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Kelly MT, Zhao B. Worm-globule transition of amphiphilic pH-responsive heterografted bottlebrushes at air-water interface. SOFT MATTER 2024; 20:1224-1235. [PMID: 38230501 DOI: 10.1039/d3sm01635h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Heterografted molecular bottlebrushes (MBBs) with side chains composed of poly(n-butyl acrylate) (PnBA) and pH-responsive poly(2-(N,N-diethylamino)ethyl methacrylate) (PDEAEMA, pKa = 7.4) have been shown to be efficient, robust, and responsive emulsifiers. However, it remains unknown how they respond to external stimuli at interfaces. In this work, the shape-changing behavior of six hetero- and homografted MBBs at air-water interfaces in response to pH changes and lateral compression was investigated using a Langmuir-Blodgett trough and atomic force microscopy. At a surface pressure of 0.5 mN m-1, PDEAEMA-containing MBBs showed no worm-globule transitions when the pH was increased from 4.0 to 10.0, at which PDEAEMA becomes insoluble in water. Upon lateral compression at pH 4.0, MBBs with a mole fraction of PDEAEMA side chains (xPDEAEMA) < 0.50 underwent pronounced worm-globule shape transitions; there was an increasing tendency for bottlebrushes to become connected with increasing xPDEAEMA. At xPDEAEMA = 0.76, the molecules remained wormlike even at high compression. These observations were presumably caused by the increased electrostatic repulsion between protonated PDEAEMA side chains in the subphase with increasing xPDEAEMA, hindering the shape change. At pH 10.0, MBBs with xPDEAEMA < 0.50 showed a lower tendency to change their wormlike morphologies upon compression than at pH 4.0. No shape transition was observed when xPDEAEMA > 0.50, attributed to the relatively high affinity toward water and the rigidity of PDEAEMA. This study revealed the shape-changing behavior of amphiphilic pH-responsive MBBs at air-water interfaces, which could be useful for future design of multicomponent MBBs for potential applications.
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Affiliation(s)
- Michael T Kelly
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA.
| | - Bin Zhao
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA.
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Kelly MT, Chen Z, Russell TP, Zhao B. Amphiphilic Heterografted Molecular Bottlebrushes with Tertiary Amine-Containing Side Chains as Efficient and Robust pH-Responsive Emulsifiers. Angew Chem Int Ed Engl 2023; 62:e202315424. [PMID: 37956395 DOI: 10.1002/anie.202315424] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 11/12/2023] [Accepted: 11/13/2023] [Indexed: 11/15/2023]
Abstract
By combining the unique characteristics of molecular bottlebrushes (MBBs) and the properties of stimuli-responsive polymers, we show that MBBs with randomly grafted poly(n-butyl acrylate) and pH-responsive poly(2-(N,N-diethylamino)ethyl methacrylate) (PDEAEMA) side chains are efficient and robust pH-responsive emulsifiers. Water-in-toluene emulsions were formed at pH 4.0 and disrupted by increasing the pH to 10.0. The emulsion generation and disruption was reversible over the ten cycles investigated, and the bottlebrushes remained intact. The exceptional emulsion stability stemmed from the high interfacial binding energy of MBBs, imparted by their large molecular size and Janus architecture at the interface, as evidenced by the interfacial jamming and wrinkling of the assemblies upon reducing the interfacial area. At pH 10.0, PDEAEMA became water-insoluble, and the MBBs desorbed from the interface, causing de-emulsification. Consequently, we have shown that the judicious design of MBBs can generate properties of particle emulsifiers from their large size, while the responsiveness of the MBBs enables more potential applications.
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Affiliation(s)
- Michael T Kelly
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA
| | - Zhan Chen
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, MA 01003, USA
| | - Thomas P Russell
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, MA 01003, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Bin Zhao
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA
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3
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Thermoresponsive Polymer Assemblies: From Molecular Design to Theranostics Application. Prog Polym Sci 2022. [DOI: 10.1016/j.progpolymsci.2022.101578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Mesoscale Modeling of Agglomeration of Molecular Bottlebrushes: Focus on Conformations and Clustering Criteria. Polymers (Basel) 2022; 14:polym14122339. [PMID: 35745920 PMCID: PMC9227207 DOI: 10.3390/polym14122339] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 06/03/2022] [Accepted: 06/06/2022] [Indexed: 02/04/2023] Open
Abstract
Using dissipative particle dynamics, we characterize dynamics of aggregation of molecular bottlebrushes in solvents of various qualities by tracking the number of clusters, the size of the largest cluster, and an average aggregation number. We focus on a low volume fraction of bottlebrushes in a range of solvents and probe three different cutoff criteria to identify bottlebrushes belonging to the same cluster. We demonstrate that the cutoff criteria which depend on both the coordination number and the length of the side chain allows one to correlate the agglomeration status with the structural characteristics of bottlebrushes in solvents of various qualities. We characterize conformational changes of the bottlebrush within the agglomerates with respect to those of an isolated bottlebrush in the same solvents. The characterization of bottlebrush conformations within the agglomerates is an important step in understanding the relationship between the bottlebrush architecture and material properties. An analysis of three distinct cutoff criteria to identify bottlebrushes belonging to the same cluster introduces a framework to identify both short-lived transient and long-lived agglomerates; the same approach could be further extended to characterize agglomerates of various macromolecules with complex architectures beyond the specific bottlebrush architecture considered herein.
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Kelly MT, Kent EW, Zhao B. Stepwise Conformational Transitions of Stimuli-Responsive Linear Ternary Heterografted Bottlebrush Polymers in Aqueous Solution. Macromolecules 2022. [DOI: 10.1021/acs.macromol.1c02662] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Michael T. Kelly
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Ethan W. Kent
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Bin Zhao
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
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Hu B, Carrillo JM, Collins L, Silmore KS, Keum J, Bonnesen PV, Wang Y, Retterer S, Kumar R, Lokitz BS. Modular Approach for the Synthesis of Bottlebrush Diblock Copolymers from Poly(Glycidyl Methacrylate)-block-Poly(Vinyldimethylazlactone) Backbones. Macromolecules 2022. [DOI: 10.1021/acs.macromol.1c01849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bin Hu
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Jan-Michael Carrillo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Liam Collins
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Kevin S. Silmore
- Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Jong Keum
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Peter V. Bonnesen
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Yangyang Wang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Scott Retterer
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Rajeev Kumar
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Bradley S. Lokitz
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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Lewoczko EM, Kelly MT, Kent EW, Zhao B. Effects of temperature on chaotropic anion-induced shape transitions of star molecular bottlebrushes with heterografted poly(ethylene oxide) and poly( N, N-dialkylaminoethyl methacrylate) side chains in acidic water. SOFT MATTER 2021; 17:6566-6579. [PMID: 34151928 DOI: 10.1039/d1sm00728a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
This article reports a study of the effects of temperature on chaotropic anion (CA)-induced star-globule shape transitions in acidic water of three-arm star bottlebrushes composed of heterografted poly(ethylene oxide) (PEO) and either poly(2-(N,N-dimethylamino)ethyl methacrylate) (PDMAEMA) or poly(2-(N,N-diethylamino)ethyl methacrylate) (PDEAEMA) (the brushes denoted as SMB-11 and -22, respectively). The brush polymers were synthesized by grafting alkyne-end-functionalized PEO and PDMAEMA or PDEAEMA onto an azide-bearing three-arm star backbone polymer using the copper(i)-catalyzed alkyne-azide cycloaddition reaction. Six anions were studied for their effects on the conformations of SMB-11 and -22 in acidic water: super CAs [Fe(CN)6]3- and [Fe(CN)6]4-, moderate CAs PF6- and ClO4-, weak CA I-, and for comparison, kosmotropic anion SO42-. At 25 °C, the addition of super and moderate CAs induced shape transitions of SMB-11 and -22 in pH 4.50 water from a starlike to a collapsed globular state stabilized by PEO side chains, which was driven by the ion pairing of protonated tertiary amine groups with CAs and the chaotropic effect. The shape changes occurred at much lower salt concentrations for super CAs than moderate CAs. Upon heating from near room temperature to 70 °C, the super CA-collapsed brushes remained in the globular state, whereas the moderate CA-collapsed brushes underwent reversible globule-to-star shape transitions. The transition temperature increased with increasing salt concentration and was found to be higher for SMB-22 at the same salt concentration, presumably caused by the chaotropic effect. In contrast, I- and SO42- had small effects on the conformations of SMB-11 and -22 at 25 °C in the studied salt concentration range, and only small and gradual size variations were observed upon heating to 70 °C. The results reported here may have potential uses in the design of stimuli-responsive systems for substance encapsulation and release.
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Affiliation(s)
- Evan M Lewoczko
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA.
| | - Michael T Kelly
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA.
| | - Ethan W Kent
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA.
| | - Bin Zhao
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA.
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Abstract
Bottlebrush polymers (BBPs), composed of relatively short polymeric side chains densely grafted on a polymer backbone, exhibit many unique characteristics and hold promise for a variety of applications. This Perspective focuses on environmentally induced shape-changing behavior of BBPs at interface and in solution, particularly worm/star-globule shape transitions. While BBPs with a single type of homopolymer or random copolymer side chains have been shown to undergo pronounced worm-to-globule shape changes in response to external stimuli, the collapsed brushes are unstable and prone to aggregation. By introducing a second, solvophilic polymer into the side chains, either as a distinct type of side chain or as the outer block of block copolymer side chains, the collapsed brushes not only are stabilized but also create unimolecular micellar nanostructures, which can be used for, e.g., encapsulation and delivery of substances. The current challenges in the design, synthesis, and characterization of stimuli-responsive shape-changing BBPs are discussed.
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Affiliation(s)
- Bin Zhao
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
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Lindsay RJ, Mansbach RA, Gnanakaran S, Shen T. Effects of pH on an IDP conformational ensemble explored by molecular dynamics simulation. Biophys Chem 2021; 271:106552. [PMID: 33581430 PMCID: PMC8024028 DOI: 10.1016/j.bpc.2021.106552] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/15/2021] [Accepted: 01/20/2021] [Indexed: 01/03/2023]
Abstract
The conformational ensemble of intrinsically disordered proteins, such as α-synuclein, are responsible for their function and malfunction. Misfolding of α-synuclein can lead to neurodegenerative diseases, and the ability to study their conformations and those of other intrinsically disordered proteins under varying physiological conditions can be crucial to understanding and preventing pathologies. In contrast to well-folded peptides, a consensus feature of IDPs is their low hydropathy and high charge, which makes their conformations sensitive to pH perturbation. We examine a prominent member of this subset of IDPs, α-synuclein, using a divide-and-conquer scheme that provides enhanced sampling of IDP structural ensembles. We constructed conformational ensembles of α-synuclein under neutral (pH ~ 7) and low (pH ~ 3) pH conditions and compared our results with available information obtained from smFRET, SAXS, and NMR studies. Specifically, α-synuclein has been found to in a more compact state at low pH conditions and the structural changes observed are consistent with those from experiments. We also characterize the conformational and dynamic differences between these ensembles and discussed the implication on promoting pathogenic fibril formation. We find that under low pH conditions, neutralization of negatively charged residues leads to compaction of the C-terminal portion of α-synuclein while internal reorganization allows α-synuclein to maintain its overall end-to-end distance. We also observe different levels of intra-protein interaction between three regions of α-synuclein at varying pH and a shift towards more hydrophilic interactions with decreasing pH.
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Affiliation(s)
- Richard J Lindsay
- UT- ORNL Graduate School of Genome Science and Technology, Knoxville, TN, 37996, USA.
| | - Rachael A Mansbach
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, NM, 87544, USA; Department of Physics, Concordia University, Montreal, Quebec, Canada.
| | - S Gnanakaran
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, NM, 87544, USA.
| | - Tongye Shen
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA.
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11
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Kent EW, Lewoczko EM, Zhao B. pH- and chaotropic anion-induced conformational changes of tertiary amine-containing binary heterografted star molecular bottlebrushes in aqueous solution. Polym Chem 2021. [DOI: 10.1039/d0py01466d] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Three-arm star-shaped, tertiary-amine-containing bottlebrushes exhibit star-globule shape transitions in response to pH changes and addition of sufficiently strong chaotropic anions.
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Affiliation(s)
- Ethan W. Kent
- Department of Chemistry
- University of Tennessee
- Knoxville
- USA
| | | | - Bin Zhao
- Department of Chemistry
- University of Tennessee
- Knoxville
- USA
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12
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Kent EW, Lewoczko EM, Zhao B. Effect of Buffer Anions on Pearl-Necklace Morphology of Tertiary Amine-Containing Binary Heterografted Linear Molecular Bottlebrushes in Acidic Aqueous Buffers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:13320-13330. [PMID: 33135416 DOI: 10.1021/acs.langmuir.0c02435] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Molecular bottlebrushes can exhibit a multitude of distinct conformations under different conditions, and precise control of their morphology can facilitate better use of such materials in potential applications. Herein, we report a study on the effect of buffer anions on the pearl-necklace morphology of linear binary heterografted molecular brushes consisting of pH-responsive poly(2-N,N-diethylamino)ethyl methacrylate) (PDEAEMA) with a pKa of 7.40 and thermoresponsive poly(ethoxydi(ethylene glycol) acrylate) (PDEGEA) with a lower critical solution temperature of 9 °C as side chains in various acidic aqueous buffers at 0 °C. The molecular brushes, denotated as BMB, were prepared by a grafting-to approach using copper(I)-catalyzed azide-alkyne cycloaddition reaction. Dynamic light scattering studies showed that the apparent hydrodynamic size of BMB in aqueous buffers with a pH of 6.50 at 1 °C decreased with increasing valency of buffer anions, from acetate anions with a charge of 1-, to phosphate anions carrying charges of 2- and 1- and citrate anions bearing charges of 3- and 2- at pH = 6.50. Atomic force microscopy revealed that BMB exhibited a pearl-necklace morphology from all three aqueous buffers with a pH of 6.50 when spin-cast at 0 °C. Analysis of AFM images showed that the average length of BMB and the number of beads per brush molecule decreased with increasing valency of buffer anions while the size and height of the beads increased. The pearl-necklace morphology of BMB was believed to be the result of microphase separation of the neutral PDEGEA and the charged PDEAEMA side chains along the brush backbone. Multivalent kosmotropic buffer anions formed bridging linkages between protonated tertiary amine moieties and thus "crosslinked" the charged PDEAEMA side chains, resulting in the shrinkage of BMB and enhanced microphase separation of two side chain polymers.
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Affiliation(s)
- Ethan W Kent
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Evan M Lewoczko
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Bin Zhao
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
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13
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Qi H, Liu X, Henn DM, Mei S, Staub MC, Zhao B, Li CY. Breaking translational symmetry via polymer chain overcrowding in molecular bottlebrush crystallization. Nat Commun 2020; 11:2152. [PMID: 32358513 PMCID: PMC7195396 DOI: 10.1038/s41467-020-15477-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 03/09/2020] [Indexed: 11/09/2022] Open
Abstract
One of the fundamental laws in crystallization is translational symmetry, which accounts for the profound shapes observed in natural mineral crystals and snowflakes. Herein, we report on the spontaneous formation of spherical hollow crystals with broken translational symmetry in crystalline molecular bottlebrush (mBB) polymers. The unique structure is named as mBB crystalsome (mBBC), highlighting its similarity to the classical molecular vesicles. Fluorescence resonance energy transfer (FRET) experiments show that the mBBC formation is driven by local chain overcrowding-induced asymmetric lamella bending, which is further confirmed by correlating crystalsome size with crystallization temperature and mBB's side chain grafting density. Our study unravels a new principle of spontaneous translational symmetry breaking, providing a general route towards designing versatile nanostructures.
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Affiliation(s)
- Hao Qi
- Department of Materials Science and Engineering, Drexel University, Philadelphia, PA, 19104, USA
| | - Xiting Liu
- Department of Materials Science and Engineering, Drexel University, Philadelphia, PA, 19104, USA
| | - Daniel M Henn
- Department of Chemistry, University of Tennessee, Knoxville, TN, 37996, USA
| | - Shan Mei
- Department of Materials Science and Engineering, Drexel University, Philadelphia, PA, 19104, USA
| | - Mark C Staub
- Department of Materials Science and Engineering, Drexel University, Philadelphia, PA, 19104, USA
| | - Bin Zhao
- Department of Chemistry, University of Tennessee, Knoxville, TN, 37996, USA.
| | - Christopher Y Li
- Department of Materials Science and Engineering, Drexel University, Philadelphia, PA, 19104, USA.
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Zhu X, Zhang J, Miao C, Li S, Zhao Y. Synthesis, thermoresponsivity and multi-tunable hierarchical self-assembly of multi-responsive (AB)mC miktobrush-coil terpolymers. Polym Chem 2020. [DOI: 10.1039/d0py00245c] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Stimuli-responsive miktobrush-coil terpolymers can exhibit unique physical properties and hierarchical self-assembly behaviors dependent on composition, concentration and external stimuli.
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Affiliation(s)
- Xiaomin Zhu
- Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
| | - Jian Zhang
- Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
| | - Cheng Miao
- Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
| | - Siyu Li
- Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
| | - Youliang Zhao
- Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application
- State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
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Ivanov IV, Meleshko TK, Kashina AV, Yakimansky AV. Amphiphilic multicomponent molecular brushes. RUSSIAN CHEMICAL REVIEWS 2019. [DOI: 10.1070/rcr4870] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Multicomponent molecular brushes containing amphiphilic polymer moieties are promising objects of research of macromolecular chemistry. The development of stimulus-responsive systems sensitive to changes in environmental parameters, based on the molecular brushes, opens up new possibilities for their applications in medicine, biochemistry and microelectronics. The review presents the current understanding of the structures of main types of amphiphilic multicomponent brushes, depending on the chemical nature and type of coupling of the backbone and side chains. The approaches to the controlled synthesis of multicomponent molecular brushes of different architecture are analyzed. Self-assembly processes of multicomponent molecular brushes in selective solvents are considered.
The bibliography includes 259 references.
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16
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Kent EW, Zhao B. Stimuli-Induced Star-Globule Shape Transitions of Dually Responsive Binary Heterografted Three-Arm Star Molecular Brushes in Aqueous Solution. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01446] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Ethan W. Kent
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Bin Zhao
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
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17
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Xiao Y, Tang C, Chen Y, Lang M. Dual stimuli-responsive polypeptide prepared by thiol-ene click reaction of poly(l-cysteine) and N, N-dimethylaminoethyl acrylate. Biopolymers 2019; 110:e23318. [PMID: 31274198 DOI: 10.1002/bip.23318] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 06/03/2019] [Accepted: 06/13/2019] [Indexed: 12/28/2022]
Abstract
Stimuli-responsive polymers that can undergo conformational changes with external triggers have enabled themselves as smart materials for various utilizations, among which biodegradability is of particular importance to be engineered for biomedical application. In this study, a thermo and pH dual responsive polypeptide (N, N-dimethylaminoethyl acrylate-modified poly(l-cysteine)) (PLC-g-DMAEA) was prepared by the combination of N-carboxyanhydride ring-open polymerization and thiol-ene click chemistry. The biodegradable poly(l-cysteine) (PLC) with pendant thiol groups provided an easily clickable backbone for postmodification, which was demonstrated by reacting with a well-known monomer of N, N-dimethylaminoethyl acrylate (DMAEA) to achieve both temperature and pH responsiveness. The irreversible thermo-response of PLC-g-DMAEA could be attributed to the ordered β-sheets formed upon heating, leading to the trapped side groups with poor water accessibility. Moreover, this copolymer precipitated at pH ranging from 7.5 to 9.7, but protonation of tertiary amine groups (pH < 7.5) and salt forming of masked thiol groups (pH > 9.7) rendered it soluble in water. Our results revealed that a ready available vinyl monomer could be easily clicked onto the biodegradable PLC and its stimuli responsiveness would be reserved. Moreover, the primary and secondary structures of PLC might influence the conformation, thus leading to the unique responsive behavior of the resulted copolymer.
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Affiliation(s)
- Yan Xiao
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, China
| | - Chenna Tang
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, China
| | - Yang Chen
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, China
| | - Meidong Lang
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, China
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