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Jennings L, Glazer P, Laan AC, de Kruijff RM, Waton G, Schosseler F, Mendes E. The role of confinement and corona crystallinity on the bending modulus of copolymer micelles measured directly by AFM flexural tests. Soft Matter 2016; 12:7324-7329. [PMID: 27506248 DOI: 10.1039/c6sm00983b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present an approach which makes it possible to directly determine the bending modulus of single elongated block copolymer micelles. This is done by forming arrays of suspended micelles onto microfabricated substrates and by performing three-point bending flexural tests, using an atomic force microscope, on their suspended portions. By coupling the direct atomic force microscopy measurements with differential scanning calorimetry data, we show that the presence of a crystalline corona strongly increases the modulus of the copolymer elongated micelles. This large increase suggests that crystallites in the corona are larger and more uniformly oriented due to confinement effects. Our findings together with this hypothesis open new interesting avenues for the preparation of core-templated polymer fibres with enhanced mechanical properties.
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Affiliation(s)
- L Jennings
- Institut Charles Sadron (UPR22-CNRS), 23 Rue du Loess, 67034 Strasbourg Cedex 2, France.
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Jennings L, Ivashchenko O, Marsman IJC, Laan AC, Denkova AG, Waton G, Beekman FJ, Schosseler F, Mendes E. In vivo biodistribution of stable spherical and filamentous micelles probed by high-sensitivity SPECT. Biomater Sci 2016; 4:1202-11. [PMID: 27286085 DOI: 10.1039/c6bm00297h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Understanding how nanoparticle properties such as size, morphology and rigidity influence their circulation time and biodistribution is essential for the development of nanomedicine therapies. Herein we assess the influence of morphology on cellular internalization, in vivo biodistribution and circulation time of nanocarriers using polystyrene-b-poly(ethylene oxide) micelles of spherical or elongated morphology. The glassy nature of polystyrene guarantees the morphological stability of the carriers in vivo and by encapsulating Indium-111 in their core, an assessment of the longitudinal in vivo biodistribution of the particles in healthy mice is performed with single photon emission computed tomography imaging. Our results show prolonged blood circulation, longer than 24 hours, for all micelle morphologies studied. Dynamics of micelle accumulation in the liver and other organs of the reticuloendothelial system show a size-dependent nature and late stage liver clearance is observed for the elongated morphology. Apparent contradictions between recent similar studies can be resolved by considering the effects of flexibility and degradation of the elongated micelles on their circulation time and biodistribution.
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Affiliation(s)
- L Jennings
- Institut Charles Sadron (CNRS), University of Strasbourg, Strasbourg, France.
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Abstract
ABSTRACTMeasurements of the breaking time of cylindrical micelles of cetyltrimethylammonium bromide in aqueous solutions have been performed by means of T-Jump experiments with light scattering detection. The results provide an unambiguous test of a recent theoretical model for stress relaxation.
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Buhler E, Oelschlaeger C, Waton G, Rawiso M, Schmidt J, Talmon Y, Candau SJ. Structural and dynamical properties of ribbonlike self-assemblies of a fluorinated cationic surfactant. Langmuir 2006; 22:2534-42. [PMID: 16519452 DOI: 10.1021/la0525832] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The structural and dynamic properties of low ionic strength micellar solutions of the cationic surfactant perfluorooctylbutane trimethylammonium bromide have been investigated by cryo-TEM, small-angle neutron scattering, small-angle X-ray scattering, T-jump and rheological experiments. The surfactant molecules self-assemble into narrow ribbons with average dimensions on the order of 4 nm x 3 nm, either under salt-free conditions or in the presence of up to 30 mM KBr or NaF. Cryo-TEM also reveals in the salt-free systems the presence of networks of multiconnected micelles. Rheological experiments showed that these surfactant systems exhibit a strong shear-thickening effect even in the presence of up to 30 mM KBr. The T-jump response of the micellar solutions was found to be multiexponential. This observation rules out the presence of only linear micelles with an exponential length distribution and suggests more complex topologies of the micellar aggregates. The relaxation time associated with the predominant process in the T-jump relaxation is strongly correlated to the critical shear rate beyond which shear thickening occurs, thus indicating that this critical shear rate is controlled by the micellar kinetics.
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Affiliation(s)
- E Buhler
- Laboratoire de Spectrométrie Physique, UMR CNRS 5588, Université Joseph Fourier de Grenoble, B.P. 87, 38402 St. Martin d'Hères, France
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Abstract
We study the temperature-induced growth of polymer micelles based on Pluronic P84 in brine (2 M NaCl) using small-angle neutron scattering, static and dynamic light scattering, and viscometry as a function of temperature and polymer concentration. Spherical micelles below 30 degrees C are shown to grow between about 30 and 40 degrees C into wormlike micelles long enough to enter the semidilute regime for polymer volume fraction larger than 0.005. The entanglements in this regime are responsible for a huge increase in the viscosity. Above about 41 degrees C, the micellar aggregates become denser as the cloud point is approached and the viscosity drops.
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Affiliation(s)
- M Duval
- Institut Charles Sadron, UPR22 (CNRS-ULP), 6 rue Boussingault, 67083 Strasbourg Cedex, France
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Buhler E, Oelschlaeger C, Waton G, Candau SJ. Viscoelastic Properties of Hydrocarbon/Fluorocarbon Mixed Wormlike Micelles at High Ionic Strength. J Phys Chem B 2004. [DOI: 10.1021/jp049466k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- E. Buhler
- Groupe de Dynamique des Phases Condensées, UMR No. 5581 CNRS, Université de Montpellier II, Case Courrier 26, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France, and Laboratoire de Dynamique des Fluides Complexes, UMR No. 7506 CNRS, Université Louis Pasteur, 4, rue Blaise Pascal, 67070 Strasbourg Cedex, France
| | - C. Oelschlaeger
- Groupe de Dynamique des Phases Condensées, UMR No. 5581 CNRS, Université de Montpellier II, Case Courrier 26, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France, and Laboratoire de Dynamique des Fluides Complexes, UMR No. 7506 CNRS, Université Louis Pasteur, 4, rue Blaise Pascal, 67070 Strasbourg Cedex, France
| | - G. Waton
- Groupe de Dynamique des Phases Condensées, UMR No. 5581 CNRS, Université de Montpellier II, Case Courrier 26, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France, and Laboratoire de Dynamique des Fluides Complexes, UMR No. 7506 CNRS, Université Louis Pasteur, 4, rue Blaise Pascal, 67070 Strasbourg Cedex, France
| | - S. J. Candau
- Groupe de Dynamique des Phases Condensées, UMR No. 5581 CNRS, Université de Montpellier II, Case Courrier 26, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France, and Laboratoire de Dynamique des Fluides Complexes, UMR No. 7506 CNRS, Université Louis Pasteur, 4, rue Blaise Pascal, 67070 Strasbourg Cedex, France
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Waton G, Michels B, Steyer A, Schosseler F. Shear-Induced Demixing and Shear-Banding Instabilities in Dilute Triblock Copolymer Solutions. Macromolecules 2004. [DOI: 10.1021/ma0349332] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- G. Waton
- Laboratoire de Dynamique des Fluides Complexes, UMR 7506, 4 rue Blaise Pascal, 67070 Strasbourg Cedex, France
| | - B. Michels
- Laboratoire de Dynamique des Fluides Complexes, UMR 7506, 4 rue Blaise Pascal, 67070 Strasbourg Cedex, France
| | - A. Steyer
- Laboratoire de Dynamique des Fluides Complexes, UMR 7506, 4 rue Blaise Pascal, 67070 Strasbourg Cedex, France
| | - F. Schosseler
- Laboratoire de Dynamique des Fluides Complexes, UMR 7506, 4 rue Blaise Pascal, 67070 Strasbourg Cedex, France
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Oelschlaeger C, Buhler E, Waton G, Candau SJ. Synergistic effects in mixed wormlike micelles of dimeric and single-chain cationic surfactants at high ionic strength. Eur Phys J E Soft Matter 2003; 11:7-20. [PMID: 15015083 DOI: 10.1140/epje/i2002-10124-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The mixed micellization between the cationic gemini surfactant [C12H25(CH3)2N+(C2H4)N+(CH3)2C12H25*2Br-] and the cationic cetyltrimethylammonium bromide (CTAB) in 150 mM KBr solutions has been investigated. The variation of the cmc of the mixtures, measured by surface tension experiments, with composition revealed synergism in micelle formation. T-Jump and light scattering experiments performed in the vicinity of the crossover volume fraction showed the existence of two micellar populations, possibly linear and toroidal micelles. Rheological and dynamic light scattering experiments allowed to fully characterize the linear viscoelasticity of the mixtures. These measurements revealed synergistic gains in viscoelastic properties with a maximum of the stress-relaxation time around the equimolar composition. These effects are ascribed to a progressive intermicellar crosslinking resulting from a continuous increase of the end-cap energy with the 12-2-12 content in the mixture.
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Affiliation(s)
- C Oelschlaeger
- Laboratoire de Dynamique des Fluides Complexes, UMR n 7506, Université Louis Pasteur, CNRS, 4 rue Blaise Pascal, 67070 Strasbourg Cedex, France
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Affiliation(s)
- B. Michels
- Laboratoire de Dynamique des Fluides Complexes,UMR 7506 du CNRS, Université Louis Pasteur, 4 rue Blaise Pascal, 67070 Strasbourg-CEDEX, France
| | - G. Waton
- Laboratoire de Dynamique des Fluides Complexes,UMR 7506 du CNRS, Université Louis Pasteur, 4 rue Blaise Pascal, 67070 Strasbourg-CEDEX, France
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Waton G, Michels B, Zana R. Dynamics of Micelles of Polyethyleneoxide-Polypropyleneoxide-Polyethyleneoxide Block Copolymers in Aqueous Solutions. J Colloid Interface Sci 1999; 212:593-596. [PMID: 10092393 DOI: 10.1006/jcis.1998.6020] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The dynamics of the micelles of five triblock poly(ethyleneoxide)-poly(propyleneoxide)-poly(ethyleneoxide) copolymers, the Pluronics P104 (EO27PO61EO27), P84 (EO19PO43EO19), P65 (EO18PO29EO18), P85 (EO26PO40EO26), and P103 (EO17PO60EO17), have been investigated using two chemical relaxation methods: the temperature-jump and the ultrasonic relaxation (absorption). In the frequency range investigated (0.5-50 MHz), the ultrasonic absorption spectra (absorption vs frequency plots) consisted in tails of relaxation curves, indicating characteristic times much longer than 0.3 µs for the exchange of copolymers between micelles and intermicellar solution. Absorption measurements at a fixed frequency yielded the critical micellization temperature of the solutions. The temperature-jump results obtained in this study together with those from a previous one for the copolymers L64 (EO13PO30EO13) and PF80 (EO73PO27EO73) (B. Michels et al., Langmuir 13, 3111, 1997) showed that the relaxation time associated with the formation/breakup of micelles becomes longer upon increasing copolymer molecular weight at constant composition. This time also increased when decreasing the length of the hydrophilic block at fixed hydrophobic block length or increasing the length of the hydrophobic block at fixed hydrophilic block length, similar to conventional surfactants. The dynamics of block copolymers micelles in aqueous solution are discussed. Copyright 1999 Academic Press.
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Affiliation(s)
- G Waton
- Laboratoire d'Ultrasons et de Dynamique des Fluides Complexes, URA 851 du CNRS, Université Louis Pasteur, 4, rue Blaise Pascal, Strasbourg Cedex, 67070, France
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Affiliation(s)
- G. Waton
- Laboratoire d'Ultrasons et de Dynamique des Fluides Complexes, URA 851 du CNRS, Université Louis Pasteur, 4 rue Blaise Pascal, 67070 Strasbourg-Cedex, France
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Affiliation(s)
- E. Faetibold
- Laboratoire d'Ultrasons et de Dynamique des Fluides Complexes, Unité de Recherche Associée au CNRS No. 851, Université Louis Pasteur, 4 rue Blaise Pascal, 67070 Strasbourg Cedex, France
| | - B. Michels
- Laboratoire d'Ultrasons et de Dynamique des Fluides Complexes, Unité de Recherche Associée au CNRS No. 851, Université Louis Pasteur, 4 rue Blaise Pascal, 67070 Strasbourg Cedex, France
| | - G. Waton
- Laboratoire d'Ultrasons et de Dynamique des Fluides Complexes, Unité de Recherche Associée au CNRS No. 851, Université Louis Pasteur, 4 rue Blaise Pascal, 67070 Strasbourg Cedex, France
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Abstract
OBJECTIVES Anaesthetized rats or surgically modified preparations such as the Shay rat are widely used to study upper gastrointestinal function in the laboratory. Despite the existence of reports demonstrating that agents such as barbiturates can influence acid output, a systematic study of the effects of anaesthetics on gastric secretion has not been undertaken. METHODS Basal and histamine-stimulated acid output were measured in chronic fistula rats after administration of injectable and volatile anaesthetics frequently used in studies of gastric secretion in anaesthetized animals. With the exception of ether, for which recovery is very rapid, sedating rather than full anaesthetic doses were used. RESULTS Chloralose (40 mg/kg) had no significant effect on gastric secretion. Pentobarbitone (25 mg/kg) inhibited basal and histamine-stimulated acid output, but the effect was relatively short-lived and secretion returned to control levels after 2 h. Urethane (750 mg/kg) markedly inhibited basal acid output and abolished the secretory response to histamine given 15 to 60 min later. The effects of urethane on acid secretion persisted for the entire 3 h duration of experiments, during which time basal acid output declined to levels observed in fully anaesthetized rats given 1.5 g/kg. Full anaesthesia with ether for 60 min also caused profound inhibition of basal secretion and, like urethane, abolished the effect of histamine despite the fact that the animals recovered consciousness within 5 min. CONCLUSIONS The differential activity of anaesthetics and profound antisecretory activity of ether and urethane should be taken into account when studying gastrointestinal function and mucosal ulceration in anaesthetized animals.
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Affiliation(s)
- S M Bastaki
- Department of Pharmacology, United Arab Emirates University, Al Ain
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Brunette* J, Rifi E, Leroy M, Mallo P, Waton G, Prevost M. LIQUID-GEL EXTRACTION OF U-ACYLPYRAZOL-5-ONATO COPPER COMPLEXES. Solvent Extraction and Ion Exchange 1987. [DOI: 10.1080/07366298708918607] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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