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Vitorazi L, Berret JF. Mixing Order Asymmetry in Nanoparticle-Polymer Complexation and Precipitation Revealed by Isothermal Titration Calorimetry. J Phys Chem B 2024; 128:7859-7870. [PMID: 39102566 DOI: 10.1021/acs.jpcb.4c02484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/07/2024]
Abstract
In recent years, there has been a renewed interest in complex coacervation, driven by concerted efforts to offer novel experimental and theoretical insights into electrostatic charge-induced association. While previous studies have primarily focused on polyelectrolytes, proteins, or surfactants, our work explores the potential of using cerium (CeO2) and iron (γ-Fe2O3) oxide nanoparticles (NPs) to develop innovative nanomaterials. By combining various charged species, such as polyelectrolytes, charged neutral block copolymers, and coated NPs, we study a wide variety of complexation patterns and compare them using isothermal titration calorimetry, light scattering, and microscopy. These techniques confirm that the titration of oppositely charged species occurs in two steps: the formation of polyelectrolyte complexes and subsequent phase (or microphase) separation, depending on the system studied. Across all examined cases, the entropic contribution to the total free energy surpasses the enthalpic contribution, in agreement with counterion release mechanisms. Furthermore, our investigation reveals a consistent asymmetry in the reaction enthalpy associated with the secondary process, with exothermic profiles observed upon the addition of cationic species to anionic ones and endothermic profiles in the reverse case.
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Affiliation(s)
- Letícia Vitorazi
- CNRS, Matière et Systèmes Complexes, Université Paris Cité, 75013 Paris, France
- Laboratório de Polímeros, Nanomateriais e Química Supramolecular, EEIMVR, Universidade Federal Fluminense, Avenida dos Trabalhadores, 420, Volta Redonda, RJ CEP 27225-125, Brazil
- Programa de Pós-Graduação em Engenharia Metalúrgica, EEIMVR, Universidade Federal Fluminense, Avenida dos Trabalhadores, 420, Volta Redonda, RJ CEP 27225-125, Brazil
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2
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Huynh TP, Wittig NKL, Andersen A, Bach-Gansmo FL, Birkedal H. Underwater Fabrication of Carbon Nanotube/Coacervate Composites. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:13010-13016. [PMID: 38858173 DOI: 10.1021/acs.langmuir.4c00715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2024]
Abstract
Soft conductive materials are of interest for a wide range of applications, but their syntheses have remained difficult. Herein, we present a convenient route for underwater fabrication of a composite made of carbon nanotubes (CNTs) and mussel-inspired complex coacervates. The key to success of this method is that CNTs were solubilized very effectively in protocoacervates, which are high-concentration solutions of polyelectrolytes at a pH where only one of them is charged, thereby impeding coacervate formation. Composite materials were formed by the simple injection of CNT-dispersed protocoacervate solutions into water under ambient conditions. The method is simple, fast, and ecofriendly, and composites of CNT-complex coacervate in the form of films or bulk materials were obtained. The composites demonstrated electrical conductivity and tunable mechanical properties, which depended on the concentration of polyelectrolytes and the CNT:protocoacervate ratio. Hence, the composites can be manipulated to attain diverse properties, for examples, tunable reduced modulus (15 to 32 GPa) and hardness (0.3 to 0.7 GPa) as well as an electrical conductivity of up to 4 × 103 S m-1.
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Affiliation(s)
- Tan-Phat Huynh
- Department of Chemistry & iNANO, Aarhus University, 14 Gustav Wieds Vej, Aarhus 8000, Denmark
| | - Nina Ko Lln Wittig
- Department of Chemistry & iNANO, Aarhus University, 14 Gustav Wieds Vej, Aarhus 8000, Denmark
| | - Amanda Andersen
- Department of Chemistry & iNANO, Aarhus University, 14 Gustav Wieds Vej, Aarhus 8000, Denmark
| | | | - Henrik Birkedal
- Department of Chemistry & iNANO, Aarhus University, 14 Gustav Wieds Vej, Aarhus 8000, Denmark
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3
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Baldim V, Yadav N, Bia N, Graillot A, Loubat C, Singh S, Karakoti AS, Berret JF. Polymer-Coated Cerium Oxide Nanoparticles as Oxidoreductase-like Catalysts. ACS APPLIED MATERIALS & INTERFACES 2020; 12:42056-42066. [PMID: 32812730 DOI: 10.1021/acsami.0c08778] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Cerium oxide nanoparticles have been shown to mimic oxidoreductase enzymes by catalyzing the decomposition of organic substrates and reactive oxygen species. This mimicry can be found in superoxide radicals and hydrogen peroxides, which are harmful molecules produced in oxidative stress-associated diseases. Despite the fact that nanoparticle functionalization is mandatory in the context of nanomedicine, the influence of polymer coatings on their enzyme-like catalytic activity is poorly understood. In this work, six polymer-coated cerium oxide nanoparticles are prepared by the association of 7.8 nm cerium oxide cores with two poly(sodium acrylate) and four poly(ethylene glycol) (PEG)-grafted copolymers with different terminal or anchoring end groups, such as phosphonic acids. The superoxide dismutase-, catalase-, peroxidase-, and oxidase-like catalytic activities of the coated nanoparticles were systematically studied. It is shown that the polymer coatings do not affect the superoxide dismutase-like, impair the catalase-like and oxidase-like, and surprisingly improves peroxidase-like catalytic activities of cerium oxide nanoparticles. It is also demonstrated that the particles coated with the PEG-grafted copolymers perform better than the poly(acrylic acid)-coated ones as oxidoreductase-like enzymes, a result that confirms the benefit of having phosphonic acids as anchoring groups at the particle surface.
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Affiliation(s)
- Victor Baldim
- Matière et systèmes complexes, Université de Paris, CNRS, 75013 Paris, France
- Electrochimie et Physicochimie aux Interfaces, Université de Versailles Saint-Quentin-en-Yvelines, 45 Avenue des États-Unis, 78035 Versailles, France
| | - Nisha Yadav
- Division of Biological and Life Sciences, School of Arts and Sciences, Ahmedabad University, Navrangpura, Ahmedabad, 380009 Gujarat, India
| | - Nicolas Bia
- SPECIFIC POLYMERS, ZAC Via Domitia, 150 Avenue des Cocardières, 34160 Castries, France
| | - Alain Graillot
- SPECIFIC POLYMERS, ZAC Via Domitia, 150 Avenue des Cocardières, 34160 Castries, France
| | - Cédric Loubat
- SPECIFIC POLYMERS, ZAC Via Domitia, 150 Avenue des Cocardières, 34160 Castries, France
| | - Sanjay Singh
- Division of Biological and Life Sciences, School of Arts and Sciences, Ahmedabad University, Navrangpura, Ahmedabad, 380009 Gujarat, India
| | - Ajay S Karakoti
- Global Innovative Center for Advanced Nanomaterials (GICAN), Faculty of Engineering and Built Environment (FEBE), The University of Newcastle, Callaghan, NSW 2308, Australia
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Korde JM, Kandasubramanian B. Fundamentals and Effects of Biomimicking Stimuli-Responsive Polymers for Engineering Functions. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b00683] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Jay M. Korde
- Biocomposite Laboratory, Department of Metallurgical & Materials Engineering, DIAT (DU), Ministry of Defence, Girinagar, Pune-411025, India
| | - Balasubramanian Kandasubramanian
- Biocomposite Laboratory, Department of Metallurgical & Materials Engineering, DIAT (DU), Ministry of Defence, Girinagar, Pune-411025, India
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Baldim V, Bedioui F, Mignet N, Margaill I, Berret JF. The enzyme-like catalytic activity of cerium oxide nanoparticles and its dependency on Ce 3+ surface area concentration. NANOSCALE 2018; 10:6971-6980. [PMID: 29610821 DOI: 10.1039/c8nr00325d] [Citation(s) in RCA: 163] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Cerium oxide nanoparticles are known to catalyze the decomposition of reactive oxygen species such as the superoxide radical and hydrogen peroxide. Herein, we examine the superoxide dismutase (SOD) and catalase (CAT) mimetic catalytic activities of nanoceria and demonstrate the existence of generic behaviors. For particles of sizes 4.5, 7.8, 23 and 28 nm, the SOD and CAT catalytic activities exhibit the characteristic shape of a Langmuir isotherm as a function of cerium concentration. The results show that the catalytic effects are enhanced for smaller particles and for the particles with the largest Ce3+ fraction. The SOD-like activity obtained from the different samples is found to superimpose on a single master curve using the Ce3+ surface area concentration as a new variable, indicating the existence of particle independent redox mechanisms. For the CAT assays, the adsorption of H2O2 molecules at the particle surface modulates the efficacy of the decomposition process and must be taken into account. We design an amperometry-based experiment to evaluate the H2O2 adsorption at nanoceria surfaces, leading to the renormalization of the particle specific area. Depending on the particle type the amount of adsorbed H2O2 molecules varies from 2 to 20 nm-2. The proposed scalings are predictive and allow the determination of the SOD and CAT catalytic properties of cerium oxide solely from physicochemical features.
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Affiliation(s)
- V Baldim
- Matière et Systèmes Complexes, UMR 7057 CNRS Université Denis Diderot Paris-VII, Bâtiment Condorcet, 10 rue Alice Domon et Léonie Duquet, 75205 Paris, France.
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6
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Borreguero JM, Pincus PA, Sumpter BG, Goswami M. Dynamics of Charged Species in Ionic-Neutral Block Copolymer and Surfactant Complexes. J Phys Chem B 2017. [PMID: 28636369 DOI: 10.1021/acs.jpcb.7b05047] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Structure-property relationships of ionic block copolymer (BCP) surfactant complexes are critical toward the progress of favorable engineering design of efficient charge-transport materials. In this article, molecular dynamics simulations are used to understand the dynamics of charged-neutral BCP and surfactant complexes. The dynamics are examined for two different systems: charged-neutral double-hydrophilic and hydrophobic-hydrophilic block copolymers with oppositely charged surfactant moieties. The dynamics of the surfactant head, tails, and charges are studied for five different BCP volume fractions. We observe that the dynamics of the different species solely depend on the balance between electrostatic and entropic interactions between the charged species and the neutral monomers. The favorable hydrophobic-hydrophobic interactions and the unfavorable hydrophobic-hydrophilic interactions determine the mobilities of the monomers. The dynamical properties of the charge species influence complex formation. Structural relaxations exhibit length-scale dependent behavior, with slower relaxation at the radius of gyration length-scale and faster relaxation at the segmental length-scale, consistent with previous results. The dynamical analysis correlates ion-exchange kinetics to the self-assembly behavior of the complexes.
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Affiliation(s)
- Jose M Borreguero
- Neutron Data Analysis & Visualization, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Philip A Pincus
- Department of Material Science, University of California , Santa Barbara, California 93106, United States
| | - Bobby G Sumpter
- Center for Nanophase Material Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.,Computer Science and Mathematics Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Monojoy Goswami
- Center for Nanophase Material Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.,Computer Science and Mathematics Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
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Unni AB, Vignaud G, Chapel JP, Giermanska J, Bal JK, Delorme N, Beuvier T, Thomas S, Grohens Y, Gibaud A. Probing the Density Variation of Confined Polymer Thin Films via Simple Model-Independent Nanoparticle Adsorption. Macromolecules 2017. [DOI: 10.1021/acs.macromol.6b02617] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- A. Beena Unni
- FRE
CNRS 3744, IRDL, Univ. Bretagne Sud, F-56100 Lorient, France
- International
and Inter University Centre for Nanoscience and Nanotechnology, Mahatma Gandhi University, Kottayam, Kerala, India 686560
| | - G. Vignaud
- FRE
CNRS 3744, IRDL, Univ. Bretagne Sud, F-56100 Lorient, France
| | - J. P. Chapel
- Centre
de Recherche Paul Pascal (CRPP), UPR 8641, CNRS, F-33600 Pessac, France
- Centre de
Recherche Paul Pascal, Université de Bordeaux, F-33600 Pessac, France
| | - J. Giermanska
- Centre
de Recherche Paul Pascal (CRPP), UPR 8641, CNRS, F-33600 Pessac, France
- Centre de
Recherche Paul Pascal, Université de Bordeaux, F-33600 Pessac, France
| | - J. K. Bal
- Centre
for Research in Nanoscience and Nanotechnology, University of Calcutta, Technology Campus, Block JD2, Sector III, Saltlake
City, Kolkata 700098, India
| | - N. Delorme
- LUNAM
Université, IMMM, Faculté de Sciences, Université du Maine, UMR 6283 CNRS, 72000 Le Mans, Cedex 9, France
| | - T. Beuvier
- LUNAM
Université, IMMM, Faculté de Sciences, Université du Maine, UMR 6283 CNRS, 72000 Le Mans, Cedex 9, France
| | - S. Thomas
- International
and Inter University Centre for Nanoscience and Nanotechnology, Mahatma Gandhi University, Kottayam, Kerala, India 686560
| | - Y. Grohens
- FRE
CNRS 3744, IRDL, Univ. Bretagne Sud, F-56100 Lorient, France
| | - A. Gibaud
- LUNAM
Université, IMMM, Faculté de Sciences, Université du Maine, UMR 6283 CNRS, 72000 Le Mans, Cedex 9, France
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Mousseau F, Vitorazi L, Herrmann L, Mornet S, Berret JF. Polyelectrolyte assisted charge titration spectrometry: Applications to latex and oxide nanoparticles. J Colloid Interface Sci 2016; 475:36-45. [DOI: 10.1016/j.jcis.2016.04.036] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 04/20/2016] [Accepted: 04/21/2016] [Indexed: 11/26/2022]
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10
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Ould-Moussa N, Safi M, Guedeau-Boudeville MA, Montero D, Conjeaud H, Berret JF. In vitro toxicity of nanoceria: effect of coating and stability in biofluids. Nanotoxicology 2013; 8:799-811. [PMID: 23914740 DOI: 10.3109/17435390.2013.831501] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Due to the increasing use of nanometric cerium oxide in applications, concerns about the toxicity of these particles have been raised and have resulted in a large number of studies. We report here on the interactions between 7 nm anionically charged cerium oxide particles and living mammalian cells. By a modification of the particle coating including low-molecular weight ligands and polymers, two generic behaviours are compared: particles coated with citrate ions that precipitate in biofluids and particles coated with poly(acrylic acid) that are stable and remain nanometric. We find that nanoceria covered with both coating agents are taken up by mouse fibroblasts and localized into membrane-bound compartments. However, flow cytometry and electron microscopy reveal that as a result of their precipitation, citrate-coated particles interact more strongly with cells. At cerium concentration above 1 mM, only citrate-coated nanoceria (and not particles coated with poly(acrylic acid)) display toxicity and moderate genotoxicity. The results demonstrate that the control of the surface chemistry of the particles and its ability to prevent aggregation can affect the toxicity of nanomaterials.
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Affiliation(s)
- Nawel Ould-Moussa
- Matière et Systèmes Complexes, UMR 7057 CNRS Université Denis Diderot Paris-VII, Bâtiment Condorcet , Paris , France
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11
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Wang Q, Jia W, Liu B, Zhao W, Li C, Zhang J, Xu G. Controllable Synthesis of Nearly Monodisperse Spherical Aggregates of CeO2Nanocrystals and Their Catalytic Activity for HCHO Oxidation. Chem Asian J 2012; 7:2258-67. [DOI: 10.1002/asia.201200432] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Indexed: 11/10/2022]
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12
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Chapel JP, Berret JF. Versatile electrostatic assembly of nanoparticles and polyelectrolytes: Coating, clustering and layer-by-layer processes. Curr Opin Colloid Interface Sci 2012. [DOI: 10.1016/j.cocis.2011.08.009] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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13
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Breton M, Berret JF, Bourgaux C, Kral T, Hof M, Pichon C, Bessodes M, Scherman D, Mignet N. Protonation of lipids impacts the supramolecular and biological properties of their self-assembly. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:12336-12345. [PMID: 21870814 DOI: 10.1021/la202439s] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We assessed in this work how a chemical structure difference could influence a supramolecular organization and then its biological properties. In our case study, we considered two amphiphilic lipidic gene vectors. The chemical difference was situated on their hydrophilic part which was either a pure neutral thiourea head or a mixture of three thiourea function derivatives, thiourea, iminothiol, and charged iminothiol. This small difference was obtained thanks to the last chemical deprotection conditions of the polar head hydroxyl groups. Light, neutron, and X-ray scattering techniques have been used to investigate the spatial structure of the liposomes and lipoplexes formed by the lipids. The chemical structure difference impacts the supramolecular assemblies of the lipids and with DNA as shown by fluorescence correlation spectroscopy (FCS), X-ray, and neutron scattering. Hence the structures formed were found to be highly different in terms of liposomes to DNA ratio and size and polydispersity of the aggregates. Finally, the transfection and internalization results proved that the differences in the structure of the lipid aggregates fully affect the biological properties of the lipopolythiourea compounds. The lipid containing three functions is a better gene transfection agent than the lipid which only contains one thiourea moiety. As a conclusion, we showed that the conditions of the last chemical step can influence the lipidic supramolecular structure which in turn strongly impacts their biological properties.
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Affiliation(s)
- Marie Breton
- UMR 8151 CNRS, Unité de Pharmacologie Chimique et Génétique, Université Paris Descartes, Chimie-ParisTech, 4 avenue de l'observatoire, 75006 Paris, U640 Inserm, France.
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14
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Berret JF. Controlling electrostatic co-assembly using ion-containing copolymers: from surfactants to nanoparticles. Adv Colloid Interface Sci 2011; 167:38-48. [PMID: 21376298 DOI: 10.1016/j.cis.2011.01.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 01/27/2011] [Accepted: 01/27/2011] [Indexed: 10/18/2022]
Abstract
In this review, we address the issue of the electrostatic complexation between charged-neutral diblock copolymers and oppositely charged nanocolloids. We show that nanocolloids such as surfactant micelles and iron oxide magnetic nanoparticles share similar properties when mixed with charged-neutral diblocks. Above a critical charge ratio, core-shell hierarchical structures form spontaneously under direct mixing conditions. The core-shell structures are identified by a combination of small-angle scattering techniques and transmission electron microscopy. The formation of multi-level objects is driven by the electrostatic attraction between opposite charges and by the release of the condensed counterions. Alternative mixing processes inspired from molecular biology are also described. The protocols applied here consist in screening the electrostatic interactions of the mixed dispersions, and then removing the salt progressively as an example by dialysis. With these techniques, the oppositely charged species are intimately mixed before they can interact, and their association is monitored by the desalting kinetics. As a result, sphere- and wire-like aggregates with remarkable superparamagnetic and stability properties are obtained. These findings are discussed in the light of a new paradigm which deals with the possibility to use inorganic nanoparticles as building blocks for the design and fabrication of supracolloidal assemblies with enhanced functionalities.
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Louguet S, Kumar AC, Sigaud G, Duguet E, Lecommandoux S, Schatz C. A physico-chemical investigation of poly(ethylene oxide)-block-poly(l-lysine) copolymer adsorption onto silica nanoparticles. J Colloid Interface Sci 2011; 359:413-22. [DOI: 10.1016/j.jcis.2011.03.093] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2011] [Revised: 03/22/2011] [Accepted: 03/24/2011] [Indexed: 10/18/2022]
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16
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Zhong S, Pochan DJ. Cryogenic Transmission Electron Microscopy for Direct Observation of Polymer and Small-Molecule Materials and Structures in Solution. POLYM REV 2010. [DOI: 10.1080/15583724.2010.493254] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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17
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Courtois J, Berret JF. Probing oppositely charged surfactant and copolymer interactions by isothermal titration microcalorimetry. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:11750-11758. [PMID: 20557117 DOI: 10.1021/la101475x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The complexation between charge-neutral block copolymers and oppositely charged surfactants was investigated by light scattering experiments and by isothermal titration calorimetry (ITC). The copolymer was poly(sodium acrylate)-b-poly(acrylamide) and the surfactant dodecyltrimethylammonium bromide (DTAB). In a previous report, we had shown that the copolymers and the surfactants coassembled spontaneously into colloidal complexes. Depending on the charge ratio, the complexes were either single surfactant micelles decorated by copolymers or core-shell hierarchical structures. ITC was performed in order to investigate the thermodynamics of the complex formation. Titrations of copolymers by surfactants and of surfactants by copolymers revealed that the electrostatic coassembly was an endothermic reaction, suggesting a process dominated by the entropy of the counterions. Here, we found that the thermodynamic quantities associated with the reaction depended on the mixing order. When surfactants were added stepwise to copolymers, the titration was associated with the formation of single micelles decorated by a unique polymer. Above a critical charge ratio, the micelles rearranged themselves into 100 nm colloidal complexes in a collective process which displayed the following features: (i) the process was very slow as compared to the time scale of Brownian diffusion, (ii) the thermodynamic signature was a endothermic peak, and (iii) the stoichiometry between the positive and negative charges was modified from n = 0.48 (single micelles) to 0.75 (core-shell complexes). When copolymers were added stepwise to surfactants, the titration resulted in the formation of the core-shell aggregates only. In both experiments, the amount of polyelectrolytes needed for complex formation exceeded the number required to compensate the net micellar charge, confirming the evidence of overcharging in the complex formation.
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Affiliation(s)
- J Courtois
- Matière et Systèmes Complexes, UMR 7057 CNRS Université Denis Diderot Paris-VII, 75205 Paris, France
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Stuart MAC, Huck WTS, Genzer J, Müller M, Ober C, Stamm M, Sukhorukov GB, Szleifer I, Tsukruk VV, Urban M, Winnik F, Zauscher S, Luzinov I, Minko S. Emerging applications of stimuli-responsive polymer materials. NATURE MATERIALS 2010; 9:101-13. [PMID: 20094081 DOI: 10.1038/nmat2614] [Citation(s) in RCA: 3673] [Impact Index Per Article: 262.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Responsive polymer materials can adapt to surrounding environments, regulate transport of ions and molecules, change wettability and adhesion of different species on external stimuli, or convert chemical and biochemical signals into optical, electrical, thermal and mechanical signals, and vice versa. These materials are playing an increasingly important part in a diverse range of applications, such as drug delivery, diagnostics, tissue engineering and 'smart' optical systems, as well as biosensors, microelectromechanical systems, coatings and textiles. We review recent advances and challenges in the developments towards applications of stimuli-responsive polymeric materials that are self-assembled from nanostructured building blocks. We also provide a critical outline of emerging developments.
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Affiliation(s)
- Martien A Cohen Stuart
- Laboratory of Physical Chemistry and Colloid Science, Wageningen University, Dreijenplein 6, 6703 HB Wageningen, The Netherlands
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Destremaut F, Salmon JB, Qi L, Chapel JP. Microfluidics with on-line dynamic light scattering for size measurements. LAB ON A CHIP 2009; 9:3289-3296. [PMID: 19865738 DOI: 10.1039/b906514h] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We present a detailed investigation on the feasibility of on-line dynamic light scattering measurements of colloidal sizes in a pressure-driven microfluidic flow. We review some theoretical arguments showing that such experiments are difficult to perform due to the Poiseuille flow that induces interferences of different Doppler shifts. Such a theoretical approach is however very useful to figure out the range of parameters where on-line size measurements are possible. We then build a dynamic light scattering setup around a microfluidic chip that enables us to estimate the size of Brownian scatterers flowing in PDMS-based microchannels, thus validating experimentally the theoretical estimations. We finally present a microfluidic chip that can mix two reactants in approximately 200 ms, and allows size measurements using dynamic light scattering at about 300 ms after complete mixing. Two applications are presented: the continuous monitoring of the viscosity of a two-fluid mixture, and the electrostatic co-assembly of oppositely charged nanoparticles and block copolymers.
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Affiliation(s)
- Fanny Destremaut
- LOF, UMR 5258 Rhodia-CNRS-Bordeaux 1, 178 avenue du Docteur Schweitzer, F-33608 Pessac cedex, France.
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Chanteau B, Fresnais J, Berret JF. Electrosteric enhanced stability of functional sub-10 nm cerium and iron oxide particles in cell culture medium. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:9064-9070. [PMID: 19572532 DOI: 10.1021/la900833v] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Applications of nanoparticles in biology require that the nanoparticles remain stable in solutions containing high concentrations of proteins and salts, as well as in cell culture media. In this work, we developed simple protocols for the coating of sub-10 nm nanoparticles and evaluated the colloidal stability of dispersions in various environments. Ligands (citric acid), oligomers [phosphonate-terminated poly(ethylene oxide)], and polymers [poly(acrylic acid)] were used as nanometer-thick adlayers for cerium (CeO2) and iron (gamma-Fe2O3) oxide nanoparticles. The organic functionalities were adsorbed on the particle surfaces via physical (electrostatic) forces. Stability assays at high ionic strengths and in cell culture media were performed by static and dynamic light scattering. Of the three coatings examined, we found that only poly(acrylic acid) fully preserved the dispersion stability over the long term (longer than weeks). The improved stability was explained by the multipoint attachments of the chains onto the particle surface and by the adlayer-mediated electrosteric interactions. These results suggest that anionically charged polymers represent an effective alternative to conventional coating agents.
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Affiliation(s)
- B Chanteau
- Matière et Systèmes Complexes, UMR 7057 CNRS Université Denis Diderot Paris-VII, Bâtiment Condorcet, 10 rue Alice Domon et Leonie Duquet, F-75205 Paris, France
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