Directeur de Recherche, CNRS
ENS – Département de chimie
24 rue Lhomond, 75005 Paris
Email: christophe.tribet@ens.psl.eu
Phone: +33 144322403
Office: E152
ORCID: http://orcid.org/0000-0002-5953-0968
Researchgate:https://www.researchgate.net/profile/Christophe_Tribet
Short bio
Development of robust macromolecular tools, that can be implemented by biologists and/or applied to manipulate living systems is a major inspiration in my work. Based on a core expertise in physical chemistry of polymer, surfactants, and soft matter science the team explore, the design of stimuli-responsive (macro)molecules 1) for protein stabilization/chaperone-like systems and 2) for use in cell biology (stimuli-responsive substrates, coatings and capsules)
With J.L. Popot in IBPC in the late 90’s, we tailored macromolecular detergents that enable the dispersion and stabilization of integral membrane proteins in water. These polymers are now quoted « amphipols » and commercially available. Since this early work, I continuously explored the use of amphiphilic assemblies (polymers, surfactants) to prevent aggregation, enhance refolding/renaturation.
In SIMM laboratory (1994-2009, ESPCI Paris), we introduced chemical modifications in polymers aiming to achieve light-responsive transitions (e.g. coacervation, physical gelation, emulsification). We investigated the use of photochrome-containing macromolecules to (photo)switch gelation, emulsion and foam stability (coll. P.Perrin & C. Monteux). This approach enabled us to trigger the permeability of bilayers and cells to various substrates (peptides, Qdots) .
Current works are aimed to provide dynamic switches (based on light, temperature or redox potential) on the surface of cell-culture substrates, and on lipid capsules. With E. Marie, we study how cell fate can be oriented on micropatterned substrates (soft adhesion, polarisation, migration) by in-situ modulation of cell-polymer interactions. We develop in addition a biosourced form of these polymer switches based on bacterial synthesis of responsive lipid capsules & microvesicles.
Education and professional experience
- 2010 – , Senior CNRS Research Scientist, « Polymer » group in Pole « Physical & Biological Chemistry of Living Matter », ENS Paris,
- 2007-2010, Senior Research Scientist, team « stimuli-responsive colloids », SIMM ESPCI Paris,
- 2005 Visiting Scientist, Université de Montreal (F. Winnik),
- 1994 CNRS Research Scientist , ESPCI Paris,
- 1993 Post-doctoral fellow, ULB, Bruxelles,
- 1993 Ph. D. Université Paris VI
- 1985/1987 B.Sc. & M.Sc. chemistry, Univ. Paris XI Orsay & ENS Cachan, France
Research interests
- Physical chemistry of protein aggregation/stability (ex: therapeutic antibodies, stabilization of enzymes),
- Polymer:biomembrane & polymer:protein assemblies (chaperon-like polymers, genetically encoded capsules),
- Dynamic polymer substrates, cell guidance, remote control of cell adhesion, permeabilization.
Teaching
- Module coordinator « physico-chimie des polymères », predoc ENS chimie (eq. M1),
- Module coordinator « cell-substrates soft interfaces », M2, master BME Biomaterial engineering, PSL Univ.,
- M2 course, MU5CI602 « biomaterials », Paris Sorbonne Univ.
- M1 & M2 PSL graduate program: stimuli-responsive polymers ; scattering methods.
Selected recent publications
– Sixdenier, L., Tribet, C., Marie, E., Adv. Funct. Mater. 2021, 2105490. Emulsion-Templated Poly(N-Isopropylacrylamide) Shells Formed by Thermo-Enhanced Interfacial Complexation.
– Royes J.; Ilioaia O.; Lubart Q.; Dubacheva G.; Bally M.; Miroux B.; Tribet C., Angew. Chem. Int. Ed., 2019, doi: 10.1002/anie.201902929, Protein-loaded Lipidic Nanocapsules from Bio-engineered Bacteria.
– Dalier F.; Dubacheva G.; Coniel M.; Galtayries A.; Marie E.; Piel M.; Tribet C., ACS Applied Materials & Interf., 2018, 10(3):2253-2258, Mixed copolymer adlayers allowing reversible thermal control of single cell aspect ratio.
– Martin N.; Costa N.; Wien F.; Winnik F.; Ortega C.; Herbet A.; Boquet D.; Tribet C., Macromolecular Biosciences, 2017, 17 (2) UNSP 1600213 DOI:10.1002/ mabi.201600213, Refolding of Aggregation-Prone ScFv Antibody Fragments Assisted by Hydrophobically Modified Poly(sodium acrylate) Derivatives.
– Lund R., Brun G., Chevallier E., Narayanan Theyencheri, Tribet C., Langmuir, 2016, 32 (11), 2539–2548, Kinetics of Photocontrollable Micelles: Light-Induced Self-Assembly and Disassembly of Azobenzene-Based Surfactants Revealed by TR-SAXS.
– Dalier F., Eghiaian F., Scheuring S., Marie E., Tribet C., Biomacromolecules, 2016, 17 (5), , 1727–1736, Temperature-Switchable Control of Ligand Display on Adlayers of Mixed Poly(lysine)-g-(PEO) and Poly(lysine)-g-(ligand-modified poly-N-isopropylacrylamide).
– Marie, E.; Sagan, S.; Cribier, S.; Tribet, C., J. Membrane Biol;, 2014, 247, 861-881 , Amphiphilic Macromolecules on Cell Membranes: From Protective Layers to Controlled Permeabilization.
– Stijn F. M. van Dongen, P. Maiuri, E. Marie, C. Tribet and M. Piel, Adv. Mater. 2013, 25(12):1687-91, Triggering Cell Adhesion, Migration or Shape Change with a Dynamic Surface Coating.
Publications
2022 |
Transition kinetics of mixed lipid:photosurfactant assemblies studied by time-resolved small angle X-ray scattering Article de journal Jorges Royes; V. A. Bjørnestad; G. Brun; Th. Narayanan; R Lund; C Tribet J Colloid Interface Sci., 610 , p. 830-841, 2022, ISBN: 0021-9797. @article{Royes2022, title = {Transition kinetics of mixed lipid:photosurfactant assemblies studied by time-resolved small angle X-ray scattering }, author = {Jorges Royes and V. A. Bj\ornestad and G. Brun and Th. Narayanan and R Lund and C Tribet}, editor = {Elsevier}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0021979721020439?via%3Dihub}, doi = {10.1016/j.jcis.2021.11.133 }, isbn = {0021-9797}, year = {2022}, date = {2022-03-15}, journal = {J Colloid Interface Sci.}, volume = {610}, pages = {830-841}, abstract = {Hypothesis: Photoswitchable surfactants are used in the design of many light-responsive colloids and/or self-assemblies. Photo-isomerization enables to control molecular equilibrium, and triggers transient reorganizations with possibly out-of-equilibrium intermediate states that have been overlooked. Here, we address this question by an in depth structural investigation of intermediate lipid-surfactant assemblies that occur during fast isothermal photo-triggered transition in lipid:surfactant mixtures. Experiments: The structural parameters of mixed assemblies of azobenzene-containing cationic surfactant (AzoTMA) and dioleoylphosphatidylcholine (DOPC) lipids were studied by light scattering and time-resolved small angle X-ray scattering. Structural and compositional information about the assemblies and unimers in bulk were determined at the photostationary states, as well as at intermediate kinetic states formed during UV or blue light illumination. Findings: DOPC:AzoTMA systems form mixed assemblies representative of phospholipid:cationic surfactant mixtures, that evolve from spheroid, to rod-like micelles, and vesicles with increasing DOPC fraction. Transient assemblies detected during the photo-triggered kinetics are similar to the ones found in stationary states. But changes of AzoTMA unimers in bulk can be considerably faster than mass reorganizations of the mixed assemblies, suggesting that out-of-equilibrium conditions are transiently reached. Mass reorganization of the surfactant-enriched assemblies is much faster than in the lipid enriched ones, providing insight into the role of lipids in a slow reorganization of the assemblies. }, keywords = {}, pubstate = {published}, tppubtype = {article} } Hypothesis: Photoswitchable surfactants are used in the design of many light-responsive colloids and/or self-assemblies. Photo-isomerization enables to control molecular equilibrium, and triggers transient reorganizations with possibly out-of-equilibrium intermediate states that have been overlooked. Here, we address this question by an in depth structural investigation of intermediate lipid-surfactant assemblies that occur during fast isothermal photo-triggered transition in lipid:surfactant mixtures. Experiments: The structural parameters of mixed assemblies of azobenzene-containing cationic surfactant (AzoTMA) and dioleoylphosphatidylcholine (DOPC) lipids were studied by light scattering and time-resolved small angle X-ray scattering. Structural and compositional information about the assemblies and unimers in bulk were determined at the photostationary states, as well as at intermediate kinetic states formed during UV or blue light illumination. Findings: DOPC:AzoTMA systems form mixed assemblies representative of phospholipid:cationic surfactant mixtures, that evolve from spheroid, to rod-like micelles, and vesicles with increasing DOPC fraction. Transient assemblies detected during the photo-triggered kinetics are similar to the ones found in stationary states. But changes of AzoTMA unimers in bulk can be considerably faster than mass reorganizations of the mixed assemblies, suggesting that out-of-equilibrium conditions are transiently reached. Mass reorganization of the surfactant-enriched assemblies is much faster than in the lipid enriched ones, providing insight into the role of lipids in a slow reorganization of the assemblies. |
UCST-Type Polymer Capsules Formed by Interfacial Complexation Article de journal L Sixdenier; A Auge; Y Zhao; E Marie; C Tribet ACS MACRO LETTERS, 11 (5), p. 651-656, 2022, ISBN: 2161-1653 J9 - ACS MACRO LETT. @article{Sixdenier2022, title = {UCST-Type Polymer Capsules Formed by Interfacial Complexation}, author = {L Sixdenier and A Auge and Y Zhao and E Marie and C Tribet}, doi = {10.1021/acsmacrolett.2c00021}, isbn = {2161-1653 J9 - ACS MACRO LETT}, year = {2022}, date = {2022-05-17}, journal = {ACS MACRO LETTERS}, volume = {11}, number = {5}, pages = {651-656}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2021 |
Emulsion-Templated Poly(N-Isopropylacrylamide) Shells Formed by Thermo-Enhanced Interfacial Complexation Article de journal L Sixdenier; C Tribet; E Marie ADVANCED FUNCTIONAL MATERIALS, 31 (51), p. 2105490, 2021, ISBN: 1616-301X 1616-3028 J9 - ADV FUNCT MATER. @article{Sixdenier2021b, title = {Emulsion-Templated Poly(N-Isopropylacrylamide) Shells Formed by Thermo-Enhanced Interfacial Complexation}, author = {L Sixdenier and C Tribet and E Marie}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202105490}, doi = {10.1002/adfm.202105490}, isbn = {1616-301X 1616-3028 J9 - ADV FUNCT MATER}, year = {2021}, date = {2021-09-17}, journal = {ADVANCED FUNCTIONAL MATERIALS}, volume = {31}, number = {51}, pages = {2105490}, abstract = {The encapsulation of fragile biomacromolecules is crucial in many biotechnological applications but remains challenging. Interfacial complexation (IC) in water-in-oil emulsions proves to be an efficient process for the formation of protective polymer layers at the surface of capsule-precursor water droplets. In this work, the enhancement of conventional IC by introducing thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) strands in the interfacial polymer layer is described. Surfactant-polymer IC is implemented in water-in-fluorocarbon oil emulsions between a water-soluble poly(L-lysine)-g-poly(N-isopropylacrylamide) cationic copolymer (PLL-g-PNIPAM) and an oil-soluble anionic surfactant. Fluorescence imaging demonstrates that the thermal collapse transition of PNIPAM strands, triggered by gentle heating, induces an enrichment of the polymer layer initially formed by IC. Spontaneous co-precipitation of nanoparticles initially dispersed in the aqueous cores-with no specific treatment-is also achieved upon PNIPAM transition. This process is leveraged to irreversibly segregate these nanoparticles in the interfacial polymer layer, resulting in gel-like mixed shells. Thermo-enhancement of conventional IC is thus a promising approach for the straightforward formation, strengthening, and functionalization of capsule shells. As implemented in mild conditions, thermo-enhanced IC is additionally compatible with the encapsulation of proteins, opening new opportunities for delivery systems of biomacromolecules.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The encapsulation of fragile biomacromolecules is crucial in many biotechnological applications but remains challenging. Interfacial complexation (IC) in water-in-oil emulsions proves to be an efficient process for the formation of protective polymer layers at the surface of capsule-precursor water droplets. In this work, the enhancement of conventional IC by introducing thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) strands in the interfacial polymer layer is described. Surfactant-polymer IC is implemented in water-in-fluorocarbon oil emulsions between a water-soluble poly(L-lysine)-g-poly(N-isopropylacrylamide) cationic copolymer (PLL-g-PNIPAM) and an oil-soluble anionic surfactant. Fluorescence imaging demonstrates that the thermal collapse transition of PNIPAM strands, triggered by gentle heating, induces an enrichment of the polymer layer initially formed by IC. Spontaneous co-precipitation of nanoparticles initially dispersed in the aqueous cores-with no specific treatment-is also achieved upon PNIPAM transition. This process is leveraged to irreversibly segregate these nanoparticles in the interfacial polymer layer, resulting in gel-like mixed shells. Thermo-enhancement of conventional IC is thus a promising approach for the straightforward formation, strengthening, and functionalization of capsule shells. As implemented in mild conditions, thermo-enhanced IC is additionally compatible with the encapsulation of proteins, opening new opportunities for delivery systems of biomacromolecules. |
2020 |
Inducible intracellular membranes: molecular aspects and emerging applications Article de journal J Royes; V Biou; N Dautin; C Tribet; B Miroux Microbial Cell Factories, 19 (1), 2020. @article{RN263, title = {Inducible intracellular membranes: molecular aspects and emerging applications}, author = {J Royes and V Biou and N Dautin and C Tribet and B Miroux}, url = {<Go to ISI>://WOS:000568404600002}, doi = {10.1186/s12934-020-01433-x}, year = {2020}, date = {2020-01-01}, journal = {Microbial Cell Factories}, volume = {19}, number = {1}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Solubilization and Stabilization of Membrane Proteins by Cycloalkane-Modified Amphiphilic Polymers Article de journal Anaïs Marconnet; Baptiste Michon; Christel Le Bon; Fabrice Giusti; Christophe Tribet; Manuela Zoonens Biomacromolecules, 21 (8), p. 3459-3467, 2020, ISSN: 1525-7797. @article{Marconnet2020, title = {Solubilization and Stabilization of Membrane Proteins by Cycloalkane-Modified Amphiphilic Polymers}, author = {Ana\"{i}s Marconnet and Baptiste Michon and Christel Le Bon and Fabrice Giusti and Christophe Tribet and Manuela Zoonens }, editor = {American Chemical Society}, url = {https://doi.org/10.1021/acs.biomac.0c00929}, doi = {10.1021/acs.biomac.0c00929}, issn = {1525-7797}, year = {2020}, date = {2020-08-10}, journal = {Biomacromolecules}, volume = {21}, number = {8}, pages = {3459-3467}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2019 |
Bacteria-Based Production of Thiol-Clickable, Genetically Encoded Lipid Nanovesicles Article de journal Jorge Royes; Oana Ilioaia; Quentin Lubart; Federica Angius; Galina V Dubacheva; Marta Bally; Bruno Miroux; Christophe Tribet Angewandte Chemie International Edition, 58 , p. 7395-7399, 2019, ISSN: 1433-7851. @article{RN1x, title = {Bacteria-Based Production of Thiol-Clickable, Genetically Encoded Lipid Nanovesicles}, author = {Jorge Royes and Oana Ilioaia and Quentin Lubart and Federica Angius and Galina V Dubacheva and Marta Bally and Bruno Miroux and Christophe Tribet}, doi = {10.1002/anie.201902929}, issn = {1433-7851}, year = {2019}, date = {2019-01-01}, journal = {Angewandte Chemie International Edition}, volume = {58}, pages = {7395-7399}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Distinctive Low-Resolution Structural Features of Dimers of Antibody–Drug Conjugates and Parent Antibody Determined by Small-Angle X-ray Scattering Article de journal Didier Law-Hine; Sergii Rudiuk; Audrey Bonestebe; Romain Ienco; Sylvain Huille; Christophe Tribet Mol. Pharmaceutics, 16 (12), p. 4902-4912, 2019. @article{Law-Hine2019, title = {Distinctive Low-Resolution Structural Features of Dimers of Antibody\textendashDrug Conjugates and Parent Antibody Determined by Small-Angle X-ray Scattering}, author = {Didier Law-Hine and Sergii Rudiuk and Audrey Bonestebe and Romain Ienco and Sylvain Huille and Christophe Tribet}, doi = {10.1021/acs.molpharmaceut.9b00792}, year = {2019}, date = {2019-10-16}, journal = {Mol. Pharmaceutics}, volume = {16}, number = {12}, pages = {4902-4912}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Redox-Triggered Control of Cell Adhesion and Deadhesion on Poly(lysine)-g-poly(ethylene oxide) Adlayers. Article de journal Louise Hespel; Julien Dupré de Baubigny; Pierre Lalanne; Simon de Beco; Mathieu Coppey; Catherine Villard; Vincent Humblot; Emmanuelle Marie; Christophe Tribet ACS Applied Bio Materials, 2 (10), p. 4367-4376, 2019. @article{Hespel2019, title = {Redox-Triggered Control of Cell Adhesion and Deadhesion on Poly(lysine)-g-poly(ethylene oxide) Adlayers.}, author = {Louise Hespel and Julien Dupr\'{e} de Baubigny and Pierre Lalanne and Simon de Beco and Mathieu Coppey and Catherine Villard and Vincent Humblot and Emmanuelle Marie and Christophe Tribet}, doi = {10.1021/acsabm.9b00601}, year = {2019}, date = {2019-09-10}, journal = {ACS Applied Bio Materials}, volume = {2}, number = {10}, pages = {4367-4376}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Tannin-controlled micelles and fibrils of kappa-casein Article de journal W Ma; C Tribet; S Guyot; D Zanchi Journal of Chemical Physics, 151 (24), 2019, ISSN: 0021-9606. @article{RN264, title = {Tannin-controlled micelles and fibrils of kappa-casein}, author = {W Ma and C Tribet and S Guyot and D Zanchi}, url = {<Go to ISI>://WOS:000513160200063}, doi = {10.1063/1.5128057}, issn = {0021-9606}, year = {2019}, date = {2019-01-01}, journal = {Journal of Chemical Physics}, volume = {151}, number = {24}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Tunable and switchable soft adsorption of polymer-coated microparticles on a flat substrate Article de journal Giuseppe Boniello; Christophe Tribet; Emmanuelle Marie; Vincent Croquette; Dražen Zanchi Colloids and Surfaces A: Physicochemical and Engineering Aspects, 575 , p. 199-204, 2019, ISSN: 0927-7757. @article{Boniello2019, title = {Tunable and switchable soft adsorption of polymer-coated microparticles on a flat substrate}, author = {Giuseppe Boniello and Christophe Tribet and Emmanuelle Marie and Vincent Croquette and Dra\v{z}en Zanchi}, editor = {Elsevier}, url = {http://www.sciencedirect.com/science/article/pii/S0927775719301797}, doi = {10.1016/j.colsurfa.2019.04.081}, issn = {0927-7757}, year = {2019}, date = {2019-08-20}, journal = {Colloids and Surfaces A: Physicochemical and Engineering Aspects}, volume = {575}, pages = {199-204}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2018 |
Mixed Copolymer Adlayers Allowing Reversible Thermal Control of Single Cell Aspect Ratio Article de journal F Dalier; G V Dubacheva; M Coniel; D Zanchi; A Galtayries; M Piel; E Marie; C Tribet Acs Applied Materials & Interfaces, 10 (3), p. 2253-2258, 2018, ISSN: 1944-8244. @article{Dalier:2018, title = {Mixed Copolymer Adlayers Allowing Reversible Thermal Control of Single Cell Aspect Ratio}, author = {F Dalier and G V Dubacheva and M Coniel and D Zanchi and A Galtayries and M Piel and E Marie and C Tribet}, doi = {10.1021/acsami.7b18513}, issn = {1944-8244}, year = {2018}, date = {2018-01-01}, journal = {Acs Applied Materials & Interfaces}, volume = {10}, number = {3}, pages = {2253-2258}, abstract = {Dynamic guidance of living cells is achieved by fine-tuning and spatiotemporal modulation on artificial polymer layers enabling reversible peptide display. Adjustment of surface composition and interactions is obtained by coadsorption of mixed poly(lysine) derivatives, grafted with either repellent PEG, RGD adhesion peptides, or T-responsive poly(N-isopropylacrylamide) strands. Deposition of mixed adlayers provides a straightforward mean to optimize complex substrates, which is here implemented to achieve (1) thermal control of ligand accessibility and (2) adjustment of relative adhesiveness between adjacent micropatterns, while preserving cell attachment during thermal cycles. The reversible polarization of HeLa cells along orthogonal stripes mimics guidance along natural matrices.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Dynamic guidance of living cells is achieved by fine-tuning and spatiotemporal modulation on artificial polymer layers enabling reversible peptide display. Adjustment of surface composition and interactions is obtained by coadsorption of mixed poly(lysine) derivatives, grafted with either repellent PEG, RGD adhesion peptides, or T-responsive poly(N-isopropylacrylamide) strands. Deposition of mixed adlayers provides a straightforward mean to optimize complex substrates, which is here implemented to achieve (1) thermal control of ligand accessibility and (2) adjustment of relative adhesiveness between adjacent micropatterns, while preserving cell attachment during thermal cycles. The reversible polarization of HeLa cells along orthogonal stripes mimics guidance along natural matrices. |
Rolling and aging in temperature-ramp soft adhesion Article de journal G Boniello; C Tribet; E Marie; V Croquette; D Zanchi Physical Review E, 97 (1), 2018. @article{Boniello:2018, title = {Rolling and aging in temperature-ramp soft adhesion}, author = {G Boniello and C Tribet and E Marie and V Croquette and D Zanchi}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85040729302&doi=10.1103%2fPhysRevE.97.012609&partnerID=40&md5=5b4fb855a186c8f56070f77a7d75f5c8}, doi = {10.1103/PhysRevE.97.012609}, year = {2018}, date = {2018-01-01}, journal = {Physical Review E}, volume = {97}, number = {1}, abstract = {Immediately before adsorption to a horizontal substrate, sinking polymer-coated colloids can undergo a complex sequence of landing, jumping, crawling, and rolling events. Using video tracking, we studied the soft adhesion to a horizontal flat plate of micron-size colloids coated by a controlled molar fraction f of the poly(lysine)-grafted-poly(N-isopropylacrylamide) (PLL-g-PNIPAM) which is a temperature-sensitive polymer. We ramp the temperature from below to above Tc=32±1C, at which the PNIPAM polymer undergoes a transition, triggering attractive interaction between microparticles and surface. The adsorption rate, the effective in-plane (x-y) diffusion constant, and the average residence time distribution over z were extracted from the Brownian motion records during last seconds before immobilization. Experimental data are understood within a rate-equations-based model that includes aging effects and includes three populations: the untethered, the rolling, and the arrested colloids. We show that preadsorption dynamics casts a characteristic scaling function α(f) proportional to the number of available PNIPAM patches met by soft contact during Brownian rolling. In particular, the increase of in-plane diffusivity with increasing f is understood: The stickiest particles have the shortest rolling regime prior to arrest, so that their motion is dominated by the untethered phase. © 2018 American Physical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Immediately before adsorption to a horizontal substrate, sinking polymer-coated colloids can undergo a complex sequence of landing, jumping, crawling, and rolling events. Using video tracking, we studied the soft adhesion to a horizontal flat plate of micron-size colloids coated by a controlled molar fraction f of the poly(lysine)-grafted-poly(N-isopropylacrylamide) (PLL-g-PNIPAM) which is a temperature-sensitive polymer. We ramp the temperature from below to above Tc=32±1C, at which the PNIPAM polymer undergoes a transition, triggering attractive interaction between microparticles and surface. The adsorption rate, the effective in-plane (x-y) diffusion constant, and the average residence time distribution over z were extracted from the Brownian motion records during last seconds before immobilization. Experimental data are understood within a rate-equations-based model that includes aging effects and includes three populations: the untethered, the rolling, and the arrested colloids. We show that preadsorption dynamics casts a characteristic scaling function α(f) proportional to the number of available PNIPAM patches met by soft contact during Brownian rolling. In particular, the increase of in-plane diffusivity with increasing f is understood: The stickiest particles have the shortest rolling regime prior to arrest, so that their motion is dominated by the untethered phase. © 2018 American Physical Society. |
2017 |
Refolding of Aggregation-Prone ScFv Antibody Fragments Assisted by Hydrophobically Modified Poly(sodium acrylate) Derivatives Article de journal N Martin; N Costa; F Wien; F M Winnik; C Ortega; A Herbet; D Boquet; C Tribet Macromolecular Bioscience, 17 (2), 2017. @article{Martin:2017, title = {Refolding of Aggregation-Prone ScFv Antibody Fragments Assisted by Hydrophobically Modified Poly(sodium acrylate) Derivatives}, author = {N Martin and N Costa and F Wien and F M Winnik and C Ortega and A Herbet and D Boquet and C Tribet}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84983541279&doi=10.1002%2fmabi.201600213&partnerID=40&md5=2dfcbb05e216980d1285b2ac92c56bde}, doi = {10.1002/mabi.201600213}, year = {2017}, date = {2017-01-01}, journal = {Macromolecular Bioscience}, volume = {17}, number = {2}, abstract = {ScFv antibody fragments are a promising alternative to full-length antibodies for both therapeutic and diagnosis applications. They can be overexpressed in bacteria, which enables easy large scale production. Since scFv are artificial constructs, they are poorly soluble and prone to aggregation, which makes them difficult to manipulate and to refold. Here, stabilization and refolding of scFv fragments from urea-unfolded solutions are reported based on the use of micromolar amounts of polymers playing the role of artificial chaperons. Using fluorescence correlation spectroscopy, the size and aggregation number of complexes of scFv with unmodified or hydrophobically modified poly(sodium acrylate) are determined. The evolution of the secondary structure along the refolding procedure, in the presence or absence of 0.4 m l-arginine at scFv:polymer textless 1:5 (w/w), is determined by high-sensitivity synchrotron-radiation circular dichroism. Measurements reveal that refolding in the presence of polymers yields native-like secondary structure, though a different folding pathway can be followed compared to refolding in the absence of polymer. This is the first report on the use of macromolecular additives to assist refolding of a multidomain protein of therapeutic interest. (Figure presented.). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim}, keywords = {}, pubstate = {published}, tppubtype = {article} } ScFv antibody fragments are a promising alternative to full-length antibodies for both therapeutic and diagnosis applications. They can be overexpressed in bacteria, which enables easy large scale production. Since scFv are artificial constructs, they are poorly soluble and prone to aggregation, which makes them difficult to manipulate and to refold. Here, stabilization and refolding of scFv fragments from urea-unfolded solutions are reported based on the use of micromolar amounts of polymers playing the role of artificial chaperons. Using fluorescence correlation spectroscopy, the size and aggregation number of complexes of scFv with unmodified or hydrophobically modified poly(sodium acrylate) are determined. The evolution of the secondary structure along the refolding procedure, in the presence or absence of 0.4 m l-arginine at scFv:polymer textless 1:5 (w/w), is determined by high-sensitivity synchrotron-radiation circular dichroism. Measurements reveal that refolding in the presence of polymers yields native-like secondary structure, though a different folding pathway can be followed compared to refolding in the absence of polymer. This is the first report on the use of macromolecular additives to assist refolding of a multidomain protein of therapeutic interest. (Figure presented.). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim |
Reversible and Dynamical Control of Aggregation and Soft Adhesion of Ŧ-Responsive Polymer-Coated Colloids Article de journal Giuseppe Boniello; Jeremy Malinge; Christophe Tribet; Emmanuelle Marie; Drazen Zanchi Colloids and Surfaces a-Physicochemical and Engineering Aspects, 532 , p. 510-515, 2017, ISSN: 0927-7757. @article{RN3h, title = {Reversible and Dynamical Control of Aggregation and Soft Adhesion of {T}-Responsive Polymer-Coated Colloids}, author = {Giuseppe Boniello and Jeremy Malinge and Christophe Tribet and Emmanuelle Marie and Drazen Zanchi}, doi = {10.1016/j.colsurfa.2017.04.011}, issn = {0927-7757}, year = {2017}, date = {2017-01-01}, journal = {Colloids and Surfaces a-Physicochemical and Engineering Aspects}, volume = {532}, pages = {510-515}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2016 |
Aggregation of Antibody Drug Conjugates at Room Temperature: SAXS and Light Scattering Evidence for Colloidal Instability of a Specific Subpopulation Article de journal B Frka-Petesic; D Zanchi; N Martin; S Carayon; S Huille; C Tribet Langmuir, 32 (19), p. 4848–4861, 2016. @article{Frka-Petesic:2016, title = {Aggregation of Antibody Drug Conjugates at Room Temperature: SAXS and Light Scattering Evidence for Colloidal Instability of a Specific Subpopulation}, author = {B Frka-Petesic and D Zanchi and N Martin and S Carayon and S Huille and C Tribet}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84969780587&doi=10.1021%2facs.langmuir.6b00653&partnerID=40&md5=d0b5c51dcec5e8d91ca097bb1878f7f9}, doi = {10.1021/acs.langmuir.6b00653}, year = {2016}, date = {2016-01-01}, journal = {Langmuir}, volume = {32}, number = {19}, pages = {4848--4861}, abstract = {Coupling a hydrophobic drug onto monoclonal antibodies via lysine residues is a common route to prepare antibody-drug conjugates (ADC), a promising class of biotherapeutics. But a few chemical modifications on protein surface often increase aggregation propensity, without a clear understanding of the aggregation mechanisms at stake (loss of colloidal stability, self-assemblies, denaturation, etc.), and the statistical nature of conjugation introduces polydispersity in the ADC population, which raises questions on whether the whole ADC population becomes unstable. To characterize the average interactions between ADC, we monitored small-angle X-ray scattering in solutions of monoclonal IgG1 human antibody drug conjugate, with average degree of conjugation of 0, 2, or 3 drug molecules per protein. To characterize stability, we studied the kinetics of aggregation at room temperature. The intrinsic Fuchs stability ratio of the ADC was estimated from the variation over time of scattered light intensity and hydrodynamic radius, in buffers of varying pH, and at diverse sucrose (0% or 10%) and NaCl (0 or 100 mM) concentrations. We show that stable ADC stock solutions became unstable upon pH shift, well below the pH of maximum average attraction between IgGs. Data indicate that aggregation can be ascribed to a fraction of ADC population usually representing less than 30 mol % of the sample. In contrast to the case of (monodisperse) monoclonal antibodies, our results suggest that a poor correlation between stability and average interaction parameters should be expected as a corollary of dispersity of ADC conjugation. In practice, the most unstable fraction of the ADC population can be removed by filtration, which affects remarkably the apparent stability of the samples. Finally, the lack of correlation between the kinetic stability and variations of the average inter-ADC interactions is tentatively attributed to the uneven nature of charge distributions and the presence of patches on the drug-modified antibodies. © 2016 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Coupling a hydrophobic drug onto monoclonal antibodies via lysine residues is a common route to prepare antibody-drug conjugates (ADC), a promising class of biotherapeutics. But a few chemical modifications on protein surface often increase aggregation propensity, without a clear understanding of the aggregation mechanisms at stake (loss of colloidal stability, self-assemblies, denaturation, etc.), and the statistical nature of conjugation introduces polydispersity in the ADC population, which raises questions on whether the whole ADC population becomes unstable. To characterize the average interactions between ADC, we monitored small-angle X-ray scattering in solutions of monoclonal IgG1 human antibody drug conjugate, with average degree of conjugation of 0, 2, or 3 drug molecules per protein. To characterize stability, we studied the kinetics of aggregation at room temperature. The intrinsic Fuchs stability ratio of the ADC was estimated from the variation over time of scattered light intensity and hydrodynamic radius, in buffers of varying pH, and at diverse sucrose (0% or 10%) and NaCl (0 or 100 mM) concentrations. We show that stable ADC stock solutions became unstable upon pH shift, well below the pH of maximum average attraction between IgGs. Data indicate that aggregation can be ascribed to a fraction of ADC population usually representing less than 30 mol % of the sample. In contrast to the case of (monodisperse) monoclonal antibodies, our results suggest that a poor correlation between stability and average interaction parameters should be expected as a corollary of dispersity of ADC conjugation. In practice, the most unstable fraction of the ADC population can be removed by filtration, which affects remarkably the apparent stability of the samples. Finally, the lack of correlation between the kinetic stability and variations of the average inter-ADC interactions is tentatively attributed to the uneven nature of charge distributions and the presence of patches on the drug-modified antibodies. © 2016 American Chemical Society. |
Kinetics of Photocontrollable Micelles: Light-Induced Self-Assembly and Disassembly of Azobenzene-Based Surfactants Revealed by TR-SAXS Article de journal R Lund; G Brun; E Chevallier; T Narayanan; C Tribet Langmuir, 32 (11), p. 2539–2548, 2016. @article{Lund:2016, title = {Kinetics of Photocontrollable Micelles: Light-Induced Self-Assembly and Disassembly of Azobenzene-Based Surfactants Revealed by TR-SAXS}, author = {R Lund and G Brun and E Chevallier and T Narayanan and C Tribet}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962194768&doi=10.1021%2facs.langmuir.5b04711&partnerID=40&md5=58ff1fd601a8b32f09cccc95ab611dd8}, doi = {10.1021/acs.langmuir.5b04711}, year = {2016}, date = {2016-01-01}, journal = {Langmuir}, volume = {32}, number = {11}, pages = {2539--2548}, abstract = {The kinetics of micelles involving photosensitive surfactants is still not well understood. In this work, we unravel the mechanistic pathways involved in the micelle formation and dissolution of photocontrollable micelles. We focus on the fast self-assembly processes of photosensitive cationic azobenzene-containing surfactants (AzoTMA) that display a change in hydrophobicity induced by a reversible cis-trans conformational transition upon exposure to light. By combining both in situ time-resolved small-angle X-ray scattering (SAXS) and light scattering, we characterized the detailed structure and phase behavior of AzoTMA in mixtures of water and dimethylformamide (DMF). Time-resolved synchrotron SAXS with monochromatic light as a trigger enabled us to observe the nonequilibrium formation and dissolution process of micelles (demicellization) directly on the nanoscale with a time resolution starting from milliseconds. The structural results show that in pure water UV-light illumination leads to a 12% reduction of the aggregation number of the micelles and more than a 50% increase in the critical micelle concentration (CMC). Close to the CMC, adjusted by the addition of DMF, UV light illumination leads to a complete dissolution of the micelles, while shining blue light reverses the process and leads to the reformation of micelles. The UV-triggered dissolution follows a two-step mechanism; the first and rapid (second time scale) release of unimers is followed by a slower decomposition of the micelles (over tens of seconds) as a result of an increase in temperature due to optical absorption. Similarly, the reverse process, i.e., micelle formation, occurs rapidly upon photoconversion to trans conformers under blue light, and micelles are disrupted at long exposure time due to the optical absorption and corresponding increase in temperature. Interestingly, the coexistence of unimers with regular micelles is found at all times, and no other transient assemblies could be detected by SAXS. © 2016 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The kinetics of micelles involving photosensitive surfactants is still not well understood. In this work, we unravel the mechanistic pathways involved in the micelle formation and dissolution of photocontrollable micelles. We focus on the fast self-assembly processes of photosensitive cationic azobenzene-containing surfactants (AzoTMA) that display a change in hydrophobicity induced by a reversible cis-trans conformational transition upon exposure to light. By combining both in situ time-resolved small-angle X-ray scattering (SAXS) and light scattering, we characterized the detailed structure and phase behavior of AzoTMA in mixtures of water and dimethylformamide (DMF). Time-resolved synchrotron SAXS with monochromatic light as a trigger enabled us to observe the nonequilibrium formation and dissolution process of micelles (demicellization) directly on the nanoscale with a time resolution starting from milliseconds. The structural results show that in pure water UV-light illumination leads to a 12% reduction of the aggregation number of the micelles and more than a 50% increase in the critical micelle concentration (CMC). Close to the CMC, adjusted by the addition of DMF, UV light illumination leads to a complete dissolution of the micelles, while shining blue light reverses the process and leads to the reformation of micelles. The UV-triggered dissolution follows a two-step mechanism; the first and rapid (second time scale) release of unimers is followed by a slower decomposition of the micelles (over tens of seconds) as a result of an increase in temperature due to optical absorption. Similarly, the reverse process, i.e., micelle formation, occurs rapidly upon photoconversion to trans conformers under blue light, and micelles are disrupted at long exposure time due to the optical absorption and corresponding increase in temperature. Interestingly, the coexistence of unimers with regular micelles is found at all times, and no other transient assemblies could be detected by SAXS. © 2016 American Chemical Society. |
J Malinge; F Mousseau; D Zanchi; G Brun; C Tribet; E Marie Journal of Colloid and Interface Science, 461 , p. 50–55, 2016. @article{Malinge:2016, title = {Tailored stimuli-responsive interaction between particles adjusted by straightforward adsorption of mixed layers of Poly(lysine)-g-PEG and Poly(lysine)-g-PNIPAM on anionic beads}, author = {J Malinge and F Mousseau and D Zanchi and G Brun and C Tribet and E Marie}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84941966040&doi=10.1016%2fj.jcis.2015.09.016&partnerID=40&md5=5f2229f36d05f3279fd26b0c88f46406}, doi = {10.1016/j.jcis.2015.09.016}, year = {2016}, date = {2016-01-01}, journal = {Journal of Colloid and Interface Science}, volume = {461}, pages = {50--55}, abstract = {We report a simple and versatile method to functionalize anionic colloid particles and control particle solubility. Poly(lysine)-based copolymers (PLL) grafted with polyethylene oxide (PLL-g-PEG) or poly(N-isopropylacrylamide) (PLL-g-PNIPAM) spontaneously adsorb on bare beads dispersed in aqueous solutions of the copolymers. The final composition of the mixed ad-layers formed (i.e. PEG/PNIPAM ratio) was adjusted by the polymer concentrations in solutions. While the (PLL-g-PEG)-coated particles were stable in a wide range of temperature, the presence of PLL-g-PNIPAM in the outer layer provided a reversible temperature-triggered aggregation at 32 ± 1. °C. In the range of PNIPAM fraction going from 100% (beads fully covered by PLL-g-PNIPAM) down to a threshold 20% weight ratio (with 80% PLL-g-PEG), the particles aggregated rapidly to form micrometer size clusters. Below 20% weight fraction of PLL-g-PNIPAM, the kinetic was drastically lowered. Using PLL derivatives provides a straightforward route allowing to control the fraction of a functional chain (here PNIPAM) deposited on PEGylated particles, and in turn to adjust surface interaction and here the rate of particle-particle aggregation as a function of the density of functional chains. This approach can be generalized to many anionic surfaces onto which PLL is known to adhere tightly, such as glass or silica. © 2015 Elsevier Inc.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report a simple and versatile method to functionalize anionic colloid particles and control particle solubility. Poly(lysine)-based copolymers (PLL) grafted with polyethylene oxide (PLL-g-PEG) or poly(N-isopropylacrylamide) (PLL-g-PNIPAM) spontaneously adsorb on bare beads dispersed in aqueous solutions of the copolymers. The final composition of the mixed ad-layers formed (i.e. PEG/PNIPAM ratio) was adjusted by the polymer concentrations in solutions. While the (PLL-g-PEG)-coated particles were stable in a wide range of temperature, the presence of PLL-g-PNIPAM in the outer layer provided a reversible temperature-triggered aggregation at 32 ± 1. °C. In the range of PNIPAM fraction going from 100% (beads fully covered by PLL-g-PNIPAM) down to a threshold 20% weight ratio (with 80% PLL-g-PEG), the particles aggregated rapidly to form micrometer size clusters. Below 20% weight fraction of PLL-g-PNIPAM, the kinetic was drastically lowered. Using PLL derivatives provides a straightforward route allowing to control the fraction of a functional chain (here PNIPAM) deposited on PEGylated particles, and in turn to adjust surface interaction and here the rate of particle-particle aggregation as a function of the density of functional chains. This approach can be generalized to many anionic surfaces onto which PLL is known to adhere tightly, such as glass or silica. © 2015 Elsevier Inc. |
Temperature-Switchable Control of Ligand Display on Adlayers of Mixed Poly(Lysine)-g-(PEO) and Poly(Lysine)-g-(Ligand-Modified Poly-N-Isopropylacrylamide) Article de journal F Dalier; F Eghiaian; S Scheuring; E Marie; C Tribet Biomacromolecules, 17 (5), p. 1727-1736, 2016, ISSN: 1525-7797. @article{Dalier:2016, title = {Temperature-Switchable Control of Ligand Display on Adlayers of Mixed Poly(Lysine)-g-(PEO) and Poly(Lysine)-g-(Ligand-Modified Poly-N-Isopropylacrylamide)}, author = {F Dalier and F Eghiaian and S Scheuring and E Marie and C Tribet}, doi = {10.1021/acs.biomac.6b00136}, issn = {1525-7797}, year = {2016}, date = {2016-05-01}, journal = {Biomacromolecules}, volume = {17}, number = {5}, pages = {1727-1736}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Temperature-Switchable Control of Ligand Display on Adlayers of Mixed Poly(Lysine)-g-(PEO) and Poly(Lysine)-g-(Ligand-Modified Poly-N-Isopropylacrylamide) Article de journal F Dalier; F Eghiaian; S Scheuring; E Marie; C Tribet Biomacromolecules, 17 , p. 1727-1736, 2016, ISSN: 1525-7797. @article{RN4d, title = {Temperature-Switchable Control of Ligand Display on Adlayers of Mixed Poly(Lysine)-g-(PEO) and Poly(Lysine)-g-(Ligand-Modified Poly-N-Isopropylacrylamide)}, author = {F Dalier and F Eghiaian and S Scheuring and E Marie and C Tribet}, doi = {10.1021/acs.biomac.6b00136}, issn = {1525-7797}, year = {2016}, date = {2016-01-01}, journal = {Biomacromolecules}, volume = {17}, pages = {1727-1736}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2015 |
Prevention of aggregation and renaturation of carbonic anhydrase via weak association with octadecyl- or azobenzene-modified poly(acrylate) derivatives Article de journal N Martin; J Ruchmann; C Tribet Langmuir, 31 (1), p. 338–349, 2015. @article{Martin:2015, title = {Prevention of aggregation and renaturation of carbonic anhydrase via weak association with octadecyl- or azobenzene-modified poly(acrylate) derivatives}, author = {N Martin and J Ruchmann and C Tribet}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84921409028&doi=10.1021%2fla503643q&partnerID=40&md5=0c8eb2479f885eab39c148d19fdc93d2}, doi = {10.1021/la503643q}, year = {2015}, date = {2015-01-01}, journal = {Langmuir}, volume = {31}, number = {1}, pages = {338--349}, abstract = {The prevention of aggregation during renaturation of urea-denatured carbonic anhydrase B (CAB) via hydrophobic and Coulomb association with anionic polymers was studied in mixed solutions of CAB and amphiphilic poly(acrylate) copolymers. The polymers were derivatives of a parent poly(acrylic acid) randomly grafted with hydrophobic side groups (either 3 mol % octadecyl group, or 1-5 mol % alkylamidoazobenzene photoresponsive groups). CAB:polymer complexes were characterized by light scattering and fluorescence correlation spectroscopy in aqueous buffers (pH 7.75 or 5.9). Circular dichroism and enzyme activity assays enabled us to study the kinetics of renaturation. All copolymers, including the hydrophilic PAA parent chain, provided a remarkable protective effect against CAB aggregation during renaturation, and most of them (but not the octadecyl-modified one) markedly enhanced the regain of activity as compared to CAB alone. The significant role of Coulomb binding in renaturation and comparatively the lack of efficacy of hydrophobic association was highlighted by measurements of activity regain before and after in situ dissociation of hydrophobic complexes (achieved by phototriggering the polarity of azobenzene-modified polymers under exposure to UV light). In the presence of polymers (CAB:polymer of 1:1 w/w ratio) at concentration ∼0.6 g L-1, the radii of the largest complexes were similar to the radii of the copolymers alone, suggesting that the binding of CAB involves one or a few polymer chain(s). These complexes dissociated by dilution (0.01 g L-1). It is concluded that prevention of irreversible aggregation and activity recovery were achieved when marginally stable complexes are formed. Reaching a balanced stability of the complex plays the main role in CAB renaturation, irrespective of the nature of the binding (by Coulomb association, with or without contribution of hydrophobic association). © 2014 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The prevention of aggregation during renaturation of urea-denatured carbonic anhydrase B (CAB) via hydrophobic and Coulomb association with anionic polymers was studied in mixed solutions of CAB and amphiphilic poly(acrylate) copolymers. The polymers were derivatives of a parent poly(acrylic acid) randomly grafted with hydrophobic side groups (either 3 mol % octadecyl group, or 1-5 mol % alkylamidoazobenzene photoresponsive groups). CAB:polymer complexes were characterized by light scattering and fluorescence correlation spectroscopy in aqueous buffers (pH 7.75 or 5.9). Circular dichroism and enzyme activity assays enabled us to study the kinetics of renaturation. All copolymers, including the hydrophilic PAA parent chain, provided a remarkable protective effect against CAB aggregation during renaturation, and most of them (but not the octadecyl-modified one) markedly enhanced the regain of activity as compared to CAB alone. The significant role of Coulomb binding in renaturation and comparatively the lack of efficacy of hydrophobic association was highlighted by measurements of activity regain before and after in situ dissociation of hydrophobic complexes (achieved by phototriggering the polarity of azobenzene-modified polymers under exposure to UV light). In the presence of polymers (CAB:polymer of 1:1 w/w ratio) at concentration ∼0.6 g L-1, the radii of the largest complexes were similar to the radii of the copolymers alone, suggesting that the binding of CAB involves one or a few polymer chain(s). These complexes dissociated by dilution (0.01 g L-1). It is concluded that prevention of irreversible aggregation and activity recovery were achieved when marginally stable complexes are formed. Reaching a balanced stability of the complex plays the main role in CAB renaturation, irrespective of the nature of the binding (by Coulomb association, with or without contribution of hydrophobic association). © 2014 American Chemical Society. |
2014 |
Amphiphilic Macromolecules on Cell Membranes: From Protective Layers to Controlled Permeabilization Article de journal E Marie; S Sagan; S Cribier; C Tribet Journal of Membrane Biology, 247 (9-10), p. 861–881, 2014. @article{Marie:2014, title = {Amphiphilic Macromolecules on Cell Membranes: From Protective Layers to Controlled Permeabilization}, author = {E Marie and S Sagan and S Cribier and C Tribet}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84910118231&doi=10.1007%2fs00232-014-9679-3&partnerID=40&md5=2902d0eb4d955e4adbccc4a486976725}, doi = {10.1007/s00232-014-9679-3}, year = {2014}, date = {2014-01-01}, journal = {Journal of Membrane Biology}, volume = {247}, number = {9-10}, pages = {861--881}, abstract = {Antimicrobial and cell-penetrating peptides have inspired developments of abiotic membrane-active polymers that can coat, penetrate, or break lipid bilayers in model systems. Application to cell cultures is more recent, but remarkable bioactivities are already reported. Synthetic polymer chains were tailored to achieve (i) high biocide efficiencies, and selectivity for bacteria (Gram-positive/Gram-negative or bacterial/mammalian membranes), (ii) stable and mild encapsulation of viable isolated cells to escape immune systems, (iii) pH-, temperature-, or light-triggered interaction with cells. This review illustrates these recent achievements highlighting the use of abiotic polymers, and compares the major structural determinants that control efficiency of polymers and peptides. Charge density, sp. of cationic and guanidinium side groups, and hydrophobicity (including polarity of stimuli-responsive moieties) guide the design of new copolymers for the handling of cell membranes. While polycationic chains are generally used as biocidal or hemolytic agents, anionic amphiphilic polymers, including Amphipols, are particularly prone to mild permeabilization and/or intracell delivery. © 2014, Springer Science+Business Media New York.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Antimicrobial and cell-penetrating peptides have inspired developments of abiotic membrane-active polymers that can coat, penetrate, or break lipid bilayers in model systems. Application to cell cultures is more recent, but remarkable bioactivities are already reported. Synthetic polymer chains were tailored to achieve (i) high biocide efficiencies, and selectivity for bacteria (Gram-positive/Gram-negative or bacterial/mammalian membranes), (ii) stable and mild encapsulation of viable isolated cells to escape immune systems, (iii) pH-, temperature-, or light-triggered interaction with cells. This review illustrates these recent achievements highlighting the use of abiotic polymers, and compares the major structural determinants that control efficiency of polymers and peptides. Charge density, sp. of cationic and guanidinium side groups, and hydrophobicity (including polarity of stimuli-responsive moieties) guide the design of new copolymers for the handling of cell membranes. While polycationic chains are generally used as biocidal or hemolytic agents, anionic amphiphilic polymers, including Amphipols, are particularly prone to mild permeabilization and/or intracell delivery. © 2014, Springer Science+Business Media New York. |
Photocontrolled ionization in the corona of rodlike assemblies of diblock copolymers Article de journal J Sun; L Jia; M Emond; M -H Li; E Marie; L Jullien; C Tribet Macromolecules, 47 (5), p. 1684–1692, 2014. @article{Sun:2014, title = {Photocontrolled ionization in the corona of rodlike assemblies of diblock copolymers}, author = {J Sun and L Jia and M Emond and M -H Li and E Marie and L Jullien and C Tribet}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84900623616&doi=10.1021%2fma402591y&partnerID=40&md5=096eeaa435f309dc54c178b236d1de7c}, doi = {10.1021/ma402591y}, year = {2014}, date = {2014-01-01}, journal = {Macromolecules}, volume = {47}, number = {5}, pages = {1684--1692}, abstract = {To remotely control ionization of polymer assemblies, we tailored amphiphilic diblock polyacrylates with varying hydrophilic and hydrophobic block lengths and containing pendant 2-hydroxyazobenzene photoswitchable groups in the hydrophilic block. Formation in water of rodlike polymer micelles was obtained upon hydrophobic assembly of the pendant cholesterol groups present in the hydrophobic block. Phototriggered variation of both pH and UV-vis spectral properties confirmed that hydroxylazobenzene moieties, gathered in the hydrophilic corona, underwent both isomerization and ionization upon exposure to UV light. Dispersions of rods can accordingly be ionized on demand. © 2014 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } To remotely control ionization of polymer assemblies, we tailored amphiphilic diblock polyacrylates with varying hydrophilic and hydrophobic block lengths and containing pendant 2-hydroxyazobenzene photoswitchable groups in the hydrophilic block. Formation in water of rodlike polymer micelles was obtained upon hydrophobic assembly of the pendant cholesterol groups present in the hydrophobic block. Phototriggered variation of both pH and UV-vis spectral properties confirmed that hydroxylazobenzene moieties, gathered in the hydrophilic corona, underwent both isomerization and ionization upon exposure to UV light. Dispersions of rods can accordingly be ionized on demand. © 2014 American Chemical Society. |
Prevention of thermally induced aggregation of igg antibodies by noncovalent interaction with poly(acrylate) derivatives Article de journal N Martin; D Ma; A Herbet; D Boquet; F M Winnik; C Tribet Biomacromolecules, 15 (8), p. 2952–2962, 2014. @article{Martin:2014, title = {Prevention of thermally induced aggregation of igg antibodies by noncovalent interaction with poly(acrylate) derivatives}, author = {N Martin and D Ma and A Herbet and D Boquet and F M Winnik and C Tribet}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84905845208&doi=10.1021%2fbm5005756&partnerID=40&md5=932101ce9d778337d2053ba18727533e}, doi = {10.1021/bm5005756}, year = {2014}, date = {2014-01-01}, journal = {Biomacromolecules}, volume = {15}, number = {8}, pages = {2952--2962}, abstract = {Prevention of thermal aggregation of antibodies in aqueous solutions was achieved by noncovalent association with hydrophobically modified poly(acrylate) copolymers. Using a polyclonal immunoglobin G (IgG) as a model system for antibodies, we have studied the mechanisms by which this multidomain protein interacts with polyanions when incubated at physiological pH and at temperatures below and above the protein unfolding/denaturation temperature, in salt-free solutions and in 0.1 M NaCl solutions. The polyanions selected were sodium poly(acrylates), random copolymers of sodium acrylate and N-n- octadecylacrylamide (3 mol %), and a random copolymer of sodium acrylate, N-n-octylacrylamide (25 mol %), and N-isopropylacrylamide (40 mol %). They were derived from two poly(acrylic acid) parent chains of Mw 5000 and 150000 g·mol-1. The IgG/polyanion interactions were monitored by static and dynamic light scattering, fluorescence correlation spectroscopy, capillary zone electrophoresis, and high sensitivity differential scanning calorimetry. In salt-free solutions, the hydrophilic PAA chains form complexes with IgG upon thermal unfolding of the protein (1:1 w/w IgG/PAA), but they do not interact with native IgG. The complexes exhibit a remarkable protective effect against IgG aggregation and maintain low aggregation numbers (average degree of oligomerization <12 at a temperature up to 85 °C). These interactions are screened in 0.1 M NaCl and, consequently, PAAs lose their protective effect. Amphiphilic PAA derivatives (1:1 w/w IgG/polymer) are able to prevent thermal aggregation (preserving IgG monomers) or retard aggregation of IgG (formation of oligomers and slow growth), revealing the importance of both hydrophobic interactions and modulation of the Coulomb interactions with or without NaCl present. This study leads the way toward the design of new formulations of therapeutic proteins using noncovalent 1:1 polymer/protein association that are transient and require a markedly lower additive concentration compared to conventional osmolyte protecting agents. They do not modify IgG permanently, which is an asset for applications in therapeutic protein formulations since the in vivo efficacy of the protein should not be affected. © 2014 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Prevention of thermal aggregation of antibodies in aqueous solutions was achieved by noncovalent association with hydrophobically modified poly(acrylate) copolymers. Using a polyclonal immunoglobin G (IgG) as a model system for antibodies, we have studied the mechanisms by which this multidomain protein interacts with polyanions when incubated at physiological pH and at temperatures below and above the protein unfolding/denaturation temperature, in salt-free solutions and in 0.1 M NaCl solutions. The polyanions selected were sodium poly(acrylates), random copolymers of sodium acrylate and N-n- octadecylacrylamide (3 mol %), and a random copolymer of sodium acrylate, N-n-octylacrylamide (25 mol %), and N-isopropylacrylamide (40 mol %). They were derived from two poly(acrylic acid) parent chains of Mw 5000 and 150000 g·mol-1. The IgG/polyanion interactions were monitored by static and dynamic light scattering, fluorescence correlation spectroscopy, capillary zone electrophoresis, and high sensitivity differential scanning calorimetry. In salt-free solutions, the hydrophilic PAA chains form complexes with IgG upon thermal unfolding of the protein (1:1 w/w IgG/PAA), but they do not interact with native IgG. The complexes exhibit a remarkable protective effect against IgG aggregation and maintain low aggregation numbers (average degree of oligomerization <12 at a temperature up to 85 °C). These interactions are screened in 0.1 M NaCl and, consequently, PAAs lose their protective effect. Amphiphilic PAA derivatives (1:1 w/w IgG/polymer) are able to prevent thermal aggregation (preserving IgG monomers) or retard aggregation of IgG (formation of oligomers and slow growth), revealing the importance of both hydrophobic interactions and modulation of the Coulomb interactions with or without NaCl present. This study leads the way toward the design of new formulations of therapeutic proteins using noncovalent 1:1 polymer/protein association that are transient and require a markedly lower additive concentration compared to conventional osmolyte protecting agents. They do not modify IgG permanently, which is an asset for applications in therapeutic protein formulations since the in vivo efficacy of the protein should not be affected. © 2014 American Chemical Society. |
Quantitative characterization by asymmetrical flow field-flow fractionation of IgG thermal aggregation with and without polymer protective agents Article de journal D Ma; N Martin; C Tribet; F M Winnik Analytical and Bioanalytical Chemistry, 406 (29), p. 7539–7547, 2014. @article{Ma:2014, title = {Quantitative characterization by asymmetrical flow field-flow fractionation of IgG thermal aggregation with and without polymer protective agents}, author = {D Ma and N Martin and C Tribet and F M Winnik}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84919897664&doi=10.1007%2fs00216-014-8200-2&partnerID=40&md5=184e664be993b1068377e8f1c0d24e94}, doi = {10.1007/s00216-014-8200-2}, year = {2014}, date = {2014-01-01}, journal = {Analytical and Bioanalytical Chemistry}, volume = {406}, number = {29}, pages = {7539--7547}, abstract = {Complexes formed between poly(acrylates) and polyclonal immunoglobulin G (IgG) in its native conformation and after heat stress were characterized using asymmetric flow field-flow fractionation (AF4) coupled with on-line UV-Vis spectroscopy and multi-angle light-scattering detection (MALS). Mixtures of IgG and poly(acrylates) of increasing structural complexity, sodium poly(acrylate) (PAA), a sodium poly(acrylate) bearing at random 3 mol % n-octadecyl groups, and a random copolymer of sodium acrylate (35 mol %), N-n-octylacrylamide (25 mol %) and N-isopropylacrylamide (40 mol %), were fractionated in a sodium phosphate buffer (0.02 M, pH 6.8) in the presence, or not, of 0.1 M NaCl. The AF4 protocol developed allowed the fractionation of solutions containing free poly(acrylates), native IgG monomer and dimer, poly(acrylates)/IgG complexes made up of one IgG molecule and a few polymer chains, and/or larger poly(acrylates)/IgG aggregates. The molar mass and recovery of the soluble analytes were obtained for mixed solutions of poly(acrylates) and native IgG and for the same solutions incubated at 65 °C for 10 min. From the combined AF4 results, we concluded that in solutions of low ionic strength, the presence of PAA increased the recovery ratio of IgG after thermal stress because of the formation of electrostatically-driven PAA/IgG complexes, but PAA had no protective effect in the presence of 0.1 M NaCl. Poly(acrylates) bearing hydrophobic groups significantly increased IgG recovery after stress, independently of NaCl concentration, because of the synergistic effect of hydrophobic and electrostatic interactions. The AF4 results corroborate conclusions drawn from a previous study combining four analytical techniques. This study demonstrates that AF4 is an efficient tool for the analysis of protein formulations subjected to stress, an important achievement given the anticipated important role of proteins in near-future human therapies. © 2014 Springer-Verlag Berlin Heidelberg.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Complexes formed between poly(acrylates) and polyclonal immunoglobulin G (IgG) in its native conformation and after heat stress were characterized using asymmetric flow field-flow fractionation (AF4) coupled with on-line UV-Vis spectroscopy and multi-angle light-scattering detection (MALS). Mixtures of IgG and poly(acrylates) of increasing structural complexity, sodium poly(acrylate) (PAA), a sodium poly(acrylate) bearing at random 3 mol % n-octadecyl groups, and a random copolymer of sodium acrylate (35 mol %), N-n-octylacrylamide (25 mol %) and N-isopropylacrylamide (40 mol %), were fractionated in a sodium phosphate buffer (0.02 M, pH 6.8) in the presence, or not, of 0.1 M NaCl. The AF4 protocol developed allowed the fractionation of solutions containing free poly(acrylates), native IgG monomer and dimer, poly(acrylates)/IgG complexes made up of one IgG molecule and a few polymer chains, and/or larger poly(acrylates)/IgG aggregates. The molar mass and recovery of the soluble analytes were obtained for mixed solutions of poly(acrylates) and native IgG and for the same solutions incubated at 65 °C for 10 min. From the combined AF4 results, we concluded that in solutions of low ionic strength, the presence of PAA increased the recovery ratio of IgG after thermal stress because of the formation of electrostatically-driven PAA/IgG complexes, but PAA had no protective effect in the presence of 0.1 M NaCl. Poly(acrylates) bearing hydrophobic groups significantly increased IgG recovery after stress, independently of NaCl concentration, because of the synergistic effect of hydrophobic and electrostatic interactions. The AF4 results corroborate conclusions drawn from a previous study combining four analytical techniques. This study demonstrates that AF4 is an efficient tool for the analysis of protein formulations subjected to stress, an important achievement given the anticipated important role of proteins in near-future human therapies. © 2014 Springer-Verlag Berlin Heidelberg. |
2013 |
Triggering Cell Adhesion, Migration or Shape Change with a Dynamic Surface Coating Article de journal S F M van Dongen; P Maiuri; E Marie; C Tribet; M Piel Advanced Materials, 25 (12), p. 1687-1691, 2013, ISSN: 0935-9648. @article{vanDongen:2013, title = {Triggering Cell Adhesion, Migration or Shape Change with a Dynamic Surface Coating}, author = {S F M {van Dongen} and P Maiuri and E Marie and C Tribet and M Piel}, doi = {10.1002/adma.201204474}, issn = {0935-9648}, year = {2013}, date = {2013-03-01}, journal = {Advanced Materials}, volume = {25}, number = {12}, pages = {1687-1691}, abstract = {There's an APP for that: cell-repellent APP (azido-[polylysine-g-PEG]) is used to create substrates for spatially controlled dynamic cell adhesion. The simple addition of a functional peptide to the culture medium rapidly triggers cell adhesion. This highly accessible yet powerful technique allows diverse applications, demonstrated through tissue motility assays, patterned coculturing and triggered cell shape change. [GRAPHICS] .}, keywords = {}, pubstate = {published}, tppubtype = {article} } There's an APP for that: cell-repellent APP (azido-[polylysine-g-PEG]) is used to create substrates for spatially controlled dynamic cell adhesion. The simple addition of a functional peptide to the culture medium rapidly triggers cell adhesion. This highly accessible yet powerful technique allows diverse applications, demonstrated through tissue motility assays, patterned coculturing and triggered cell shape change. [GRAPHICS] . |
2012 |
Importance of the Dynamics of Adsorption and of a Transient Interfacial Stress on the Formation of Aggregates of IgG Antibodies Article de journal S Rudiuk; L Cohen-Tannoudji; S Huille; C Tribet Soft Matter, 8 (9), p. 2651-2661, 2012, ISSN: 1744-683X. @article{Rudiuk:2012, title = {Importance of the Dynamics of Adsorption and of a Transient Interfacial Stress on the Formation of Aggregates of IgG Antibodies}, author = {S Rudiuk and L {Cohen-Tannoudji} and S Huille and C Tribet}, doi = {10.1039/c2sm07017k}, issn = {1744-683X}, year = {2012}, date = {2012-01-01}, journal = {Soft Matter}, volume = {8}, number = {9}, pages = {2651-2661}, abstract = {It is common knowledge that aggregation of proteins may occur in aqueous solutions under mechanical stress (shaking or high shear), even in solutions that are stable at rest. Addition of surfactants is a practical generic means to prevent this stress-induced aggregation (e. g. in formulations of therapeutic proteins), which suggests that interfaces contribute to destabilization. We studied here the role of interfacial stress by applying brief mechanical impacts on the air-water interface, in the presence or absence of surfactants, in solutions of immunoglobulin G (IgG), a class of proteins of high importance to the developments of new therapeutics. A variety of surfactants was tested including the neutral ones Tween80, C10-C14 fos-cholines, alkylaminoxide, surfactin, and two ionic ones, TTAB and lauroylsarcosine sodium salt. We determined the presence of aggregates in solution by light scattering. Irrespective of the type of antibody, either human polyclonal or a monoclonal one, we show that the amount of aggregated IgG increases in proportion to the number of impacts on the interface. In the absence of stress, we recorded images of oblate aggregates of IgG (ca. 12 nm height and 200-1200 nm diameter) present at the air-water interface (fluorescence microscopy using anti-Fab or anti-Fc markers, and AFM scans after transfer on freshly cleaved mica). Our results evidence that aggregates are formed at the air-water interface, and are brought in solution by transient stresses applied on the water surface. Rupture of interfacial films is an important source of aggregates in solution. Finally, the role of surface dynamics in the protection brought by surfactants is discussed based on the comparison of protective efficiencies with dynamic surface tension properties (measured by the maximum bubble pressure method). Our work indicates that better protection is conferred by surfactants showing the faster interfacial dynamics, which corresponds also to conditions of faster lowering of the interfacial energy at a short time scale.}, keywords = {}, pubstate = {published}, tppubtype = {article} } It is common knowledge that aggregation of proteins may occur in aqueous solutions under mechanical stress (shaking or high shear), even in solutions that are stable at rest. Addition of surfactants is a practical generic means to prevent this stress-induced aggregation (e. g. in formulations of therapeutic proteins), which suggests that interfaces contribute to destabilization. We studied here the role of interfacial stress by applying brief mechanical impacts on the air-water interface, in the presence or absence of surfactants, in solutions of immunoglobulin G (IgG), a class of proteins of high importance to the developments of new therapeutics. A variety of surfactants was tested including the neutral ones Tween80, C10-C14 fos-cholines, alkylaminoxide, surfactin, and two ionic ones, TTAB and lauroylsarcosine sodium salt. We determined the presence of aggregates in solution by light scattering. Irrespective of the type of antibody, either human polyclonal or a monoclonal one, we show that the amount of aggregated IgG increases in proportion to the number of impacts on the interface. In the absence of stress, we recorded images of oblate aggregates of IgG (ca. 12 nm height and 200-1200 nm diameter) present at the air-water interface (fluorescence microscopy using anti-Fab or anti-Fc markers, and AFM scans after transfer on freshly cleaved mica). Our results evidence that aggregates are formed at the air-water interface, and are brought in solution by transient stresses applied on the water surface. Rupture of interfacial films is an important source of aggregates in solution. Finally, the role of surface dynamics in the protection brought by surfactants is discussed based on the comparison of protective efficiencies with dynamic surface tension properties (measured by the maximum bubble pressure method). Our work indicates that better protection is conferred by surfactants showing the faster interfacial dynamics, which corresponds also to conditions of faster lowering of the interfacial energy at a short time scale. |
Nanoemulsions with Enhanced Temperature Stability Using Thermo-Sensitive Association of Nonionic Surfactant and Amphiphilic Polyelectrolytes Article de journal J Galindo-Alvarez; V Sadtler; P Marchal; P Perrin; C Tribet; E Marie; A Durand Colloids and Surfaces a-Physicochemical and Engineering Aspects, 396 , p. 115-121, 2012, ISSN: 0927-7757. @article{RN11e, title = {Nanoemulsions with Enhanced Temperature Stability Using Thermo-Sensitive Association of Nonionic Surfactant and Amphiphilic Polyelectrolytes}, author = {J {Galindo-Alvarez} and V Sadtler and P Marchal and P Perrin and C Tribet and E Marie and A Durand}, doi = {10.1016/j.colsurfa.2011.12.051}, issn = {0927-7757}, year = {2012}, date = {2012-01-01}, journal = {Colloids and Surfaces a-Physicochemical and Engineering Aspects}, volume = {396}, pages = {115-121}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Non-Monotonous Variation of the LCST of Light-Responsive, Amphiphilic Poly(NIPAM) Derivatives Article de journal Y J Liu; A Pallier; J Sun; S Rudiuk; D Baigl; M Piel; E Marie; C Tribet Soft Matter, 8 (32), p. 8446-8455, 2012, ISSN: 1744-683X. @article{Liu:2012, title = {Non-Monotonous Variation of the LCST of Light-Responsive, Amphiphilic Poly(NIPAM) Derivatives}, author = {Y J Liu and A Pallier and J Sun and S Rudiuk and D Baigl and M Piel and E Marie and C Tribet}, doi = {10.1039/c2sm25959a}, issn = {1744-683X}, year = {2012}, date = {2012-08-01}, journal = {Soft Matter}, volume = {8}, number = {32}, pages = {8446-8455}, abstract = {The response to light of macromolecules in aqueous media is a significant concern for the design of complex fluids, and (bio) materials imparted with stimuli-triggered properties. It is common knowledge that polymer chains containing photochrome groups can be tailored to undergo a transition between poor and good solvent conditions upon exposure to light, thanks to the photoswitch of the polarity/hydrophobicity of their photochromes. In water, marked photo-responses are typically achieved in the vicinity of the low critical solution temperature (LCST) of polymers. To understand and optimize the variation of the LCST of amphiphilic polymers in response to exposure to UV-visible light, we studied the LCST properties of a homologous set of derivatives of poly(N-isopropylacrylamide). The chains contained a hydrophilic oligo(ethylene oxide) side group (at 20 mol%) and a light-responsive azobenzene introduced at a varying integration level (ranging from 0% to 24 mol%). Turbidity measurements showed that the LCST passes through a minimum value upon increasing the density of the hydrophobic azobenzene. At a low % of azobenzene, the LCST displayed the conventional decrease with increasing hydrophobicity of the polymers, from ca. 56 degrees C in the absence of azobenzene down to ca. 35 degrees C for the polymer containing 5 mol% azobenzene. Conversely, beyond 11 mol% azobenzene, the LCST increased upon increasing the hydrophobicity of the polymers, and a "reverse" response to exposure to light was observed. Namely the LCST decreased by up to 5 degrees C upon the photoconversion of azobenzene from the trans, apolar isomer, to the cis, polar, i.e. more water soluble isomer. This counterintuitive behavior was accompanied by the formation of clusters of chains, whose diameter (similar to 20 nm) was measured by dynamic light scattering. AFM and UV-visible spectra confirmed the presence of hydrophobic associates between the azobenzene groups. We ascribed the origin of the "reverse" responses to the presence of these clusters. We proposed accordingly a model of the partitioning of azobenzene between water and the hydrophobic core of the clusters, which allowed us to calculate the LCST as a function of polymer composition. Fitting experimental data to the model quantitatively indicated that self-assemblies scavenge the hydrophobic photochromes and in turn tune their contribution to the LCST.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The response to light of macromolecules in aqueous media is a significant concern for the design of complex fluids, and (bio) materials imparted with stimuli-triggered properties. It is common knowledge that polymer chains containing photochrome groups can be tailored to undergo a transition between poor and good solvent conditions upon exposure to light, thanks to the photoswitch of the polarity/hydrophobicity of their photochromes. In water, marked photo-responses are typically achieved in the vicinity of the low critical solution temperature (LCST) of polymers. To understand and optimize the variation of the LCST of amphiphilic polymers in response to exposure to UV-visible light, we studied the LCST properties of a homologous set of derivatives of poly(N-isopropylacrylamide). The chains contained a hydrophilic oligo(ethylene oxide) side group (at 20 mol%) and a light-responsive azobenzene introduced at a varying integration level (ranging from 0% to 24 mol%). Turbidity measurements showed that the LCST passes through a minimum value upon increasing the density of the hydrophobic azobenzene. At a low % of azobenzene, the LCST displayed the conventional decrease with increasing hydrophobicity of the polymers, from ca. 56 degrees C in the absence of azobenzene down to ca. 35 degrees C for the polymer containing 5 mol% azobenzene. Conversely, beyond 11 mol% azobenzene, the LCST increased upon increasing the hydrophobicity of the polymers, and a "reverse" response to exposure to light was observed. Namely the LCST decreased by up to 5 degrees C upon the photoconversion of azobenzene from the trans, apolar isomer, to the cis, polar, i.e. more water soluble isomer. This counterintuitive behavior was accompanied by the formation of clusters of chains, whose diameter (similar to 20 nm) was measured by dynamic light scattering. AFM and UV-visible spectra confirmed the presence of hydrophobic associates between the azobenzene groups. We ascribed the origin of the "reverse" responses to the presence of these clusters. We proposed accordingly a model of the partitioning of azobenzene between water and the hydrophobic core of the clusters, which allowed us to calculate the LCST as a function of polymer composition. Fitting experimental data to the model quantitatively indicated that self-assemblies scavenge the hydrophobic photochromes and in turn tune their contribution to the LCST. |
Photocontrol of the translocation of molecules, peptides, and quantum dots through cell and lipid membranes doped with azobenzene copolymers Article de journal S C Sebai; D Milioni; A Walrant; I D Alves; S Sagan; C Huin; L Auvray; D Massotte; S Cribier; C Tribet Angewandte Chemie - International Edition, 51 (9), p. 2132–2136, 2012. @article{Sebai:2012, title = {Photocontrol of the translocation of molecules, peptides, and quantum dots through cell and lipid membranes doped with azobenzene copolymers}, author = {S C Sebai and D Milioni and A Walrant and I D Alves and S Sagan and C Huin and L Auvray and D Massotte and S Cribier and C Tribet}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84857620113&doi=10.1002%2fanie.201106777&partnerID=40&md5=59665347132c0f785629622246a0c138}, doi = {10.1002/anie.201106777}, year = {2012}, date = {2012-01-01}, journal = {Angewandte Chemie - International Edition}, volume = {51}, number = {9}, pages = {2132--2136}, abstract = {Light opens: Photocontrolled transmembrane passage of soluble dyes and delivery of small peptides into mammalian cells has been achieved using azobenzene-modified polymers (AMPs) as permeabilizing agents. Irradiation with UV and visible light triggers polarity switches upon cis-trans isomerization of the azobenzene moieties. Photoresponsive permeability and pore opening promoted by trans-AMPs, but not cis-AMPs, in supported lipid bilayers are observed. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Light opens: Photocontrolled transmembrane passage of soluble dyes and delivery of small peptides into mammalian cells has been achieved using azobenzene-modified polymers (AMPs) as permeabilizing agents. Irradiation with UV and visible light triggers polarity switches upon cis-trans isomerization of the azobenzene moieties. Photoresponsive permeability and pore opening promoted by trans-AMPs, but not cis-AMPs, in supported lipid bilayers are observed. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. |
Photofoams: Remote control of foam destabilization by exposure to light using an azobenzene surfactant Article de journal E Chevallier; C Monteux; F Lequeux; C Tribet Langmuir, 28 (5), p. 2308–2312, 2012. @article{Chevallier:2012, title = {Photofoams: Remote control of foam destabilization by exposure to light using an azobenzene surfactant}, author = {E Chevallier and C Monteux and F Lequeux and C Tribet}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84856759450&doi=10.1021%2fla204200z&partnerID=40&md5=d245c53f3716d5fe93c71b5817943c52}, doi = {10.1021/la204200z}, year = {2012}, date = {2012-01-01}, journal = {Langmuir}, volume = {28}, number = {5}, pages = {2308--2312}, abstract = {We report evidence for photocontrolled stability and breakage of aqueous foams made from solutions of a cationic azobenzene-containing surfactant over a wide range of concentrations. Exposure to UV or visible lights results in shape and polarity switches in the surfactant molecule, which in turn affects several properties including critical micelle concentration, equilibrium surface tension, and the air-water interfacial composition (cis isomers are displaced by trans ones). We demonstrate that the trans isomer stabilizes foams, whereas the cis isomer forms unstable foams, a property that does not correlate with effects of light on surface tension, nor with total surfactant concentration. Achieving in situ breakage of foam is accordingly ascribed to the remote control of the dynamics of adsorption/desorption of the surfactant, accompanied by gradients of concentrations out of equilibrium. Photomodulation of adsorption kinetics and/or diffusion dynamics on interfaces is reached here by a noninvasive clean trigger, bringing a new tool for the study of foams. © 2012 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report evidence for photocontrolled stability and breakage of aqueous foams made from solutions of a cationic azobenzene-containing surfactant over a wide range of concentrations. Exposure to UV or visible lights results in shape and polarity switches in the surfactant molecule, which in turn affects several properties including critical micelle concentration, equilibrium surface tension, and the air-water interfacial composition (cis isomers are displaced by trans ones). We demonstrate that the trans isomer stabilizes foams, whereas the cis isomer forms unstable foams, a property that does not correlate with effects of light on surface tension, nor with total surfactant concentration. Achieving in situ breakage of foam is accordingly ascribed to the remote control of the dynamics of adsorption/desorption of the surfactant, accompanied by gradients of concentrations out of equilibrium. Photomodulation of adsorption kinetics and/or diffusion dynamics on interfaces is reached here by a noninvasive clean trigger, bringing a new tool for the study of foams. © 2012 American Chemical Society. |