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Bjørnestad VA, Li X, Tribet C, Lund R, Cascella M. Micelle kinetics of photoswitchable surfactants: Self-assembly pathways and relaxation mechanisms. J Colloid Interface Sci 2023; 646:883-899. [PMID: 37235934 DOI: 10.1016/j.jcis.2023.05.057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/19/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023]
Abstract
HYPOTHESIS A key question in the kinetics of surfactant self-assembly is whether exchange of unimers or fusion/fission of entire micelles is the dominant pathway. In this study, an isomerizable surfactant is used to explore fundamental out-of-equilibrium kinetics and mechanisms for growth and dissolution of micelles. EXPERIMENTS The kinetics of cationic surfactant 4-butyl-4'-(3-trimethylammoniumpropoxy)-phenylazobenzene was studied using molecular dynamics simulations. The fusion and exchange processes were investigated using umbrella sampling. Equilibrium states were validated by comparison with small-angle X-ray scattering data. The photo-isomerization event was simulated by modifying the torsion potential of the photo-responsive group to emulate the trans-to-cis transition. FINDINGS Micelle growth is dominated by unimer exchange processes, whereas, depending on the conditions, dissolution can occur both through fission and unimer expulsion. Fusion barriers increase steeply with the aggregation number making this an unlikely pathway to equilibrium for micelles of sizes that fit with the experimental data. The barriers for unimer expulsion remain constant and are much lower for unimer insertion, making exchange more likely at high aggregation. When simulating photo-conversion events, both fission and a large degree of unimer expulsion can occur depending on the extent of the out-of-equilibrium stress that is put on the system.
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Affiliation(s)
- Victoria Ariel Bjørnestad
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, Sem Sælands vei 26, Oslo, 0371, Norway
| | - Xinmeng Li
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, Sem Sælands vei 26, Oslo, 0371, Norway
| | - Christophe Tribet
- PASTEUR, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, Paris, 75005, France
| | - Reidar Lund
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, Sem Sælands vei 26, Oslo, 0371, Norway.
| | - Michele Cascella
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, Sem Sælands vei 26, Oslo, 0371, Norway.
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2
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Lodge TP, Seitzinger CL, Seeger SC, Yang S, Gupta S, Dorfman KD. Dynamics and Equilibration Mechanisms in Block Copolymer Particles. ACS POLYMERS AU 2022; 2:397-416. [PMID: 36536887 PMCID: PMC9756915 DOI: 10.1021/acspolymersau.2c00033] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 08/10/2022] [Accepted: 08/10/2022] [Indexed: 06/17/2023]
Abstract
Self-assembly of block copolymers into interesting and useful nanostructures, in both solution and bulk, is a vibrant research arena. While much attention has been paid to characterization and prediction of equilibrium phases, the associated dynamic processes are far from fully understood. Here, we explore what is known and not known about the equilibration of particle phases in the bulk, and spherical micelles in solution. The presumed primary equilibration mechanisms are chain exchange, fusion, and fragmentation. These processes have been extensively studied in surfactants and lipids, where they occur on subsecond time scales. In contrast, increased chain lengths in block copolymers create much larger barriers, and time scales can become prohibitively slow. In practice, equilibration of block copolymers is achievable only in proximity to the critical micelle temperature (in solution) or the order-disorder transition (in the bulk). Detailed theories for these processes in block copolymers are few. In the bulk, the rate of chain exchange can be quantified by tracer diffusion measurements. Often the rate of equilibration, in terms of number density and aggregation number of particles, is much slower than chain exchange, and consequently observed particle phases are often metastable. This is particularly true in regions of the phase diagram where Frank-Kasper phases occur. Chain exchange in solution has been explored quantitatively by time-resolved SANS, but the results are not well captured by theory. Computer simulations, particularly via dissipative particle dynamics, are beginning to shed light on the chain escape mechanism at the molecular level. The rate of fragmentation has been quantified in a few experimental systems, and TEM images support a mechanism akin to the anaphase stage of mitosis in cells, via a thin neck that pinches off to produce two smaller micelles. Direct measurements of micelle fusion are quite rare. Suggestions for future theoretical, computational, and experimental efforts are offered.
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Affiliation(s)
- Timothy P. Lodge
- Department
of Chemistry, University of Minnesota 207 Pleasant St SE, Minneapolis, Minnesota 55455, United States
- Department
of Chemical Engineering & Materials Science, University of Minnesota 451 Washington Ave SE, Minneapolis, Minnesota 55455, United States
| | - Claire L. Seitzinger
- Department
of Chemistry, University of Minnesota 207 Pleasant St SE, Minneapolis, Minnesota 55455, United States
| | - Sarah C. Seeger
- Department
of Chemical Engineering & Materials Science, University of Minnesota 451 Washington Ave SE, Minneapolis, Minnesota 55455, United States
| | - Sanghee Yang
- Department
of Chemistry, University of Minnesota 207 Pleasant St SE, Minneapolis, Minnesota 55455, United States
| | - Supriya Gupta
- Department
of Chemistry, University of Minnesota 207 Pleasant St SE, Minneapolis, Minnesota 55455, United States
| | - Kevin D. Dorfman
- Department
of Chemical Engineering & Materials Science, University of Minnesota 451 Washington Ave SE, Minneapolis, Minnesota 55455, United States
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3
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Liu Q, Ding S, Shi G, Zhu A. Rational design of a self-assembled surfactant film in nanopipettes: combined fluorescence and electrochemical sensing. Chem Commun (Camb) 2022; 58:2140-2143. [PMID: 35040861 DOI: 10.1039/d1cc06667f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, a generalizable method based on the formation of a self-assembled surfactant film was reported to build a nanopipette system. Using this nanopipette, it was found that arginine metabolism shows an age-related difference in Alzheimer's disease.
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Affiliation(s)
- Qi Liu
- School of Chemistry and Molecular Engineering, Engineering Research Center of Nanophotonics and Advanced Instrument, Ministry of Education, Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration, East China Normal University, 500 Dong Chuan Road, Shanghai 200241, People's Republic of China.
| | - Shushu Ding
- School of Chemistry and Molecular Engineering, Engineering Research Center of Nanophotonics and Advanced Instrument, Ministry of Education, Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration, East China Normal University, 500 Dong Chuan Road, Shanghai 200241, People's Republic of China.
| | - Guoyue Shi
- School of Chemistry and Molecular Engineering, Engineering Research Center of Nanophotonics and Advanced Instrument, Ministry of Education, Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration, East China Normal University, 500 Dong Chuan Road, Shanghai 200241, People's Republic of China.
| | - Anwei Zhu
- School of Chemistry and Molecular Engineering, Engineering Research Center of Nanophotonics and Advanced Instrument, Ministry of Education, Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration, East China Normal University, 500 Dong Chuan Road, Shanghai 200241, People's Republic of China.
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4
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Hellmann N, Schneider D. A complex unfolding pathway of α-helical membrane proteins in SDS-containing micelles. Biophys J 2021; 120:3857-3859. [PMID: 34416174 DOI: 10.1016/j.bpj.2021.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 07/20/2021] [Accepted: 08/03/2021] [Indexed: 11/19/2022] Open
Affiliation(s)
- Nadja Hellmann
- Department of Chemistry, Biochemistry, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Dirk Schneider
- Department of Chemistry, Biochemistry, Johannes Gutenberg-University Mainz, Mainz, Germany; Institute of Molecular Physiology, Johannes Gutenberg-University Mainz, Mainz, Germany.
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5
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Early JT, Block A, Yager KG, Lodge TP. Molecular Weight Dependence of Block Copolymer Micelle Fragmentation Kinetics. J Am Chem Soc 2021; 143:7748-7758. [PMID: 33988984 DOI: 10.1021/jacs.1c02147] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The effect of molecular weight (M) on the fragmentation kinetics of micelles formed by 1,2-polybutadiene-block-poly(ethylene oxide) (PB-PEO) copolymers was studied in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. A series of six samples, with total M ranging from 104 to 105 g mol-1 and nearly constant composition (fPEO ≈ 0.4), were examined; all six formed spherical micelles with PEO coronas. Nonequilibrium PB-PEO micelles were prepared by direct dissolution, a process that systematically produces nanoparticles with mean aggregation numbers more than twice the equilibrium values. When subjected to high temperature annealing (170 °C), the average micelle radius was found to decrease substantially, as determined by temperature-jump dynamic light scattering (T-jump DLS) and time-resolved small-angle X-ray scattering (TR-SAXS). The characteristic fragmentation times (τ) were found to increase strongly with increasing degree of polymerization N, as τ ∼ N1.8. This result compares favorably with the prediction of a previously untested model.
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Affiliation(s)
| | | | - Kevin G Yager
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
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Vafaei S, Allabush F, Tabaei SR, Male L, Dafforn TR, Tucker JHR, Mendes PM. Förster Resonance Energy Transfer Nanoplatform Based on Recognition-Induced Fusion/Fission of DNA Mixed Micelles for Nucleic Acid Sensing. ACS NANO 2021; 15:8517-8524. [PMID: 33961404 PMCID: PMC8158853 DOI: 10.1021/acsnano.1c00156] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 04/29/2021] [Indexed: 05/29/2023]
Abstract
The dynamic nature of micellar nanostructures is employed to form a self-assembled Förster resonance energy transfer (FRET) nanoplatform for enhanced sensing of DNA. The platform consists of lipid oligonucleotide FRET probes incorporated into micellar scaffolds, where single recognition events result in fusion and fission of DNA mixed micelles, triggering the fluorescence response of multiple rather than a single FRET pair. In comparison to conventional FRET substrates where a single donor interacts with a single acceptor, the micellar multiplex FRET system showed ∼20- and ∼3-fold enhancements in the limit of detection and FRET efficiency, respectively. This supramolecular signal amplification approach could potentially be used to improve FRET-based diagnostic assays of nucleic acid and non-DNA based targets.
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Affiliation(s)
- Setareh Vafaei
- School
of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Francia Allabush
- School
of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
- School
of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Seyed R. Tabaei
- School
of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Louise Male
- School
of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Timothy R. Dafforn
- School
of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - James H. R. Tucker
- School
of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Paula M. Mendes
- School
of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
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7
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Wen B, Bai B, Larson RG. Surfactant desorption and scission free energies for cylindrical and spherical micelles from umbrella-sampling molecular dynamics simulations. J Colloid Interface Sci 2021; 599:773-784. [PMID: 33989930 DOI: 10.1016/j.jcis.2021.04.138] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/27/2021] [Accepted: 04/28/2021] [Indexed: 11/28/2022]
Abstract
HYPOTHESIS The free energies associated with adsorption/desorption of individual surfactants from micelles and the fusion/scission of long micelles can be used to estimate the rate constants for micellar kinetics as functions of surfactant and salt concentration. EXPERIMENTS We compute the escape free energies △Gesc of surfactant from micelles and the scission free energies △Gsciss of long micelles from coarse-grained molecular dynamics simulations coupled with umbrella sampling, for micelles of both sodium dodecylsulfate (SDS) in sodium chloride (NaCl) and cetyltrimethylammonium chloride (CTAC) in sodium salicylate (NaSal). FINDINGS For spherical micelles, △Gesc values have maxima at certain aggregation numbers, and at salt-to-surfactant molar concentration ratios R near unity, consistent with experiments. For cylindrical micelles, SDS/NaCl shows a minimum, and CTAC/NaSal a maximum in △Gesc, both at R ~ 0.7, while △Gsciss of CTAC micelles also peaks at around R ~ 0.7 and that of SDS micelles increases monotonically with R. We explain the non-monotonic dependence of escape and scission free energies on R by a combination of electrostatic screening and the decrease of micelle radius with increasing R. Transitions from predominantly spherical to cylindrical micelles, and between adsorption/desorption and fusion/scission kinetics with changing salt concentration can be inferred from the free energies for CTAC/NaSal.
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Affiliation(s)
- Boyao Wen
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, United States; State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
| | - Bofeng Bai
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
| | - Ronald G Larson
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, United States.
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Chang D, Liu J, Fang B, Xu Z, Li Z, Liu Y, Brassart L, Guo F, Gao W, Gao C. Reversible fusion and fission of graphene oxide-based fibers. Science 2021; 372:614-617. [PMID: 33958473 DOI: 10.1126/science.abb6640] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 03/16/2021] [Indexed: 01/03/2023]
Abstract
Stimuli-responsive fusion and fission are widely observed in both bio-organizations and artificial molecular assemblies. However, the design of a system with structure and property persistence during repeated fusion and fission remains challenging. We show reversible fusion and fission of wet-spun graphene oxide (GO) fibers, in which a number of macroscopic fibers can fuse into a thicker one and can also separate into original individual fibers under stimulation of solvents. The dynamic geometrical deformation of GO fiber shells, caused by solvent evaporation and infiltration, is the key to the reversible fusion-fission cycles. This principle is extended to implement flexible transitions between complex fiber assemblies and the inclusion or expulsion of guest compounds.
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Affiliation(s)
- Dan Chang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Key Laboratory of Adsorption and Separation Materials and Technologies of Zhejiang Province, Zhejiang University, Hangzhou 310027, China
| | - Jingran Liu
- State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace, Xi'an Jiaotong University, Xi'an 710049, China
| | - Bo Fang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Key Laboratory of Adsorption and Separation Materials and Technologies of Zhejiang Province, Zhejiang University, Hangzhou 310027, China
| | - Zhen Xu
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Key Laboratory of Adsorption and Separation Materials and Technologies of Zhejiang Province, Zhejiang University, Hangzhou 310027, China
| | - Zheng Li
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Key Laboratory of Adsorption and Separation Materials and Technologies of Zhejiang Province, Zhejiang University, Hangzhou 310027, China.
| | - Yilun Liu
- State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Laurence Brassart
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Fan Guo
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Key Laboratory of Adsorption and Separation Materials and Technologies of Zhejiang Province, Zhejiang University, Hangzhou 310027, China
| | - Weiwei Gao
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Key Laboratory of Adsorption and Separation Materials and Technologies of Zhejiang Province, Zhejiang University, Hangzhou 310027, China
| | - Chao Gao
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Key Laboratory of Adsorption and Separation Materials and Technologies of Zhejiang Province, Zhejiang University, Hangzhou 310027, China.
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9
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Ho Lee K, Ireland M, Miller BL, Wyslouzil BE, Winter JO. Synthesis of polymer nanoparticles via electrohydrodynamic emulsification-mediated self-assembly. J Colloid Interface Sci 2021; 586:445-456. [PMID: 33162039 DOI: 10.1016/j.jcis.2020.10.108] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 10/05/2020] [Accepted: 10/25/2020] [Indexed: 11/24/2022]
Abstract
HYPOTHESIS Electrospray can rapidly produce fine, organic solvent-in-water emulsions in the absence of surfactant via electrohydrodynamic emulsification (EE), a reverse configuration of traditional electrospray. This paper investigates whether EE can produce high-quality nanocomposites comprised of block co-polymers and organic nanoparticles (NPs) via the interfacial instability (IS) self-assembly method. Surfactant-free approaches may increase encapsulation efficiency and product uniformity, process speed, and ease of downstream product purification. EXPERIMENTS All particles were produced using EE-mediated self-assembly (SA) (EE-SA). Particles were produced using poly(lactic-co-glycolic acid) (PLGA) polymers as proof of concept. Then, block copolymer (BCP) micelles were synthesized from polystyrene-block-poly(ethylene oxide) (PS-b-PEO) (PS 9.5 kDa:PEO 18.0 kDa) in the presence and absence of superparamagnetic iron oxide nanoparticles (SPIONs) or quantum dots (QDs). Encapsulant concentration was varied, and the effect of encapsulant NP ligands on final particle size was investigated. FINDINGS EE-SA generated both pure polymer NPs and nanocomposites containing SPIONs and QDs. PLGA particles spanned from sub- to super-micron sizes. PS-b-PEO NPs and nanocomposites were highly monodisperse, and more highly loaded than those made via a conventional, surfactant-rich IS process. Free ligands decreased the size of pure BCP particles. Increasing encapsulant levels led to a morphological transition from spherical to worm-like to densely loaded structures.
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Affiliation(s)
- Kil Ho Lee
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 W. Woodruff Ave., Columbus, OH 43210, USA
| | - Megan Ireland
- Department of Biomedical Engineering, The Ohio State University, 151 W. Woodruff Ave., Columbus, OH 43210, USA
| | - Brandon L Miller
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 W. Woodruff Ave., Columbus, OH 43210, USA
| | - Barbara E Wyslouzil
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 W. Woodruff Ave., Columbus, OH 43210, USA; Department of Chemistry and Biochemistry, The Ohio State University, 151 W. Woodruff Ave., Columbus, OH 43210, USA.
| | - Jessica O Winter
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 W. Woodruff Ave., Columbus, OH 43210, USA; Department of Biomedical Engineering, The Ohio State University, 151 W. Woodruff Ave., Columbus, OH 43210, USA.
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10
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Landazuri G, Fernandez V, Soltero J, Rharbi Y. Length of the Core Forming Block Effect on Fusion and Fission Dynamics at Equilibrium in PEO–PPO–PEO Triblock Copolymer Micelles in the Spherical Regime. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c01520] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- G. Landazuri
- Université Grenoble Alpes—LRP, F-38041 Grenoble, France
- CNRS, LRP, F-38041 Grenoble, France
- Departamento de Ingeniería Química, CUCEI, Universidad de Guadalajara, Blvd. M. García Barragán # 1421, Guadalajara, Jalisco 44430, Mexico
| | - V.V.A. Fernandez
- Université Grenoble Alpes—LRP, F-38041 Grenoble, France
- CNRS, LRP, F-38041 Grenoble, France
- Departamento de Ciencias Tecnológicas, Universidad de Guadalajara, Av. Universidad No. 1115, Ocotlán, Jalisco 47820, Mexico
| | - J.F.A. Soltero
- Université Grenoble Alpes—LRP, F-38041 Grenoble, France
- CNRS, LRP, F-38041 Grenoble, France
- Departamento de Ingeniería Química, CUCEI, Universidad de Guadalajara, Blvd. M. García Barragán # 1421, Guadalajara, Jalisco 44430, Mexico
| | - Y. Rharbi
- Université Grenoble Alpes—LRP, F-38041 Grenoble, France
- CNRS, LRP, F-38041 Grenoble, France
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Early JT, Yager KG, Lodge TP. Direct Observation of Micelle Fragmentation via In Situ Liquid-Phase Transmission Electron Microscopy. ACS Macro Lett 2020; 9:756-761. [PMID: 35648564 DOI: 10.1021/acsmacrolett.0c00273] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Recently, attention has been directed toward understanding the dynamics and relaxation kinetics of block copolymer micelles, including mechanisms such as micelle fragmentation and fusion. The few prior studies on block copolymer micelle fragmentation relied on ensemble averaging techniques such as small-angle X-ray scattering and dynamic light scattering; some individual particles were imaged by ex situ transmission electron microscopy. Here we report the direct observation of fragmentation for three molecular weights of 1,2-polybutadiene-block-poly(ethylene oxide) (PB-PEO) micelles in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide using high-temperature liquid-phase transmission electron microscopy (LP-TEM). The use of in situ LP-TEM provides unique insights into the evolution of block copolymer micelles during fragmentation. Specifically, upon heating to 170 °C, a sequence of morphological transitions from a spherical micelle to a prolate ellipsoid, then a "peanut" shape, followed by a two-spherical-compartment micelle was observed, where the last is presumed to be the transition state.
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Affiliation(s)
| | - Kevin G. Yager
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
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12
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Amann M, Diget JS, Lyngsø J, Pedersen JS, Narayanan T, Lund R. Kinetic Pathways for Polyelectrolyte Coacervate Micelle Formation Revealed by Time-Resolved Synchrotron SAXS. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01072] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Matthias Amann
- Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo, Norway
| | - Jakob Stensgaard Diget
- Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo, Norway
| | - Jeppe Lyngsø
- Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
| | - Jan Skov Pedersen
- Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
| | - Theyencheri Narayanan
- European Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, 38043 Grenoble, France
| | - Reidar Lund
- Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo, Norway
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13
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Early JT, Lodge TP. Fragmentation of 1,2-Polybutadiene-block-Poly(ethylene oxide) Micelles in Imidazolium-Based Ionic Liquids. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01530] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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14
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Daskalakis V. Protein-protein interactions within photosystem II under photoprotection: the synergy between CP29 minor antenna, subunit S (PsbS) and zeaxanthin at all-atom resolution. Phys Chem Chem Phys 2018; 20:11843-11855. [PMID: 29658553 DOI: 10.1039/c8cp01226a] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The assembly and disassembly of protein complexes within cells are crucial life-sustaining processes. In photosystem II (PSII) of higher plants, there is a delicate yet obscure balance between light harvesting and photo-protection under fluctuating light conditions, that involves protein-protein complexes. Recent breakthroughs in molecular dynamics (MD) simulations are combined with new approaches herein to provide structural and energetic insight into such a complex between the CP29 minor antenna and the PSII subunit S (PsbS). The microscopic model involves extensive sampling of bound and dissociated states at atomic resolution in the presence of photo-protective zeaxanthin (Zea), and reveals well defined protein-protein cross-sections. The complex is placed within PSII, and macroscopic connections are emerging (PsbS-CP29-CP24-CP47) along the energy transfer pathways from the antenna to the PSII core. These connections explain macroscopic observations in the literature, while the previously obscured atomic scale details are now revealed. The implications of these findings are discussed in the context of the Non-Photochemical Quenching (NPQ) of chlorophyll fluorescence, the down-regulatory mechanism of photosynthesis, that enables the protection of PSII against excess excitation load. Zea is found at the PsbS-CP29 cross-section and a pH-dependent equilibrium between PsbS dimer/monomers and the PsbS-CP29 dissociation/association is identified as the target for engineering tolerant plants with increased crop and biomass yields. Finally, the new MD based approaches can be used to probe protein-protein interactions in general, and the PSII structure provided can initiate large scale molecular simulations of the photosynthetic apparatus, under NPQ conditions.
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Affiliation(s)
- Vangelis Daskalakis
- Department of Environmental Science and Technology, Cyprus University of Technology (CUT), 30 Archbishop Kyprianou Str., 3603, Limassol, Cyprus.
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15
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Shchekin AK, Adzhemyan LT, Babintsev IA, Volkov NA. Kinetics of Aggregation and Relaxation in Micellar Surfactant Solutions. COLLOID JOURNAL 2018. [DOI: 10.1134/s1061933x18020084] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Liu R, Liu M, Hood D, Chen CY, MacNevin CJ, Holten D, Lindsey JS. Chlorophyll-Inspired Red-Region Fluorophores: Building Block Synthesis and Studies in Aqueous Media. Molecules 2018; 23:molecules23010130. [PMID: 29320445 PMCID: PMC6017558 DOI: 10.3390/molecules23010130] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 01/04/2018] [Accepted: 01/06/2018] [Indexed: 02/04/2023] Open
Abstract
Fluorophores that absorb and emit in the red spectral region (600-700 nm) are of great interest in photochemistry and photomedicine. Eight new target chlorins (and 19 new chlorins altogether)-analogues of chlorophyll-of different polarities have been designed and synthesized for various applications; seven of the chlorins are equipped with a bioconjugatable tether. Hydrophobic or amphiphilic chlorins in a non-polar organic solvent (toluene), polar organic solvent (DMF), and aqueous or aqueous micellar media show a sharp emission band in the red region and modest fluorescence quantum yield (Φf = 0.2-0.3). A Poisson analysis implies most micelles are empty and few contain >1 chlorin. Water-soluble chlorins each bearing three PEG (oligoethyleneglycol) groups exhibit narrow emission bands (full-width-at-half maximum <25 nm). The lifetime of the lowest singlet excited state and the corresponding yields and rate constants for depopulation pathways (fluorescence, intersystem crossing, internal conversion) are generally little affected by the PEG groups or dissolution in aqueous or organic media. A set of chlorin-avidin conjugates revealed a 2-fold increase in Φf with increased average chlorin/avidin ratio (2.3-12). In summary, the chlorins of various polarities described herein are well suited as red-emitting fluorophores for applications in aqueous or organic media.
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Affiliation(s)
- Rui Liu
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA; (R.L.); (M.L.)
| | - Mengran Liu
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA; (R.L.); (M.L.)
| | - Don Hood
- Department of Chemistry, Washington University, St. Louis, MO 63130-4889, USA;
| | - Chih-Yuan Chen
- NIRvana Sciences, Inc., Research Triangle Park, NC 27709, USA; (C.-Y.C.); (C.J.M.)
| | | | - Dewey Holten
- Department of Chemistry, Washington University, St. Louis, MO 63130-4889, USA;
- Correspondence: (D.H.); (J.S.L.); Tel.: +1-314-935-6502 (D.H.); +1-919-515-6406 (J.S.L.)
| | - Jonathan S. Lindsey
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA; (R.L.); (M.L.)
- Correspondence: (D.H.); (J.S.L.); Tel.: +1-314-935-6502 (D.H.); +1-919-515-6406 (J.S.L.)
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17
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Zheng X, Zhu L, Zeng X, Meng L, Zhang L, Wang D, Huang X. Kinetics-Controlled Amphiphile Self-Assembly Processes. J Phys Chem Lett 2017; 8:1798-1803. [PMID: 28365997 DOI: 10.1021/acs.jpclett.7b00160] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Amphiphile self-assembly is an essential bottom-up approach of fabricating advanced functional materials. Self-assembled materials with desired structures are often obtained through thermodynamic control. Here, we demonstrate that the selection of kinetic pathways can lead to drastically different self-assembled structures, underlining the significance of kinetic control in self-assembly. By constructing kinetic network models from large-scale molecular dynamics simulations, we show that two largely similar amphiphiles, 1-[11-oxo-11-(pyren-1-ylmethoxy)-undecyl]pyridinium bromide (PYR) and 1-(11-((5a1,8a-dihydropyren-1-yl)methylamino)-11-oxoundecyl)pyridinium bromide (PYN), prefer distinct kinetic assembly pathways. While PYR prefers an incremental growth mechanism and forms a nanotube, PYN favors a hopping growth pathway leading to a vesicle. Such preference was found to originate from the subtle difference in the distributions of hydrophobic and hydrophilic groups in their chemical structures, which leads to different rates of the adhesion process among the aggregating micelles. Our results are in good agreement with experimental results, and accentuate the role of kinetics in the rational design of amphiphile self-assembly.
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Affiliation(s)
- Xiaoyan Zheng
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong
- HKUST-Shenzhen Research Institute , Nanshan, Shenzhen 518057, People's Republic of China
| | - Lizhe Zhu
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong
| | - Xiangze Zeng
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong
| | - Luming Meng
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong
| | - Lu Zhang
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong
| | - Dong Wang
- Key Laboratory of Organic OptoElectronics and Molecular Engineering, Department of Chemistry, Tsinghua University , Beijing 100084, People's Repulic of China
| | - Xuhui Huang
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction, Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong
- HKUST-Shenzhen Research Institute , Nanshan, Shenzhen 518057, People's Republic of China
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18
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Deans RM, Taniguchi M, Chandrashaker V, Ptaszek M, Chambers DR, Soares ARM, Lindsey JS. Complexity in structure-directed prebiotic chemistry. Unexpected compositional richness from competing reactants in tetrapyrrole formation. NEW J CHEM 2016. [DOI: 10.1039/c6nj00543h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Acyclic reactants afford “partially defective” pyrroles that interfere with chain growth of “normal” pyrroles on the path to tetrapyrrole macrocycles.
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Affiliation(s)
- Richard M. Deans
- Department of Chemistry
- North Carolina State University
- Raleigh
- USA
| | | | | | - Marcin Ptaszek
- Department of Chemistry
- North Carolina State University
- Raleigh
- USA
| | - Dana R. Chambers
- Department of Chemistry
- North Carolina State University
- Raleigh
- USA
| | - Ana R. M. Soares
- Department of Chemistry
- North Carolina State University
- Raleigh
- USA
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19
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Kageyama Y, Ikegami T, Hiramatsu N, Takeda S, Sugawara T. Structure and growth behavior of centimeter-sized helical oleate assemblies formed with assistance of medium-length carboxylic acids. SOFT MATTER 2015; 11:3550-3558. [PMID: 25781720 DOI: 10.1039/c5sm00370a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The nonequilibrium organization of self-assemblies from small building-block molecules offers an attractive and essential means to develop advanced functional materials and to understand the intrinsic nature of life systems. Fatty acids are well-known amphiphiles that form self-assemblies of several shapes. Here, we found that the lengths of helical structures of oleic acid formed in a buffered aqueous solution are dramatically different by the presence or absence of certain amphiphilic carboxylic acids. For example, under the coexistence of a small amount of N-decanoyl-l-alanine, we observed the formation of over 1 centimeter-long helical assemblies of oleate with a regular pitch and radius, whereas mainly less than 100 μm-long helices formed without this additive. Such long helical assemblies are unique in terms of their highly dimensional helical structure and growth dynamics. Results from the real-time observation of self-assembly formation, site-selective small-angle X-ray scattering, high-performance liquid chromatography analysis, and pH titration experiments suggested that the coexisting carboxylates assist in elongation by supplying oleate molecules to a scaffold for oleate helical assembly.
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Affiliation(s)
- Yoshiyuki Kageyama
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan.
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20
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Alexy EJ, Hintz CW, Hughes HM, Taniguchi M, Lindsey JS. Paley's watchmaker analogy and prebiotic synthetic chemistry in surfactant assemblies. Formaldehyde scavenging by pyrroles leading to porphyrins as a case study. Org Biomol Chem 2015; 13:10025-31. [DOI: 10.1039/c5ob01409c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Facile exchange of micromolar dialkylpyrrolic constituents among a Poisson distribution of aqueous micelles overcomes immense statistical odds against reaction.
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Affiliation(s)
- Eric J. Alexy
- Department of Chemistry
- North Carolina State University
- Raleigh
- USA
| | - Carl W. Hintz
- Department of Chemistry
- North Carolina State University
- Raleigh
- USA
| | - Hubert M. Hughes
- Department of Chemistry
- North Carolina State University
- Raleigh
- USA
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