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Chen SY, Fiedler MK, Gronauer TF, Omelko O, von Wrisberg MK, Wang T, Schneider S, Sieber SA, Zacharias M. Unraveling the mechanism of small molecule induced activation of Staphylococcus aureus signal peptidase IB. Commun Biol 2024; 7:895. [PMID: 39043865 PMCID: PMC11266668 DOI: 10.1038/s42003-024-06575-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 07/11/2024] [Indexed: 07/25/2024] Open
Abstract
Staphylococcus aureus signal peptidase IB (SpsB) is an essential enzyme for protein secretion. While inhibition of its activity by small molecules is a well-precedented mechanism to kill bacteria, the mode of activation is however less understood. We here investigate the activation mechanism of a recently introduced activator, the antibiotic compound PK150, and demonstrate by combined experimental and Molecular Dynamics (MD) simulation studies a unique principle of enzyme stimulation. Mass spectrometric studies with an affinity-based probe of PK150 unravel the binding site of PK150 in SpsB which is used as a starting point for MD simulations. Our model shows the localization of the molecule in an allosteric pocket next to the active site which shields the catalytic dyad from excess water that destabilizes the catalytic geometry. This mechanism is validated by the placement of mutations aligning the binding pocket of PK150. While the mutants retain turnover of the SpsB substrate, no stimulation of activity is observed upon PK150 addition. Overall, our study elucidates a previously little investigated mechanism of enzyme activation and serves as a starting point for the development of future enzyme activators.
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Affiliation(s)
- Shu-Yu Chen
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, Zurich, 8093, Switzerland
- TUM School of Natural Sciences, Department Biosciences, Theoretical Biophysics (T38), Center for Functional Protein Assemblies (CPA), Technical University Munich (TUM), Ernst-Otto-Fischer Str. 8, Garching, 85748, Germany
| | - Michaela K Fiedler
- TUM School of Natural Sciences, Department Biosciences, Chair of Organic Chemistry II, Center for Functional Protein Assemblies (CPA), Technical University Munich (TUM), Ernst-Otto-Fischer Str. 8, Garching, 85748, Germany
| | - Thomas F Gronauer
- TUM School of Natural Sciences, Department Biosciences, Chair of Organic Chemistry II, Center for Functional Protein Assemblies (CPA), Technical University Munich (TUM), Ernst-Otto-Fischer Str. 8, Garching, 85748, Germany
| | - Olesia Omelko
- TUM School of Natural Sciences, Department Biosciences, Chair of Organic Chemistry II, Center for Functional Protein Assemblies (CPA), Technical University Munich (TUM), Ernst-Otto-Fischer Str. 8, Garching, 85748, Germany
| | - Marie-Kristin von Wrisberg
- Department of Chemistry, Ludwig-Maximilians University Munich (LMU), Butenandtstr. 5-13, Munich, 81377, Germany
| | - Tao Wang
- TUM School of Natural Sciences, Department Biosciences, Chair of Organic Chemistry II, Center for Functional Protein Assemblies (CPA), Technical University Munich (TUM), Ernst-Otto-Fischer Str. 8, Garching, 85748, Germany
| | - Sabine Schneider
- Department of Chemistry, Ludwig-Maximilians University Munich (LMU), Butenandtstr. 5-13, Munich, 81377, Germany
| | - Stephan A Sieber
- TUM School of Natural Sciences, Department Biosciences, Chair of Organic Chemistry II, Center for Functional Protein Assemblies (CPA), Technical University Munich (TUM), Ernst-Otto-Fischer Str. 8, Garching, 85748, Germany.
| | - Martin Zacharias
- TUM School of Natural Sciences, Department Biosciences, Theoretical Biophysics (T38), Center for Functional Protein Assemblies (CPA), Technical University Munich (TUM), Ernst-Otto-Fischer Str. 8, Garching, 85748, Germany.
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Francisco Rincón-Romero J, Ríos F, Reyes Requena A, Luzón-González G, Isabel García-López A. Surface and Thermodynamics Properties of Commercial Fatty-Alcohol Ethoxylate Surfactants. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Labrasol mediated enhanced solubilization of natural hydrophobic drugs in Pluronic micelles: Physicochemical and in vitro release studies. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Prasanthan P, Kishore N. Self-assemblies of pluronic micelles in partitioning of anticancer drugs and effectiveness of this system towards target protein. RSC Adv 2021; 11:22057-22069. [PMID: 35480822 PMCID: PMC9034178 DOI: 10.1039/d1ra03770f] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 06/17/2021] [Indexed: 12/24/2022] Open
Abstract
Micelles formed by pluronic triblock copolymers are known to be a promising class of drug delivery vehicles. Quantitative mechanistic insights into the ability of pluronic micelles to improve the solubility of poorly water soluble drugs, encapsulation and delivery of hydrophilic drugs are not available. The current study evaluated the energetics of encapsulation of chemotherapeutic drugs gemcitabine, cytarabine, and hydroxyurea in pluronic F127 and F68 micelles. In addition, the interactions of the drugs released from pluronic micellar media with serum albumin, which is a major circulatory transport protein, and subsequent conformational changes have also been analyzed with the help of calorimetry and spectroscopy. All the drugs showed improved partitioning in F127 micelles, the extent of which slightly increased with temperature rise. Interestingly, drug–protein binding is enhanced upon delivery from pluronic micelles without affecting the conformational integrity of the protein. This study highlights the role of drug functionalities, hydrophobicity, and steric factors towards their partitioning in pluronic micelles. Such studies are important in understanding physicochemical aspects of drug encapsulation and release, and lead to establishing structure–property–energetics correlations for developing suitable nano-drug delivery vehicles. Micelles formed by pluronic triblock copolymers are known to be a promising class of drug delivery vehicles.![]()
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Affiliation(s)
- Pooja Prasanthan
- Department of Chemistry, Indian Institute of Technology Bombay Powai Mumbai 400 076 India
| | - Nand Kishore
- Department of Chemistry, Indian Institute of Technology Bombay Powai Mumbai 400 076 India
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Spiering VJ, Lutzki J, Gradzielski M. Thermodynamics of micellization of nonionic surfactants – The effect of incorporating CO2 moieties into the head group. J Colloid Interface Sci 2021; 581:794-805. [DOI: 10.1016/j.jcis.2020.07.141] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 01/24/2023]
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Kaur H, Aggarwal N, Sood AK, Banipal TS. Analysis of micellar, thermodynamic and structural parameters of gemini surfactants in aqueous solutions of vitamins. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Al-Azemi TF, Vinodh M. Pillar[5]arene-based self-assembled linear supramolecular polymer driven by guest halogen–halogen interactions in solid and solution states. Polym Chem 2020. [DOI: 10.1039/d0py00327a] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A pillar[5]arene-based linear supramolecular polymer mediated by guest halogen–halogen interactions (C–Br⋯Br–C) was studied in both the solution and solid states.
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Affiliation(s)
| | - Mickey Vinodh
- Chemistry Department
- Kuwait University
- Safat 13060
- Kuwait
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Warring SL, Krasowska M, Beattie DA, McQuillan AJ. Adsorption of a Polyethoxylated Surfactant from Aqueous Solution to Silica Nanoparticle Films Studied with In Situ Attenuated Total Reflection Infrared Spectroscopy and Colloid Probe Atomic Force Microscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:13481-13490. [PMID: 30343576 DOI: 10.1021/acs.langmuir.8b01351] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Polyethoxylated (PEO) surfactant adsorption to silica under aqueous conditions is an important physical process in a multitude of industries. Consequently, a considerable number of spectroscopic and other studies have been carried out to ascertain the molecular/structural details of the adsorbed surfactant and the kinetics of PEO surfactant adsorption. However, the use of infrared spectroscopy to probe surfactant adsorption at the silica/aqueous solution interface has been limited because of the instability of silica particle films under aqueous conditions and the opacity of silicon prisms below 1300 cm-1 typically employed for these studies. The work presented here provides infrared spectroscopic measurements of silica particle films formed from differing suspension pH on a diamond internal reflection prism to probe silica particle film stability as a function of pH. The films formed from a suspension pH of 2.5 were found to be the most stable owing to a sol-gel transition of the colloidal suspension upon drying and the reduction in electrostatic repulsion between silica nanoparticles, creating a tightly packed nanoparticle film. Colloid probe atomic force microscopy (CP-AFM) was used to confirm the alteration of surface forces between silica nanoparticles as a function of pH. Particle films from silica suspensions of pH 2.5 were formed in situ on an attenuated total reflection infrared diamond prism and used to probe Triton X-100 adsorption from an aqueous solution. The obtained infrared spectra revealed a critical surface aggregation concentration at a solution concentration of 0.14 mmol L-1, Triton X-100 forms discrete micelles at the silica surface, and the PEO head group preferentially adopts a helical conformation. Most intriguingly, a breakup of the silica particle film was observed at the critical micelle concentration of the surfactant. This is due to the repulsive steric forces arising from the interactions between the PEO corona of the surfactant micelles formed at the silica surface, as confirmed by the CP-AFM measurements.
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Affiliation(s)
- Suzanne L Warring
- Department of Chemistry , University of Otago , Dunedin 9054 , New Zealand
| | | | | | - A James McQuillan
- Department of Chemistry , University of Otago , Dunedin 9054 , New Zealand
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Pal A, Maan R. Investigations of interactions between surface active ionic liquid 1-butyl-3-methyl imidazolium dodecylbenzenesulfonate and cationic polyelectrolyte poly(diallyldimethylammonium chloride) in aqueous solution. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.01.108] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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11
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Use of isothermal titration calorimetry to study surfactant aggregation in colloidal systems. Biochim Biophys Acta Gen Subj 2015; 1860:999-1016. [PMID: 26459003 DOI: 10.1016/j.bbagen.2015.10.003] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 09/23/2015] [Accepted: 10/07/2015] [Indexed: 02/01/2023]
Abstract
BACKGROUND Isothermal titration calorimetry (ITC) is a general technique that allows for precise and highly sensitive measurements. These measurements may provide a complete and accurate thermodynamic description of association processes in complex systems such as colloidal mixtures. SCOPE OF THE REVIEW This review will address uses of ITC for studies of surfactant aggregation to form micelles, with emphasis on the thermodynamic studies of homologous surfactant series. We will also review studies on surfactant association with polymers of different molecular characteristics and with colloidal particles. GENERAL SIGNIFICANCE ITC studies on the association of different homologous series of surfactants provide quantitative information on independent contribution from their apolar hydrocarbon chains and polar headgroups to the different thermodynamic functions associated with micellization (Gibbs energy, enthalpy and entropy). Studies on surfactant association to polymers by ITC provide a comprehensive description of the association process, including examples in which particular features revealed by ITC were elucidated by using ancillary techniques such as light or X-ray scattering measurements. Examples of uses of ITC to follow surfactant association to biomolecules such as proteins or DNA, or nanoparticles are also highlighted. Finally, recent theoretical models that were proposed to analyze ITC data in terms of binding/association processes are discussed. MAJOR CONCLUSIONS This review stresses the importance of using direct calorimetric measurements to obtain and report accurate thermodynamic data, even in complex systems. These data, whenever possible, should be confirmed and associated with other ancillary techniques that allow elucidation of the nature of the transformations detected by calorimetric results, providing a complete description of the process under scrutiny.
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Thanassoulas A, Barthélémy P, Navailles L, Sigaud G. From nucleobases to nucleolipids: an ITC approach on the thermodynamics of their interactions in aqueous solutions. J Phys Chem B 2014; 118:6570-85. [PMID: 24911942 DOI: 10.1021/jp411459w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Hybrid constructions based on nucleosides and lipophilic components, known as nucleolipids, have become an extremely interesting class of molecules, especially for their potential biomedical applications. In this matter, it seemed important to define the nature and estimate the strength of their interaction with polynucleotides by different ways. We report in this work a systematic investigation through isothermal titration calorimetry of the thermodynamics of the association and dissociation of adenine and thymine derivatives, not previously performed. Then we use the results obtained on these simple systems as a basis for comparison with the binding of phospholipids functionalized with adenosine and thymidine to polyadenylic or polyuridylic acids applying the same experimental technique.
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Wang M, Wu C, Tang Y, Fan Y, Han Y, Wang Y. Interactions of cationic trimeric, gemini and monomeric surfactants with trianionic curcumin in aqueous solution. SOFT MATTER 2014; 10:3432-3440. [PMID: 24647897 DOI: 10.1039/c4sm00086b] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Interactions of trianionic curcumin (Cur(3-)) with a series of cationic surfactants, monomeric surfactant dodecyl trimethylammonium bromide (DTAB), dimeric surfactant hexamethylene-1,6-bis(dodecyldimethylammonium bromide) (12-6-12) and trimeric surfactant tri(dodecyldimethylammonioacetoxy)diethyltriamine trichloride (DTAD), have been investigated in aqueous solution of pH 13.0. Surface tension and spectral measurements indicate that the cationic surfactants display a similar surfactant concentration dependent interaction process with Cur(3-), involving three interaction stages. At first the three cationic surfactants electrostatically bind on Cur(3-) to form the surfactant-Cur(3-) complex. Then the bound and unbound cationic surfactants with Cur(3-) aggregate into surfactant-Cur(3-) mixed micelles through hydrophobic interactions above the critical micelle concentration of the surfactants (CMCC) in the presence of Cur(3-). Finally excess unbound surfactants self-assemble into micelles like those without Cur(3-). For all the three surfactants, the addition of Cur(3-) only decreases the critical micelle concentration of 12-6-12 but does not affect the critical micelle concentration of DTAB and DTAD. As the oligomeric degree of surfactants increases, the intermolecular interaction of the cationic surfactants with Cur(3-) increases and the surfactant amount needed for Cur(3-) encapsulation decreases. Compared with 12-6-12, either the weaker interaction of DTAB with Cur(3-) or stronger interaction of DTAD with Cur(3-) limits the stability or solubility of Cur(3-) in surfactant micelles. Therefore, gemini surfactant 12-6-12 is the best choice to effectively suppress Cur(3-) degradation at very low concentrations. Isothermal titration microcalorimetry, surface tension and (1)H NMR results reveal that 12-6-12 and Cur(3-) form a (12-6-12)2-Cur(3-) complex and start to form micelles at extremely decreased concentrations, where either 12-6-12 or Cur(3-) works as a bridge linkage and the resultant structure exhibits the characteristics of oligomeric surfactants.
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Affiliation(s)
- Meina Wang
- Key Laboratory of Colloid and Interface Science, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
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Turcu I, Mic M. Size Dependence of Molecular Self-Assembling in Stacked Aggregates. 2. Heat Exchange Effects. J Phys Chem B 2013; 117:9083-93. [DOI: 10.1021/jp403768x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ioan Turcu
- Department of Molecular and Biomolecular Physics, National Institute of Isotopic and Molecular Technology, 400293 Cluj-Napoca, Romania
| | - Mihaela Mic
- Department of Molecular and Biomolecular Physics, National Institute of Isotopic and Molecular Technology, 400293 Cluj-Napoca, Romania
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Mechanism on the interaction between amimo sulfonate amphoteric surfactant and sodium dodecyl benzene sulfonate in aqueous solution. Colloids Surf A Physicochem Eng Asp 2013. [DOI: 10.1016/j.colsurfa.2013.03.036] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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16
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Ali HES. Synthesis, Characterization and Thermodynamic Parameters of Anionic Gemini Surfactants with Different Spacer Groups. TENSIDE SURFACT DET 2013. [DOI: 10.3139/113.100349] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
The aim of this work is to investigate the micellization and adsorption thermodynamics (ΔmicH°, ΔmicG°, ΔmicS°, ΔadsH°, ΔadsG°, ΔadsS°) for three novel anionic Gemini surfactants with the same structure except the spacer length of the polymethylene chain have been synthesized based on nonylphenol (NP). The surface tension at cmc (γcmc) and critical micelle concentration (cmc) of the surfactants in aqueous solutions have been investigated. C20 values (surfactant concentration in the solution phase that will reduce the surface tension of the solvent by 20 mNm−1) were also obtained. The critical micellar concentration (cmc) and the minimum average area per surfactant molecule (Amin) at the air-water interface of Gemini surfactant decrease with increasing number of methylene moieties in the spacer and, consequently, with the enhanced hydrophilic character of the molecule. The results were discussed with particular emphasis on the effect of the length spacer on the hydrophilic character of the spacer group. The surface studies of the molecules confirm that the exothermic values of the differential enthalpy of micellization (ΔmicH°) decrease as the methylene moieties are lengthened. Moreover, the values of the free energy (ΔmicG°) and entropy (ΔmicS°) of micellization indicate an entropy driven phenomenon for all surfactants. The effect of length spacer on surfactant adsorption for Gemini surfactants was utilized to calculate such thermodynamic parameters as the free energy of adsorption (ΔadsG°) and the heat of adsorption (ΔadsH°). The low value of ΔadsH° is an evidence for the physical adsorption of anionic surfactants. The relatively large value of entropic contribution (TΔadsS°) indicates that the adsorption of anionic surfactants is entropically governed.
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Li Z, Amado E, Kressler J. Self-assembly behavior of fluorocarbon-end-capped poly(glycerol methacrylate) in aqueous solution. Colloid Polym Sci 2012. [DOI: 10.1007/s00396-012-2803-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Viades-Trejo J, Abascal-González DM, Gracia-Fadrique J. Critical Micelle Concentration of Poly(Oxy-1,2-Ethanediyl), α-Nonyl Phenol-ω-Hydroxy Ethers (C9H19C6H4E i=6,10.5,12,17.5) by Surface Equations of State. J SURFACTANTS DETERG 2012. [DOI: 10.1007/s11743-012-1346-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Martínez-Gallegos JF, Bravo-Rodríguez V, Jurado-Alameda E, García-López AI. Polyoxyethylene alkyl and nonyl phenol ethers complexation with potato starch. Food Hydrocoll 2011. [DOI: 10.1016/j.foodhyd.2011.01.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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El-Shamy OAA, Khid TT, Doheim MM. Effect of Ethoxlate Chain Length on the Pour Point Depressant of Middle Distillate Fuel Oil. J DISPER SCI TECHNOL 2011. [DOI: 10.1080/01932691003800023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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22
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Deleu M, Damez C, Gatard S, Nott K, Paquot M, Bouquillon S. Synthesis and physico-chemical characterization of bolaamphiphiles derived from alkenyl d-xylosides. NEW J CHEM 2011. [DOI: 10.1039/c1nj20158a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kadam Y, Singh K, Marangoni D, Ma J, Aswal V, Bahadur P. Thermodynamic of micelle formation of nonlinear block co-polymer Tetronic® T904 in aqueous salt solution. Colloids Surf A Physicochem Eng Asp 2010. [DOI: 10.1016/j.colsurfa.2010.08.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Bianco CL, Schneider CS, Santonicola M, Lenhoff AM, Kaler EW. Effects of urea on the microstructure and phase behavior of aqueous solutions of polyoxyethylene surfactants. Ind Eng Chem Res 2010; 50:85-96. [PMID: 21359094 DOI: 10.1021/ie101011v] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Membrane proteins are made soluble in aqueous buffers by the addition of various surfactants (detergents) to form so-called protein-detergent complexes (PDCs). Properties of membrane proteins are commonly assessed by unfolding the protein in the presence of surfactant in a buffer solution by adding urea. The stability of the protein under these conditions is then monitored by biophysical methods such as fluorescence or circular dichroism spectroscopy. Often overlooked in these experiments is the effect of urea on the phase behavior and micellar microstructure of the different surfactants used to form the PDCs. Here the effect of urea on five polyoxyethylene surfactants - n-octylytetraoxyethylene (C(8)E(4)), n-octylpentaoxyethylene (C(8)E(5)), n-decylhexaoxyethylene (C(10)E(6)), n-dodecylhexaoxyethylene (C(12)E(6)) and n-dodecyloctaoxylethylene (C(12)E(8)) - is explored. The presence of urea increases the critical micelle concentration (CMC) of all surfactants studied, indicating that the concentration of both the surfactant and urea should be considered in membrane protein folding studies. The cloud point temperature of all surfactants studied also increases with increasing urea concentration. Small-angle neutron scattering shows a urea-induced transition from an elongated to a globular shape for micelles of C(8)E(4) and C(12)E(6). In contrast, C(8)E(5) and C(12)E(8) form more globular micelles at room temperature and the micelles remain globular as the urea concentration is increased. The effects of increasing urea concentration on micelle structure are analogous to those of decreasing the temperature. The large changes in micelle structure observed here could also affect membrane protein unfolding studies by changing the structure of the PDC.
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Affiliation(s)
- Carolina L Bianco
- Department of Chemical Engineering, University of Delaware, Newark, DE 19716
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McAuley WJ, Jones DS, Kett VL. Characterisation of the interaction of lactate dehydrogenase with Tween-20 using isothermal titration calorimetry, interfacial rheometry and surface tension measurements. J Pharm Sci 2010; 98:2659-69. [PMID: 19472341 DOI: 10.1002/jps.21640] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In this study the nature of the interaction between Tween-20 and lactate dehydrogenase (LDH) was investigated using isothermal titration calorimetry (ITC). In addition the effects of the protein and surfactant on the interfacial properties were followed with interfacial rheology and surface tension measurements in order to understand the mechanism by which the surfactant prevents protein adsorption to the air-water interface. Comparisons were made with Tween-40 and Tween-80 in order to further investigate the mechanism. ITC measurements indicated a weak, probably hydrophobic, interaction between Tween-20 and LDH. Prevention of LDH adsorption to the air-water interface by the Tween surfactants was correlated with surface energy rather than surfactant CMC. While surface pressure appears to be the main driving force for the displacement of LDH from the air-water interface by Tween-20 a solubilisation mechanism may exist for other protein molecules. More generally the results of this study highlight the value of the use of ITC and interfacial measurements in characterising the surface behaviour of mixed surfactant and protein systems.
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Affiliation(s)
- William J McAuley
- The School of Pharmacy, The Queen's University of Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK
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Design and technical evaluation of a conceptual process for transferring solvent precipitated asphaltenes into water utilising surfactant phase behaviour. Chem Eng Res Des 2010. [DOI: 10.1016/j.cherd.2009.07.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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What can isothermal titration microcalorimetry experiments tell us about the self-organization of surfactants into micelles? J Mol Recognit 2009; 23:335-42. [DOI: 10.1002/jmr.998] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Bouchemal K, Agnely F, Koffi A, Ponchel G. A concise analysis of the effect of temperature and propanediol-1, 2 on Pluronic F127 micellization using isothermal titration microcalorimetry. J Colloid Interface Sci 2009; 338:169-76. [DOI: 10.1016/j.jcis.2009.05.075] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 05/28/2009] [Accepted: 05/29/2009] [Indexed: 10/20/2022]
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Talwar S, Harding J, Oleson KR, Khan SA. Surfactant-mediated modulation of hydrophobic interactions in associative polymer solutions containing cyclodextrin. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:794-802. [PMID: 19072321 DOI: 10.1021/la803056e] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The ability of nonionic surfactants to modulate the rheological characteristics of comblike hydrophobically modified associative polymer solutions containing cyclodextrin (CD) is examined. Addition of either alpha- or beta-CD to these polymers results in a marked decrease in solution viscosity and viscoelastic properties because of the encapsulation of the polymer hydrophobes by CD. Nonionic surfactants, introduced to such a system, alter the hydrophobic interactions by competing with the polymer hydrophobes for complexation with the CDs. In this regard, nonylphenol ethoxylates (NPe) with different ethylene oxide chain lengths, which determine the hydrophilic-lipophilic balance (HLB) of the surfactant, are used. Our results reveal that the extent and rate of recovery of zero shear viscosity as well as dynamic moduli are strongly influenced by the type of CD (alpha versus beta) as well as the HLB of the surfactant. For polymer solutions containing alpha-CD, recovery is observed solely in the presence of a low-HLB surfactant (NP6 and NP8). Additionally, in the case of NP6, the viscosity increases monotonically above the original hydrophobically modified alkali-soluble emulsion viscosity with surfactant addition, whereas for that of a higher HLB surfactant (NP15), the viscosity shows no appreciable change. In the case of beta-CD, on the other hand, a complete recovery as well as further enhancement of rheological properties is achieved using the above surfactants. However, the trends of viscosity modulation are dissimilar for different surfactants as we witness a monotonous increase in the case of NP6 while a maximum in viscosity is observed in the presence of NP8 and NP15. The contrasting observations can be explained in terms of varying affinities of alpha- and beta-CDs to bind with NP surfactants and the existence of different micellar structures in solution as governed by surfactant HLB. These results are further confirmed by UV/vis spectroscopy and cloud point measurements.
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Affiliation(s)
- Sachin Talwar
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, USA
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Han Y, Huang X, Cao M, Wang Y. Micellization of Surfactin and Its Effect on the Aggregate Conformation of Amyloid β(1-40). J Phys Chem B 2008; 112:15195-201. [DOI: 10.1021/jp805966x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Yuchun Han
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Xu Huang
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Meiwen Cao
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Yilin Wang
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
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Bouchemal K. New challenges for pharmaceutical formulations and drug delivery systems characterization using isothermal titration calorimetry. Drug Discov Today 2008; 13:960-72. [PMID: 18617012 DOI: 10.1016/j.drudis.2008.06.004] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2008] [Revised: 02/29/2008] [Accepted: 06/04/2008] [Indexed: 11/25/2022]
Abstract
Long viewed as the 'method of choice' for characterizing thermodynamics and stoichiometry of molecular interactions, with high sensitivity, isothermal titration calorimetry (ITC) has been applied to many areas of pharmaceutical analysis. This review highlights ITC employment to measure binding thermodynamics and their use for pharmaceutical formulations and drug delivery system characterization particularly cyclodextrin-guest interactions, investigation of micellar-based systems, polyelectrolytes, nucleic acid interactions with multivalent cations and the optimization of DNA targeting and delivery. Furthermore, the potential of ITC for the characterization of different functionalities carried by nanoparticles as well as their interaction with living systems was outlined.
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Affiliation(s)
- Kawthar Bouchemal
- Université Paris-Sud 11, School of Pharmacy, UMR CNRS 8612, 5 Rue J.B. Clément, 92296 Châtenay Malabry, France.
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Effect of the side chain of N-acyl amino acid surfactants on micelle formation: An isothermal titration calorimetry study. Colloids Surf A Physicochem Eng Asp 2008. [DOI: 10.1016/j.colsurfa.2007.10.028] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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33
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de Miranda JA, Cacita N, Okano LT. Evaluation of amylopectin clusters and their interaction with nonionic surfactants. Colloids Surf B Biointerfaces 2007; 60:19-27. [PMID: 17601711 DOI: 10.1016/j.colsurfb.2007.05.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2007] [Revised: 05/02/2007] [Accepted: 05/21/2007] [Indexed: 11/19/2022]
Abstract
The interaction between polyoxyethylene (7 and 23) dodecyl ether (Unitol L-70 and L-230, respectively) and polyoxyethylene (9.5) nonylphenol ether (Renex 95) with amylopectin was studied employing the relative intensities of pyrene fluorescence emission bands 1 to 3, and excimer to monomer ratios. The pyrene concentration was very low (1mumol/L), and the probe was added to amylopectin solution by two different methods. These experimental conditions have given information about how amylopectin branch structure affects the molecular diffusion in aqueous solution. Amylopectin clusters are formed from the biopolymer outer branches. The cluster polarity is similar to ethylene glycol, confirmed by the Reichardt dye measurements. Inside the clusters, amylopectin-Unitol surfactant complexes can form with cac and cmc dependent on the biopolymer concentration. The micellar aggregation number of 60+/-5 was determined through pyrene steady-state fluorescence quenching experiments.
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Affiliation(s)
- Jacques A de Miranda
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto - USP, Av. dos Bandeirantes, 3900, Ribeirão Preto, SP 14040-901, Brazil
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Wang C, Ravi P, Tam KC. Supramolecular complex of [60]fullerene-grafted polyelectrolyte and surfactant: mechanism and nanostructures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:8798-805. [PMID: 17658759 DOI: 10.1021/la700600r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Water-soluble, pH-responsive mono- and di-[60]fullerene end-capped poly(acrylic acid)s (PAA-C60 and C60-PAA-C60) were synthesized using the atom transfer radical polymerization technique. Isothermal titration calorimetry, dynamic light scattering, UV-vis spectroscopy, and transmission electron microscopy were employed to study the supramolecular complexation between fullerene end-capped PAAs and nonionic surfactant, polyethylene glycol (9-10) tert-octylphenyl ether, also known as Triton X100 (TX100) at different pH values. At pH < 4, TX100 bound specifically to C60 domains driven by hydrophobic and pi-pi interactions between TX100 and fullerene molecules. The binding was exothermic, and the magnitude of the interaction decreased gradually with increasing pH. The amount of polymer-bound TX100 was proportional to the fullerene content, which was approximately 1.3 and approximately 2.5 mM for 5 mM (concentration of carboxylic groups) PAA-C60 and C60-PAA-C60, respectively. Morphological transformations resulting in the formation of polymer/surfactant complex (PSC) precipitates in the course of binding were observed for both polymers. The PSC of PAA-C60 possessed a dense spherical structure, whereas the PSC of C60-PAA-C60 possessed a lamellar stacking structure. The PSC precipitates resolubilized in excess amounts of TX100 to form stable aggregates.
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Affiliation(s)
- Chang Wang
- Singapore-MIT Alliance, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
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Shalaby MN. BEHAVIOR STUDY OF SOME COMMERCIAL NONIONIC COMPOUNDS IN COMPARISON WITH ANIONIC SURFACTANT. CHEM ENG COMMUN 2007. [DOI: 10.1080/00986440600983502] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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37
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Liao D, Dai S, Tam KC. Interaction between Fluorocarbon End-Capped Poly(ethylene oxide) and Cyclodextrins. Macromolecules 2007. [DOI: 10.1021/ma0622884] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Dongsheng Liao
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Sheng Dai
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Kam Chiu Tam
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
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Dai S, Tam KC. Effect of Cosolvents on the Binding Interaction between Poly(ethylene oxide) and Sodium Dodecyl Sulfate. J Phys Chem B 2006; 110:20794-800. [PMID: 17048889 DOI: 10.1021/jp061438+] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The micellization of sodium dodecyl sulfate (SDS) in different glycol-water solvent mixtures was studied using the isothermal titration calorimetric (ITC) technique. At the same time, microcalorimetric titrations were also carried out to monitor the binding interaction of SDS and poly(ethylene oxide) (PEO) in the presence of different cosolvents. The demicellization of SDS in mixtures of water and cosolvents is different from that in water due to the reduction in solvent polarity and charge interaction of surfactants. The critical micelle concentration (cmc) first decreases with the addition of a small amount of cosolvents and then increases at higher cosolvent concentrations. The thermodynamics of surfactant micellization can be analyzed using the solubility parameters of solvent mixtures. For the binding interaction between SDS and PEO in different solvent mixtures, the dehydration process at low SDS concentrations is replaced by the chain solubilization process with decreasing solvent polarity. With further reduction in the solvent polarity, the binding interaction between SDS and PEO becomes weak and no aggregates can be formed beyond a certain glycol concentration. The binding interaction between SDS and PEO in different solvent mixtures was analyzed and ascribed to the effects of PEO solubility and hydrophobicity of SDS.
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Affiliation(s)
- Sheng Dai
- Singapore-MIT Alliance and School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Republic of Singapore
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Hou SG, Sun HW, Gao Y. Sorption of small metabolites of nonylphenol polyethoxylates in single and complex systems on aquatic suspended particulate matter. CHEMOSPHERE 2006; 63:31-8. [PMID: 16213551 DOI: 10.1016/j.chemosphere.2005.07.069] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2004] [Revised: 07/22/2005] [Accepted: 07/27/2005] [Indexed: 05/04/2023]
Abstract
Sorption of nonylphenol (NP), nonylphenol monoethoxylate (NP1EO) and nonylphenol diethoxylate (NP2EO) as well as their binary and ternary mixtures were studied and compared on three simulated suspended particulate matters (SPMs). Sorption dynamics of NP on the three SPMs could be divided into two phases, the rapid sorption phase and the slow sorption phase. A third phase, 'apparent desorption' occurred before the slow sorption phase for NP1EO and NP2EO as well as for all mixtures. Initial sorption rate increased with the OC% content of the SPMs. At low concentration, the sorption of NP, NP1EO and NP2EO (only at low concentration for 3# SPM) followed linear isotherm on the three SPMs. The linear Kd value of NP or NP1EO increased with the OC% content of SPM. In mixtures, sorption of NP, NP1EO and NP2EO increased significantly, and a 'critical point', after which sorption increased significantly, was observed in certain sorption isotherms.
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Affiliation(s)
- Shao-gang Hou
- College of Environmental Science and Engineering, Nankai University, 94th of Weijin Road of Nankai District, Tianjin 300071, People's Republic of China
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Dai S, Tam KC. Isothermal titration calorimetric studies on the temperature dependence of binding interactions between poly(propylene glycol)s and sodium dodecyl sulfate. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:2177-83. [PMID: 15835668 DOI: 10.1021/la0357559] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Isothermal titration calorimetry (ITC) is a sensitive research tool for examining the binding interactions between surfactant and polymer where the differential enthalpy during the binding process is monitored. In addition to the critical micelle concentration (cmc) and the micellization enthalpy (deltaHm), the effective micellar charge fraction (beta) of the ionic surfactant micellization process can also be determined from ITC thermograms. Poly(propylene glycol) (PPG) exhibits a lower critical solution temperature (LCST) ranging from 15 to 42 degrees C, depending on the molecular weights. We report, for the first time, the binding interactions between sodium dodecyl sulfate (SDS) and 1,000, 2,000 and 3,000 Da PPGs, where different binding mechanisms are in operation, depending on the temperature. At temperatures lower than the LCST, the binding interactions are similar to those of SDS and low molecular weight poly(ethylene glycol)s (MW < 3500 Da). At temperatures greater than the LCST, the binding interactions are dominated by direct solubilization of PPG chains into mixed micellar cores. At temperatures near the LCST, the binding interactions are controlled by the balance ofthe PPG solubilization at low SDS concentrations and polymer-induced micellization at high SDS concentrations.
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Affiliation(s)
- S Dai
- Singapore-MIT Alliance, School of Mechanical and Production Engineering, Nanyang Technological University, Singapore 639798, Republic of Singapore
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