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1. Influence of Substrate Hydrophilicity on Structural Properties of Supported Lipid Systems on Graphene, Graphene Oxides, and Silica

Author

Timothée Rivel, Mariia Savenko, Christophe Ramseyer, and Semen O. Yesylevskyy

Subjects
Materials science, Silicon dioxide, Lipid Bilayers, Molecular Conformation, 02 engineering and technology, Model lipid bilayer, 010402 general chemistry, 01 natural sciences, law.invention, chemistry.chemical_compound, law, Monolayer, Materials Chemistry, Physical and Theoretical Chemistry, Lipid bilayer, Graphene, Bilayer, Substrate (chemistry), Silicon Dioxide, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Surfaces, Coatings and Films, chemistry, Chemical engineering, Phosphatidylcholines, Graphite, lipids (amino acids, peptides, and proteins), 0210 nano-technology, Hydrophobic and Hydrophilic Interactions, Layer (electronics)
Abstract

Pristine graphene, a range of graphene oxides, and silica substrates were used to investigate the effect of surface hydrophilicity on supported lipid bilayers by means of all-atom molecular dynamics simulations. Supported 1,2-dioleoyl-sn-glycero-3-phosphocholine lipid bilayers were found in close-contact conformations with hydrophilic substrates with as low as 5% oxidation level, while self-assembled monolayers occur on pure hydrophobic graphene only. Lipids and water at the surface undergo large redistribution to maintain the stability of the supported bilayers. Deposition of bicelles on increasingly hydrophilic substrates shows the continuous process of reshaping of the supported system and makes intermediate stages between self-assembled monolayers and supported bilayers. The bilayer thickness changes with hydrophilicity in a complex manner, while the number of water molecules per lipid in the hydration layer increases together with hydrophilicity.

Published
2021
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2. Adsorption of water in Na-LTA zeolites: an ab initio molecular dynamics investigation

Author

Didier Ducret, J.-E. Groetz, Freddy Torrealba Anzola, Michael Badawi, Christophe Ramseyer, Caroline Chambelland, Manuel Grivet, Joharimanitra Randrianandraina, Bruno Cardey, Laboratoire Chrono-environnement (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Laboratoire de Physique et Chimie Théoriques (LPCT), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Centre CEA de Valduc (CEA-Valduc), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE)

Subjects
Range (particle radiation), Tritiated water, Chemistry, Cationic polymerization, General Physics and Astronomy, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Ring (chemistry), 01 natural sciences, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, chemistry.chemical_compound, [CHIM.POLY]Chemical Sciences/Polymers, Adsorption, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Chemical physics, Ab initio quantum chemistry methods, Molecule, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Physical and Theoretical Chemistry, 0210 nano-technology, Zeolite, [CHIM.RADIO]Chemical Sciences/Radiochemistry
Abstract

The very wide range of applications of LTA zeolites, including the storage of tritiated water, implies that a detailed and accurate atomic-scale description of the adsorption processes taking place in their structure is crucial. To unravel with an unprecedented accuracy the mechanisms behind the water filling in NaA, we have conducted a systematic ab initio molecular dynamics investigation. Two LTA structural models, the conventional Z4A and the reduced one ZK4, have been used for static and dynamic ab initio calculations, respectively. After assessing this reduced model with comparative static DFT calculations, we start the filling of the α and β cages by water, molecule by molecule. This allowed us to thoroughly study the interaction of water molecules with the zeolite structure and between water molecules, progressively forming H-bond chains and ring patterns as the cage is being filled. The adsorption energies could then be calculated with an unprecedented accuracy, which showed that the interaction of the molecules with the zeolite weakens as their number increases. By these methods, we have been able to highlight the primary role of Na+ cations in the interaction of water with zeolite, and inversely, the role of water in the displacement of cations when it is sufficiently solvated, allowing the passage between the α and β cages. This phenomenon is possible thanks to the inhomogeneous distribution of water molecules on the cationic sites, as shown by our AIMD simulations, which allows the formation of water clusters. These results are important because they help in understanding how the coverage of cationic sites by water will affect the adsorption of other molecules inside the Na-LTA zeolite.

Published
2021
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3. Stacking as a key property for creating nanoparticles with tunable shape: The case of squalenoyl-doxorubicin

Author

Barbara Stella, Franco Dosio, Jean-Philippe Michel, David Chapron, Patrick Couvreur, Claudie Bourgaux, Julie Mougin, Christophe Ramseyer, and Semen O. Yesylevskyy

Subjects
Materials science, Stacking, General Physics and Astronomy, Nanoparticle, Antineoplastic Agents, Nanotechnology, 02 engineering and technology, squalene, 010402 general chemistry, 01 natural sciences, bioconjugate, cylindrical nanoparticles, doxorubicin, elongated nanoparticles, nanomedicine, stacking, Hydrophobic effect, Drug Delivery Systems, polycyclic compounds, General Materials Science, Bioconjugation, General Engineering, 021001 nanoscience & nanotechnology, 3. Good health, 0104 chemical sciences, Ionic strength, Drug delivery, Nanoparticles, Nanomedicine, 0210 nano-technology, Hydrophobic and Hydrophilic Interactions, Conjugate
Abstract

The development of elongated nanoparticles for drug delivery is of growing interest in recent years, due to longer blood circulation and improved efficacy compared to spherical counterparts. Squalenoyl-doxorubicin (SQ-Dox) conjugate was previously shown to form elongated nanoparticles with improved therapeutic efficacy and decreased toxicity compared to free doxorubicin. By using experimental and computational techniques, we demonstrate here that the specific physical properties of SQ-Dox, which include stacking and electrostatic interactions of doxorubicin as well as hydrophobic interactions of squalene, are involved in the formation of nanoassemblies with diverse elongated structures. We show that SQ-Dox bioconjugate concentration, ionic strength, and anion nature can be used to modulate the shape and stiffness of SQ-Dox nanoparticles. As those parameters are involved in nanoparticle behavior in biological media, these findings could bring interesting opportunities for drug delivery and serve as an example for the design of original nanodrugs with stacking properties tuned for particular clinical purposes.

Published
2019

4. Albumin-driven disassembly of lipidic nanoparticles: the specific case of the squalene-adenosine nanodrug

Author

Marie Rouquette, Frédéric Gobeaux, Fabienne Testard, Semen O Yesylevsky, Didier Desmaële, Jean Philippe Renault, Joëlle Bizeau, Christophe Ramseyer, Frank Wien, Laurent Marichal, Isabelle Grillo, Sinda Lepetre-Mouelhi, Patrick Guenoun, Patrick Couvreur, Firmin Samson, Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire (LIONS), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Intégrative de la Cellule (I2BC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Department of Physics of Biological Systems, Institute of Metal Physics of the National Academy of Sciences of Ukraine, Laboratoire Chrono-environnement (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Institut Galien Paris-Saclay (IGPS), Institut de Chimie du CNRS (INC)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), NATO grant SPS-G5291, ANR-11-IDEX-0003,IPS,Idex Paris-Saclay(2011), ANR-10-INBS-0005,FRISBI,Infrastructure Française pour la Biologie Structurale Intégrée(2010), European Project: 690853, European Project: 654000, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), ILL, Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Squalene, Adenosine, complexation, serum albumin, Serum albumin, 02 engineering and technology, Plasma protein binding, 010402 general chemistry, 01 natural sciences, Mice, Drug Stability, medicine, Animals, Humans, General Materials Science, Prodrugs, Colloids, Bovine serum albumin, ComputingMilieux_MISCELLANEOUS, Binding Sites, biology, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Chemistry, Albumin, Isothermal titration calorimetry, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Human serum albumin, disassembly, 0104 chemical sciences, nanodrug, biology.protein, Biophysics, Nanomedicine, Nanoparticles, 0210 nano-technology, Fetal bovine serum, medicine.drug, Protein Binding
Abstract

International audience; In the field of nanomedicine, nanostructured nanoparticles (NPs) made of self-assembling prodrugs emerged in the recent years with promising properties. In particular, squalene-based drug nanoparticles have already shown their efficiency through in vivo experiments. However, a complete pattern of their stability and interactions in the blood stream is still lacking. In this work we assess the behavior of squalene-adenosine (SQAd) nanoparticles-whose neuroprotective effect has already been demonstrated in murine models-in the presence of fetal bovine serum (FBS) and of bovine serum albumin (BSA), the main protein of blood plasma. Extensive physicochemical characterizations were performed using Small Angle Neutron Scattering (SANS), cryogenic transmission electron microscopy (Cryo-TEM), circular dichroism (CD), steady-state fluorescence spectroscopy (SSFS) and isothermal titration calorimetry (ITC) and in silico by means of ensemble docking simulations with human serum albumin (HSA). Significant changes in the colloidal stability of the nanoparticles in the presence of serum albumin were observed. SANS, CD and SSFS analyses demonstrated an interaction 2 between SQAd and BSA, with a partial disassembly of the nanoparticles in the presence of BSA and the formation of a complex between SQAd and BSA. The interaction free energy of SQAd nanoparticles with BSA derived from ITC experiments, is about-8 kcal/mol which is further supported in silico by ensemble docking simulations. Overall, our results show that serum albumin partially disassembles SQAd nanoparticles by extracting individual SQAd monomers from them. As a consequence, the SQAd nanoparticles would act as a circulating reservoir in the blood stream. The approach developed in this study could be extended to other soft organic nanoparticles.

Published
2020
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5. Squalene versus cholesterol: Which is the best nanocarrier for the delivery to cells of the anticancer drug gemcitabine?

Author

Arnaud Peramo, Semen O. Yesylevskyy, Christophe Ramseyer, Dunja Sobot, Patrick Couvreur, Simona Mura, Didier Desmaële, Stéphanie Denis, Bruno Cardey, Institut Galien Paris-Sud (IGPS), Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Physico-chimie, pharmacotechnie, biopharmacie (PCPB), and Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0301 basic medicine, Cholesterol, General Chemical Engineering, 02 engineering and technology, General Chemistry, Pharmacology, 021001 nanoscience & nanotechnology, Anticancer drug, Gemcitabine, 3. Good health, 03 medical and health sciences, Squalene, chemistry.chemical_compound, 030104 developmental biology, chemistry, medicine, [CHIM]Chemical Sciences, Nanocarriers, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS, medicine.drug
Abstract

Comptes Rendus Chimie - In Press.Proof corrected by the author Available online since jeudi 22 mars 2018

Published
2018
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6. Low density lipoproteins and human serum albumin as the carriers of squalenoylated drugs: insights from molecular simulations

Author

Mariia Savenko, Simona Mura, Patrick Couvreur, Christophe Ramseyer, Semen O. Yesylevskyy, Laboratoire Chrono-environnement ( LCE ), Université Bourgogne Franche-Comté ( UBFC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Physico-chimie, pharmacotechnie, biopharmacie ( PCPB ), Université Paris-Sud - Paris 11 ( UP11 ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Physico-chimie, pharmacotechnie, biopharmacie (PCPB), and Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Squalene, [PHYS.PHYS.PHYS-BIO-PH]Physics [physics]/Physics [physics]/Biological Physics [physics.bio-ph], Drug Compounding, Pharmaceutical Science, Serum Albumin, Human, 02 engineering and technology, Plasma protein binding, Molecular Dynamics Simulation, 010402 general chemistry, 01 natural sciences, Molecular Docking Simulation, Deoxycytidine, chemistry.chemical_compound, [ PHYS.PHYS.PHYS-BIO-PH ] Physics [physics]/Physics [physics]/Biological Physics [physics.bio-ph], Lipid droplet, Drug Discovery, medicine, Moiety, Humans, ComputingMilieux_MISCELLANEOUS, Drug Carriers, Binding Sites, Adenine, [SDV.SP]Life Sciences [q-bio]/Pharmaceutical sciences, 021001 nanoscience & nanotechnology, Human serum albumin, Gemcitabine, 3. Good health, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Lipoproteins, LDL, [ SDV.SP ] Life Sciences [q-bio]/Pharmaceutical sciences, chemistry, Docking (molecular), Doxorubicin, [ CHIM.THEO ] Chemical Sciences/Theoretical and/or physical chemistry, Biophysics, Molecular Medicine, Nanoparticles, 0210 nano-technology, Drug carrier, Hydrophobic and Hydrophilic Interactions, medicine.drug, Protein Binding
Abstract

We have studied the interaction of three clinically promising squalenoylated drugs (gemcitabine-squalene, adenine-squalene, and doxorubicin-squalene) with low-density lipoproteins (LDL) by means of atomistic molecular dynamics simulations. It is shown that all studied squalenoylated drugs accumulate inside the LDL particles. This effect is promoted by the squalene moiety, which acts as an anchor and drives the hydrophilic drugs into the hydrophobic core of the LDL lipid droplet. Our data suggest that LDL particles could be a universal carriers of squalenoylated drugs in the bloodstream. Interaction of gemcitabine-squalene with human serum albumin (HSA) was also studied by ensemble of docking simulations. It is shown that HSA could also act as a passive carrier of this bioconjugate. It should be noted that the binding of squalene moiety to HSA was unspecific and did not occur in the binding pockets devoted to fatty acids.

Published
2018
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7. Uptake and Translocation Mechanisms of Cationic Amino Derivatives Functionalized on Pristine C60 by Lipid Membranes: A Molecular Dynamics Simulation Study

Author

Mounir Tarek, Christophe Ramseyer, Sebastian Kraszewski, Nanomédecine, imagerie, thérapeutique - UFC (EA 4662) (NIT / NANOMEDECINE), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Structure et Réactivité des Systèmes Moléculaires Complexes (SRSMC), and Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Fullerene, Stereochemistry, Lipid Bilayers, Molecular Conformation, General Physics and Astronomy, free-energy profiles, 02 engineering and technology, Molecular Dynamics Simulation, Conjugated system, 010402 general chemistry, 01 natural sciences, Molecular dynamics, Deprotonation, General Materials Science, Amines, Lipid bilayer, [PHYS.PHYS]Physics [physics]/Physics [physics], passive diffusion, Chemistry, Cell Membrane, General Engineering, Cationic polymerization, Biological Transport, 021001 nanoscience & nanotechnology, molecular dynamics, 0104 chemical sciences, Membrane, uptake, drug vectors, Biophysics, cationic functionalization, Fullerenes, Protons, 0210 nano-technology, Drug carrier, Hydrophobic and Hydrophilic Interactions
Abstract

International audience; Bioactive molecules, cationic peptides among them, are nowadays well-recognized in modern pharmacology for their drug potential. However, they usually suffer from poor translocation across cell membranes, and specific drug carriers should be designed to circumvent this problem. In the present study, the uptake mechanism of fullerene bearing cationic ammonium groups by membranes modeled as lipid bilayers is investigated using extensive molecular dynamics simulations and free-energy calculations. Three main results issued from this work can be drawn. First, the fullerene core appears to be a good drug vector since it greatly enhances the uptake of the cationic groups by the membrane. Second, we show that the amino derivatives should be deprotonated at the lipid headgroup level in order to fully translocate the membrane by passive diffusion. Finally, the fullerenes bearing too many cationic groups display mostly a hydrophilic character; thus, the lipophilic fullerene core is not anymore effective as an insertion enhancer. Therefore, the lipid bilayer appears to be very selective with respect to the amount of amino groups conjugated with C60.

Published
2011
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8. CHARACTERIZATION OF SURFACE DEFECTS THROUGH THE MODIFICATION OF THE INFRARED PROFILE OF ADMOLECULES: APPLICATION TO <font>CO</font> MOLECULES ADSORBED ON (100) <font>MgO</font> AND <font>NaCl</font> SURFACES

Author

Hanen Zorgati, Christophe Ramseyer, Claude Girardet, Moncef Said, Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire de Physique Moléculaire (UMR 6624) (LPM), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Surface (mathematics), 010304 chemical physics, Infrared, Chemistry, Analytical chemistry, Ionic bonding, Infrared spectroscopy, 02 engineering and technology, Surfaces and Interfaces, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Surfaces, Coatings and Films, Characterization (materials science), Dipole, Adsorption, probe molecule, 0103 physical sciences, Materials Chemistry, Molecule, Physics::Chemical Physics, Surface defects, infrared spectroscopy, 0210 nano-technology
Abstract

International audience; Real surfaces display defects originating either from thermodynamic principles or from local instabilities. In order to help and characterize these surfaces and their defects, infrared spectroscopy of physisorbed test molecules can be used. As an example, we study the behavior of the infrared response of CO molecules randomly deposited on ionic surfaces of MgO and NaCl with the concentration of dipolar defects randomly distributed on these surfaces. The vibrational peak is shifted and asymmetrically broadened when the defect concentration increases as a result of surface inhomogeneity, in semi-quantitative agreement with experimental data.

Published
2010
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9. Affinity of C60 Neat Fullerenes with Membrane Proteins: A Computational Study on Potassium Channels

Author

Mounir Tarek, Werner Treptow, Sebastian Kraszewski, Christophe Ramseyer, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Structure et Réactivité des Systèmes Moléculaires Complexes (SRSMC), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), and Universidade de Brasilia [Brasília] (UnB)

Subjects
Potassium Channels, binding, Fullerene, ionic channels, General Physics and Astronomy, 02 engineering and technology, Plasma protein binding, Molecular Dynamics Simulation, 010402 general chemistry, 01 natural sciences, Cell membrane, Protein structure, medicine, Organic chemistry, Computer Simulation, General Materials Science, Ion channel, [PHYS]Physics [physics], Chemistry, Cell Membrane, General Engineering, Tetraethylammonium, fullerenes, toxicity, 021001 nanoscience & nanotechnology, molecular dynamics, Potassium channel, Protein Structure, Tertiary, 0104 chemical sciences, medicine.anatomical_structure, Membrane, Membrane protein, Biophysics, Thermodynamics, 0210 nano-technology, Ion Channel Gating, Protein Binding
Abstract

International audience; Most studies of the interactions of neat and functionalized fullerenes with cells have focused so far on their ability to cross the cell membrane envelopes. Membranes are, however, also host to a large number of proteins responsible for various cellular functions. Among these, ion channels are prominent components of the nervous system. Recently, it was shown that fullerenes may act as blockers or modulators of a variety of K+ channels. Here we use computer simulations to investigate the propensity of such nanocompounds to bind to K+ channels. Our results based on extensive atomistic molecular dynamics simulations reveal a variety of specific binding sites depending on the structure and properties of the channel. The corresponding binding free energies and putative mechanisms suggest that C60 may indeed effectively hinder the function of K+ channels and hence induce toxicity.

Published
2010
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10. Growth of perfect and smooth Ag and Co monatomic wires on Pt vicinal surfaces: A kinetic Monte Carlo study

Author

Christophe Ramseyer, Hedi Garbouj, Moncef Said, D. Spanjaard, Fabien Picaud, Marie-Catherine Desjonquères, Université de Monastir - University of Monastir (UM), Faculté des Sciences de Monastir (FSM), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Laboratoire de Physique des Solides (LPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie des Surfaces et Interfaces (LCSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)

Subjects
[PHYS]Physics [physics], Diffusion barrier, Chemistry, Nanowire, 02 engineering and technology, Surfaces and Interfaces, Large range, Atmospheric temperature range, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Surfaces, Coatings and Films, Monatomic ion, Crystallography, Chemical physics, 0103 physical sciences, Materials Chemistry, Kinetic Monte Carlo, Diffusion (business), 010306 general physics, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS, Vicinal
Abstract

Growing perfect monatomic chains on surfaces is generally a hard task since it depends strongly on the experimental conditions and on the species used as templates or adsorbates. In the present study, the growth of Co and Ag monatomic wires on a Pt(9 9 7) vicinal surface is investigated over a large range of temperature. A semi-empirical potential is used to extract the main diffusion barriers responsible for the growth of Co and Ag wires on the Pt(9 9 7) vicinal surface. Kinetic Monte Carlo simulations are performed to investigate the wire formation at step-edges. We show that step decoration occurs at 150 K for Ag and at temperatures higher than 250 K for Co in agreement with growth experiments. If no interdiffusion is taken into account, Co and Ag behave similarly and perfect wires form between 150 and 500 K for Ag and between 300 and 500 K for Co. In the case of Co, an exchange mechanism leading to interlayer diffusion at step-edges is shown to strongly influence the temperature range for which the perfect wires are observed. An activation barrier of 0.65 eV for this mechanism is found to be adequate to reproduce the experimental features observed by Gambardella et al. [P. Gambardella, M. Blanc, L. Burgi, K. Kuhnke, K. Kern, Surf. Sci., 449 (2000) 93]. At higher temperatures, above 500 K, detachment from steps strongly hinders the wire formation at step feet. As a main conclusion, the exchange diffusion barrier can be extracted directly from the comparison between observation of step decoration and numerical simulations.

Published
2009
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11. How do functionalized carbon nanotubes land on, bind to and pierce through model and plasma membranes

Author

Alberto Bianco, Mounir Tarek, Christophe Ramseyer, Kostas Kostarelos, Hanene Ali-Boucetta, Lara Lacerda, Sebastian Kraszewski, Maurizio Prato, Immunopathologie et chimie thérapeutique (ICT), Centre National de la Recherche Scientifique (CNRS)-Institut de biologie moléculaire et cellulaire (IBMC), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), BB/J008656/1, Institut de biologie moléculaire et cellulaire (IBMC), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Lara, Lacerda, Hanene Ali, Boucetta, Sebastian, Kraszewski, Mounir, Tarek, Prato, Maurizio, Christophe, Ramseyer, Kostas, Kostarelo, and Alberto, Bianco

Subjects
Cytoplasm, Nanotube, chemistry, metabolism, Materials science, Nanotechnology, 02 engineering and technology, Carbon nanotube, [CHIM.THER]Chemical Sciences/Medicinal Chemistry, Molecular Dynamics Simulation, 010402 general chemistry, 01 natural sciences, Quantitative Biology::Cell Behavior, law.invention, Quantitative Biology::Subcellular Processes, Cell membrane, Molecular dynamics, Microscopy, Electron, Transmission, law, Cell Line, Tumor, medicine, Animals, Humans, General Materials Science, Nanotubes, Carbon, Carbon chemistry, Cell Membrane, Temperature, Plasma, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, 0104 chemical sciences, medicine.anatomical_structure, Membrane, Liposomes, Chimie/Chimie thérapeutique, Carbon Nanotubes, 0210 nano-technology
Abstract

Study of the mechanisms understanding how chemically functionalized carbon nanotubes internalize into mammalian cells is important in view of their design as new tools for therapeutic and diagnostic applications. The initial contact between the nanotube and the cell membrane allows elucidation of the types of interaction that are occurring and the contribution from the types of functional groups at the nanotube surface. Here we offer a combination of experimental and theoretical evidence of the initial phases of interaction between functionalized carbon nanotubes with model and cellular membranes. Both experimental and theoretical data reveal the critical parameters to determine direct translocation of the nanotubes through the membrane into the cytoplasm as a result of three distinct processes that can be summarized as landing, piercing and uptake. journal article research support, non-u.s. gov't 2013 Nov 07 2013 09 05 imported

Published
2013
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12. Insertion kinetics of small nucleotides through single walled carbon nanotube

Author

Christophe Ramseyer, Fabien Picaud, Sebastian Kraszewski, Arnaud Clavier, Laboratoire Chrono-environnement ( LCE ), Université Bourgogne Franche-Comté ( UBFC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)

Subjects
Guanine, Stereochemistry, Static Electricity, DNA, Single-Stranded, Bioengineering, 02 engineering and technology, Carbon nanotube, Molecular Dynamics Simulation, 010402 general chemistry, 01 natural sciences, Applied Microbiology and Biotechnology, law.invention, chemistry.chemical_compound, symbols.namesake, law, Water environment, Molecule, A-DNA, [PHYS]Physics [physics], [ PHYS ] Physics [physics], Nanotubes, Carbon, Nucleotides, General Medicine, Sequence Analysis, DNA, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Thymine, Crystallography, Kinetics, chemistry, symbols, Thermodynamics, van der Waals force, 0210 nano-technology, Cytosine, Biotechnology
Abstract

International audience; We report molecular dynamic simulations showing that a DNA molecule constituted by five unique bases can be spontaneously inserted into single walled carbon nanotube (SWCNT) in normal conditions (P, T and water environment) depending on the tube radius value. The van der Waals and electrostatic interactions play a central role for the rapid insertion process. Our study shows also that the Guanine molecule inserts the fastest compared to thymine, adenine and cytosine bases, respectively. The differences of insertion time could be exploited for applications concerning for example DNA sequencing

Published
2013
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13. Theoretical study of amino derivatives and anticancer platinum drug grafted on various carbon nanostructures

Author

Eric Duverger, Christophe Ramseyer, Fabien Picaud, Sebastian Kraszewski, Nanomédecine, imagerie, thérapeutique - UFC (EA 4662) (NIT / NANOMEDECINE), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Nanomédecine, imagerie, thérapeutique - UFC ( NIT / NANOMEDECINE ), Université Bourgogne Franche-Comté ( UBFC ) -Université de Franche-Comté ( UFC ), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies ( FEMTO-ST ), Université de Technologie de Belfort-Montbeliard ( UTBM ) -Ecole Nationale Supérieure de Mécanique et des Microtechniques ( ENSMM ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Laboratoire Chrono-environnement ( LCE ), Université Bourgogne Franche-Comté ( UBFC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Université de Franche-Comté ( UFC ) -Université Bourgogne Franche-Comté ( UBFC ), Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), and Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC)

Subjects
Thiosemicarbazones, Fullerene, Organoplatinum Compounds, General Physics and Astronomy, chemistry.chemical_element, Antineoplastic Agents, 02 engineering and technology, Carbon nanotube, 010402 general chemistry, 01 natural sciences, law.invention, chemistry.chemical_compound, symbols.namesake, law, Organic chemistry, Physical and Theoretical Chemistry, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, [PHYS]Physics [physics], [ PHYS ] Physics [physics], Nanotubes, Carbon, 021001 nanoscience & nanotechnology, Combinatorial chemistry, Carbon, 0104 chemical sciences, Nanostructures, Carbon nanobud, chemistry, symbols, Quantum Theory, Density functional theory, [ SPI.NANO ] Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, van der Waals force, 0210 nano-technology, Platinum, Azo Compounds, Derivative (chemistry)
Abstract

International audience; ensity functional theory calculations with van der Waals approximation have been conducted to analyze the functionalization of various carbon-based nanostructures (fullerene, metallic, and semi-conducting nanotubes) with amino derivative groups. The results obtained with azomethine, show the formation of a five membered ring on fullerenes, and on nanotubes consistent with experimental observations. The attachment of an azomethine plus subsequent drug like a Pt(IV) complex does not perturb the cycloaddition process. Moreover, all theoretical results show that the length of different amino derivatives with subsequent Pt(IV) complex does not affect the complexed therapeutic agent when it is attached onto these carbon-based nanostructures.

Published
2013
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14. Insertion of short amino-functionalized single-walled carbon nanotubes into phospholipid bilayer occurs by passive diffusion

Author

Mounir Tarek, Christophe Ramseyer, Sebastian Kraszewski, Alberto Bianco, Nanomédecine, imagerie, thérapeutique - UFC ( NIT / NANOMEDECINE ), Université Bourgogne Franche-Comté ( UBFC ) -Université de Franche-Comté ( UFC ), Immunologie et chimie thérapeutiques ( ICT ), Cancéropôle du Grand Est-Centre National de la Recherche Scientifique ( CNRS ), Structure et Réactivité des Systèmes Moléculaires Complexes ( SRSMC ), Université de Lorraine ( UL ) -Centre National de la Recherche Scientifique ( CNRS ), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules ( UTINAM ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Nanomédecine, imagerie, thérapeutique - UFC (EA 4662) (NIT / NANOMEDECINE), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Immunologie et chimie thérapeutiques (ICT), Cancéropôle du Grand Est-Centre National de la Recherche Scientifique (CNRS), Structure et Réactivité des Systèmes Moléculaires Complexes (SRSMC), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), and Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC)

Subjects
Medical Physics, Lipid Bilayers, lcsh:Medicine, [CHIM.THER]Chemical Sciences/Medicinal Chemistry, 02 engineering and technology, Molecular Dynamics, Biophysics Simulations, 01 natural sciences, law.invention, Diffusion, Molecular dynamics, chemistry.chemical_compound, Computational Chemistry, law, Nanotechnology, Drug Interactions, Lipid bilayer phase behavior, Amines, Lipid bilayer, lcsh:Science, Phospholipids, Nanoneedle, Numerical Analysis, Multidisciplinary, Chemistry, Physics, Bilayer, [ CHIM.THER ] Chemical Sciences/Medicinal Chemistry, 021001 nanoscience & nanotechnology, Membrane, Biochemistry, Thermodynamics, Medicine, Biophysic Al Simulations, Chimie/Chimie thérapeutique, Protons, 0210 nano-technology, Research Article, Computer Modeling, Drugs and Devices, Materials Science, Biophysics, Phospholipid, Carbon nanotube, Molecular Dynamics Simulation, 010402 general chemistry, chemistry, Biology, Computerized Simulations, Nanotubes, Carbon, lcsh:R, Computational Biology, Biological Transport, 0104 chemical sciences, Computer Science, Bionanotechnology, lcsh:Q
Abstract

Carbon nanotubes have been proposed to be efficient nanovectors able to deliver genetic or therapeutic cargo into living cells. However, a direct evidence of the molecular mechanism of their translocation across cell membranes is still needed. Here, we report on an extensive computational study of short (5 nm length) pristine and functionalized single-walled carbon nanotubes uptake by phospholipid bilayer models using all-atom molecular dynamics simulations. Our data support the hypothesis of a direct translocation of the nanotubes through the phospholipid membrane. We find that insertion of neat nanotubes within the bilayer is a "nanoneedle" like process, which can often be divided in three consecutive steps: landing and floating, penetration of the lipid headgroup area and finally sliding into the membrane core. The presence of functional groups at moderate concentrations does not modify the overall scheme of diffusion mechanism, provided that their deprotonated state favors translocation through the lipid bilayer. journal article research support, non-u.s. gov't 2012 2012 07 16 imported

Published
2012
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15. New Bioinspired Membrane Made of a Biological Ion Channel Confined into the Cylindrical Nanopore of a Solid-State Polymer

Author

Sebastien Balme, Lydie Berardo, Christophe Ramseyer, Jean-Marc Janot, Sebastian Kraszewski, Daniel Bonhenry, Fabien Picaud, François Henn, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Institut Européen des membranes (IEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)

Subjects
Nanostructure, Materials science, Macromolecular Substances, Surface Properties, [PHYS.PHYS.PHYS-BIO-PH]Physics [physics]/Physics [physics]/Biological Physics [physics.bio-ph], Molecular Conformation, Ionic bonding, Bioengineering, Nanotechnology, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Ion Channels, Fluorescence spectroscopy, Ion, Biomimetic Materials, Materials Testing, [CHIM]Chemical Sciences, General Materials Science, Particle Size, Thin film, ComputingMilieux_MISCELLANEOUS, Ion channel, Mechanical Engineering, Gramicidin, Membranes, Artificial, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Nanostructures, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Nanopore, Membrane, Chemical physics, Crystallization, 0210 nano-technology, Porosity
Abstract

International audience; A hybrid nanoporous membrane made of a solid-state polymeric thin film in which an ion channel is confined is realized. The primary and extremely encouraging results obtained by confocal fluorescence spectroscopy and ion diffusion measurement demonstrate respectively that (i) the considered ion channel, that is, Gramicidin-A, can be confined selectively inside the nanopores and (ii) the ionic permeability of the membrane is enhanced. Atomistic molecular simulations are also reported and fruitfully compared to the experimental findings.

Published
2011
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16. Formation of one-dimensional ordered alloy at step edges: an atomistic study of the (2x1) Ni/Pt alloy on the Pt(997) surface

Author

Pietro Gambardella, Moncef Said, Fabien Picaud, Christophe Ramseyer, D. Spanjaard, Wafa Essolaani, Marie-Catherine Desjonquères, Université de Monastir - University of Monastir (UM), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), ICN2 - Institut Catala de Nanociencia i Nanotecnologia (ICN2), Universitat Autònoma de Barcelona (UAB), Laboratoire de Physique des Solides (LPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Service de Physique et de Chimie des Surfaces et Interfaces (SPCSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)

Subjects
Materials science, Monte Carlo method, Alloy, 02 engineering and technology, Growth, engineering.material, 01 natural sciences, Metal Magnetic heterostructures, law.invention, Monte Carlo simulations, Metal, Condensed Matter::Materials Science, law, 0103 physical sciences, Monolayer, Materials Chemistry, Kinetic Monte Carlo, 010306 general physics, Scanning tunneling microscopy, Deposition (law), [PHYS]Physics [physics], Surfaces and Interfaces, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Surfaces, Coatings and Films, Crystallography, visual_art, engineering, visual_art.visual_art_medium, Scanning tunneling microscope, 0210 nano-technology, Surface defects, Vicinal
Abstract

International audience; Kinetic Monte Carlo simulations based on a semi-empirical description of the metal–metal interactions are developed to interpret the formation of a one-dimensional Ni/Pt alloy observed at the step feet of the vicinal Pt(997) surface. Deposition of 0.15 monolayer of Ni atoms at T < 300 K leads to the formation of a (2 × 1) well-ordered nanowire in agreement with scanning tunneling microscopy observations. Exchange process between Ni and Pt atoms at the upper step edge and neighboring influence appear to be the key point to explain such a well-ordered 1D alloy. In addition, a subtle decoration of the step adsorption sites is also necessary.

Published
2011
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17. Heterogeneous against homogeneous spectral response of polar molecules adsorbed on a real surface

Author

Claude Girardet, H. Zorgati, Christophe Ramseyer, Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM), Laboratoire de Physique Moléculaire (UMR 6624) (LPM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
Surface (mathematics), [PHYS]Physics [physics], 010304 chemical physics, Infrared, Chemistry, Chemical polarity, Analytical chemistry, General Physics and Astronomy, Ionic bonding, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Crystallographic defect, Dipole, Adsorption, Chemical physics, 0103 physical sciences, Molecule, Physics::Chemical Physics, Physical and Theoretical Chemistry, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract

We study the influence of point defects on the infrared response of polar molecules randomly deposited on a real ionic surface. When compared to the spectral response of the same species adsorbed on a perfect surface, the vibrational spectrum of physisorbed molecules perturbed by the defects displays shifts and broadenings characterizing the heterogeneity of the surface. This latter spectrum is expressed as a weighted sum of the spectral responses of individual molecules, each having specific shifts and broadenings which can be partitioned into (i) homogeneous contributions due to the interaction of the molecules with the perfect surface, (ii) defect contributions due to direct interaction with the defects, and (iii) mixed contributions due to the dynamical coupling between vibrational and external modes. Applications are carried out to the vibration of CO and to the ν 1 and ν 2 vibrations of NH 3 molecules adsorbed on MgO(1 0 0) surfaces containing various concentrations of dipolar defects.

Published
2009
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18. Probing defect species on real surfaces from the analysis of the spectral profile of admolecules

Author

Moncef Said, Claude Girardet, Christophe Ramseyer, Hanen Zorgati, Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM), Laboratoire de Physique Moléculaire (UMR 6624) (LPM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
[PHYS]Physics [physics], 010304 chemical physics, Chemistry, Infrared, Monte Carlo method, Analytical chemistry, Ionic bonding, Infrared spectroscopy, 02 engineering and technology, Surfaces and Interfaces, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Surfaces, Coatings and Films, Dipole, Adsorption, Physisorption, Chemical physics, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Materials Chemistry, Molecule, Physics::Chemical Physics, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract

The analysis of changes in the vibrational spectrum of infrared active molecules adsorbed on a ionic surface containing point or extended defects can be an efficient method to determine the nature and density of surface defects. We study the infrared response of ammonia molecules deposited on a ionic surface of MgO containing charge vacancies and dipolar defects in various concentrations and distributions and show significant changes assigned to the defects signature. A Monte Carlo approach is used to randomly deposit the probe molecules on the surface displaying random or regularly arranged defects at low temperature.

Published
2009

19. A Stable Room-Temperature Molecular Assembly of Zwitterionic Organic Dipoles Guided by a Si(111)-7x7 Template Effect

Author

Frank Palmino, Younes Makoudi, Frédéric Chérioux, Eric Duverger, Christophe Ramseyer, Madjid Arab, Fabien Picaud, Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Institut des Matériaux, de Microélectronique et des Nanosciences de Provence (IM2NP), Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Laboratoire de Physique Moléculaire (UMR 6624) (LPM), Université de Franche-Comté (UFC), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Centre de biophysique moléculaire (CBM), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université d'Orléans (UO), and Nanomédecine, imagerie, thérapeutique - UFC (EA 4662) (NIT / NANOMEDECINE)

Subjects
Chemistry, 010405 organic chemistry, [CHIM.ORGA]Chemical Sciences/Organic chemistry, scanning probe microscopy, chirality, Nanotechnology, surface chemistry, 02 engineering and technology, General Chemistry, General Medicine, semiconductors, 021001 nanoscience & nanotechnology, 010402 general chemistry, 01 natural sciences, Catalysis, zwitterions, 0104 chemical sciences, Dipole, Crystallography, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract

International audience; Chiral Assemblies of Achiral Molecules: High resolution STM images of zwitterionic organic dipoles deposited on Si- (111)-7x7 show a chiral molecular assembly on this surface . Density functional calculations demonstrate that a sulfonato group can act as an electrostatic shield that protects the pi-skeleton of organic molecules from the dangling bonds of semiconductor surfaces, which is a major advance in the deposition of pi-conjugated molecules.

Published
2007
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20. Direct growth of the multi-walled carbon nanotubes as a tool to detect ammonia at room temperature

Author

M. Mayne-L’hermite, J. Glory, Madjid Arab, Franck Berger, Christophe Ramseyer, Fabien Picaud, Institut des Matériaux, de Microélectronique et des Nanosciences de Provence (IM2NP), Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), ecoRisQ, Laboratoire de Physique Moléculaire (UMR 6624) (LPM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Francis PERRIN (LFP - URA 2453), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Service des Photons, Atomes et Molécules (SPAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Laboratoire de chimie physique et rayonnements (UMR E4) (LCPR), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Franche-Comté (UFC)

Subjects
Materials science, General Physics and Astronomy, Nanotechnology, 02 engineering and technology, Carbon nanotube, 010402 general chemistry, 01 natural sciences, law.invention, Condensed Matter::Materials Science, Potential applications of carbon nanotubes, law, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Physical and Theoretical Chemistry, Carbon nanofiber, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Optical properties of carbon nanotubes, Carbon nanotube quantum dot, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Carbon nanobud, Chemical engineering, Carbide-derived carbon, Carbon nanotube supported catalyst, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], 0210 nano-technology
Abstract

International audience; In this work, we report on the application of multi-walled carbon nanotubes as gas sensors. We use the vertical growth of aligned carbon nanotubes on structure surfaces composed by a set of Ni electrodes and SiO2 surfaces fraction. The results show that carbon nanotubes could be efficient in terms of sensibility for detection of pollutant species like NH3 even at ambient temperature. The determination of the adsorption energies for various species on the basis of a semi-empirical potential approach show that gases, particularly the polar one, are able to bind strongly on carbon nanotubes surfaces and could explain at least qualitatively the experimental results.

Published
2006
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21. Controlling potassium selectivity and proton blocking in a hybrid biological/solid-state polymer nanoporous membrane

Author

Jhon Capomanes, Philippe Déjardin, Sebastien Balme, Christophe Ramseyer, Mathilde Lepoitevin, François Henn, Fabien Picaud, Jean-Marc Janot, Sebastian Kraszewski, Institut Européen des membranes (IEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), Laboratoire Charles Coulomb (L2C), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and ANR-12-BS08-0023,TRANSION,TRANSport IONique au sein de canaux-ioniques biologiques confinés dans des nanopores: approche expérimentale et théorique(2012)

Subjects
Polymers, Diffusion, Inorganic chemistry, 02 engineering and technology, Molecular Dynamics Simulation, Ion, Nanopores, 03 medical and health sciences, Molecule, General Materials Science, Semipermeable membrane, 030304 developmental biology, chemistry.chemical_classification, 0303 health sciences, Chemistry, Electric Conductivity, Gramicidin, Polymer, Permeation, 021001 nanoscience & nanotechnology, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Membrane, Chemical engineering, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Potassium, Protons, 0210 nano-technology, Selectivity, Hydrophobic and Hydrophilic Interactions
Abstract

International audience; Specific separations of protons and cations are usually performed by electromembrane processes, which require external electric energy. An easier process would be using a membrane able to separate both entities by passive diffusion. Presently, such synthetic nanoporous membranes do not exist. Here, we report the production of a robust hybrid biological/artificial solid-state membrane, which allows selective permeation of alkali metal cations without competing or concurrent permeation of protons. This membrane is simple to prepare and is based on the hydrophobic nature of the polymeric pore walls, and the confined gramicidin A molecules within. This work opens a new route for separation in the domain of nanobiofiltration, especially for tunable nanodevices based on differential ion conduction, with a fundamental understanding of the confinement mechanism.

Published
2013
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22. Characterization of single wall carbon nanotubes by means of rare gas adsorption

Author

Fabrice Valsaque, Edward McRae, Christophe Ramseyer, Moulay-Rachid Babaa, Madjid Arab, Fabien Picaud, Institut des Matériaux, de Microélectronique et des Nanosciences de Provence (IM2NP), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Moléculaire (UMR 6624) (LPM), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Institut Bisontin en Sciences Fondamentales (IBSF), Laboratoire de chimie du solide minéral (LCSM), and Université Paul Verlaine - Metz (UPVM)-Université Henri Poincaré - Nancy 1 (UHP)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Rare gas, Langmuir, Nanotube, Materials science, General Physics and Astronomy, Thermodynamics, Nanotechnology, 02 engineering and technology, Carbon nanotube, 021001 nanoscience & nanotechnology, 01 natural sciences, Characterization (materials science), law.invention, Adsorption, law, Bundle, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Hexagonal lattice, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Physical and Theoretical Chemistry, 010306 general physics, 0210 nano-technology
Abstract

International audience; Based on the formalisms of Langmuir and Fowler, theoretical adsorption isotherms are calculated for different bundle geometries of single wall carbon nanotubes in a triangular lattice. The authors show the dependence of the adsorption properties on the nanotube diameter and on the specific morphology of the bundles they constitute. The authors demonstrate how isotherm curve analysis can help to experimentally determine what kinds of tubes form a given bundle and the ratio of open to closed tubes in a sample having undergone a complete or incomplete opening protocol. In spite of the model’s simplicity, quite satisfactory agreement is observed between experiments and the authors’ calculations.

Published
2007
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23. Numerical studies of the membrane fluorescent dyes dynamics in ground and excited states

Author

Piotr Jurkiewicz, Christophe Ramseyer, Justyna Barucha-Kraszewska, Martin Hof, Sebastian Kraszewski, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
Lipid Bilayers, Biophysics, Analytical chemistry, 02 engineering and technology, Molecular Dynamics Simulation, Molecular dynamics, 010402 general chemistry, 01 natural sciences, Biochemistry, chemistry.chemical_compound, Fluorescent probe, Excited state, 2-Naphthylamine, Lipid bilayer, ComputingMilieux_MISCELLANEOUS, Fluorescent Dyes, [PHYS]Physics [physics], Laurdan, Chemistry, Relaxation (NMR), Membrane, Cell Biology, 021001 nanoscience & nanotechnology, Fluorescence, 0104 chemical sciences, Chemical physics, Picosecond, Solvent relaxation, Prodan, 0210 nano-technology, Laurates
Abstract

Fluorescence methods are widely used in studies of biological and model membranes. The dynamics of membrane fluorescent markers in their ground and excited electronic states and correlations with their molecular surrounding within the fully hydrated phospholipid bilayer are still not well understood. In the present work, Quantum Mechanical (QM) calculations and Molecular Dynamics (MD) simulations are used to characterize location and interactions of two membrane polarity probes (Prodan; 6-propionyl-2-dimethylaminonaphthalene and its derivative Laurdan; 2-dimethylamino-6-lauroylnaphthalene) with the dioleoylphosphatidylcholine (DOPC) lipid bilayer model. MD simulations with fluorophores in ground and excited states are found to be a useful tool to analyze the fluorescent dye dynamics and their immediate vicinity. The results of QM calculations and MD simulations are in excellent agreement with available experimental data. The calculation shows that the two amphiphilic dyes initially placed in bulk water diffuse within 10ns towards their final location in the lipid bilayer. Analysis of solvent relaxation process in the aqueous phase occurs on the picoseconds timescale whereas it takes nanoseconds at the lipid/water interface. Four different relaxation time constants, corresponding to different relaxation processes, where observed when the dyes were embedded into the membrane.

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