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Suek NW, Lamm MH. Computer simulation of architectural and molecular weight effects on the assembly of amphiphilic linear-dendritic block copolymers in solution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:3030-3036. [PMID: 18288872 DOI: 10.1021/la703006w] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Langevin dynamics simulations are performed on linear-dendritic diblock copolymers containing bead-spring, freely jointed chains composed of hydrophobic linear monomers and hydrophilic dendritic monomers. The critical micelle concentration (CMC), micelle size distribution, and shape are examined as a function of dendron generation and architecture. For diblock copolymers with a linear block of fixed length, it is found that the CMC increases with increasing dendron generation. This trend qualitatively agrees with experiments on linear-dendritic diblock and triblock copolymers with hydrophilic dendritic blocks and hydrophobic linear blocks. The flexibility of the dendritic block is altered by varying the number of spacer monomers between branch points in the dendron. When comparing linear-dendritic diblock copolymers with similar molecular weights, it is shown that increasing the number of spacer monomers in the dendron lowers the CMC due to an increase in flexibility of the dendritic block. Analysis on the micellar structure shows that linear-dendritic diblock copolymers pack more densely than what would be expected for a linear-linear diblock copolymer of the same molecular weight.
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Affiliation(s)
- Nicholas W Suek
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, USA
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2
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Lee E, Jeong YH, Kim JK, Lee M. Controlled Self-Assembly of Asymmetric Dumbbell-Shaped Rod Amphiphiles: Transition from Toroids to Planar Nets. Macromolecules 2007. [DOI: 10.1021/ma071511+] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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3
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Gao Y, Zhang X, Yang M, Zhang X, Wang W, Wegner G, Burger C. Synthesis and Cylinder Microdomain Structures of Hybrid Block Copolymers of π-Conjugated and Dendritic Poly(phenylazomethine)s and Flexible and Linear PEO. Macromolecules 2007. [DOI: 10.1021/ma062881l] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yang Gao
- The Key Laboratory of Functional Polymer Materials and Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Xiwen Zhang
- The Key Laboratory of Functional Polymer Materials and Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Miao Yang
- The Key Laboratory of Functional Polymer Materials and Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Xinjun Zhang
- The Key Laboratory of Functional Polymer Materials and Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Wei Wang
- The Key Laboratory of Functional Polymer Materials and Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Gerhard Wegner
- Max-Planck-Institute for Polymer Research, Ackermannweg 10, Postfach 3148, D-55128, Mainz, Germany
| | - Christian Burger
- Chemistry Department, Stony Brook University, Stony Brook, New York 11794-3400
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4
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Reynhout IC, Cornelissen JJLM, Nolte RJM. Self-Assembled Architectures from Biohybrid Triblock Copolymers. J Am Chem Soc 2007; 129:2327-32. [PMID: 17274615 DOI: 10.1021/ja066790f] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The synthesis and self-assembly behavior of biohybrid ABC triblock copolymers consisting of a synthetic diblock, polystyrene-b-polyethylene glycol (PSm-b-PEG113), where m is varied, and a hemeprotein, myoglobin (Mb) or horse radish peroxidase (HRP), is described. The synthetic diblock copolymer is first functionalized with the heme cofactor and subsequently reconstituted with the apoprotein or the apoenzyme to yield the protein-containing ABC triblock copolymer. The obtained amphiphilic block copolymers self-assemble in aqueous solution into a large variety of aggregate structures. Depending on the protein and the polystyrene block length, micellar rods, vesicles, toroids, figure eight structures, octopus structures, and spheres with a lamellar surface are formed.
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Affiliation(s)
- Irene C Reynhout
- Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
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5
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Zhou Y, Yan D, Dong W, Tian Y. Temperature-Responsive Phase Transition of Polymer Vesicles: Real-Time Morphology Observation and Molecular Mechanism. J Phys Chem B 2007; 111:1262-70. [PMID: 17243669 DOI: 10.1021/jp0673563] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Novel thermosensitive polymer vesicles with controlled temperature-responsive phase transition at the lower critical solution temperature (LCST) varying from 8 to 81 degrees C were prepared via self-assembly of amphiphilic hyperbranched star copolymers having a hydrophobic hyperbranched poly[3-ethyl-3-(hydroxymethyl)oxetane] (HBPO) core and many hydrophilic polyethylene oxide (PEO) arms. Real-time optical microscopic observation revealed that the polymer vesicles have undergone sequential morphology changes including enrichment, aggregation, fusion, and vesicle-to-membrane transformation near the LCST. Molecular-level investigation indicates that the LCST transition results from the decreasing water solubility of the polymer vesicles with increasing temperature based on the partial dehydration of the PEO vesicle corona. On the basis of these results, a LCST transition mechanism, in view of the molecular configuration, balance of hydrophilic and hydrophobic moieties, and the vesicle morphology transformations, was proposed. As far as we know, the work presented here is the first demonstration of thermosensitive vesicles based on PEO, and the finding may be useful to design the thermosensitive core-shell structures by introducing the PEO segments.
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Affiliation(s)
- Yongfeng Zhou
- College of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, People's Republic of China
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6
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Santini CMB, Hatton TA, Hammond PT. Solution behavior of linear-dendritic rod diblock copolymers in methanol. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:7487-98. [PMID: 16922525 DOI: 10.1021/la060341b] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The solution behavior of spherical dendrimers as well as hybrid-linear dendritic diblock copolymers has been extensively studied, and the size, shape, and ability of these polymers to encapsulate small molecules have led to their comparison with traditional micelles. We have recently reported the synthesis of a new dendritic copolymer architecture, the linear-dendritic rod diblock copolymer, and in this work, we examine the solution behavior of these unique polymers in methanol at 25 degrees C, using dynamic light scattering and intrinsic viscosity measurements. The diblock copolymers consist of a linear poly(ethylene oxide)-poly(ethylene imine) diblock copolymer backbone around which poly(amido amine) branches have been divergently synthesized from the poly(ethylene imine) block. The hydrodynamic radii and the viscometric radii of the polymers were found to increase slowly with increasing generation up to generation 3.5; however, after generation 3.5, the radii were found to increase very rapidly. This increase can be explained by an elongation of the dendritic block into a more rodlike configuration and a corresponding breakdown of the spherical approximation used to calculate the radii. The intrinsic viscosity of the amine and ester terminated polymers was found to follow two very different trends at low generation; however, at higher generations, they followed similar, yet slightly different, curves with the values for the amine terminated polymers only a little larger than those of the ester terminated polymers. At low generations, the chemistry of the end groups and its interaction with the solvent were found to be more important, whereas at higher generations, the highly branched nature of the dendritic block was the more important factor. For the ester terminated polymers, a maximum in the intrinsic viscosity occurred at generation 1.5. Since this maximum occurred at a much lower generation number than is traditionally seen for spherical dendrimers, new scaling relations for the intrinsic viscosity of dendritic rod polymers were developed and were found to support this observation. A minimum in the intrinsic viscosity was also observed at generation 3.5 for the ester terminated polymers and a minimum or leveling off in the intrinsic viscosity at generation 4.0 was found for the amine terminated polymers, which can be attributed to the transitioning of the polymers to a more elongated, rodlike shape and the increased influence of the shape factor on the intrinsic viscosity.
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Affiliation(s)
- Catherine M B Santini
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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7
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Nguyen PM, Hammond PT. Amphiphilic linear-dendritic triblock copolymers composed of poly(amidoamine) and poly(propylene oxide) and their micellar-phase and encapsulation properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:7825-32. [PMID: 16922570 DOI: 10.1021/la0607050] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
A novel amphiphilic ABA dendritic-linear-dendritic block copolymer consisting of poly(amidoamine) and poly(propylene oxide) has been synthesized. The solution-phase behavior of the block copolymer was studied as a function of the generation of the dendritic block, ionic strength, and solution pH. The triblock self-assembles in aqueous media to form stable micelles with CMC values ranging from 10(-6) to 10(-5) M. Dynamic light scattering results indicate the formation of particles ranging from 9 to 18 nm in diameter, with smaller diameters exhibited at higher generations. Additional experiments were performed to assess the feasibility of the nanoparticles for drug delivery applications. Drug loading studies were performed with a model hydrophobic drug, triclosan, resulting in high loading efficiencies ranging from 79 to 86%w/w. The dendritic-linear-dendritic block copolymer synthesized was found to be a promising candidate for drug delivery due to its relative stability in aqueous solution and its drug encapsulation and release properties.
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Affiliation(s)
- Phuong M Nguyen
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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8
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Gao WP, Bai Y, Chen EQ, Li ZC, Han BY, Yang WT, Zhou QF. Controlling Vesicle Formation via Interpolymer Hydrogen-Bonding Complexation between Poly(ethylene oxide)-block-polybutadiene and Poly(acrylic acid) in Solution. Macromolecules 2006. [DOI: 10.1021/ma0603579] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wei-Ping Gao
- Department of Polymer Science and Engineering and The Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China, and College of Material Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yu Bai
- Department of Polymer Science and Engineering and The Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China, and College of Material Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Er-Qiang Chen
- Department of Polymer Science and Engineering and The Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China, and College of Material Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Zi-Chen Li
- Department of Polymer Science and Engineering and The Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China, and College of Material Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Bing-Yong Han
- Department of Polymer Science and Engineering and The Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China, and College of Material Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Wan-Tai Yang
- Department of Polymer Science and Engineering and The Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China, and College of Material Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Qi-Feng Zhou
- Department of Polymer Science and Engineering and The Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China, and College of Material Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
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9
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Bernaerts KV, Willet N, Van Camp W, Jérôme R, Du Prez FE. pH-Responsive Diblock Copolymers Prepared by the Dual Initiator Strategy. Macromolecules 2006. [DOI: 10.1021/ma052625t] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Katrien V. Bernaerts
- Department of Organic Chemistry, Polymer Chemistry Research Group, Ghent University, Krijgslaan 281 (S4-bis), 9000 Ghent, Belgium, and Center for Education and Research on Macromolecules (CERM), University of Liège, Sart-Tilman B6a, B-4000 Liège, Belgium
| | - Nicolas Willet
- Department of Organic Chemistry, Polymer Chemistry Research Group, Ghent University, Krijgslaan 281 (S4-bis), 9000 Ghent, Belgium, and Center for Education and Research on Macromolecules (CERM), University of Liège, Sart-Tilman B6a, B-4000 Liège, Belgium
| | - Wim Van Camp
- Department of Organic Chemistry, Polymer Chemistry Research Group, Ghent University, Krijgslaan 281 (S4-bis), 9000 Ghent, Belgium, and Center for Education and Research on Macromolecules (CERM), University of Liège, Sart-Tilman B6a, B-4000 Liège, Belgium
| | - Robert Jérôme
- Department of Organic Chemistry, Polymer Chemistry Research Group, Ghent University, Krijgslaan 281 (S4-bis), 9000 Ghent, Belgium, and Center for Education and Research on Macromolecules (CERM), University of Liège, Sart-Tilman B6a, B-4000 Liège, Belgium
| | - Filip E. Du Prez
- Department of Organic Chemistry, Polymer Chemistry Research Group, Ghent University, Krijgslaan 281 (S4-bis), 9000 Ghent, Belgium, and Center for Education and Research on Macromolecules (CERM), University of Liège, Sart-Tilman B6a, B-4000 Liège, Belgium
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10
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Marcos AG, Pusel TM, Thomann R, Pakula T, Okrasa L, Geppert S, Gronski W, Frey H. Linear-Hyperbranched Block Copolymers Consisting of Polystyrene and Dendritic Poly(carbosilane) Block. Macromolecules 2006. [DOI: 10.1021/ma051526c] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alejandra García Marcos
- Institut für Organische Chemie, Organische und Makromolekulare Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany, Institut für Makromolekulare Chemie, Hermann-Staudinger Haus, Albert-Ludwig Universität Freiburg, Stefan-Meier Strasse 31, 79104 Freiburg, Germany, and Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Thomas M. Pusel
- Institut für Organische Chemie, Organische und Makromolekulare Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany, Institut für Makromolekulare Chemie, Hermann-Staudinger Haus, Albert-Ludwig Universität Freiburg, Stefan-Meier Strasse 31, 79104 Freiburg, Germany, and Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Ralf Thomann
- Institut für Organische Chemie, Organische und Makromolekulare Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany, Institut für Makromolekulare Chemie, Hermann-Staudinger Haus, Albert-Ludwig Universität Freiburg, Stefan-Meier Strasse 31, 79104 Freiburg, Germany, and Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Tadeusz Pakula
- Institut für Organische Chemie, Organische und Makromolekulare Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany, Institut für Makromolekulare Chemie, Hermann-Staudinger Haus, Albert-Ludwig Universität Freiburg, Stefan-Meier Strasse 31, 79104 Freiburg, Germany, and Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Lidia Okrasa
- Institut für Organische Chemie, Organische und Makromolekulare Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany, Institut für Makromolekulare Chemie, Hermann-Staudinger Haus, Albert-Ludwig Universität Freiburg, Stefan-Meier Strasse 31, 79104 Freiburg, Germany, and Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Steffen Geppert
- Institut für Organische Chemie, Organische und Makromolekulare Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany, Institut für Makromolekulare Chemie, Hermann-Staudinger Haus, Albert-Ludwig Universität Freiburg, Stefan-Meier Strasse 31, 79104 Freiburg, Germany, and Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Wolfram Gronski
- Institut für Organische Chemie, Organische und Makromolekulare Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany, Institut für Makromolekulare Chemie, Hermann-Staudinger Haus, Albert-Ludwig Universität Freiburg, Stefan-Meier Strasse 31, 79104 Freiburg, Germany, and Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Holger Frey
- Institut für Organische Chemie, Organische und Makromolekulare Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany, Institut für Makromolekulare Chemie, Hermann-Staudinger Haus, Albert-Ludwig Universität Freiburg, Stefan-Meier Strasse 31, 79104 Freiburg, Germany, and Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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11
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Passeno LM, Mackay ME, Baker GL, Vestberg R, Hawker CJ. Conformational Changes of Linear−Dendrimer Diblock Copolymers in Dilute Solution. Macromolecules 2005. [DOI: 10.1021/ma0517291] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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Rigler P, Meier W. Encapsulation of Fluorescent Molecules by Functionalized Polymeric Nanocontainers: Investigation by Confocal Fluorescence Imaging and Fluorescence Correlation Spectroscopy. J Am Chem Soc 2005; 128:367-73. [PMID: 16390167 DOI: 10.1021/ja056719u] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nanocontainers (NCs) were prepared from amphiphilic triblock copolymers, having an average molecular weight of around 8000 g/mol, by using previously published preparation methods consisting of dispersing the polymer in an aqueous buffer solution containing molecules for encapsulation. A small molecular weight fluorophore, sulforhodamine B, as well as the fluorescent protein avidin labeled with Alexa 488 were encapsulated, and the resulting nanocontainers were characterized using fluorescence correlation spectroscopy (FCS) and fluorescence cross-correlation spectroscopy (FCCS). Nanocontainer size determination by FCS is very robust and compares well with results obtained from photon correlation spectroscopy: the measured diameters of the polymeric nanocontainers vary between 140 and 172 nm. Encapsulation of fluorescent molecules was determined by evaluating the molecular brightness of nanocontainers with an encapsulated fluorescently labeled protein (avidin-Alexa 488). Results indicate that the number of encapsulated avidin-Alexa 488 molecules corresponds well with the initial concentration of the fluorescently labeled protein and the encapsulated volume. A nanocontainer binding assay was developed using biotinylated fluorescently labeled nanocontainers. Binding of biotinylated nanocontainers to fluorescently labeled streptavidin was followed by fluorescence cross-correlation spectroscopy. The intrinsic dissociation constant, K(d), of labeled streptavidin to the ligand-modified nanocontainers is 1.7 +/- 0.4 x 10(-8) M, and about 1921 +/- 357 molecules of labeled streptavidin are bound to each nanocontainer.
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Affiliation(s)
- Per Rigler
- Physikalische Chemie, Universität Basel, Klingelbergstrasse 80, 4056 Basel, Switzerland
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13
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Kim Y, Pyun J, Fréchet JMJ, Hawker CJ, Frank CW. The dramatic effect of architecture on the self-assembly of block copolymers at interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:10444-58. [PMID: 16262305 DOI: 10.1021/la047122f] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Dramatic morphological changes are observed in the Langmuir-Blodgett (LB) film assemblies of poly(ethylene glycol)-b-(styrene-r-benzocyclobutene) block copolymer (PEG-b-(S-r-BCB)) after intramolecular cross-linking of the S-r-BCB block to form a linear-nanoparticle structure. To isolate architectural effects and allow direct comparison, the linear block copolymer precursor and the linear-nanoparticle block copolymer resulting from selective intramolecular cross-linking of the BCB units were designed to have exactly the same molecular weight and chemical composition but different architecture. It was found that the effect of architecture is pronounced with these macromolecular isomers, which self-assemble into dramatically different surface aggregates. The linear block copolymer forms disklike surface assemblies over the range of compression states, while the linear-nanoparticle block copolymer exhibits long (>10 microm) wormlike aggregates whose length increases as a function of increasing cross-linking density. It is shown that the driving force behind the morphological change is a combination of the altered molecular geometry and the restricted degree of stretching of the nanoparticle block because of the intramolecular cross-linking. A modified approach to interpret the pi-A isotherm, which includes presence of the block copolymer aggregates, is also presented, while the surface rheological properties of the block copolymers at the air-water interface provide in-situ evidence of the aggregates' presence at the air-water interface.
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Affiliation(s)
- Yoojin Kim
- Department of Chemical Engineering, Stanford University, California 94305-5025, USA
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14
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Yang M, Wang W, Yuan F, Zhang X, Li J, Liang F, He B, Minch B, Wegner G. Soft Vesicles Formed by Diblock Codendrimers of Poly(benzyl ether) and Poly(methallyl dichloride). J Am Chem Soc 2005; 127:15107-11. [PMID: 16248650 DOI: 10.1021/ja052713t] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The synthesis of a block codendrimer (g3-PBE-b-g3-PMDC), composed of a third-generation poly(benzyl ether) (PBE) monodendron and an aliphatic polyether (PMDC) monodendron is reported. In THF/diiospropyl ether (1:1) the PMDC block functions as a "hydrophilic" block, while the PBE acts as a "hydrophobic" block. The codendrimer can form interdigitated layers leading to vesicle formation. Tapping mode atomic force microscopy (AFM), dynamic light scattering (DLS), and transmission electron microscopy (TEM) were used to characterize the vesicles. The effect of molecular architecture on the formation of the interdigitated layers and vesicles was studied.
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Affiliation(s)
- Miao Yang
- Key Laboratory of Functional Polymer Materials of Ministry of Education and Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
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15
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Moses JI, Fouchet T, Bézard B, Gladstone GR, Lellouch E, Feuchtgruber H. Photochemistry and diffusion in Jupiter's stratosphere: Constraints from ISO observations and comparisons with other giant planets. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2005je002411] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- J. I. Moses
- Lunar and Planetary Institute; Houston Texas USA
| | - T. Fouchet
- LESIA; Observatoire de Paris; Meudon France
- Université Paris 6; Paris France
| | - B. Bézard
- LESIA; Observatoire de Paris; Meudon France
| | - G. R. Gladstone
- Space Sciences Department; Southwest Research Institute; San Antonio Texas USA
| | | | - H. Feuchtgruber
- Max-Planck-Institut für Extraterrestrische Physik; Garching Germany
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16
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Gomez ED, Rappl TJ, Agarwal V, Bose A, Schmutz M, Marques CM, Balsara NP. Platelet Self-Assembly of an Amphiphilic A−B−C−A Tetrablock Copolymer in Pure Water. Macromolecules 2005. [DOI: 10.1021/ma047466c] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Enrique D. Gomez
- Department of Chemical Engineering, University of California, Berkeley, California 94720; Department of Chemical Engineering, University of Rhode Island, Kingston, Rhode Island 02881; ICS-CNRS UPR 22, 6 rue de Boussingault, 67083 Strasbourg Cedex, France; LDFC-CNRS-ULP UMR 7506, Institut de Physique, 3 rue de l'Université, 67084 Strasbourg Cedex, France; and Materials Sciences Division and Environmental Energy and Technologies Division, Lawrence Berkeley National Laboratory, University of California,
| | - Timothy J. Rappl
- Department of Chemical Engineering, University of California, Berkeley, California 94720; Department of Chemical Engineering, University of Rhode Island, Kingston, Rhode Island 02881; ICS-CNRS UPR 22, 6 rue de Boussingault, 67083 Strasbourg Cedex, France; LDFC-CNRS-ULP UMR 7506, Institut de Physique, 3 rue de l'Université, 67084 Strasbourg Cedex, France; and Materials Sciences Division and Environmental Energy and Technologies Division, Lawrence Berkeley National Laboratory, University of California,
| | - Vivek Agarwal
- Department of Chemical Engineering, University of California, Berkeley, California 94720; Department of Chemical Engineering, University of Rhode Island, Kingston, Rhode Island 02881; ICS-CNRS UPR 22, 6 rue de Boussingault, 67083 Strasbourg Cedex, France; LDFC-CNRS-ULP UMR 7506, Institut de Physique, 3 rue de l'Université, 67084 Strasbourg Cedex, France; and Materials Sciences Division and Environmental Energy and Technologies Division, Lawrence Berkeley National Laboratory, University of California,
| | - Arijit Bose
- Department of Chemical Engineering, University of California, Berkeley, California 94720; Department of Chemical Engineering, University of Rhode Island, Kingston, Rhode Island 02881; ICS-CNRS UPR 22, 6 rue de Boussingault, 67083 Strasbourg Cedex, France; LDFC-CNRS-ULP UMR 7506, Institut de Physique, 3 rue de l'Université, 67084 Strasbourg Cedex, France; and Materials Sciences Division and Environmental Energy and Technologies Division, Lawrence Berkeley National Laboratory, University of California,
| | - Marc Schmutz
- Department of Chemical Engineering, University of California, Berkeley, California 94720; Department of Chemical Engineering, University of Rhode Island, Kingston, Rhode Island 02881; ICS-CNRS UPR 22, 6 rue de Boussingault, 67083 Strasbourg Cedex, France; LDFC-CNRS-ULP UMR 7506, Institut de Physique, 3 rue de l'Université, 67084 Strasbourg Cedex, France; and Materials Sciences Division and Environmental Energy and Technologies Division, Lawrence Berkeley National Laboratory, University of California,
| | - Carlos M. Marques
- Department of Chemical Engineering, University of California, Berkeley, California 94720; Department of Chemical Engineering, University of Rhode Island, Kingston, Rhode Island 02881; ICS-CNRS UPR 22, 6 rue de Boussingault, 67083 Strasbourg Cedex, France; LDFC-CNRS-ULP UMR 7506, Institut de Physique, 3 rue de l'Université, 67084 Strasbourg Cedex, France; and Materials Sciences Division and Environmental Energy and Technologies Division, Lawrence Berkeley National Laboratory, University of California,
| | - Nitash P. Balsara
- Department of Chemical Engineering, University of California, Berkeley, California 94720; Department of Chemical Engineering, University of Rhode Island, Kingston, Rhode Island 02881; ICS-CNRS UPR 22, 6 rue de Boussingault, 67083 Strasbourg Cedex, France; LDFC-CNRS-ULP UMR 7506, Institut de Physique, 3 rue de l'Université, 67084 Strasbourg Cedex, France; and Materials Sciences Division and Environmental Energy and Technologies Division, Lawrence Berkeley National Laboratory, University of California,
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17
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Pyun J, Tang C, Kowalewski T, Fréchet JMJ, Hawker CJ. Synthesis and Direct Visualization of Block Copolymers Composed of Different Macromolecular Architectures. Macromolecules 2005. [DOI: 10.1021/ma047375f] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jeffrey Pyun
- IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, Department of Chemistry, University of California, Berkeley, California 94720, and Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Chuanbing Tang
- IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, Department of Chemistry, University of California, Berkeley, California 94720, and Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Tomasz Kowalewski
- IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, Department of Chemistry, University of California, Berkeley, California 94720, and Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Jean M. J. Fréchet
- IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, Department of Chemistry, University of California, Berkeley, California 94720, and Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - Craig J. Hawker
- IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, Department of Chemistry, University of California, Berkeley, California 94720, and Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
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18
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Teobaldi G, Melle-Franco M, Zerbetto F. Understanding the Cosolvation Effect of Dendrimers. J Chem Theory Comput 2005; 1:194-200. [DOI: 10.1021/ct0499332] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gilberto Teobaldi
- Dipartimento di Chimica “G. Ciamician”, Università di Bologna, V. F. Selmi 2, 40126 Bologna, Italy
| | - Manuel Melle-Franco
- Dipartimento di Chimica “G. Ciamician”, Università di Bologna, V. F. Selmi 2, 40126 Bologna, Italy
| | - Francesco Zerbetto
- Dipartimento di Chimica “G. Ciamician”, Università di Bologna, V. F. Selmi 2, 40126 Bologna, Italy
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19
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Basu S, Vutukuri DR, Shyamroy S, Sandanaraj BS, Thayumanavan S. Invertible amphiphilic homopolymers. J Am Chem Soc 2004; 126:9890-1. [PMID: 15303841 DOI: 10.1021/ja047816a] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Stimuli-responsive polymers and assemblies are viable candidates for the so-called "smart" materials. In this communication, we report a new class of amphiphilic homopolymers that forms micelle-like structures in polar solvents and inverted micelle-like structures in apolar solvents. We demonstrate that these superstructures are the result of the changes in the molecular-level conformations in the monomer.
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Affiliation(s)
- Subhadeep Basu
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA
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20
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Gillies ER, Jonsson TB, Fréchet JMJ. Stimuli-Responsive Supramolecular Assemblies of Linear-Dendritic Copolymers. J Am Chem Soc 2004; 126:11936-43. [PMID: 15382929 DOI: 10.1021/ja0463738] [Citation(s) in RCA: 494] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
With the goal of developing a pH-responsive micelle system, linear-dendritic block copolymers comprising poly(ethylene oxide) and either a polylysine or polyester dendron were prepared and hydrophobic groups were attached to the dendrimer periphery by highly acid-sensitive cyclic acetals. These copolymers were designed to form stable micelles in aqueous solution at neutral pH but to disintegrate into unimers at mildly acidic pH following loss of the hydrophobic groups upon acetal hydrolysis. Micelle formation was demonstrated by encapsulation of the fluorescent probe Nile Red, and the micelle sizes were determined by dynamic light scattering. The structure of the dendrimer block, its generation, and the synthetic method for linking the acetal groups to its periphery all had an influence on the critical micelle concentration and the micelle size. The rate of hydrolysis of the acetals at the micelle core was measured for each system at pH 7.4 and pH 5, and it was found that all systems were stable at neutral pH but underwent significant hydrolysis at pH 5 over several hours. The rate of hydrolysis at pH 5 was dependent on the structure of the copolymer, most notably the hydrophobicity of the core-forming block. To demonstrate the potential of these systems for controlled release, the release of Nile Red as a "model payload" was examined. At pH 7.4, the fluorescence of micelle-encapsulated Nile Red was relatively constant, indicating it was retained in the micelle, while at pH 5, the fluorescence decreased, consistent with its release into the aqueous environment. The rate of release was strongly correlated with the rate of acetal hydrolysis and was therefore controlled by the chemical structure of the copolymer. The mechanism of Nile Red release was investigated by monitoring the change in size of the micelles over time at acidic pH. Dynamic light scattering measurement showed a size decrease over time, eventually reaching the size of a unimer, thus providing evidence for the proposed micelle disintegration.
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Affiliation(s)
- Elizabeth R Gillies
- Center for New Directions in Organic Synthesis, Department of Chemistry, University of California, Berkeley, California 94720-1460, USA
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21
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Choucair A, Lavigueur C, Eisenberg A. Polystyrene-b-poly(acrylic acid) vesicle size control using solution properties and hydrophilic block length. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:3894-900. [PMID: 15969376 DOI: 10.1021/la035924p] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Polymeric vesicles have attracted considerable attention in recent years, since they are a model for biological membranes and have versatile structures with several practical applications. In this study, we prepare vesicles from polystyrene-b-poly(acrylic acid) block copolymer in dioxane/water and dioxane/THF/water mixtures. We then examine the ability of additives (such as NaCl, HCl, or NaOH), solvent composition, and hydrophilic block length to control vesicle size. Using turbidity measurements and transmission electron microscopy (TEM) we show that larger vesicles can be prepared from a given copolymer by adding NaCl or HCl, while adding NaOH yields smaller vesicles. The solvent composition (ratio of dioxane to THF, as well as the water content) can also determine the vesicle size. From a given copolymer, smaller vesicles can be prepared by increasing the THF content in the THF/dioxane solvent mixture. In a given solvent mixture, vesicle size increases with water content, but such an increase is most pronounced when dioxane is used as the solvent. In THF-rich solutions, on the other hand, vesicle size changes only slightly with the water concentration. As to the effect of the acrylic acid block length, the results show that block copolymers with shorter hydrophilic blocks assemble into larger vesicles. The effect of additives and solvent composition on vesicle size is related to their influence on chain repulsion and aggregation number, whereas the effect of acrylic acid block length occurs because of the relationship among the block length, the width of the molecular weight distribution, and the stabilization of the vesicle curvature.
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Affiliation(s)
- Amira Choucair
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 2K6, Canada
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22
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Langereis S, de Lussanet QG, van Genderen MHP, Backes WH, Meijer EW. Multivalent Contrast Agents Based on Gadolinium−Diethylenetriaminepentaacetic Acid-Terminated Poly(propylene imine) Dendrimers for Magnetic Resonance Imaging. Macromolecules 2004. [DOI: 10.1021/ma035983+] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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23
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Johnson MA, Iyer J, Hammond PT. Microphase Segregation of PEO−PAMAM Linear−Dendritic Diblock Copolymers. Macromolecules 2004. [DOI: 10.1021/ma030450m] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mark A. Johnson
- Department of Chemical Engineering, Massachusetts Institute of Technology, Room 66-550, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307
| | - Jyotsna Iyer
- Department of Chemical Engineering, Massachusetts Institute of Technology, Room 66-550, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307
| | - Paula T. Hammond
- Department of Chemical Engineering, Massachusetts Institute of Technology, Room 66-550, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307
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24
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Haraguchi N, Hirao A. Synthesis of Well-Defined Star−Linear Block Polystyrenes by Coupling Reaction of Chain-Functionalized Polystyrenes with a Definite Number of Benzyl Bromide Moieties with Polystyryllithiums. Macromolecules 2003. [DOI: 10.1021/ma034799l] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Naoki Haraguchi
- Polymeric and Organic Materials Department, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1, Ohokayama, Meguro-ku, Tokyo 152-8552, Japan
| | - Akira Hirao
- Polymeric and Organic Materials Department, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1, Ohokayama, Meguro-ku, Tokyo 152-8552, Japan
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25
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Du J, Chen Y, Zhang Y, Han CC, Fischer K, Schmidt M. Organic/Inorganic Hybrid Vesicles Based on A Reactive Block Copolymer. J Am Chem Soc 2003; 125:14710-1. [PMID: 14640638 DOI: 10.1021/ja0368610] [Citation(s) in RCA: 206] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Presented in this communication is a novel hybrid vesicle with a cross-linked polyorganosiloxane wall based on a new reactive block copolymer, poly(ethylene oxide)-block-poly(3-(trimethoxysilyl)propyl methacrylate) (PEO-b-PTMSPMA), which was synthesized by atom transfer radical polymerization. The vesicles were prepared first by self-assembly of the block copolymer in a selective solvent, and then the PTMSPMA block was subjected to hydrolysis and polycondensation reaction to fix vesicle wall in the presence of triethylamine as a catalyst. Transmission electron microscopy, scanning electron microscopy, NMR, and light scattering have been used to characterize the vesicles.
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Affiliation(s)
- Jianzhong Du
- State Key Laboratory of Polymer Physics and Chemistry, Joint Laboratory of Polymer Science and Materials, Institute of Chemistry, The Chinese Academy of Sciences, Beijing 100080, China
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26
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Li BS, Cheuk KKL, Yang D, Lam JWY, Wan LJ, Bai C, Tang BZ. Self-Assembling of an Amphiphilic Polyacetylene Carrying l-Leucine Pendants: A Homopolymer Case. Macromolecules 2003. [DOI: 10.1021/ma034275l] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Bing Shi Li
- Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China; and Department of Chemistry, Institute of Nano Science and Technology, Open Laboratory of Chirotechnology of the Institute of Molecular Technology for Drug Discovery and Synthesis, Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Kevin K. L. Cheuk
- Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China; and Department of Chemistry, Institute of Nano Science and Technology, Open Laboratory of Chirotechnology of the Institute of Molecular Technology for Drug Discovery and Synthesis, Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Deliang Yang
- Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China; and Department of Chemistry, Institute of Nano Science and Technology, Open Laboratory of Chirotechnology of the Institute of Molecular Technology for Drug Discovery and Synthesis, Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Jacky W. Y. Lam
- Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China; and Department of Chemistry, Institute of Nano Science and Technology, Open Laboratory of Chirotechnology of the Institute of Molecular Technology for Drug Discovery and Synthesis, Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Li Jun Wan
- Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China; and Department of Chemistry, Institute of Nano Science and Technology, Open Laboratory of Chirotechnology of the Institute of Molecular Technology for Drug Discovery and Synthesis, Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Chunli Bai
- Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China; and Department of Chemistry, Institute of Nano Science and Technology, Open Laboratory of Chirotechnology of the Institute of Molecular Technology for Drug Discovery and Synthesis, Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Ben Zhong Tang
- Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China; and Department of Chemistry, Institute of Nano Science and Technology, Open Laboratory of Chirotechnology of the Institute of Molecular Technology for Drug Discovery and Synthesis, Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China
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27
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Teobaldi G, Zerbetto F. Molecular dynamics of a dendrimer-dye guest-host system. J Am Chem Soc 2003; 125:7388-93. [PMID: 12797813 DOI: 10.1021/ja027905s] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We use molecular dynamics to investigate the instantaneous structure of a fourth generation (dansyl terminated) dendrimer of propylene amine dissolved in CH(2)Cl(2), and of the same system upon the subsequent encapsulation of several eosin Y dyes. Calculations, in a cubic box with up to approximately 3500 solvent molecules and a maximum of 12 eosins, show that one of the effects of the presence of the guest molecules is to "close" the structure of the box where they are contained. Multiple entrances-exits of the guest molecules in the dendrimer are observed in less than a nanosecond, until the excess eosins are irreversibly expelled and their number is finally brought down to the experimental limit of 6. The guest molecules are distributed at two main distances from the center of the dendrimer and their surroundings are far from static. Eosins move inside the hyperbranched molecule in a way similar to what the solvent molecules do and sometimes aggregate.
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Affiliation(s)
- Gilberto Teobaldi
- Dipartimento di Chimica G. Ciamician, Università di Bologna, V. F. Selmi 2, 40126 Bologna, Italy
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28
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Li J, Li X, Ni X, Leong KW. Synthesis and Characterization of New Biodegradable Amphiphilic Poly(ethylene oxide)-b-poly[(R)-3-hydroxy butyrate]-b-poly(ethylene oxide) Triblock Copolymers. Macromolecules 2003. [DOI: 10.1021/ma025725x] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jun Li
- Institute of Materials Research and Engineering (IMRE), 3 Research Link, Singapore 117602, Republic of Singapore; Division of Bioengineering, Faculty of Engineering, National University of Singapore, Singapore 117576, Republic of Singapore; and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205
| | - Xu Li
- Institute of Materials Research and Engineering (IMRE), 3 Research Link, Singapore 117602, Republic of Singapore; Division of Bioengineering, Faculty of Engineering, National University of Singapore, Singapore 117576, Republic of Singapore; and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205
| | - Xiping Ni
- Institute of Materials Research and Engineering (IMRE), 3 Research Link, Singapore 117602, Republic of Singapore; Division of Bioengineering, Faculty of Engineering, National University of Singapore, Singapore 117576, Republic of Singapore; and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205
| | - Kam W. Leong
- Institute of Materials Research and Engineering (IMRE), 3 Research Link, Singapore 117602, Republic of Singapore; Division of Bioengineering, Faculty of Engineering, National University of Singapore, Singapore 117576, Republic of Singapore; and Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205
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29
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Klok HA, Hwang JJ, Hartgerink JD, Stupp SI. Self-Assembling Biomaterials: l-Lysine-Dendron-Substituted Cholesteryl-(l-lactic acid)n̄. Macromolecules 2002. [DOI: 10.1021/ma011964t] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Harm-Anton Klok
- Department of Materials Science and Engineering, Department of Chemistry, Medical School, Northwestern University, Evanston, Illinois 60208
| | - Julia J. Hwang
- Department of Materials Science and Engineering, Department of Chemistry, Medical School, Northwestern University, Evanston, Illinois 60208
| | - Jeffrey D. Hartgerink
- Department of Materials Science and Engineering, Department of Chemistry, Medical School, Northwestern University, Evanston, Illinois 60208
| | - Samuel I. Stupp
- Department of Materials Science and Engineering, Department of Chemistry, Medical School, Northwestern University, Evanston, Illinois 60208
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30
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Zubarev ER, Stupp SI. Dendron rodcoils: synthesis of novel organic hybrid structures. J Am Chem Soc 2002; 124:5762-73. [PMID: 12010051 DOI: 10.1021/ja020071t] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Convergent and divergent syntheses of novel organic hybrid structures termed dendron rodcoils (DRC) containing dendritic, rodlike, and coillike segments are described. The aryl ester dendron masked with 32 trifluoromethyl groups is prepared via a convergent approach using 5-(tert-butyldimethylsiloxy)isophthalic acid as the monomer unit. The activation of the focal point of the dendron allows for successful coupling between the dendron and the diblock rodcoil molecules synthesized separately. In another example, the dendritic block is grown via divergent strategy from the terminus of rodcoil using 3,5-bis(tert-butyldimethylsiloxy)benzoic acid as an AB(2) monomer. A combination of catalyzed esterification reactions and silyl deprotection chemistry proved to be a very efficient method for construction of these nanosized structures with unusual molecular architecture. Both synthetic strategies allowed for the preparation of DRCs with nearly monodisperse dendritic blocks as demonstrated by NMR, MALDI-TOF, and GPC measurements.
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Affiliation(s)
- Eugene R Zubarev
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3108, USA
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31
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Abstract
A new type of giant amphiphilic molecule has been synthesized by covalently connecting a lipase enzyme headgroup to a maleimide-functionalized polystyrene tail (40 repeat units). The resulting biohybrid forms catalytic micellar rods in water.
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Affiliation(s)
- Kelly Velonia
- Department of Organic Chemistry, NSR Center, University of Nijmegen, Toernooiveld 1, NL-6525 ED Nijmegen, The Netherlands
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32
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Sommerdijk NAJM, Holder SJ, Hiorns RC, Jones RG, Nolte RJM. Self-Assembled Structures from an Amphiphilic Multiblock Copolymer Containing Rigid Semiconductor Segments. Macromolecules 2000. [DOI: 10.1021/ma0011385] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nico A. J. M. Sommerdijk
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513 5600 MB Eindhoven, The Netherlands; the Centre of Materials Research, School of Physical Sciences, University of Kent, Canterbury, Kent, United Kingdom; and the Department of Organic Chemistry, NSR Centre, University of Nijmegen, Nijmegen, The Netherlands
| | - Simon J. Holder
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513 5600 MB Eindhoven, The Netherlands; the Centre of Materials Research, School of Physical Sciences, University of Kent, Canterbury, Kent, United Kingdom; and the Department of Organic Chemistry, NSR Centre, University of Nijmegen, Nijmegen, The Netherlands
| | - Roger C. Hiorns
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513 5600 MB Eindhoven, The Netherlands; the Centre of Materials Research, School of Physical Sciences, University of Kent, Canterbury, Kent, United Kingdom; and the Department of Organic Chemistry, NSR Centre, University of Nijmegen, Nijmegen, The Netherlands
| | - Richard G. Jones
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513 5600 MB Eindhoven, The Netherlands; the Centre of Materials Research, School of Physical Sciences, University of Kent, Canterbury, Kent, United Kingdom; and the Department of Organic Chemistry, NSR Centre, University of Nijmegen, Nijmegen, The Netherlands
| | - Roeland J. M. Nolte
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513 5600 MB Eindhoven, The Netherlands; the Centre of Materials Research, School of Physical Sciences, University of Kent, Canterbury, Kent, United Kingdom; and the Department of Organic Chemistry, NSR Centre, University of Nijmegen, Nijmegen, The Netherlands
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33
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Bosman AW, Janssen HM, Meijer EW. About Dendrimers: Structure, Physical Properties, and Applications. Chem Rev 1999; 99:1665-1688. [PMID: 11849007 DOI: 10.1021/cr970069y] [Citation(s) in RCA: 1696] [Impact Index Per Article: 67.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- A. W. Bosman
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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34
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Krasnopolsky VA, Mumma MJ, Abbott M, Flynn BC, Meech KJ, Yeomans DK, Feldman PD, Cosmovici CB. Detection of soft X-rays and a sensitive search for noble gases in comet Hale-Bopp. Science 1997; 277:1488-91. [PMID: 9278508 DOI: 10.1126/science.277.5331.1488] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
An image of comet Hale-Bopp (C/1995 O1) in soft x-rays reveals a central emission offset from the nucleus, as well as an extended emission feature that does not correlate with the dust jets seen at optical wavelengths. Neon was found to be depleted in the cometary ice by more than a factor of 25 relative to solar abundance, which suggests that ices in Hale-Bopp formed at (or later experienced) temperatures higher than 25 kelvin. A helium line emission at a wavelength of 584 angstroms was detected and may be attributable to charge transfer of solar wind alpha particles in the cometary coma. Ionized oxygen and another helium line contribute to an emission observed at 538 angstroms.
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Affiliation(s)
- V A Krasnopolsky
- Catholic University of America, Washington, DC 20064, USA. 20771, USA
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35
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Zeng F, Zimmerman SC. Dendrimers in Supramolecular Chemistry: From Molecular Recognition to Self-Assembly. Chem Rev 1997; 97:1681-1712. [PMID: 11851463 DOI: 10.1021/cr9603892] [Citation(s) in RCA: 994] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fanwen Zeng
- Department of Chemistry, 600 South Mathews Avenue, University of Illinois, Urbana, Illinois 61801
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