly of Glycan Fragments into Microarrays Article de journal Dans: CHEMBIOCHEM, 12 (1), p. 56–60, 2011, ISSN: 1439-4227. @article{huang_combinatorial_2011, title = {Combinatorial Self-Assembly of Glycan Fragments into Microarrays}, author = {Huang, Kuo-Ting and Gorska, Katarzyna and Alvarez, Susana and Barluenga, Sofia and Winssinger, Nicolas}, doi = {10.1002/cbic.201000567}, issn = {1439-4227}, year = {2011}, date = {2011-01-01}, journal = {CHEMBIOCHEM}, volume = {12}, number = {1}, pages = {56--60}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Collin, Jean-Paul ; Durot, Stephanie ; Keller, Michel ; Sauvage, Jean-Pierre ; Trolez, Yann ; Cetina, Mario ; Rissanen, Kari Synthesis of [5]Rotaxanes Containing Bi- and Tridentate Coordination Sites in the Axis Article de journal Dans: CHEMISTRY-A EUROPEAN JOURNAL, 17 (3), p. 947–957, 2011, ISSN: 0947-6539. @article{collin_synthesis_2011, title = {Synthesis of [5]Rotaxanes Containing Bi- and Tridentate Coordination Sites in the Axis}, author = {Collin, Jean-Paul and Durot, Stephanie and Keller, Michel and Sauvage, Jean-Pierre and Trolez, Yann and Cetina, Mario and Rissanen, Kari}, doi = {10.1002/chem.201002220}, issn = {0947-6539}, year = {2011}, date = {2011-01-01}, journal = {CHEMISTRY-A EUROPEAN JOURNAL}, volume = {17}, number = {3}, pages = {947--957}, abstract = {A new example of a linear [5]rotaxane has been synthesized by using the traditional “gathering-and-threading” approach but based on an unusual axle incorporating a symmetrical bis(bidentate) chelating fragment built on a 4,7-phenanthroline core. The stoppering reaction is particularly noteworthy since, instead of using a trivial bulky stopper as precursor to the blocking group, two semistoppered copper-complexed [2]pseudorotaxanes (namely [2]semirotaxanes) are used, which leads to the desired [5]rotaxane in good yield. The efficiency of the method relies on the use of “click” chemistry, with its very mild conditions, and on the protection by a transition-metal (copper(I)) of the various coordinating groups present in the fragments to be interconnected (terpy and bidentate chelating groups), thus inhibiting potential detrimental side reactions during the copper-catalyzed stoppering reaction. Since the external fragments and the central core of the system contain tri- and bidentate chelating units, respectively, the axle of the final [5]rotaxane incorporates two types of coordinating units: two external terpy groups (terpy: 2,2':6',2 `'-terpyridine) and two central bidentate ligands. Such a situation enables the system to tidy two different metals centers, and to localize them in a priori well-defined positions. This is what was observed when mixing the free ligand with a mixture of Zn2+ and Li+: the zinc(II) ions were unambiguously shown to occupy the external sites, whereas the Li+ cations were found in the central part of the [5]rotaxane. An X-ray diffraction study carried out on a [3]pseudorotaxane, the axis of which is similar to the central part of the [5]rotaxane axle, demonstrates that Zn2+ is clearly five-coordinate, the fifth ligand being a counterion, even when the coordination site of the pseudorotaxane is designed for four-coordinate metals, which is in marked contrast with copper(I) or Li+.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A new example of a linear [5]rotaxane has been synthesized by using the traditional “gathering-and-threading” approach but based on an unusual axle incorporating a symmetrical bis(bidentate) chelating fragment built on a 4,7-phenanthroline core. The stoppering reaction is particularly noteworthy since, instead of using a trivial bulky stopper as precursor to the blocking group, two semistoppered copper-complexed [2]pseudorotaxanes (namely [2]semirotaxanes) are used, which leads to the desired [5]rotaxane in good yield. The efficiency of the method relies on the use of “click” chemistry, with its very mild conditions, and on the protection by a transition-metal (copper(I)) of the various coordinating groups present in the fragments to be interconnected (terpy and bidentate chelating groups), thus inhibiting potential detrimental side reactions during the copper-catalyzed stoppering reaction. Since the external fragments and the central core of the system contain tri- and bidentate chelating units, respectively, the axle of the final [5]rotaxane incorporates two types of coordinating units: two external terpy groups (terpy: 2,2':6',2 `'-terpyridine) and two central bidentate ligands. Such a situation enables the system to tidy two different metals centers, and to localize them in a priori well-defined positions. This is what was observed when mixing the free ligand with a mixture of Zn2+ and Li+: the zinc(II) ions were unambiguously shown to occupy the external sites, whereas the Li+ cations were found in the central part of the [5]rotaxane. An X-ray diffraction study carried out on a [3]pseudorotaxane, the axis of which is similar to the central part of the [5]rotaxane axle, demonstrates that Zn2+ is clearly five-coordinate, the fifth ligand being a counterion, even when the coordination site of the pseudorotaxane is designed for four-coordinate metals, which is in marked contrast with copper(I) or Li+. |
Collin, Jean-Paul ; Durot, Stephanie ; Sauvage, Jean-Pierre ; Trolez, Yann Synthesis of [2]-, [3]-, and [4]rotaxanes whose axis contains two bidentate and two tridentate chelates Article de journal Dans: NEW JOURNAL OF CHEMISTRY, 35 (10), p. 2009–2012, 2011, ISSN: 1144-0546. @article{collin_synthesis_2011-1, title = {Synthesis of [2]-, [3]-, and [4]rotaxanes whose axis contains two bidentate and two tridentate chelates}, author = {Collin, Jean-Paul and Durot, Stephanie and Sauvage, Jean-Pierre and Trolez, Yann}, doi = {10.1039/c1nj20213h}, issn = {1144-0546}, year = {2011}, date = {2011-01-01}, journal = {NEW JOURNAL OF CHEMISTRY}, volume = {35}, number = {10}, pages = {2009--2012}, abstract = {A [3]rotaxane consisting of two 30-membered rings threaded by a symmetrical filament-like fragment was synthesized thanks to the copper(I)-template effect. The filament incorporates two tridentate coordinating units and two bidentate chelating groups. In addition to the [3]rotaxane, two homologous compounds were isolated in very significant yields: the corresponding [2]- and [4]-rotaxanes containing the same thread as the [3]rotaxane and encompassing one or three rings respectively.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A [3]rotaxane consisting of two 30-membered rings threaded by a symmetrical filament-like fragment was synthesized thanks to the copper(I)-template effect. The filament incorporates two tridentate coordinating units and two bidentate chelating groups. In addition to the [3]rotaxane, two homologous compounds were isolated in very significant yields: the corresponding [2]- and [4]-rotaxanes containing the same thread as the [3]rotaxane and encompassing one or three rings respectively. |
Gorska, Katarzyna ; Manicardi, Alex ; Barluenga, Sofia ; Winssinger, Nicolas DNA-templated release of functional molecules with an azide-reduction-triggered immolative linker Article de journal Dans: CHEMICAL COMMUNICATIONS, 47 (15), p. 4364–4366, 2011, ISSN: 1359-7345. @article{gorska_dna-templated_2011, title = {DNA-templated release of functional molecules with an azide-reduction-triggered immolative linker}, author = {Gorska, Katarzyna and Manicardi, Alex and Barluenga, Sofia and Winssinger, Nicolas}, doi = {10.1039/c1cc10222b}, issn = {1359-7345}, year = {2011}, date = {2011-01-01}, journal = {CHEMICAL COMMUNICATIONS}, volume = {47}, number = {15}, pages = {4364--4366}, abstract = {Nucleic acid templated reactions have attracted significant attention for nucleic acid sensing. Herein we report a general design which extends the potential of nucleic acid templated reactions to unleash the function of a broad diversity of small molecules such as a transcription factor agonist, a cytotoxic or a fluorophore.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Nucleic acid templated reactions have attracted significant attention for nucleic acid sensing. Herein we report a general design which extends the potential of nucleic acid templated reactions to unleash the function of a broad diversity of small molecules such as a transcription factor agonist, a cytotoxic or a fluorophore. |
Roche, Cecile ; Sauvage, Jean-Pierre ; Sour, Angelique ; Strutt, Nathan L A [3]rotaxane composed of a zinc porphyrin tetra-substituted with coordinating macrocycles and of two short rigid axles Article de journal Dans: NEW JOURNAL OF CHEMISTRY, 35 (12), p. 2820–2825, 2011, ISSN: 1144-0546. @article{roche_[3]rotaxane_2011, title = {A [3]rotaxane composed of a zinc porphyrin tetra-substituted with coordinating macrocycles and of two short rigid axles}, author = {Roche, Cecile and Sauvage, Jean-Pierre and Sour, Angelique and Strutt, Nathan L.}, doi = {10.1039/c1nj20734b}, issn = {1144-0546}, year = {2011}, date = {2011-01-01}, journal = {NEW JOURNAL OF CHEMISTRY}, volume = {35}, number = {12}, pages = {2820--2825}, abstract = {The syntheses of a porphyrin bearing four peripheral rings and of the corresponding [3]rotaxane are reported. The porphyrinic tetra-macrocycle consists of four 1,10-phenanthroline-containing rings attached to the meso positions of a central zinc porphyrin via single C-C bonds. The [3] rotaxane is composed of one central porphyrin and of two short rigid axles that contain two bidentate coordination sites and end with bulky stoppers. The rotaxane displays a novel architecture where each axle is threaded through two adjacent rings of the porphyrin. The free-base porphyrin was synthesised in 25% yield under optimised conditions. A microwave-enhanced procedure derived from the Adler-Rothemund method was developed for this condensation. The “gathering-and-threading” effect of copper(I) and subsequent stoppering by click chemistry were used to synthesise the [3]rotaxane in a two-step, one-pot reaction.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The syntheses of a porphyrin bearing four peripheral rings and of the corresponding [3]rotaxane are reported. The porphyrinic tetra-macrocycle consists of four 1,10-phenanthroline-containing rings attached to the meso positions of a central zinc porphyrin via single C-C bonds. The [3] rotaxane is composed of one central porphyrin and of two short rigid axles that contain two bidentate coordination sites and end with bulky stoppers. The rotaxane displays a novel architecture where each axle is threaded through two adjacent rings of the porphyrin. The free-base porphyrin was synthesised in 25% yield under optimised conditions. A microwave-enhanced procedure derived from the Adler-Rothemund method was developed for this condensation. The “gathering-and-threading” effect of copper(I) and subsequent stoppering by click chemistry were used to synthesise the [3]rotaxane in a two-step, one-pot reaction. |
Ciobanu, Mihai ; Huang, Kuo-Ting ; Daguer, Jean-Pierre ; Barluenga, Sofia ; Chaloin, Olivier ; Schaeffer, Evelyne ; Mueller, Christopher G; Mitchell, Daniel A; Winssinger, Nicolas Selection of a synthetic glycan oligomer from a library of DNA-templated fragments against DC-SIGN and inhibition of HIV gp120 binding to dendritic cells Article de journal Dans: CHEMICAL COMMUNICATIONS, 47 (33), p. 9321–9323, 2011, ISSN: 1359-7345. @article{ciobanu_selection_2011, title = {Selection of a synthetic glycan oligomer from a library of DNA-templated fragments against DC-SIGN and inhibition of HIV gp120 binding to dendritic cells}, author = {Ciobanu, Mihai and Huang, Kuo-Ting and Daguer, Jean-Pierre and Barluenga, Sofia and Chaloin, Olivier and Schaeffer, Evelyne and Mueller, Christopher G. and Mitchell, Daniel A. and Winssinger, Nicolas}, doi = {10.1039/c1cc13213j}, issn = {1359-7345}, year = {2011}, date = {2011-01-01}, journal = {CHEMICAL COMMUNICATIONS}, volume = {47}, number = {33}, pages = {9321--9323}, abstract = {We report the synthesis of a nucleic acid-encoded carbohydrate library, its combinatorial self-assembly into 37 485 pairs and a screen against DC-SIGN leading to the identification of consensus ligand motifs. A prototypical example from the selected pairs was shown to have enhanced binding. A dendrimer incorporating the selected motifs inhibited gp120's binding to dendritic cells with higher efficiency than mannan.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report the synthesis of a nucleic acid-encoded carbohydrate library, its combinatorial self-assembly into 37 485 pairs and a screen against DC-SIGN leading to the identification of consensus ligand motifs. A prototypical example from the selected pairs was shown to have enhanced binding. A dendrimer incorporating the selected motifs inhibited gp120's binding to dendritic cells with higher efficiency than mannan. |
Daguer, Jean Pierre ; Ciobanu, Mihai ; Alvarez, Susana ; Barluenga, Sofia ; Winssinger, Nicolas DNA-templated combinatorial assembly of small molecule fragments amenable to selection/amplification cycles Article de journal Dans: CHEMICAL SCIENCE, 2 (4), p. 625–632, 2011, ISSN: 2041-6520. @article{daguer_dna-templated_2011, title = {DNA-templated combinatorial assembly of small molecule fragments amenable to selection/amplification cycles}, author = {Daguer, Jean Pierre and Ciobanu, Mihai and Alvarez, Susana and Barluenga, Sofia and Winssinger, Nicolas}, doi = {10.1039/c0sc00574f}, issn = {2041-6520}, year = {2011}, date = {2011-01-01}, journal = {CHEMICAL SCIENCE}, volume = {2}, number = {4}, pages = {625--632}, abstract = {The discovery of small molecule probes which selectively modulate biological pathways is a cornerstone in the development of new therapeutics. Progress in our ability to access libraries of biologically relevant small molecules in conjunction with streamlined screening technologies have also enabled a more systematic approach to chemical biology. Nevertheless, the current state of the art still requires a large infrastructure and only a small fraction of the proteome has been addressed thus far. The emergence of technologies based on nucleic acid encoding of small molecules presents a new screening paradigm. We describe a method based on DNA-templated combinatorial display of PNA-encoded drug fragments affording 62 500 combinations which can be amplified following a selection. This concept was demonstrated with a screen against a representative target, carbonic anhydrase, by iterative cycles of affinity selection, amplification of DNA template and “translation” back into selected library members. The results show a clear convergence towards combinations which, upon resynthesis as covalent adducts, proved to bind cooperatively to carbonic anhydrase.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The discovery of small molecule probes which selectively modulate biological pathways is a cornerstone in the development of new therapeutics. Progress in our ability to access libraries of biologically relevant small molecules in conjunction with streamlined screening technologies have also enabled a more systematic approach to chemical biology. Nevertheless, the current state of the art still requires a large infrastructure and only a small fraction of the proteome has been addressed thus far. The emergence of technologies based on nucleic acid encoding of small molecules presents a new screening paradigm. We describe a method based on DNA-templated combinatorial display of PNA-encoded drug fragments affording 62 500 combinations which can be amplified following a selection. This concept was demonstrated with a screen against a representative target, carbonic anhydrase, by iterative cycles of affinity selection, amplification of DNA template and “translation” back into selected library members. The results show a clear convergence towards combinations which, upon resynthesis as covalent adducts, proved to bind cooperatively to carbonic anhydrase. |
Gorska, Katarzyna ; Keklikoglou, Ioanna ; Tschulena, Ulrich ; Winssinger, Nicolas Rapid fluorescence imaging of miRNAs in human cells using templated Staudinger reaction Article de journal Dans: CHEMICAL SCIENCE, 2 (10), p. 1969–1975, 2011, ISSN: 2041-6520. @article{gorska_rapid_2011, title = {Rapid fluorescence imaging of miRNAs in human cells using templated Staudinger reaction}, author = {Gorska, Katarzyna and Keklikoglou, Ioanna and Tschulena, Ulrich and Winssinger, Nicolas}, doi = {10.1039/c1sc00216c}, issn = {2041-6520}, year = {2011}, date = {2011-01-01}, journal = {CHEMICAL SCIENCE}, volume = {2}, number = {10}, pages = {1969--1975}, abstract = {It is generally accepted that microRNAs (miRNAs) play a crucial role in gene expression regulation and that their aberrant expression is intimately linked with pathologies, most notably cancer. There is thus significant interest in detecting and quantifying these important regulators. Herein, we report the fluorescence imaging of miRNAs within a few hours using a nucleic-acid templated Staudinger reaction. A good correlation between the level of miRNAs and the fluorescence intensity was observed across different cell lines. This method was shown to also be applicable for suspended cells with fluorescence quantification by flow cytometry.}, keywords = {}, pubstate = {published}, tppubtype = {article} } It is generally accepted that microRNAs (miRNAs) play a crucial role in gene expression regulation and that their aberrant expression is intimately linked with pathologies, most notably cancer. There is thus significant interest in detecting and quantifying these important regulators. Herein, we report the fluorescence imaging of miRNAs within a few hours using a nucleic-acid templated Staudinger reaction. A good correlation between the level of miRNAs and the fluorescence intensity was observed across different cell lines. This method was shown to also be applicable for suspended cells with fluorescence quantification by flow cytometry. |
Beneyton, Thomas ; Beyl, Yvonne ; Guschin, Dmitrii A; Griffiths, Andrew D; Taly, Valerie ; Schuhmann, Wolfgang The Thermophilic CotA Laccase from Bacillus subtilis: Bioelectrocatalytic Evaluation of O2 Reduction in the Direct and Mediated Electron Transfer Regime Article de journal Dans: Electroanalysis, 23 (8), p. 1781–1789, 2011, ISSN: 1521-4109. @article{beneyton_thermophilic_2011, title = {The Thermophilic CotA Laccase from Bacillus subtilis: Bioelectrocatalytic Evaluation of O2 Reduction in the Direct and Mediated Electron Transfer Regime}, author = {Beneyton, Thomas and Beyl, Yvonne and Guschin, Dmitrii A. and Griffiths, Andrew D. and Taly, Valerie and Schuhmann, Wolfgang}, url = {http://onlinelibrary.wiley.com/doi/10.1002/elan.201100054/abstract}, doi = {10.1002/elan.201100054}, issn = {1521-4109}, year = {2011}, date = {2011-01-01}, urldate = {2016-05-30}, journal = {Electroanalysis}, volume = {23}, number = {8}, pages = {1781--1789}, abstract = {The thermophilic bacterial laccase CotA from Bacillus subtilis adsorbed on graphite electrodes enables monitoring of the temperature dependent direct biocatalytic O2 reduction. Its entrapment in two different Os-complex modified redox hydrogels is the basis for mediated bioelectroreduction of O2. Besides the temperature and pH dependence of the bioelectrocatalytic response chloride and fluoride inhibition studies demonstrate that the Os-complexes are bound to the T1 copper centre of the enzyme. The interaction between CotA and the Os-complex modified polymers prevents inhibition by chloride ions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The thermophilic bacterial laccase CotA from Bacillus subtilis adsorbed on graphite electrodes enables monitoring of the temperature dependent direct biocatalytic O2 reduction. Its entrapment in two different Os-complex modified redox hydrogels is the basis for mediated bioelectroreduction of O2. Besides the temperature and pH dependence of the bioelectrocatalytic response chloride and fluoride inhibition studies demonstrate that the Os-complexes are bound to the T1 copper centre of the enzyme. The interaction between CotA and the Os-complex modified polymers prevents inhibition by chloride ions. |
Briseño-Roa, Luis ; Oliynyk, Zoryana ; Timperley, Christopher M; Griffiths, Andrew D; Fersht, Alan R Highest paraoxonase turnover rate found in a bacterial phosphotriesterase variant Article de journal Dans: Protein engineering, design & selection: PEDS, 24 (1-2), p. 209–211, 2011, ISSN: 1741-0134. @article{briseno-roa_highest_2011, title = {Highest paraoxonase turnover rate found in a bacterial phosphotriesterase variant}, author = {Briseño-Roa, Luis and Oliynyk, Zoryana and Timperley, Christopher M. and Griffiths, Andrew D. and Fersht, Alan R.}, doi = {10.1093/protein/gzq046}, issn = {1741-0134}, year = {2011}, date = {2011-01-01}, journal = {Protein engineering, design & selection: PEDS}, volume = {24}, number = {1-2}, pages = {209--211}, abstract = {The bacterial phosphotriesterase (PTE) catalyses the hydrolysis of the man-made pesticide paraoxon with a diffusion-limited efficiency. Here we describe the selection and characterisation of PTE variant SS0.2 that possesses the highest paraoxonase turnover number so far described (k(cat) = 31,000 s⁻¹). The PTE-SS0.2 was selected from a library of binding-site mutants using a novel screening method that combines partial lysis of bacterial colonies and fluorogenic probes.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The bacterial phosphotriesterase (PTE) catalyses the hydrolysis of the man-made pesticide paraoxon with a diffusion-limited efficiency. Here we describe the selection and characterisation of PTE variant SS0.2 that possesses the highest paraoxonase turnover number so far described (k(cat) = 31,000 s⁻¹). The PTE-SS0.2 was selected from a library of binding-site mutants using a novel screening method that combines partial lysis of bacterial colonies and fluorogenic probes. |
Briseño-Roa, Luis ; Timperley, Christopher M; Griffiths, Andrew D; Fersht, Alan R Phosphotriesterase variants with high methylphosphonatase activity and strong negative trade-off against phosphotriesters Article de journal Dans: Protein engineering, design & selection: PEDS, 24 (1-2), p. 151–159, 2011, ISSN: 1741-0134. @article{briseno-roa_phosphotriesterase_2011, title = {Phosphotriesterase variants with high methylphosphonatase activity and strong negative trade-off against phosphotriesters}, author = {Briseño-Roa, Luis and Timperley, Christopher M. and Griffiths, Andrew D. and Fersht, Alan R.}, doi = {10.1093/protein/gzq076}, issn = {1741-0134}, year = {2011}, date = {2011-01-01}, journal = {Protein engineering, design & selection: PEDS}, volume = {24}, number = {1-2}, pages = {151--159}, abstract = {The most lethal organophosphorus nerve agents (NA), like sarin, soman, agent-VX and Russian-VX, share a methylphosphonate moiety. Pseudomonas diminuta phosphotriesterase (PTE) catalyses the hydrolysis of methylphosphonate NA analogues with a catalytic efficiency orders of magnitude lower than that towards the pesticide paraoxon. With a view to obtaining PTE variants that more readily accept methylphosphonate NA, textbackslashtextbackslashtextbackslashtextasciitilde75,000 PTE variants of the substrate-binding residues Gly-60, Ile-106, Leu-303 and Ser-308 were screened with fluorogenic analogues of the NA Russian-VX and cyclosarin. Seven new PTE variants were isolated, purified and their k(cat)/K(M) determined against five phosphotriesters and five methylphosphonate analogues of sarin, cyclosarin, soman, agent-VX and Russian-VX. The novel PTE variants exhibited as much as a 10-fold increase in activity towards the methylphosphonate compounds–many reaching a k(cat)/K(M) of 10⁶ M⁻¹ s⁻¹–and as much as a 29,000-fold decrease in their phosphotriesterase activity. The mutations found in two of the variants, SS0.5 (G60V/I106L/S308G) and SS4.5 (G60V/I106A/S308G), were modelled into a high-resolution structure of PTE-wild type and docked with analogues of cyclosarin and Russian-VX using Autodock 4.2. The kinetic data and docking simulations suggest that the increase in activity towards the methylphosphonates and the loss of function against the phosphotriesters were due to an alteration of the shape and hydrophobicity of the binding pocket that hinders the productive binding of non-chiral racemic phosphotriesters, yet allows the binding of the highly asymmetric methylphosphonates.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The most lethal organophosphorus nerve agents (NA), like sarin, soman, agent-VX and Russian-VX, share a methylphosphonate moiety. Pseudomonas diminuta phosphotriesterase (PTE) catalyses the hydrolysis of methylphosphonate NA analogues with a catalytic efficiency orders of magnitude lower than that towards the pesticide paraoxon. With a view to obtaining PTE variants that more readily accept methylphosphonate NA, textbackslashtextbackslashtextbackslashtextasciitilde75,000 PTE variants of the substrate-binding residues Gly-60, Ile-106, Leu-303 and Ser-308 were screened with fluorogenic analogues of the NA Russian-VX and cyclosarin. Seven new PTE variants were isolated, purified and their k(cat)/K(M) determined against five phosphotriesters and five methylphosphonate analogues of sarin, cyclosarin, soman, agent-VX and Russian-VX. The novel PTE variants exhibited as much as a 10-fold increase in activity towards the methylphosphonate compounds–many reaching a k(cat)/K(M) of 10⁶ M⁻¹ s⁻¹–and as much as a 29,000-fold decrease in their phosphotriesterase activity. The mutations found in two of the variants, SS0.5 (G60V/I106L/S308G) and SS4.5 (G60V/I106A/S308G), were modelled into a high-resolution structure of PTE-wild type and docked with analogues of cyclosarin and Russian-VX using Autodock 4.2. The kinetic data and docking simulations suggest that the increase in activity towards the methylphosphonates and the loss of function against the phosphotriesters were due to an alteration of the shape and hydrophobicity of the binding pocket that hinders the productive binding of non-chiral racemic phosphotriesters, yet allows the binding of the highly asymmetric methylphosphonates. |
Beneyton, T; El Harrak, A; Griffiths, A D; Hellwig, P; Taly, V Immobilization of CotA, an extremophilic laccase from Bacillus subtilis, on glassy carbon electrodes for biofuel cell applications Article de journal Dans: Electrochemistry Communications, 13 (1), p. 24–27, 2011, ISSN: 1388-2481. @article{beneyton_immobilization_2011, title = {Immobilization of CotA, an extremophilic laccase from Bacillus subtilis, on glassy carbon electrodes for biofuel cell applications}, author = {Beneyton, T. and El Harrak, A. and Griffiths, A. D. and Hellwig, P. and Taly, V.}, url = {http://www.sciencedirect.com/science/article/pii/S1388248110004686}, doi = {10.1016/j.elecom.2010.11.003}, issn = {1388-2481}, year = {2011}, date = {2011-01-01}, urldate = {2016-05-30}, journal = {Electrochemistry Communications}, volume = {13}, number = {1}, pages = {24--27}, abstract = {Thanks to their high stability over a wide range of experimental conditions, extremophilic enzymes represent an interesting alternative to mesophilic enzymes as catalysts for biofuel cell applications. In the present work, we report for the first time the immobilization of a thermophilic laccase (CotA from Bacillus subtilis endospore coat) on glassy carbon electrodes functionalized via electrochemical reduction of in situ generated aminophenyl monodiazonium salts. We compare the performance of CotA-modified electrodes for the reduction of O2 to mutant variants and demonstrate that the measured electrical current is directly correlated to the catalytic efficiencies (kcat/Km) of the immobilized enzyme. CotA-modified electrodes showed an optimal operation temperature of 45–50 °C and stable catalytic activity for at least 7 weeks.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Thanks to their high stability over a wide range of experimental conditions, extremophilic enzymes represent an interesting alternative to mesophilic enzymes as catalysts for biofuel cell applications. In the present work, we report for the first time the immobilization of a thermophilic laccase (CotA from Bacillus subtilis endospore coat) on glassy carbon electrodes functionalized via electrochemical reduction of in situ generated aminophenyl monodiazonium salts. We compare the performance of CotA-modified electrodes for the reduction of O2 to mutant variants and demonstrate that the measured electrical current is directly correlated to the catalytic efficiencies (kcat/Km) of the immobilized enzyme. CotA-modified electrodes showed an optimal operation temperature of 45–50 °C and stable catalytic activity for at least 7 weeks. |
Hutchison, James A; O'Carroll, Deirdre M; Schwartz, Tal ; Genet, Cyriaque ; Ebbesen, Thomas W Absorption-Induced Transparency Article de journal Dans: ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 50 (9), p. 2085–2089, 2011, ISSN: 1433-7851. @article{hutchison_absorption-induced_2011, title = {Absorption-Induced Transparency}, author = {Hutchison, James A. and O'Carroll, Deirdre M. and Schwartz, Tal and Genet, Cyriaque and Ebbesen, Thomas W.}, doi = {10.1002/anie.201006019}, issn = {1433-7851}, year = {2011}, date = {2011-01-01}, journal = {ANGEWANDTE CHEMIE-INTERNATIONAL EDITION}, volume = {50}, number = {9}, pages = {2085--2089}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2010 |
Palma, Carlos-Andres ; Samori, Paolo ; Cecchini, Marco Atomistic Simulations of 2D Bicomponent Self-Assembly: From Molecular Recognition to Self-Healing Article de journal Dans: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 132 (50), p. 17880–17885, 2010, ISSN: 0002-7863. @article{palma_atomistic_2010, title = {Atomistic Simulations of 2D Bicomponent Self-Assembly: From Molecular Recognition to Self-Healing}, author = {Palma, Carlos-Andres and Samori, Paolo and Cecchini, Marco}, doi = {10.1021/ja107882e}, issn = {0002-7863}, year = {2010}, date = {2010-12-01}, journal = {JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, volume = {132}, number = {50}, pages = {17880--17885}, abstract = {Supramolecular two-dimensional engineering epitomizes the design of complex molecular architectures through recognition events in multicomponent self-assembly. Despite being the subject of in-depth experimental studies, such articulated phenomena have not been yet elucidated in time and space with atomic precision. Here we use atomistic molecular dynamics to simulate the recognition of complementary hydrogen-bonding modules forming 2D porous networks on graphite. We describe the transition path from the melt to the crystalline hexagonal phase and show that self-assembly proceeds through a series of intermediate states featuring a plethora of polygonal types. Finally, we design a novel bicomponent system possessing kinetically improved self-healing ability in silico, thus demonstrating that a priori engineering of 2D self-assembly is possible.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Supramolecular two-dimensional engineering epitomizes the design of complex molecular architectures through recognition events in multicomponent self-assembly. Despite being the subject of in-depth experimental studies, such articulated phenomena have not been yet elucidated in time and space with atomic precision. Here we use atomistic molecular dynamics to simulate the recognition of complementary hydrogen-bonding modules forming 2D porous networks on graphite. We describe the transition path from the melt to the crystalline hexagonal phase and show that self-assembly proceeds through a series of intermediate states featuring a plethora of polygonal types. Finally, we design a novel bicomponent system possessing kinetically improved self-healing ability in silico, thus demonstrating that a priori engineering of 2D self-assembly is possible. |
Bjoerk, Jonas ; Hanke, Felix ; Palma, Carlos-Andres ; Samori, Paolo ; Cecchini, Marco ; Persson, Mats Adsorption of Aromatic and Anti-Aromatic Systems on Graphene through pi-pi Stacking Article de journal Dans: JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 1 (23), p. 3407–3412, 2010, ISSN: 1948-7185. @article{bjoerk_adsorption_2010, title = {Adsorption of Aromatic and Anti-Aromatic Systems on Graphene through pi-pi Stacking}, author = {Bjoerk, Jonas and Hanke, Felix and Palma, Carlos-Andres and Samori, Paolo and Cecchini, Marco and Persson, Mats}, doi = {10.1021/jz101360k}, issn = {1948-7185}, year = {2010}, date = {2010-12-01}, journal = {JOURNAL OF PHYSICAL CHEMISTRY LETTERS}, volume = {1}, number = {23}, pages = {3407--3412}, abstract = {The adsorption of neutral (poly)-aromatic, antiaromatic, and more generally pi-conjugated systems on graphene is studied as a prototypical case of pi-pi stacking. To account for dispersive interactions, we compare the recent van der Waals density functional (vdw-DF) with three semiempirical corrections to density functional theory and two empirical force fields. The adsorption energies of the molecules binding to graphene predicted by the vdw-DF were found to be in excellent agreement with temperature desorption experiments reported in literature, whereas the results of the remaining functionals and force fields only preserved the correct trends. The comparison of the dispersive versus electrostatic contributions to the total binding energies in the aromatic and antiaromatic systems suggests that pi-pi interactions can be regarded as being prevalently dispersive in nature at large separations, whereas close to equilibrium bonding distance, it is a complex interplay between dispersive and electrostatic Coulombic interactions. Moreover our results surprisingly indicate that the magnitude of pi-pi interactions normalized both per number of total atoms and carbon atoms increases significantly with the relative number of hydrogen atoms in the studied systems.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The adsorption of neutral (poly)-aromatic, antiaromatic, and more generally pi-conjugated systems on graphene is studied as a prototypical case of pi-pi stacking. To account for dispersive interactions, we compare the recent van der Waals density functional (vdw-DF) with three semiempirical corrections to density functional theory and two empirical force fields. The adsorption energies of the molecules binding to graphene predicted by the vdw-DF were found to be in excellent agreement with temperature desorption experiments reported in literature, whereas the results of the remaining functionals and force fields only preserved the correct trends. The comparison of the dispersive versus electrostatic contributions to the total binding energies in the aromatic and antiaromatic systems suggests that pi-pi interactions can be regarded as being prevalently dispersive in nature at large separations, whereas close to equilibrium bonding distance, it is a complex interplay between dispersive and electrostatic Coulombic interactions. Moreover our results surprisingly indicate that the magnitude of pi-pi interactions normalized both per number of total atoms and carbon atoms increases significantly with the relative number of hydrogen atoms in the studied systems. |
Kikkawa, Yoshihiro ; Kihara, Hideyuki ; Takahashi, Mayuko ; Kanesato, Masatoshi ; Balaban, Teodor Silviu ; Lehn, Jean-Marie Two-Dimensional Structures of Anthracene Derivatives: Photodimerization and Host-Guest Chemistry Article de journal Dans: JOURNAL OF PHYSICAL CHEMISTRY B, 114 (50), p. 16718–16722, 2010, ISSN: 1520-6106. @article{kikkawa_two-dimensional_2010, title = {Two-Dimensional Structures of Anthracene Derivatives: Photodimerization and Host-Guest Chemistry}, author = {Kikkawa, Yoshihiro and Kihara, Hideyuki and Takahashi, Mayuko and Kanesato, Masatoshi and Balaban, Teodor Silviu and Lehn, Jean-Marie}, doi = {10.1021/jp108069a}, issn = {1520-6106}, year = {2010}, date = {2010-12-01}, journal = {JOURNAL OF PHYSICAL CHEMISTRY B}, volume = {114}, number = {50}, pages = {16718--16722}, abstract = {By using a simple anthracene derivative with four alkoxy tails, a two-dimensional patterned surface was fabricated. The two-dimensional structures were directly visualized by scanning tunneling microscopy (STM) at the solid/liquid interface. The anthracene derivative formed highly ordered structures displaying cavities into which solvent molecules of 1-phenyloctane were coadsorbed. The functionality of the patterned surface was demonstrated by activating host-guest chemistry as the solvent molecules could be replaced by coronene, whose size is almost identical to the cavities formed by the anthracene derivative. Furthermore, [4 + 4] photodimerization of the anthracene derivative was performed at the solid/liquid interface and revealed that the physical height and electron density of the states were changed, resulting in the increase of an apparent height in the STM images. We demonstrate thus that the porous network of the two-dimensional pattern created by the anthracene derivative can be applied for selectively incorporating guest molecules and for photoprocessing.}, keywords = {}, pubstate = {published}, tppubtype = {article} } By using a simple anthracene derivative with four alkoxy tails, a two-dimensional patterned surface was fabricated. The two-dimensional structures were directly visualized by scanning tunneling microscopy (STM) at the solid/liquid interface. The anthracene derivative formed highly ordered structures displaying cavities into which solvent molecules of 1-phenyloctane were coadsorbed. The functionality of the patterned surface was demonstrated by activating host-guest chemistry as the solvent molecules could be replaced by coronene, whose size is almost identical to the cavities formed by the anthracene derivative. Furthermore, [4 + 4] photodimerization of the anthracene derivative was performed at the solid/liquid interface and revealed that the physical height and electron density of the states were changed, resulting in the increase of an apparent height in the STM images. We demonstrate thus that the porous network of the two-dimensional pattern created by the anthracene derivative can be applied for selectively incorporating guest molecules and for photoprocessing. |
Duarte, Carolina D; Greferath, Ruth ; Nicolau, Claude ; Lehn, Jean-Marie myo-Inositol Trispyrophosphate: A Novel Allosteric Effector of Hemoglobin with High Permeation Selectivity across the Red Blood Cell Plasma Membrane Article de journal Dans: CHEMBIOCHEM, 11 (18), p. 2543–2548, 2010, ISSN: 1439-4227. @article{duarte_myo-inositol_2010, title = {myo-Inositol Trispyrophosphate: A Novel Allosteric Effector of Hemoglobin with High Permeation Selectivity across the Red Blood Cell Plasma Membrane}, author = {Duarte, Carolina D. and Greferath, Ruth and Nicolau, Claude and Lehn, Jean-Marie}, doi = {10.1002/cbic.201000499}, issn = {1439-4227}, year = {2010}, date = {2010-12-01}, journal = {CHEMBIOCHEM}, volume = {11}, number = {18}, pages = {2543--2548}, abstract = {myo-Inositol trispyrophosphate (ITPP), a novel membrane-permeant allosteric effector of hemoglobin (Hb), enhances the regulated oxygen release capacity of red blood cells, thus counteracting the effects of hypoxia in diseases such as cancer and cardiovascular ailments. ITPP-induced shifting of the oxygen-hemoglobin equilibrium curve in red blood cells (RBCs) was inhibited by DIDS and NAP-taurine, indicating that band 3 protein, an anion transporter mainly localized on the RBC membrane, allows ITPP entry into RBCs. The maximum intracellular concentration of ITPP, determined by ion chromatography, was 5.5 x 10(-3)M, whereas a drop in concentration to the limit of detection was observed in NAP-taurine-treated RBCs. The dissociation constant of ITPP binding to RBC ghosts was found to be 1.72 x 10(-5)M. All data obtained indicate that ITPP uptake is mediated by band 3 protein and is thus highly tissue-selective towards RBCs, a feature of major importance for its potential therapeutic use.}, keywords = {}, pubstate = {published}, tppubtype = {article} } myo-Inositol trispyrophosphate (ITPP), a novel membrane-permeant allosteric effector of hemoglobin (Hb), enhances the regulated oxygen release capacity of red blood cells, thus counteracting the effects of hypoxia in diseases such as cancer and cardiovascular ailments. ITPP-induced shifting of the oxygen-hemoglobin equilibrium curve in red blood cells (RBCs) was inhibited by DIDS and NAP-taurine, indicating that band 3 protein, an anion transporter mainly localized on the RBC membrane, allows ITPP entry into RBCs. The maximum intracellular concentration of ITPP, determined by ion chromatography, was 5.5 x 10(-3)M, whereas a drop in concentration to the limit of detection was observed in NAP-taurine-treated RBCs. The dissociation constant of ITPP binding to RBC ghosts was found to be 1.72 x 10(-5)M. All data obtained indicate that ITPP uptake is mediated by band 3 protein and is thus highly tissue-selective towards RBCs, a feature of major importance for its potential therapeutic use. |
Grad, Iwona ; Cederroth, Christopher R; Walicki, Joel ; Grey, Corinne ; Barluenga, Sofia ; Winssinger, Nicolas ; De Massy, Bernard ; Nef, Serge ; Picard, Didier The Molecular Chaperone Hsp90 alpha Is Required for Meiotic Progression of Spermatocytes beyond Pachytene in the Mouse Article de journal Dans: PLOS ONE, 5 (12), 2010, ISSN: 1932-6203. @article{grad_molecular_2010, title = {The Molecular Chaperone Hsp90 alpha Is Required for Meiotic Progression of Spermatocytes beyond Pachytene in the Mouse}, author = {Grad, Iwona and Cederroth, Christopher R. and Walicki, Joel and Grey, Corinne and Barluenga, Sofia and Winssinger, Nicolas and De Massy, Bernard and Nef, Serge and Picard, Didier}, doi = {10.1371/journal.pone.0015770}, issn = {1932-6203}, year = {2010}, date = {2010-12-01}, journal = {PLOS ONE}, volume = {5}, number = {12}, abstract = {The molecular chaperone Hsp90 has been found to be essential for viability in all tested eukaryotes, from the budding yeast to Drosophila. In mammals, two genes encode the two highly similar and functionally largely redundant isoforms Hsp90 alpha and Hsp90 beta. Although they are co-expressed in most if not all cells, their relative levels vary between tissues and during development. Since mouse embryos lacking Hsp90 beta die at implantation, and despite the fact that Hsp90 inhibitors being tested as anti-cancer agents are relatively well tolerated, the organismic functions of Hsp90 in mammals remain largely unknown. We have generated mouse lines carrying gene trap insertions in the Hsp90 alpha gene to investigate the global functions of this isoform. Surprisingly, mice without Hsp90 alpha are apparently normal, with one major exception. Mutant male mice, whose Hsp90 beta levels are unchanged, are sterile because of a complete failure to produce sperm. While the development of the male reproductive system appears to be normal, spermatogenesis arrests specifically at the pachytene stage of meiosis I. Over time, the number of spermatocytes and the levels of the meiotic regulators and Hsp90 interactors Hsp70-2, NASP and Cdc2 are reduced. We speculate that Hsp90 alpha may be required to maintain and to activate these regulators and/or to disassemble the synaptonemal complex that holds homologous chromosomes together. The link between fertility and Hsp90 is further supported by our finding that an Hsp90 inhibitor that can cross the blood-testis barrier can partially phenocopy the genetic defects.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The molecular chaperone Hsp90 has been found to be essential for viability in all tested eukaryotes, from the budding yeast to Drosophila. In mammals, two genes encode the two highly similar and functionally largely redundant isoforms Hsp90 alpha and Hsp90 beta. Although they are co-expressed in most if not all cells, their relative levels vary between tissues and during development. Since mouse embryos lacking Hsp90 beta die at implantation, and despite the fact that Hsp90 inhibitors being tested as anti-cancer agents are relatively well tolerated, the organismic functions of Hsp90 in mammals remain largely unknown. We have generated mouse lines carrying gene trap insertions in the Hsp90 alpha gene to investigate the global functions of this isoform. Surprisingly, mice without Hsp90 alpha are apparently normal, with one major exception. Mutant male mice, whose Hsp90 beta levels are unchanged, are sterile because of a complete failure to produce sperm. While the development of the male reproductive system appears to be normal, spermatogenesis arrests specifically at the pachytene stage of meiosis I. Over time, the number of spermatocytes and the levels of the meiotic regulators and Hsp90 interactors Hsp70-2, NASP and Cdc2 are reduced. We speculate that Hsp90 alpha may be required to maintain and to activate these regulators and/or to disassemble the synaptonemal complex that holds homologous chromosomes together. The link between fertility and Hsp90 is further supported by our finding that an Hsp90 inhibitor that can cross the blood-testis barrier can partially phenocopy the genetic defects. |
Stein, Benedikt ; Laluet, Jean-Yves ; Devaux, Eloise ; Genet, Cyriaque ; Ebbesen, Thomas W Surface Plasmon Mode Steering and Negative Refraction Article de journal Dans: PHYSICAL REVIEW LETTERS, 105 (26), 2010, ISSN: 0031-9007. @article{stein_surface_2010, title = {Surface Plasmon Mode Steering and Negative Refraction}, author = {Stein, Benedikt and Laluet, Jean-Yves and Devaux, Eloise and Genet, Cyriaque and Ebbesen, Thomas W.}, doi = {10.1103/PhysRevLett.105.266804}, issn = {0031-9007}, year = {2010}, date = {2010-12-01}, journal = {PHYSICAL REVIEW LETTERS}, volume = {105}, number = {26}, abstract = {The propagation of surface plasmon beams through singly and doubly periodic metallic gratings is analyzed both in real and Fourier spaces. Large beam steering effects are experimentally revealed by probing the isofrequency surfaces (IFS) related to propagating plasmonic Bloch waves inside the gratings. In particular, negative refraction is demonstrated close to the Bragg condition. We analyze how the local structure of the IFS can amplify the sensitivity of surface plasmon-based sensors.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The propagation of surface plasmon beams through singly and doubly periodic metallic gratings is analyzed both in real and Fourier spaces. Large beam steering effects are experimentally revealed by probing the isofrequency surfaces (IFS) related to propagating plasmonic Bloch waves inside the gratings. In particular, negative refraction is demonstrated close to the Bragg condition. We analyze how the local structure of the IFS can amplify the sensitivity of surface plasmon-based sensors. |
Schoen, Peter ; Bonod, Nicolas ; Devaux, Eloise ; Wenger, Jerome ; Rigneault, Herve ; Ebbesen, Thomas W; Brasselet, Sophie Enhanced second-harmonic generation from individual metallic nanoapertures Article de journal Dans: OPTICS LETTERS, 35 (23), p. 4063–4065, 2010, ISSN: 0146-9592. @article{schoen_enhanced_2010, title = {Enhanced second-harmonic generation from individual metallic nanoapertures}, author = {Schoen, Peter and Bonod, Nicolas and Devaux, Eloise and Wenger, Jerome and Rigneault, Herve and Ebbesen, Thomas W. and Brasselet, Sophie}, doi = {10.1364/OL.35.004063}, issn = {0146-9592}, year = {2010}, date = {2010-12-01}, journal = {OPTICS LETTERS}, volume = {35}, number = {23}, pages = {4063--4065}, abstract = {We demonstrate the ability of single-subwavelength-size nanoapertures fabricated in a gold metal thin film to enhance second-harmonic generation (SHG) as compared to a bare metal film. Nonlinear microscopy imaging with polarization resolution is used to quantify the SHG enhancement in circular and triangular nanoaperture shapes. The dependence of the measured SHG enhancement on circular aperture diameters is seen to originate from both phase retardation effects and field enhancements at the nanoaperture edge. Triangular nanoapertures exhibit superior SHG enhancement compared with circular ones, as expected from their noncentrosymmetric shape. (C) 2010 Optical Society of America}, keywords = {}, pubstate = {published}, tppubtype = {article} } We demonstrate the ability of single-subwavelength-size nanoapertures fabricated in a gold metal thin film to enhance second-harmonic generation (SHG) as compared to a bare metal film. Nonlinear microscopy imaging with polarization resolution is used to quantify the SHG enhancement in circular and triangular nanoaperture shapes. The dependence of the measured SHG enhancement on circular aperture diameters is seen to originate from both phase retardation effects and field enhancements at the nanoaperture edge. Triangular nanoapertures exhibit superior SHG enhancement compared with circular ones, as expected from their noncentrosymmetric shape. (C) 2010 Optical Society of America |
Liscio, Andrea ; Orgiu, Emanuele ; Mativetsky, Jeffrey M; Palermo, Vincenzo ; Samori, Paolo Bottom-Up Fabricated Asymmetric Electrodes for Organic Electronics Article de journal Dans: ADVANCED MATERIALS, 22 (44), p. 5018+, 2010, ISSN: 0935-9648. @article{liscio_bottom-up_2010, title = {Bottom-Up Fabricated Asymmetric Electrodes for Organic Electronics}, author = {Liscio, Andrea and Orgiu, Emanuele and Mativetsky, Jeffrey M. and Palermo, Vincenzo and Samori, Paolo}, doi = {10.1002/adma.201002215}, issn = {0935-9648}, year = {2010}, date = {2010-11-01}, journal = {ADVANCED MATERIALS}, volume = {22}, number = {44}, pages = {5018+}, abstract = {A new method for obtaining asymmetric (nano) electrodes through the adsorption and electrochemical desorption of self-assembled monolayers on gold is described. The selective work function modification is demonstrated by Kelvin probe force microscopy and electrical characterization of organic field-effect transistors. The proposed method is simple, fast, and could allow parallel, large-scale fabrication of asymmetric electrodes for micro-and large-area electronics.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A new method for obtaining asymmetric (nano) electrodes through the adsorption and electrochemical desorption of self-assembled monolayers on gold is described. The selective work function modification is demonstrated by Kelvin probe force microscopy and electrical characterization of organic field-effect transistors. The proposed method is simple, fast, and could allow parallel, large-scale fabrication of asymmetric electrodes for micro-and large-area electronics. |
Folmer-Andersen, Frantz J; Buhler, Eric ; Candau, Sauveur-Jean ; Joulie, Sebastien ; Schmutz, Marc ; Lehn, Jean-Marie Cooperative, bottom-up generation of rigid-rod nanostructures through dynamic polymer chemistry Article de journal Dans: POLYMER INTERNATIONAL, 59 (11, SI), p. 1477–1491, 2010, ISSN: 0959-8103. @article{folmer-andersen_cooperative_2010, title = {Cooperative, bottom-up generation of rigid-rod nanostructures through dynamic polymer chemistry}, author = {Folmer-Andersen, J. Frantz and Buhler, Eric and Candau, Sauveur-Jean and Joulie, Sebastien and Schmutz, Marc and Lehn, Jean-Marie}, doi = {10.1002/pi.2864}, issn = {0959-8103}, year = {2010}, date = {2010-11-01}, journal = {POLYMER INTERNATIONAL}, volume = {59}, number = {11, SI}, pages = {1477--1491}, abstract = {A set of carbazole-and benzene derived di(aldehyde) and di(acylhydrazine) monomers containing hexaglyme groups to impart water solubility has been synthesized Mixing a given di(aldehyde) and di(acylhydrazine) pair in acidic aqueous solution causes polymerization through reversible acylhydrazone condensation The structures of the resultant amphiphilic polyacylhydrazones have been studied using H-1 NMR spectroscopy, matrix assisted laser desorption ionization mass spectrometry, small angle neutron scattering, transmission electron microscopy, size exclusion chromatography/multi-angle laser light scattering (SEC-MALLS) and UV-visible and fluorescence spectrophotometries All the available data support the existence of structurally related rod like nanostructures of variable lengths and constant diameters of approximately 5 nm in all cases, which are interpreted as corresponding to individually folded polymer chains On the basis of these studies, molecular models are proposed in which the hydrophobic, aromatic polymer backbones assume helical conformations allowing for hydrophobically driven pi stacking, while exposing the hydrophilic hexaglyme groups to the solvent The molecular models are in agreement with the observed physical dimensions of the nanostructures, and are further supported by the observation of strong hypochromic effects on changing the solvent from dimethylformamide to water Additionally, the reversible polymerization process is found to be cooperative H-1 NMR and SEC MALLS studies reveal severe deviations from statistically predicted product distributions under imbalanced stoichiometry, which are characteristic of nucleation-elongation behaviour (C) 2010 Society of Chemical Industry}, keywords = {}, pubstate = {published}, tppubtype = {article} } A set of carbazole-and benzene derived di(aldehyde) and di(acylhydrazine) monomers containing hexaglyme groups to impart water solubility has been synthesized Mixing a given di(aldehyde) and di(acylhydrazine) pair in acidic aqueous solution causes polymerization through reversible acylhydrazone condensation The structures of the resultant amphiphilic polyacylhydrazones have been studied using H-1 NMR spectroscopy, matrix assisted laser desorption ionization mass spectrometry, small angle neutron scattering, transmission electron microscopy, size exclusion chromatography/multi-angle laser light scattering (SEC-MALLS) and UV-visible and fluorescence spectrophotometries All the available data support the existence of structurally related rod like nanostructures of variable lengths and constant diameters of approximately 5 nm in all cases, which are interpreted as corresponding to individually folded polymer chains On the basis of these studies, molecular models are proposed in which the hydrophobic, aromatic polymer backbones assume helical conformations allowing for hydrophobically driven pi stacking, while exposing the hydrophilic hexaglyme groups to the solvent The molecular models are in agreement with the observed physical dimensions of the nanostructures, and are further supported by the observation of strong hypochromic effects on changing the solvent from dimethylformamide to water Additionally, the reversible polymerization process is found to be cooperative H-1 NMR and SEC MALLS studies reveal severe deviations from statistically predicted product distributions under imbalanced stoichiometry, which are characteristic of nucleation-elongation behaviour (C) 2010 Society of Chemical Industry |
Davies, J I; Wilson, C D; Auld, R; Baes, M; Barlow, M J; Bendo, G J; Bock, J J; Boselli, A; Bradford, M; Buat, V; Castro-Rodriguez, N; Chanial, P; Charlot, S; Ciesla, L; Clements, D L; Cooray, A; Cormier, D; Cortese, L; Dwek, E; Eales, S A; Elbaz, D; Galametz, M; Galliano, F; Gear, W K; Glenn, J; Gomez, H L; Griffin, M; Hony, S; Isaak, K G; Levenson, L R; Lu, N; Madden, S; O'Halloran, B; Okumura, K; Oliver, S; Page, M J; Panuzzo, P; Papageorgiou, A; Parkin, T J; Perez-Fournon, I; Pohlen, M; Rangwala, N; Rigby, E E; Roussel, H; Rykala, A; Sacchi, N; Sauvage, M; Schulz, B; Schirm, M R P; Smith, M W L; Spinoglio, L; Stevens, J A; Srinivasan, S; Symeonidis, M; Trichas, M; Vaccari, M; Vigroux, L; Wozniak, H; Wright, G S; Zeilinger, W W On the origin of M81 group extended dust emission Article de journal Dans: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 409 (1), p. 102–108, 2010, ISSN: 0035-8711. @article{davies_origin_2010, title = {On the origin of M81 group extended dust emission}, author = {Davies, J. I. and Wilson, C. D. and Auld, R. and Baes, M. and Barlow, M. J. and Bendo, G. J. and Bock, J. J. and Boselli, A. and Bradford, M. and Buat, V. and Castro-Rodriguez, N. and Chanial, P. and Charlot, S. and Ciesla, L. and Clements, D. L. and Cooray, A. and Cormier, D. and Cortese, L. and Dwek, E. and Eales, S. A. and Elbaz, D. and Galametz, M. and Galliano, F. and Gear, W. K. and Glenn, J. and Gomez, H. L. and Griffin, M. and Hony, S. and Isaak, K. G. and Levenson, L. R. and Lu, N. and Madden, S. and O'Halloran, B. and Okumura, K. and Oliver, S. and Page, M. J. and Panuzzo, P. and Papageorgiou, A. and Parkin, T. J. and Perez-Fournon, I. and Pohlen, M. and Rangwala, N. and Rigby, E. E. and Roussel, H. and Rykala, A. and Sacchi, N. and Sauvage, M. and Schulz, B. and Schirm, M. R. P. and Smith, M. W. L. and Spinoglio, L. and Stevens, J. A. and Srinivasan, S. and Symeonidis, M. and Trichas, M. and Vaccari, M. and Vigroux, L. and Wozniak, H. and Wright, G. S. and Zeilinger, W. W.}, doi = {10.1111/j.1365-2966.2010.17774.x}, issn = {0035-8711}, year = {2010}, date = {2010-11-01}, journal = {MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY}, volume = {409}, number = {1}, pages = {102--108}, abstract = {Galactic cirrus emission at far-infrared wavelengths affects many extragalactic observations. Separating this emission from that associated with extragalactic objects is both important and difficult. In this paper we discuss a particular case, the M81 group, and the identification of diffuse structures prominent in the infrared, but also detected at optical wavelengths. The origin of these structures has previously been controversial, ranging from them being the result of a past interaction between M81 and M82 or due to more local Galactic emission. We show that over an order of a few arcmin scales, the far-infrared (Herschel 250 mu m) emission correlates spatially very well with a particular narrow-velocity (2-3 km s(-1)) component of the Galactic HI. We find no evidence that any of the far-infrared emission associated with these features actually originates in the M81 group. Thus we infer that the associated diffuse optical emission must be due to galactic light-back scattered off dust in our galaxy. Ultraviolet observations pick out young stellar associations around M81, but no detectable far-infrared emission. We consider in detail one of the Galactic cirrus features, finding that the far-infrared HI relation breaks down below arcmin scales and that at smaller scales there can be quite large dust-temperature variations.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Galactic cirrus emission at far-infrared wavelengths affects many extragalactic observations. Separating this emission from that associated with extragalactic objects is both important and difficult. In this paper we discuss a particular case, the M81 group, and the identification of diffuse structures prominent in the infrared, but also detected at optical wavelengths. The origin of these structures has previously been controversial, ranging from them being the result of a past interaction between M81 and M82 or due to more local Galactic emission. We show that over an order of a few arcmin scales, the far-infrared (Herschel 250 mu m) emission correlates spatially very well with a particular narrow-velocity (2-3 km s(-1)) component of the Galactic HI. We find no evidence that any of the far-infrared emission associated with these features actually originates in the M81 group. Thus we infer that the associated diffuse optical emission must be due to galactic light-back scattered off dust in our galaxy. Ultraviolet observations pick out young stellar associations around M81, but no detectable far-infrared emission. We consider in detail one of the Galactic cirrus features, finding that the far-infrared HI relation breaks down below arcmin scales and that at smaller scales there can be quite large dust-temperature variations. |
Chen, Ruihong ; Yu, Jin-Chen ; Liu, Chian ; Jaffer, Zahara M; Chabala, John C; Winssinger, Nicolas ; Rubenstein, Allan E PRECLINICAL EVALUATION OF NXD30001, A NOVEL HSP90 INHIBITOR, FOR EFFICACY IN GLIOMA Article de journal Dans: NEURO-ONCOLOGY, 12 (4), p. 90, 2010, ISSN: 1522-8517. @article{chen_preclinical_2010, title = {PRECLINICAL EVALUATION OF NXD30001, A NOVEL HSP90 INHIBITOR, FOR EFFICACY IN GLIOMA}, author = {Chen, Ruihong and Yu, Jin-Chen and Liu, Chian and Jaffer, Zahara M. and Chabala, John C. and Winssinger, Nicolas and Rubenstein, Allan E.}, issn = {1522-8517}, year = {2010}, date = {2010-11-01}, journal = {NEURO-ONCOLOGY}, volume = {12}, number = {4}, pages = {90}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Rodrigo, Sergio G; Mahboub, O; Degiron, A; Genet, Cyriaque ; Garcia-Vidal, F J; Martin-Moreno, L; Ebbesen, Thomas W Holes with very acute angles: a new paradigm of extraordinary optical transmission through strongly localized modes Article de journal Dans: OPTICS EXPRESS, 18 (23), p. 23691–23697, 2010, ISSN: 1094-4087. @article{rodrigo_holes_2010, title = {Holes with very acute angles: a new paradigm of extraordinary optical transmission through strongly localized modes}, author = {Rodrigo, Sergio G. and Mahboub, O. and Degiron, A. and Genet, Cyriaque and Garcia-Vidal, F. J. and Martin-Moreno, L. and Ebbesen, Thomas W.}, doi = {10.1364/OE.18.023691}, issn = {1094-4087}, year = {2010}, date = {2010-11-01}, journal = {OPTICS EXPRESS}, volume = {18}, number = {23}, pages = {23691--23697}, abstract = {It is shown that submicrometer holes with very acute angles present extraordinary optical transmission peaks associated to strongly localized modes. The positions of these peaks are: (i) strongly redshifted with respect to the peak position that could be expected if the considered hole were in a film made of perfect electric conductor, (ii) independent on the angle of incidence for a large range of angles and (iii) strongly dependent on the direction of the incident electric field. In addition, it is demonstrated that these properties are linked to the mechanisms leading to the existence of channel-plasmon-polaritons. (C) 2010 Optical Society of America}, keywords = {}, pubstate = {published}, tppubtype = {article} } It is shown that submicrometer holes with very acute angles present extraordinary optical transmission peaks associated to strongly localized modes. The positions of these peaks are: (i) strongly redshifted with respect to the peak position that could be expected if the considered hole were in a film made of perfect electric conductor, (ii) independent on the angle of incidence for a large range of angles and (iii) strongly dependent on the direction of the incident electric field. In addition, it is demonstrated that these properties are linked to the mechanisms leading to the existence of channel-plasmon-polaritons. (C) 2010 Optical Society of America |
Mativetsky, Jeffrey M; Treossi, Emanuele ; Orgiu, Emanuele ; Melucci, Manuela ; Veronese, Giulio Paolo ; Samori, Paolo ; Palermo, Vincenzo Local Current Mapping and Patterning of Reduced Graphene Oxide Article de journal Dans: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 132 (40), p. 14130–14136, 2010, ISSN: 0002-7863. @article{mativetsky_local_2010, title = {Local Current Mapping and Patterning of Reduced Graphene Oxide}, author = {Mativetsky, Jeffrey M. and Treossi, Emanuele and Orgiu, Emanuele and Melucci, Manuela and Veronese, Giulio Paolo and Samori, Paolo and Palermo, Vincenzo}, doi = {10.1021/ja104567f}, issn = {0002-7863}, year = {2010}, date = {2010-10-01}, journal = {JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, volume = {132}, number = {40}, pages = {14130--14136}, abstract = {Conductive atomic force microscopy (C-AFM) has been used to correlate the detailed structural and electrical characteristics of graphene derived from graphene oxide. Uniform large currents were measured over areas exceeding tens of micrometers in few-layer films, supporting the use of graphene as a transparent electrode material. Moreover, defects such as electrical discontinuities were easily detected. Multilayer films were found to have a higher conductivity per layer than single layers. It is also shown that a local AFM-tip-induced electrochemical reduction process can be used to pattern conductive pathways on otherwise-insulating graphene oxide. Transistors with micrometer-scale tip-reduced graphene channels that featured ambipolar transport and an 8 order of magnitude increase in current density upon reduction were successfully fabricated.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Conductive atomic force microscopy (C-AFM) has been used to correlate the detailed structural and electrical characteristics of graphene derived from graphene oxide. Uniform large currents were measured over areas exceeding tens of micrometers in few-layer films, supporting the use of graphene as a transparent electrode material. Moreover, defects such as electrical discontinuities were easily detected. Multilayer films were found to have a higher conductivity per layer than single layers. It is also shown that a local AFM-tip-induced electrochemical reduction process can be used to pattern conductive pathways on otherwise-insulating graphene oxide. Transistors with micrometer-scale tip-reduced graphene channels that featured ambipolar transport and an 8 order of magnitude increase in current density upon reduction were successfully fabricated. |
Gassman, Natalie R; Nelli, Patrick J; Dutta, Samrat ; Kuhn, Adam ; Bonin, Keith ; Pianowski, Zbigniew ; Winssinger, Nicolas ; Guthold, Martin ; Macosko, Jed C Selection of bead-displayed, PNA-encoded chemicals Article de journal Dans: JOURNAL OF MOLECULAR RECOGNITION, 23 (5), p. 414–422, 2010, ISSN: 0952-3499. @article{gassman_selection_2010, title = {Selection of bead-displayed, PNA-encoded chemicals}, author = {Gassman, Natalie R. and Nelli, J. Patrick and Dutta, Samrat and Kuhn, Adam and Bonin, Keith and Pianowski, Zbigniew and Winssinger, Nicolas and Guthold, Martin and Macosko, Jed C.}, doi = {10.1002/jmr.1007}, issn = {0952-3499}, year = {2010}, date = {2010-10-01}, journal = {JOURNAL OF MOLECULAR RECOGNITION}, volume = {23}, number = {5}, pages = {414--422}, abstract = {The lack of efficient identification and isolation methods for specific molecular binders has fundamentally limited drug discovery. Here, we have developed a method to select peptide nucleic acid (PNA) encoded molecules with specific functional properties from combinatorially generated libraries. This method consists of three essential stages: (1) creation of a Lab-on-Bead (TM) library, a one-bead, one-sequence library that, in turn, displays a library of candidate molecules, (2) fluorescence microscopy-aided identification of single target-bound beads and the extraction - wet or dry - of these beads and their attached candidate molecules by a micropipette manipulator, and (3) identification of the target-binding candidate molecules via amplification and sequencing. This novel integration of techniques harnesses the sensitivity of DNA detection methods and the multiplexed and miniaturized nature of molecule screening to efficiently select and identify target-binding molecules from large nucleic acid encoded chemical libraries. Beyond its potential to accelerate assays currently used for the discovery of new drug candidates, its simple bead-based design allows for easy screening over a variety of prepared surfaces that can extend this technique's application to the discovery of diagnostic reagents and disease markers. Copyright (C) 2009 John Wiley & Sons, Ltd. Supporting information may be found in the online version of this paper.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The lack of efficient identification and isolation methods for specific molecular binders has fundamentally limited drug discovery. Here, we have developed a method to select peptide nucleic acid (PNA) encoded molecules with specific functional properties from combinatorially generated libraries. This method consists of three essential stages: (1) creation of a Lab-on-Bead (TM) library, a one-bead, one-sequence library that, in turn, displays a library of candidate molecules, (2) fluorescence microscopy-aided identification of single target-bound beads and the extraction - wet or dry - of these beads and their attached candidate molecules by a micropipette manipulator, and (3) identification of the target-binding candidate molecules via amplification and sequencing. This novel integration of techniques harnesses the sensitivity of DNA detection methods and the multiplexed and miniaturized nature of molecule screening to efficiently select and identify target-binding molecules from large nucleic acid encoded chemical libraries. Beyond its potential to accelerate assays currently used for the discovery of new drug candidates, its simple bead-based design allows for easy screening over a variety of prepared surfaces that can extend this technique's application to the discovery of diagnostic reagents and disease markers. Copyright (C) 2009 John Wiley & Sons, Ltd. Supporting information may be found in the online version of this paper. |
Djaker, Nadia ; Hostein, Richard ; Devaux, Eloise ; Ebbesen, Thomas W; Rigneault, Herve ; Wenger, Jerome Surface Enhanced Raman Scattering on a Single Nanometric Aperture Article de journal Dans: JOURNAL OF PHYSICAL CHEMISTRY C, 114 (39), p. 16250–16256, 2010, ISSN: 1932-7447. @article{djaker_surface_2010, title = {Surface Enhanced Raman Scattering on a Single Nanometric Aperture}, author = {Djaker, Nadia and Hostein, Richard and Devaux, Eloise and Ebbesen, Thomas W. and Rigneault, Herve and Wenger, Jerome}, doi = {10.1021/jp104971p}, issn = {1932-7447}, year = {2010}, date = {2010-10-01}, journal = {JOURNAL OF PHYSICAL CHEMISTRY C}, volume = {114}, number = {39}, pages = {16250--16256}, abstract = {Arrays of nanoapertures have been demonstrated to realize efficient, robust, and reproducible substrates for surface-enhanced Raman scattering SERS spectroscopy. However, little attention has been devoted to single nanoapertures, although a thorough understanding of the SERS phenomenon in a single aperture is essential for the rationale optimization of nanoaperture arrays SERS. In this study, single nanoapertures milled in optically thick gold films are quantitatively evaluated for the first time to determine the SERS enhancement factors using para-mercaptoaniline as nonresonant analyte. We determine a peak enhancement factor of 2 x 10(5) for a single 100 nm diameter aperture. Although this is a moderate enhancement factor, we believe that nanoapertures deserve special attention to highlight the physical and chemical phenomena leading to SERS enhancement and better understand the design of nanoaperture arrays for SERS substrates. The experimental data are supported by numerical simulations and argue for a careful consideration of aperture diameter, incident polarization, analyte deposition method, and nature of the gold adhesion layer while designing aperture-based SERS substrates and evaluating SERS enhancement factors.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Arrays of nanoapertures have been demonstrated to realize efficient, robust, and reproducible substrates for surface-enhanced Raman scattering SERS spectroscopy. However, little attention has been devoted to single nanoapertures, although a thorough understanding of the SERS phenomenon in a single aperture is essential for the rationale optimization of nanoaperture arrays SERS. In this study, single nanoapertures milled in optically thick gold films are quantitatively evaluated for the first time to determine the SERS enhancement factors using para-mercaptoaniline as nonresonant analyte. We determine a peak enhancement factor of 2 x 10(5) for a single 100 nm diameter aperture. Although this is a moderate enhancement factor, we believe that nanoapertures deserve special attention to highlight the physical and chemical phenomena leading to SERS enhancement and better understand the design of nanoaperture arrays for SERS substrates. The experimental data are supported by numerical simulations and argue for a careful consideration of aperture diameter, incident polarization, analyte deposition method, and nature of the gold adhesion layer while designing aperture-based SERS substrates and evaluating SERS enhancement factors. |
Zhu, Haihao ; Woolfenden, Steve ; Bronson, Roderick T; Jaffer, Zahara M; Barluenga, Sofia ; Winssinger, Nicolas ; Rubenstein, Allan E; Chen, Ruihong ; Charest, Al The Novel Hsp90 Inhibitor NXD30001 Induces Tumor Regression in a Genetically Engineered Mouse Model of Glioblastoma Multiforme Article de journal Dans: MOLECULAR CANCER THERAPEUTICS, 9 (9), p. 2618–2626, 2010, ISSN: 1535-7163. @article{zhu_novel_2010, title = {The Novel Hsp90 Inhibitor NXD30001 Induces Tumor Regression in a Genetically Engineered Mouse Model of Glioblastoma Multiforme}, author = {Zhu, Haihao and Woolfenden, Steve and Bronson, Roderick T. and Jaffer, Zahara M. and Barluenga, Sofia and Winssinger, Nicolas and Rubenstein, Allan E. and Chen, Ruihong and Charest, Al}, doi = {10.1158/1535-7163.MCT-10-0248}, issn = {1535-7163}, year = {2010}, date = {2010-09-01}, journal = {MOLECULAR CANCER THERAPEUTICS}, volume = {9}, number = {9}, pages = {2618--2626}, abstract = {Glioblastoma multiforme (GBM) has an abysmal prognosis. We now know that the epidermal growth factor receptor (EGFR) signaling pathway and the loss of function of the tumor suppressor genes p16Ink4a/p19ARF and PTEN play a crucial role in GBM pathogenesis: initiating the early stages of tumor development, sustaining tumor growth, promoting infiltration, and mediating resistance to therapy. We have recently shown that this genetic combination is sufficient to promote the development of GBM in adult mice. Therapeutic agents raised against single targets of the EGFR signaling pathway have proven rather inefficient in GBM therapy, showing the need for combinatorial therapeutic approaches. An effective strategy for concurrent disruption of multiple signaling pathways is via the inhibition of the molecular chaperone heat shock protein 90 (Hsp90). Hsp90 inhibition leads to the degradation of so-called client proteins, many of which are key effectors of GBM pathogenesis. NXD30001 is a novel second generation Hsp90 inhibitor that shows improved pharmacokinetic parameters. Here we show that NXD30001 is a potent inhibitor of GBM cell growth in vitro consistent with its capacity to inhibit several key targets and regulators of GBM biology. We also show the efficacy of NXD30001 in vivo in an EGFR-driven genetically engineered mouse model of GBM. Our findings establish that the Hsp90 inhibitor NXD30001 is a therapeutically multivalent molecule, whose actions strike GBM at the core of its drivers of tumorigenesis and represent a compelling rationale for its use in GBM treatment. Mol Cancer Ther; 9(9); 2618-26. (C) 2010 AACR.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Glioblastoma multiforme (GBM) has an abysmal prognosis. We now know that the epidermal growth factor receptor (EGFR) signaling pathway and the loss of function of the tumor suppressor genes p16Ink4a/p19ARF and PTEN play a crucial role in GBM pathogenesis: initiating the early stages of tumor development, sustaining tumor growth, promoting infiltration, and mediating resistance to therapy. We have recently shown that this genetic combination is sufficient to promote the development of GBM in adult mice. Therapeutic agents raised against single targets of the EGFR signaling pathway have proven rather inefficient in GBM therapy, showing the need for combinatorial therapeutic approaches. An effective strategy for concurrent disruption of multiple signaling pathways is via the inhibition of the molecular chaperone heat shock protein 90 (Hsp90). Hsp90 inhibition leads to the degradation of so-called client proteins, many of which are key effectors of GBM pathogenesis. NXD30001 is a novel second generation Hsp90 inhibitor that shows improved pharmacokinetic parameters. Here we show that NXD30001 is a potent inhibitor of GBM cell growth in vitro consistent with its capacity to inhibit several key targets and regulators of GBM biology. We also show the efficacy of NXD30001 in vivo in an EGFR-driven genetically engineered mouse model of GBM. Our findings establish that the Hsp90 inhibitor NXD30001 is a therapeutically multivalent molecule, whose actions strike GBM at the core of its drivers of tumorigenesis and represent a compelling rationale for its use in GBM treatment. Mol Cancer Ther; 9(9); 2618-26. (C) 2010 AACR. |
Devaux, Eloise ; Laluet, Jean-Yves ; Stein, Benedikt ; Genet, Cyriaque ; Ebbesen, Thomas ; Weeber, Jean-Claude ; Dereux, Alain Refractive micro-optical elements for surface plasmons: from classical to gradient index optics Article de journal Dans: OPTICS EXPRESS, 18 (20), p. 20610–20619, 2010, ISSN: 1094-4087. @article{devaux_refractive_2010, title = {Refractive micro-optical elements for surface plasmons: from classical to gradient index optics}, author = {Devaux, Eloise and Laluet, Jean-Yves and Stein, Benedikt and Genet, Cyriaque and Ebbesen, Thomas and Weeber, Jean-Claude and Dereux, Alain}, doi = {10.1364/OE.18.020610}, issn = {1094-4087}, year = {2010}, date = {2010-09-01}, journal = {OPTICS EXPRESS}, volume = {18}, number = {20}, pages = {20610--20619}, abstract = {Controlling the propagation of surface plasmons along a metal-dielectric interface is a key feature for the development of surface plasmon based circuits. We have designed various two-dimensional refractive dielectric optical elements for surface plasmons (SP) and characterized their capacity to route SP, using near-or far-field techniques. We first present basic devices analogous to usual optical components and the associated challenges for SP optics. We then use a metamaterial approach to locally vary the refractive index and fabricate gradient index structures for SP circuitry. (C) 2010 Optical Society of America}, keywords = {}, pubstate = {published}, tppubtype = {article} } Controlling the propagation of surface plasmons along a metal-dielectric interface is a key feature for the development of surface plasmon based circuits. We have designed various two-dimensional refractive dielectric optical elements for surface plasmons (SP) and characterized their capacity to route SP, using near-or far-field techniques. We first present basic devices analogous to usual optical components and the associated challenges for SP optics. We then use a metamaterial approach to locally vary the refractive index and fabricate gradient index structures for SP circuitry. (C) 2010 Optical Society of America |
Ciesielski, Artur ; Palma, Carlos-Andres ; Bonini, Massimo ; Samori, Paolo Towards Supramolecular Engineering of Functional Nanomaterials: Pre-Programming Multi-Component 2D Self-Assembly at Solid-Liquid Interfaces Article de journal Dans: ADVANCED MATERIALS, 22 (32), p. 3506–3520, 2010, ISSN: 0935-9648. @article{ciesielski_towards_2010, title = {Towards Supramolecular Engineering of Functional Nanomaterials: Pre-Programming Multi-Component 2D Self-Assembly at Solid-Liquid Interfaces}, author = {Ciesielski, Artur and Palma, Carlos-Andres and Bonini, Massimo and Samori, Paolo}, doi = {10.1002/adma.201001582}, issn = {0935-9648}, year = {2010}, date = {2010-08-01}, journal = {ADVANCED MATERIALS}, volume = {22}, number = {32}, pages = {3506--3520}, abstract = {Materials with a preprogrammed order at the supramolecular level can be engineered with a sub-nanometer precision making use of reversible non-covalent interactions. The intrinsic ability of supramolecular materials to recognize and exchange their constituents makes them constitutionally dynamic materials. The tailoring of the materials properties relies on the full control over the self-assembly behavior of molecular modules exposing recognition sites and incorporating functional units. In this review we focus on three classes of weak-interactions to form complex 2D architectures starting from properly designed molecular modules: van der Waals, metallo-ligand and hydrogen bonding. Scanning tunneling microscopy studies will provide evidence with a sub-nanometer resolution, on the formation of responsive multicomponent architectures with controlled geometries and properties. Such endeavor enriches the scientist capability of generating more and more complex smart materials featuring controlled functions and unprecedented properties.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Materials with a preprogrammed order at the supramolecular level can be engineered with a sub-nanometer precision making use of reversible non-covalent interactions. The intrinsic ability of supramolecular materials to recognize and exchange their constituents makes them constitutionally dynamic materials. The tailoring of the materials properties relies on the full control over the self-assembly behavior of molecular modules exposing recognition sites and incorporating functional units. In this review we focus on three classes of weak-interactions to form complex 2D architectures starting from properly designed molecular modules: van der Waals, metallo-ligand and hydrogen bonding. Scanning tunneling microscopy studies will provide evidence with a sub-nanometer resolution, on the formation of responsive multicomponent architectures with controlled geometries and properties. Such endeavor enriches the scientist capability of generating more and more complex smart materials featuring controlled functions and unprecedented properties. |
Samori, Cristian ; Sainz, Raquel ; Menard-Moyon, Cecilia ; Toma, Francesca M; Venturelli, Enrica ; Singh, Prabhpreet ; Ballestri, Marco ; Prato, Maurizio ; Bianco, Alberto Potentiometric titration as a straightforward method to assess the number of functional groups on shortened carbon nanotubes Article de journal Dans: CARBON, 48 (9), p. 2447–2454, 2010, ISSN: 0008-6223. @article{samori_potentiometric_2010, title = {Potentiometric titration as a straightforward method to assess the number of functional groups on shortened carbon nanotubes}, author = {Samori, Cristian and Sainz, Raquel and Menard-Moyon, Cecilia and Toma, Francesca M. and Venturelli, Enrica and Singh, Prabhpreet and Ballestri, Marco and Prato, Maurizio and Bianco, Alberto}, doi = {10.1016/j.carbon.2010.03.015}, issn = {0008-6223}, year = {2010}, date = {2010-08-01}, journal = {CARBON}, volume = {48}, number = {9}, pages = {2447--2454}, abstract = {The conditions for oxidizing multi-walled carbon nanotubes to shorten them to a narrow length distribution have been optimized. One of the most difficult achievements is to fully characterize this material from a chemical point of view, and to find a good quantitative correlation among different techniques. Herein, we report on the combination of different methods to determine the number of functional groups generated during strong acid treatment and a further amidation reaction. A good correlation was found using the colorimetric Kaiser test, thermogravimetric analysis and potentiometric argentometric titration. The final technique, used for the first time in this field, is highly versatile and, being non-destructive, allows a complete recovery of the starting material. Short carbon nanotubes are particularly useful for applications in biomedicine, and the control and precise assessment of their functionalization is critical when used as carriers for therapeutic molecules. (C) 2010 Elsevier Ltd. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The conditions for oxidizing multi-walled carbon nanotubes to shorten them to a narrow length distribution have been optimized. One of the most difficult achievements is to fully characterize this material from a chemical point of view, and to find a good quantitative correlation among different techniques. Herein, we report on the combination of different methods to determine the number of functional groups generated during strong acid treatment and a further amidation reaction. A good correlation was found using the colorimetric Kaiser test, thermogravimetric analysis and potentiometric argentometric titration. The final technique, used for the first time in this field, is highly versatile and, being non-destructive, allows a complete recovery of the starting material. Short carbon nanotubes are particularly useful for applications in biomedicine, and the control and precise assessment of their functionalization is critical when used as carriers for therapeutic molecules. (C) 2010 Elsevier Ltd. All rights reserved. |
Publications (FR)
2011 |
Integration of self-assembled discotic-based fibres into field-effect transistors: a comparison of preparation approaches Article de journal Dans: JOURNAL OF MATERIALS CHEMISTRY, 21 (1), p. 206–213, 2011, ISSN: 0959-9428. |
Charge transport in graphene-polythiophene blends as studied by Kelvin Probe Force Microscopy and transistor characterization Article de journal Dans: JOURNAL OF MATERIALS CHEMISTRY, 21 (9), p. 2924–2931, 2011, ISSN: 0959-9428. |
Polyamine functionalized carbon nanotubes: synthesis, characterization, cytotoxicity and siRNA binding Article de journal Dans: JOURNAL OF MATERIALS CHEMISTRY, 21 (13), p. 4850–4860, 2011, ISSN: 0959-9428. |
Supramolecular assembly/reassembly processes: molecular motors and dynamers operating at surfaces Article de journal Dans: NANOSCALE, 3 (4), p. 1397–1410, 2011, ISSN: 2040-3364. |
Self-templating 2D supramolecular networks: a new avenue to reach control over a bilayer formation Article de journal Dans: NANOSCALE, 3 (10), p. 4125–4129, 2011, ISSN: 2040-3364. |
Photoinduced work function changes by isomerization of a densely packed azobenzene-based SAM on Au: a joint experimental and theoretical study Article de journal Dans: PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 13 (32), p. 14302–14310, 2011, ISSN: 1463-9076. |
Polyphosphates and Pyrophosphates of Hexopyranoses as Allosteric Effectors of Human Hemoglobin: Synthesis, Molecular Recognition, and Effect on Oxygen Release Article de journal Dans: CHEMMEDCHEM, 6 (1), p. 153–168, 2011, ISSN: 1860-7179. |
Tetrakisphosphates and Bispyrophosphates of myo-Inositol Derivatives as Allosteric Effectors of Human Hemoglobin: Synthesis, Molecular Recognition, and Oxygen Release Article de journal Dans: CHEMMEDCHEM, 6 (1), p. 169–180, 2011, ISSN: 1860-7179. |
Modulation of self-assembly and magnetism of Cu(II) grids in solution Article de journal Dans: CHEMICAL COMMUNICATIONS, 47 (39), p. 10951–10953, 2011, ISSN: 1359-7345. |
Configurational and Constitutional Information Storage: Multiple Dynamics in Systems Based on Pyridyl and Acyl Hydrazones Article de journal Dans: CHEMISTRY-A EUROPEAN JOURNAL, 17 (1), p. 248–258, 2011, ISSN: 0947-6539. |
A new hydrogen bonding motif involved in self-recognition in the solid state by functionalised macrocycles Article de journal Dans: CRYSTENGCOMM, 13 (7), p. 2346–2349, 2011, ISSN: 1466-8033. |
Structural and metallo selectivity in the assembly of [2 x 2] grid-type metallosupramolecular species: Mechanisms and kinetic control Article de journal Dans: DALTON TRANSACTIONS, 40 (45), p. 12320–12332, 2011, ISSN: 1477-9226. |
Release of bioactive volatiles from supramolecular hydrogels: influence of reversible acylhydrazone formation on gel stability and volatile compound evaporation Article de journal Dans: ORGANIC & BIOMOLECULAR CHEMISTRY, 9 (8), p. 2906–2919, 2011, ISSN: 1477-0520. |
Scaling concepts in cell physics: paradigms for cell adhesion Article de journal Dans: SOFT MATTER, 7 (3), p. 824–829, 2011, ISSN: 1744-683X. |
SPONTANEOUS MECHANICAL OSCILLATIONS: IMPLICATIONS FOR DEVELOPING ORGANISMS incollection Dans: {Labouesse, M} (Ed.): FORCES AND TENSION IN DEVELOPMENT, 95 , p. 67–91, 2011, ISBN: 978-0-12-385065-2. |
A noncovalently assembled porphyrinic catenane consisting of two interlocking [43]-membered rings Article de journal Dans: NEW JOURNAL OF CHEMISTRY, 35 (8), p. 1751–1757, 2011, ISSN: 1144-0546. |
Bigger, better, faster: molecular shuttles with sterically non-hindering biisoquinoline chelates Article de journal Dans: SUPRAMOLECULAR CHEMISTRY, 23 (1-2, SI), p. 42–52, 2011, ISSN: 1061-0278. |
Donor-acceptor molecular figures-of-eight Article de journal Dans: CHEMICAL COMMUNICATIONS, 47 (43), p. 11870–11872, 2011, ISSN: 1359-7345. |
Combinatorial Self-Assembly of Glycan Fragments into Microarrays Article de journal Dans: CHEMBIOCHEM, 12 (1), p. 56–60, 2011, ISSN: 1439-4227. |
Synthesis of [5]Rotaxanes Containing Bi- and Tridentate Coordination Sites in the Axis Article de journal Dans: CHEMISTRY-A EUROPEAN JOURNAL, 17 (3), p. 947–957, 2011, ISSN: 0947-6539. |
Synthesis of [2]-, [3]-, and [4]rotaxanes whose axis contains two bidentate and two tridentate chelates Article de journal Dans: NEW JOURNAL OF CHEMISTRY, 35 (10), p. 2009–2012, 2011, ISSN: 1144-0546. |
DNA-templated release of functional molecules with an azide-reduction-triggered immolative linker Article de journal Dans: CHEMICAL COMMUNICATIONS, 47 (15), p. 4364–4366, 2011, ISSN: 1359-7345. |
A [3]rotaxane composed of a zinc porphyrin tetra-substituted with coordinating macrocycles and of two short rigid axles Article de journal Dans: NEW JOURNAL OF CHEMISTRY, 35 (12), p. 2820–2825, 2011, ISSN: 1144-0546. |
Selection of a synthetic glycan oligomer from a library of DNA-templated fragments against DC-SIGN and inhibition of HIV gp120 binding to dendritic cells Article de journal Dans: CHEMICAL COMMUNICATIONS, 47 (33), p. 9321–9323, 2011, ISSN: 1359-7345. |
DNA-templated combinatorial assembly of small molecule fragments amenable to selection/amplification cycles Article de journal Dans: CHEMICAL SCIENCE, 2 (4), p. 625–632, 2011, ISSN: 2041-6520. |
Rapid fluorescence imaging of miRNAs in human cells using templated Staudinger reaction Article de journal Dans: CHEMICAL SCIENCE, 2 (10), p. 1969–1975, 2011, ISSN: 2041-6520. |
The Thermophilic CotA Laccase from Bacillus subtilis: Bioelectrocatalytic Evaluation of O2 Reduction in the Direct and Mediated Electron Transfer Regime Article de journal Dans: Electroanalysis, 23 (8), p. 1781–1789, 2011, ISSN: 1521-4109. |
Highest paraoxonase turnover rate found in a bacterial phosphotriesterase variant Article de journal Dans: Protein engineering, design & selection: PEDS, 24 (1-2), p. 209–211, 2011, ISSN: 1741-0134. |
Phosphotriesterase variants with high methylphosphonatase activity and strong negative trade-off against phosphotriesters Article de journal Dans: Protein engineering, design & selection: PEDS, 24 (1-2), p. 151–159, 2011, ISSN: 1741-0134. |
Immobilization of CotA, an extremophilic laccase from Bacillus subtilis, on glassy carbon electrodes for biofuel cell applications Article de journal Dans: Electrochemistry Communications, 13 (1), p. 24–27, 2011, ISSN: 1388-2481. |
Absorption-Induced Transparency Article de journal Dans: ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 50 (9), p. 2085–2089, 2011, ISSN: 1433-7851. |
2010 |
Atomistic Simulations of 2D Bicomponent Self-Assembly: From Molecular Recognition to Self-Healing Article de journal Dans: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 132 (50), p. 17880–17885, 2010, ISSN: 0002-7863. |
Adsorption of Aromatic and Anti-Aromatic Systems on Graphene through pi-pi Stacking Article de journal Dans: JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 1 (23), p. 3407–3412, 2010, ISSN: 1948-7185. |
Two-Dimensional Structures of Anthracene Derivatives: Photodimerization and Host-Guest Chemistry Article de journal Dans: JOURNAL OF PHYSICAL CHEMISTRY B, 114 (50), p. 16718–16722, 2010, ISSN: 1520-6106. |
myo-Inositol Trispyrophosphate: A Novel Allosteric Effector of Hemoglobin with High Permeation Selectivity across the Red Blood Cell Plasma Membrane Article de journal Dans: CHEMBIOCHEM, 11 (18), p. 2543–2548, 2010, ISSN: 1439-4227. |
The Molecular Chaperone Hsp90 alpha Is Required for Meiotic Progression of Spermatocytes beyond Pachytene in the Mouse Article de journal Dans: PLOS ONE, 5 (12), 2010, ISSN: 1932-6203. |
Surface Plasmon Mode Steering and Negative Refraction Article de journal Dans: PHYSICAL REVIEW LETTERS, 105 (26), 2010, ISSN: 0031-9007. |
Enhanced second-harmonic generation from individual metallic nanoapertures Article de journal Dans: OPTICS LETTERS, 35 (23), p. 4063–4065, 2010, ISSN: 0146-9592. |
Bottom-Up Fabricated Asymmetric Electrodes for Organic Electronics Article de journal Dans: ADVANCED MATERIALS, 22 (44), p. 5018+, 2010, ISSN: 0935-9648. |
Cooperative, bottom-up generation of rigid-rod nanostructures through dynamic polymer chemistry Article de journal Dans: POLYMER INTERNATIONAL, 59 (11, SI), p. 1477–1491, 2010, ISSN: 0959-8103. |
On the origin of M81 group extended dust emission Article de journal Dans: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 409 (1), p. 102–108, 2010, ISSN: 0035-8711. |
PRECLINICAL EVALUATION OF NXD30001, A NOVEL HSP90 INHIBITOR, FOR EFFICACY IN GLIOMA Article de journal Dans: NEURO-ONCOLOGY, 12 (4), p. 90, 2010, ISSN: 1522-8517. |
Holes with very acute angles: a new paradigm of extraordinary optical transmission through strongly localized modes Article de journal Dans: OPTICS EXPRESS, 18 (23), p. 23691–23697, 2010, ISSN: 1094-4087. |
Local Current Mapping and Patterning of Reduced Graphene Oxide Article de journal Dans: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 132 (40), p. 14130–14136, 2010, ISSN: 0002-7863. |
Selection of bead-displayed, PNA-encoded chemicals Article de journal Dans: JOURNAL OF MOLECULAR RECOGNITION, 23 (5), p. 414–422, 2010, ISSN: 0952-3499. |
Surface Enhanced Raman Scattering on a Single Nanometric Aperture Article de journal Dans: JOURNAL OF PHYSICAL CHEMISTRY C, 114 (39), p. 16250–16256, 2010, ISSN: 1932-7447. |
The Novel Hsp90 Inhibitor NXD30001 Induces Tumor Regression in a Genetically Engineered Mouse Model of Glioblastoma Multiforme Article de journal Dans: MOLECULAR CANCER THERAPEUTICS, 9 (9), p. 2618–2626, 2010, ISSN: 1535-7163. |
Refractive micro-optical elements for surface plasmons: from classical to gradient index optics Article de journal Dans: OPTICS EXPRESS, 18 (20), p. 20610–20619, 2010, ISSN: 1094-4087. |
Towards Supramolecular Engineering of Functional Nanomaterials: Pre-Programming Multi-Component 2D Self-Assembly at Solid-Liquid Interfaces Article de journal Dans: ADVANCED MATERIALS, 22 (32), p. 3506–3520, 2010, ISSN: 0935-9648. |
Potentiometric titration as a straightforward method to assess the number of functional groups on shortened carbon nanotubes Article de journal Dans: CARBON, 48 (9), p. 2447–2454, 2010, ISSN: 0008-6223. |