References of "Duwez, Anne-Sophie"
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See detailCoulombic driven multi-conformational aspects of oligorotaxane switches studied by ion mobility mass spectrometry and molecular dynamics
Hanozin, Emeline ULg; Mignolet, Benoît ULg; Morsa, Denis ULg et al

Conference (2017, June)

Introduction Artificial Molecular Machines (AMMs), such as Mechanically Interlocked Molecules (MIMs) and foldamers, have recently raised tremendous interest due to their unique properties. Under the ... [more ▼]

Introduction Artificial Molecular Machines (AMMs), such as Mechanically Interlocked Molecules (MIMs) and foldamers, have recently raised tremendous interest due to their unique properties. Under the influence of an appropriate stimuli (pH, redox potential, light…), such molecules are able to reversibly switch between distinct conformational states. Scientists may capitalize on such exclusive properties to get a better understanding of the biomacromolecular level or to design innovative “smart” materials. At the interface between foldamers and MIMs, oligorotaxanes exhibit a spring-like folded secondary structure with remarkable mechanical and physicochemical properties. In the present study, we use ion mobility coupled with mass spectrometry (IM-MS) to probe the conformational states of differentially charged oligorotaxanes in the gas phase. Method Oligorotaxanes are donor-acceptor polymers composed of a π electron-donating dumbbell over which a discrete number of π electron-accepting tetracationic cyclophanes are threaded. The numerous intra-molecular interactions provide them a highly-stabilized rigid rod-like structure in solution. We use IM-MS as implemented in the Synapt G2 HDMS (Waters, Manchester, UK) to investigate the structure of the ionized oligorotaxanes. Our purposes are to probe (i) the different populations of stable conformers generated according to the charge state z and (ii) the reversibility of an electron-driven or thermal-driven conformational change in the gas phase implemented via an electron transfer or collisional activation process prior to the mobility separation. Our experimental observations are supported by electronic structure optimizations at the PM6 and DFT levels coupled with Born-Oppenheimer Molecular Dynamics simulations. Preliminary data Our results highlight a progressive elongation of the oligorotaxane structure with increasing charge numbers until it reaches a maximum extension state. Matching the experimental data with theoretical simulations, we find that the oligorotaxanes adopt an entropically-favored globular shape at low z. As z increases, coulombic repulsions occurring between the cyclophanes gradually outweigh the stabilizing π-stacking interactions and force the structure to elongate. This process occurs in a multistep fashion, each corresponding to a distinct group of helical-shaped conformers, before it eventually results in a fully stretched structure. On the other hand, our results also highlight that a charge reduction driven by a non-dissociative electron transfer process leads to a refolding of the structure so that it adopts a size similar to its electrospray-generated counterpart when the appropriate number of electrons is added. This observation may be imparted to the gradual decrease of the Coulomb repulsions between the cyclophanes mediated through increasing numbers of transferred electrons. These results suggests that the transition from one conformer to another is reversible so that the electrostatic balance between the cyclophanes may be used to further tune the structural state adopted by this artificial molecular switch. The second stimulus relied on collisional activation whose inelastic component provides a way to build up energy into the accessible vibrational degrees of freedom. The conformational landscapes of such-activated oligorotaxanes ions were found unchanged in term of collision cross section position but the repartition of population was altered with a promotion of the most elongated conformer, provided the absence of selective fragmentation. Altogether, these results highlight the feasibility of handling the elongation state of oligorotaxanes in the gas phase through appropriate inputs and underline its conformational reversibility properties. Novel aspect Stimuli-induced reversible conformational rearrangements of innovative AMMs studied by IM-MS and molecular dynamics in the gas phase. [less ▲]

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See detailReal-time capture of the folding-unfolding transitions in a single oligorotaxane foldamer
Sluysmans, Damien ULg; Hubert, Sandrine ULg; Bruns, Carson et al

Poster (2016, October 13)

Detailed reference viewed: 4 (0 ULg)
See detailSingle-Molecule Force Spectroscopy on Synthetic Helical Nanoarchitectures
Devaux, Floriane ULg; Li, Xuesong; Huc, Ivan et al

Poster (2016, September)

Inspired by the many folded conformations of the molecular machineries in nature, chemists have been developing the syntheses of artificial folded molecular architectures, namely foldamers. The ... [more ▼]

Inspired by the many folded conformations of the molecular machineries in nature, chemists have been developing the syntheses of artificial folded molecular architectures, namely foldamers. The investigation of these molecules using AFM-based Single Molecule Force Spectrosocopy (SMFS) allows the elucidation of both mechanochemical properties and conformational dynamics on the unimolecular scale in solution. The stepwise synthesis of aromatic oligoamide-based foldamers was designed to produce well-defined helically-folded molecular architectures. A PEO tether was coupled to one end of the foldamer. SMFS pulling experiments on this system yielded specific and reproducible force-extension patterns characteristic of single foldamers. Those patterns were further analyzed to determine unfolding forces and dynamics as well as to propose mechanistics hypotheses of the unfolding process. Several helical foldamers presenting variable lengths were considered. The force values measured for those foldamers are higher than those previously measured in natural biopolymers showing a high stability under a load and a propensity for the development of emergent properties. In addition, the increased stability of these aromatic oligoamide foldamers was confirmed by the observation of almost instantaneous reversibility of the unfolding under load. [less ▲]

Detailed reference viewed: 14 (0 ULg)
See detailProbing single molecules with the AFM: Force, motion, dynamics, and function
Duwez, Anne-Sophie ULg

Conference (2016, July 18)

Detailed reference viewed: 17 (2 ULg)
See detailSingle Molecule force spectroscopy on helical foldamers
Devaux, Floriane ULg; Li, Xuesong; Huc, Ivan et al

Conference (2016, July 07)

Detailed reference viewed: 7 (4 ULg)
See detailReal-time capture of the folding-unfolding transitions in a single oligorotaxane foldamer
Sluysmans, Damien ULg; Hubert, Sandrine ULg; Bruns, Carson et al

Scientific conference (2016, July)

Detailed reference viewed: 8 (4 ULg)
See detailSingle molecule force spectroscopy on helical foldamers
Devaux, Floriane ULg; Li, Xuesong; Huc, Ivan et al

Poster (2016, May 27)

Detailed reference viewed: 13 (2 ULg)
See detailReal-time capture of the folding-unfolding transitions in a single oligorotaxane foldamer
Sluysmans, Damien ULg; Stoddart, J. Fraser; Duwez, Anne-Sophie ULg

Conference (2016, May)

Detailed reference viewed: 13 (2 ULg)
See detailSingle-Molecule Force spectroscopy on synthetic Foldamers
Devaux, Floriane ULg; Li, Xuesong; Huc, Ivan et al

Poster (2016, April 26)

Detailed reference viewed: 3 (0 ULg)
See detailSingle molecule force spectroscopy on oligorotaxane foldamers
Sluysmans, Damien ULg; Stoddart, J. Fraser; Duwez, Anne-Sophie ULg

Conference (2016, April)

Detailed reference viewed: 7 (2 ULg)
See detailSingle-Molecule Force spectroscopy on synthetic helical Nanoarchitectures
Devaux, Floriane ULg; Li, Xuesong; Huc, Ivan et al

Conference (2016, March 16)

Detailed reference viewed: 2 (2 ULg)
See detailSingle molecule force spectroscopy on synthetic foldamers
Devaux, Floriane ULg; Li, Xuesong; Ivan, Huc et al

Poster (2016, January)

Inspired by the many folded conformations of the molecular machineries responsible for chemical reactions and mechanical tasks in nature, such as enzyme catalysis and duplication in nucleic acids ... [more ▼]

Inspired by the many folded conformations of the molecular machineries responsible for chemical reactions and mechanical tasks in nature, such as enzyme catalysis and duplication in nucleic acids, chemists have been developing the syntheses of artificial folded molecular architectures, namely foldamers (Guichard and Huc, 2011). The investigation of these molecules using AFM-based Single Molecule Force Spectrosocopy (SMFS) allows the elucidation of both mechanochemical properties and conformational dynamics on the unimolecular scale in solution. The stepwise synthesis of aromatic oligoamide-based foldamers was designed (Jiang et al., 2003; Huc, 2004) to produce well-defined helically-folded molecular architectures. A poly(ethylene oxide) PEO tether was coupled to one end of the foldamer. This tether design enables the coupling with the AFM tip and increases the number of potentially accessible physicochemical parameters through SMFS experiments. SMFS pulling experiments on this system yielded specific and reproducible force-extension patterns characteristic of single foldamers. Those patterns were further analyzed to determine unfolding forces and dynamics as well as to propose mechanistics hypotheses of the unfolding process. Several helical foldamers presenting variable lengths were considered. Experiments in multiple solvents pointed out a variation in the foldamer stability, leading to different average forces values. This last study enabled us to modulate the intramolecular interactions responsible for the folding and to evaluate the mechanochemical properties of the helix. The force values measured for those foldamers are higher than those previously measured in natural biopolymers (Clausen-Schaumann et al., 2000; Janshoff et al., 2000), showing a high stability under a load and a propensity for the development of emergent properties. In addition, the increased stability of these aromatic oligoamide foldamers was confirmed by the observation of almost instantaneous reversibility of the unfolding under load. [less ▲]

Detailed reference viewed: 104 (7 ULg)
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Peer Reviewed
See detailLiquid-Assisted Plasma-Enhanced Chemical Vapor Deposition of Catechol and Quinone-Functionalized Coatings: Insights into the Surface Chemistry and Morphology
Mauchauffé, Rodolphe; Moreno-Couranjou, Maryline; Boscher, N. D. et al

in Plasma Processes and Polymers (2016), 13(8), 843-856

Detailed reference viewed: 34 (6 ULg)
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See detailForce measurements reveal how small binders perturb the dissociation mechanisms of DNA duplex sequences
Burmistrova, Anastasia; Fresch, Barbara ULg; Sluysmans, Damien ULg et al

in Nanoscale (2016), 8

The force-driven separation of double-stranded DNA is crucial to the accomplishment of cellular pro- cesses like genome transactions. Ligands binding to short DNA sequences can have a local stabilizing or ... [more ▼]

The force-driven separation of double-stranded DNA is crucial to the accomplishment of cellular pro- cesses like genome transactions. Ligands binding to short DNA sequences can have a local stabilizing or destabilizing effect and thus severely affect these processes. Although the design of ligands that bind to specific sequences is a field of intense research with promising biomedical applications, so far, their effect on the force-induced strand separation has remained elusive. Here, by means of AFM-based single mole- cule force spectroscopy, we show the co-existence of two different mechanisms for the separation of a short DNA duplex and demonstrate how they are perturbed by small binders. With the support of Mole- cular Dynamics simulations, we evidence that above a critical pulling rate one of the dissociation pathways becomes dominant, with a dramatic effect on the rupture forces. Around the critical threshold, we observe a drop of the most probable rupture forces for ligand-stabilized duplexes. Our results offer a deep understanding of how a stable DNA–ligand complex behaves under force-driven strand separation [less ▲]

Detailed reference viewed: 102 (27 ULg)
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See detailFast Atmospheric Plasma Deposition of Bio-Inspired Catechol/Quinone-Rich Nanolayers to Immobilize NDM-1 Enzymes for Water Treatment
Mauchauffé, Rodolphe; Bonot, Sébastien; Moreno-Couranjou, Maryline et al

in Advanced Materials Interfaces (2016), 3(8), 101002

Detailed reference viewed: 26 (4 ULg)
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See detailLow bandgap copolymers based on monofluorinated isoindigo towards efficient polymer solar cells
Tomassetti, Mirco ULg; Ouhib, Farid ULg; Wislez, Arnaud ULg et al

in Polymer Chemistry (2015), 6(33), 6040-6049

To explore the effectiveness of monofluorinated isoindigo as an electron-deficient building block in push–pull conjugated polymers for organic solar cell applications, four low bandgap copolymers are ... [more ▼]

To explore the effectiveness of monofluorinated isoindigo as an electron-deficient building block in push–pull conjugated polymers for organic solar cell applications, four low bandgap copolymers are effectively synthesized and characterized. The effects of fluorine introduction, thiophene spacer length and polymer molar mass on the general electro-optical polymer characteristics, thin film blend micro- structure and electronic performance are investigated. Isoindigo monofluorination effectively improves the power conversion efficiency from 2.8 up to 5.0% upon molar mass optimization, without using any processing additives or post-treatments. [less ▲]

Detailed reference viewed: 31 (6 ULg)