1
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Zhang Z, Li S, Wang H, Shan Y. The Effects of the Carrier and Ligand Spatial Conformation on RNA Nanodrug Cell Delivery. Anal Chem 2024. [PMID: 39096242 DOI: 10.1021/acs.analchem.4c02270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2024]
Abstract
Small interfering RNA (siRNA) highlights the immense therapeutic potential for cancer treatment. The major challenge in siRNA therapy is the effective RNA nanodrug delivery system, which is facilitated by the ligand and the carrier. In this study, we analyzed the binding specificity of linear RGD and circular RGD to αVβ3 integrins by mapping the morphology using super-resolution direct stochastic optical reconstruction microscopy. Meanwhile, the binding dynamics was investigated using single-molecule force spectroscopy. Then, the effects of the ligand and carrier on RNA nanodrug cell entry dynamic parameters were evaluated at the single particle level by the force tracing technique. Furthermore, the delivery efficiency of RNA nanodrugs was assessed using AFM-based nanoindentation at the single cell level. This report will provide valuable insights for rational design strategies aiming to achieve improved efficiency for nanodrug delivery systems.
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Affiliation(s)
- Zhuang Zhang
- School of Chemistry and Life Science, Advanced Institute of Materials Science, Changchun University of Technology, Changchun 130012, China
| | - Siying Li
- School of Chemistry and Life Science, Advanced Institute of Materials Science, Changchun University of Technology, Changchun 130012, China
| | - Hongda Wang
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Yuping Shan
- School of Chemistry and Life Science, Advanced Institute of Materials Science, Changchun University of Technology, Changchun 130012, China
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2
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Bettens T, Alonso M, Geerlings P, De Proft F. Mechanochemical Felkin-Anh Model: Achieving Forbidden Reaction Outcomes with Mechanical Force. J Org Chem 2023; 88:2046-2056. [PMID: 36735279 DOI: 10.1021/acs.joc.2c02318] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Anti-Felkin-Anh diastereoselectivity can be achieved for nucleophilic additions to α-chiral ketones upon stretching the ketone with a mechanical pulling force. Herein, a mechanochemical Felkin-Anh model is proposed for predicting the outcome of a nucleophilic addition to an α-chiral ketone. Essentially, the fully stretched chiral ketone has one substituent shielding each side of the carbonyl, in contrast to the Felkin-Anh model, in which free rotation around a bond is required to achieve the two rotamers of the ketone. Depending on the pulling scenario, either Felkin-Anh or anti-Felkin-Anh diastereoselectivity is obtained. The model is entirely based on the distance between the pulling points, which is maximized in the anti-periplanar arrangement. The major diastereomer is associated with the approach with the least steric interactions. The intuitive model is validated by means of mechanochemical density functional theory calculations. Importantly, the ketone is fully stretched in the sub 1 nN force regime, thus minimizing the risk of undesired homolytic bond rupture. Moreover, the mechanical force is not used for lowering the reaction barriers associated with the nucleophilic addition; instead, it is solely applied for locking the conformation of a molecule and provoking otherwise inaccessible reaction pathways on the force-modified potential energy surface.
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Affiliation(s)
- Tom Bettens
- Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050Brussels, Belgium
| | - Mercedes Alonso
- Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050Brussels, Belgium
| | - Paul Geerlings
- Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050Brussels, Belgium
| | - Frank De Proft
- Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050Brussels, Belgium
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3
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Jiang C, Liu Y, Wang L, Lu F. Interaction between Heavy Water and Single-Strand DNA: A SERS Study. Molecules 2022; 27:molecules27186023. [PMID: 36144761 PMCID: PMC9505314 DOI: 10.3390/molecules27186023] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 09/03/2022] [Accepted: 09/09/2022] [Indexed: 11/16/2022] Open
Abstract
The structure and function of biological macromolecules change due to intermolecular deuterium bond formation or deuterium substitution with environmental D2O. In this study, surface-enhanced Raman spectroscopy (SERS) was used to detect interaction sites between D2O and ssDNA and their action mechanisms. SERS peaks of ssDNA changed with increasing D2O proportions, and the site of action mainly involved A and G bases, whose number strengthened the interaction between sequences and D2O and hence the SERS peak intensities. Fixing the number of A and G bases prevented changes in their positions from significantly altering the map. We also identified the interaction between ssDNA sequences that easily formed a G-quadruplex structure and D2O. The amplitude of the SERS peak intensity change reflected the ssDNA structural stability and number of active sites. These findings are highly significant for exploring genetic exchanges and mutations and could be used to determine the stability and structural changes of biological macromolecules.
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Affiliation(s)
- Chengshun Jiang
- College of Pharmacy, Naval Medical University, Shanghai 200433, China
- College of Pharmacy, Fujian University of Traditional Chinese Medicine, Fuzhou 350122, China
| | - Yan Liu
- College of Pharmacy, Naval Medical University, Shanghai 200433, China
| | - Lianghua Wang
- College of Basic Medical Sciences, Naval Medical University, Shanghai 200433, China
| | - Feng Lu
- College of Pharmacy, Naval Medical University, Shanghai 200433, China
- College of Pharmacy, Fujian University of Traditional Chinese Medicine, Fuzhou 350122, China
- Shanghai Key Laboratory for Pharmaceutical Metabolite Research, Naval Medical University, Shanghai 200433, China
- Correspondence:
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4
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Chen Y, Mellot G, van Luijk D, Creton C, Sijbesma RP. Mechanochemical tools for polymer materials. Chem Soc Rev 2021; 50:4100-4140. [DOI: 10.1039/d0cs00940g] [Citation(s) in RCA: 112] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This review aims to provide a field guide for the implementation of mechanochemistry in synthetic polymers by summarizing the molecules, materials, and methods that have been developed in this field.
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Affiliation(s)
- Yinjun Chen
- Department of Chemical Engineering & Chemistry and Institute for Complex Molecular Systems
- Eindhoven University of Technology
- 5600 MB Eindhoven
- The Netherlands
| | - Gaëlle Mellot
- Laboratoire Sciences et Ingénierie de la Matière Molle
- ESPCI Paris
- PSL University
- Sorbonne Université
- CNRS
| | - Diederik van Luijk
- Department of Chemical Engineering & Chemistry and Institute for Complex Molecular Systems
- Eindhoven University of Technology
- 5600 MB Eindhoven
- The Netherlands
| | - Costantino Creton
- Laboratoire Sciences et Ingénierie de la Matière Molle
- ESPCI Paris
- PSL University
- Sorbonne Université
- CNRS
| | - Rint P. Sijbesma
- Department of Chemical Engineering & Chemistry and Institute for Complex Molecular Systems
- Eindhoven University of Technology
- 5600 MB Eindhoven
- The Netherlands
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5
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Traeger H, Kiebala DJ, Weder C, Schrettl S. From Molecules to Polymers-Harnessing Inter- and Intramolecular Interactions to Create Mechanochromic Materials. Macromol Rapid Commun 2020; 42:e2000573. [PMID: 33191595 DOI: 10.1002/marc.202000573] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/16/2020] [Indexed: 12/30/2022]
Abstract
The development of mechanophores as building blocks that serve as predefined weak linkages has enabled the creation of mechanoresponsive and mechanochromic polymer materials, which are interesting for a range of applications including the study of biological specimens or advanced security features. In typical mechanophores, covalent bonds are broken when polymers that contain these chemical motifs are exposed to mechanical forces, and changes of the optical properties upon bond scission can be harnessed as a signal that enables the detection of applied mechanical stresses and strains. Similar chromic effects upon mechanical deformation of polymers can also be achieved without relying on the scission of covalent bonds. The dissociation of motifs that feature directional noncovalent interactions, the disruption of aggregated molecules, and conformational changes in molecules or polymers constitute an attractive element for the design of mechanoresponsive and mechanochromic materials. In this article, it is reviewed how such alterations of molecules and polymers can be exploited for the development of mechanochromic materials that signal deformation without breaking covalent bonds. Recent illustrative examples are highlighted that showcase how the use of such mechanoresponsive motifs enables the visual mapping of stresses and damage in a reversible and highly sensitive manner.
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Affiliation(s)
- Hanna Traeger
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, Fribourg, CH-1700, Switzerland
| | - Derek J Kiebala
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, Fribourg, CH-1700, Switzerland
| | - Christoph Weder
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, Fribourg, CH-1700, Switzerland
| | - Stephen Schrettl
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, Fribourg, CH-1700, Switzerland
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6
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Hydrogen-bonded host-guest systems are stable in ionic liquids. Sci Rep 2020; 10:15414. [PMID: 32963260 PMCID: PMC7508985 DOI: 10.1038/s41598-020-71803-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 07/17/2020] [Indexed: 11/08/2022] Open
Abstract
We show that H-bonded host–guest systems associate in ionic liquids (ILs), pure salts with melting point below room temperature, in which dipole–dipole electrostatic interactions should be negligible in comparison with dipole-charge interactions. Binding constants (Ka) obtained from titrations of four H-bonded host–guest systems in two organic solvents and two ionic liquids yield smaller yet comparable Ka values in ionic liquids than in organic solvents. We also detect the association event using force spectroscopy, which confirms that the binding is not solely due to (de)solvation processes. Our results indicate that classic H-bonded host–guest supramolecular chemistry takes place in ILs. This implies that strong H-bonds are only moderately affected by surroundings composed entirely of charges, which can be interpreted as an indication that the balance of Coulombic to covalent forces in strong H-bonds is not tipped towards the former.
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7
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Bao Y, Luo Z, Cui S. Environment-dependent single-chain mechanics of synthetic polymers and biomacromolecules by atomic force microscopy-based single-molecule force spectroscopy and the implications for advanced polymer materials. Chem Soc Rev 2020; 49:2799-2827. [PMID: 32236171 DOI: 10.1039/c9cs00855a] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
"The Tao begets the One. One begets all things of the world." This quote from Tao Te Ching is still inspiring for scientists in chemistry and materials science: The "One" can refer to a single molecule. A macroscopic material is composed of numerous molecules. Although the relationship between the properties of the single molecule and macroscopic material is not well understood yet, it is expected that a deeper understanding of the single-chain mechanics of macromolecules will certainly facilitate the development of materials science. Atomic force microscopy-based single-molecule force spectroscopy (AFM-SMFS) has been exploited extensively as a powerful tool to study the single-chain behaviors of macromolecules. In this review, we summarize the recent advances in the emerging field of environment-dependent single-chain mechanics of synthetic polymers and biomacromolecules by means of AFM-SMFS. First, the single-chain inherent elasticities of several typical linear macromolecules are introduced, which are also confirmed by one of three polymer models with theoretical elasticities of the corresponding macromolecules obtained from quantum mechanical (QM) calculations. Then, the effects of the external environments on the single-chain mechanics of synthetic polymers and biomacromolecules are reviewed. Finally, the impacts of single-chain mechanics of macromolecules on the development of polymer science especially polymer materials are illustrated.
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Affiliation(s)
- Yu Bao
- Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China.
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8
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Bose A, Mal P. Mechanochemistry of supramolecules. Beilstein J Org Chem 2019; 15:881-900. [PMID: 31019581 PMCID: PMC6466741 DOI: 10.3762/bjoc.15.86] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Accepted: 03/22/2019] [Indexed: 12/21/2022] Open
Abstract
The urge to use alternative energy sources has gained significant attention in the eye of chemists in recent years. Solution-based traditional syntheses are extremely useful, although they are often associated with certain disadvantages like generation of waste as by-products, use of large quantities of solvents which causes environmental hazard, etc. Contrastingly, achieving syntheses through mechanochemical methods are generally time-saving, environmentally friendly and more economical. This review is written to shed some light on supramolecular chemistry and the synthesis of various supramolecules through mechanochemistry.
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Affiliation(s)
- Anima Bose
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), HBNI, Bhubaneswar, PO Bhimpur-Padanpur, Via Jatni, District Khurda, Odisha 752050, India
| | - Prasenjit Mal
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), HBNI, Bhubaneswar, PO Bhimpur-Padanpur, Via Jatni, District Khurda, Odisha 752050, India
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9
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Bowser BH, Craig SL. Empowering mechanochemistry with multi-mechanophore polymer architectures. Polym Chem 2018. [DOI: 10.1039/c8py00720a] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Multi-mechanophore polymers provide advantages in characterization and function relative to chain-centered, single mechanophore polymers.
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10
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Akbulatov S, Boulatov R. Experimental Polymer Mechanochemistry and its Interpretational Frameworks. Chemphyschem 2017; 18:1422-1450. [PMID: 28256793 DOI: 10.1002/cphc.201601354] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Indexed: 12/15/2022]
Abstract
Polymer mechanochemistry is an emerging field at the interface of chemistry, materials science, physics and engineering. It aims at understanding and exploiting unique reactivities of polymer chains confined to highly non-equilibrium stretched geometries by interactions with their surroundings. Macromolecular chains or their segments become stretched in bulk polymers under mechanical loads or when polymer solutions are sonicated or flow rapidly through abrupt contractions. An increasing amount of empirical data suggests that mechanochemical phenomena are widespread wherever polymers are used. In the past decade, empirical mechanochemistry has progressed enormously, from studying fragmentations of commodity polymers by simple backbone homolysis to demonstrations of self-strengthening and stress-reporting materials and mechanochemical cascades using purposefully designed monomers. This progress has not yet been matched by the development of conceptual frameworks within which to rationalize, systematize and generalize empirical mechanochemical observations. As a result, mechanistic and/or quantitative understanding of mechanochemical phenomena remains, with few exceptions, tentative. In this review we aim at systematizing reported macroscopic manifestations of polymer mechanochemistry, and critically assessing the interpretational framework that underlies their molecular rationalizations from a physical chemist's perspective. We propose a hierarchy of mechanochemical phenomena which may guide the development of multiscale models of mechanochemical reactivity to match the breadth and utility of the Eyring equation of chemical kinetics. We discuss the limitations of the approaches to quantifying and validating mechanochemical reactivity, with particular focus on sonicated polymer solutions, in order to identify outstanding questions that need to be solved for polymer mechanochemistry to become a rigorous, quantitative field. We conclude by proposing 7 problems whose solution may have a disproportionate impact on the development of polymer mechanochemistry.
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Affiliation(s)
- Sergey Akbulatov
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK
| | - Roman Boulatov
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK
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11
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He C, Li H. Staphylokinase Displays Surprisingly Low Mechanical Stability. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:1077-1083. [PMID: 28040904 DOI: 10.1021/acs.langmuir.6b04425] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Single-molecule force spectroscopy (SMFS) and molecular dynamics (MD) simulations have revealed that shear topology is an important structural feature for mechanically stable proteins. Proteins containing a β-grasp fold display the typical shear topology and are generally of significant mechanical stability. In an effort to experimentally identify mechanically strong proteins using single-molecule atomic force microscopy, we found that staphylokinase (SAK), which has a typical β-grasp fold and was predicted to be mechanically stable in coarse-grained MD simulations, displays surprisingly low mechanical stability. At a pulling speed of 400 nm/s, SAK unfolds at ∼60 pN, making it the mechanically weakest protein among the β-grasp fold proteins that have been characterized experimentally. In contrast, its structural homologous protein streptokinase β domain displays significant mechanical stability under the same experimental condition. Our results showed that the large malleability of native-state SAK is largely responsible for its low mechanical stability. The molecular origin of this large malleability of SAK remains unknown. Our results reveal a hidden complexity in protein mechanics and call for a detailed investigation into the molecular determinants of the protein mechanical malleability.
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Affiliation(s)
- Chengzhi He
- Department of Chemistry, University of British Columbia , Vancouver, BC V6T 1Z1, Canada
| | - Hongbin Li
- Department of Chemistry, University of British Columbia , Vancouver, BC V6T 1Z1, Canada
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12
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Luo Z, Zhang B, Qian HJ, Lu ZY, Cui S. Effect of the size of solvent molecules on the single-chain mechanics of poly(ethylene glycol): implications on a novel design of a molecular motor. NANOSCALE 2016; 8:17820-17827. [PMID: 27722448 DOI: 10.1039/c6nr05863a] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Excluded-volume (EV) interaction, also known as the EV effect, can drive the collapse of polymer chains in a polymer solution and promote the crystallization of polymer chains. Herein we report, for the first time, the effect of EV interaction on the single-chain mechanics of a polymer, poly(ethylene glycol) (PEG). By using AFM-based single-molecule force spectroscopy, the single-chain mechanics of a PEG chain has been detected in various nonpolar organic solvents with different molecule sizes. It is observed that the nonpolar solvents can be classified into two categories. In the small-sized organic solvents (e.g., tetrachloroethane and n-nonane), PEG presents its inherent elasticity, which is consistent with the theoretical single-chain elasticity from quantum mechanical calculations. However, in the middle-sized solvents (e.g., n-dodecane and n-hexadecane), the single-chain entropic elasticity of PEG is influenced by EV interactions noticeably, which indicates that the PEG chain tends to adopt a compact conformation under these conditions. To stretch a PEG chain from a free state to a fully extended state, more energy (1.54 kBT per repeating unit) is needed in small-sized organic solvents than in middle-sized organic solvents. It is expected that a partially stretched PEG chain would shrink to some extent when the solvent is changed from a middle-sized organic solvent to a small-sized one. Accordingly, a novel design of a PEG-based single-molecule motor that works with solvent stimuli is proposed.
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Affiliation(s)
- Zhonglong Luo
- Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China.
| | - Bo Zhang
- Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China.
| | - Hu-Jun Qian
- State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China
| | - Zhong-Yuan Lu
- State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China
| | - Shuxun Cui
- Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China.
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13
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Luo Z, Zhang A, Chen Y, Shen Z, Cui S. How Big Is Big Enough? Effect of Length and Shape of Side Chains on the Single-Chain Enthalpic Elasticity of a Macromolecule. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b00247] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Zhonglong Luo
- Key
Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China
| | - Afang Zhang
- Department
of Polymer Materials, College of Materials Science and Engineering, Shanghai University, Nanchen Road 333, Shanghai 200444, China
| | - Yongming Chen
- School
of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Zhihao Shen
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory of Polymer
Chemistry and Physics of Ministry of Education, Center for Soft Matter
Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Shuxun Cui
- Key
Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China
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14
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Tischer T, Gralla-Koser R, Trouillet V, Barner L, Barner-Kowollik C, Lee-Thedieck C. Direct Mapping of RAFT Controlled Macromolecular Growth on Surfaces via Single Molecule Force Spectroscopy. ACS Macro Lett 2016; 5:498-503. [PMID: 35607229 DOI: 10.1021/acsmacrolett.6b00106] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Single molecule force spectroscopy (SMFS) is employed to gain insight into reversible addition-fragmentation chain transfer (RAFT) polymerization processes with living characteristics on glass surfaces. Surface-initiated (SI)-RAFT was selected to grow poly(hydroxyethyl methacrylate) (PHEMA). After aminolysis of the RAFT chain termini, thiol moieties serve as anchoring points for the gold tip of an atomic force microscope. The results allow to directly monitor the macromolecular growth of the surface-initiated polymerization. The obtained SMFS-based molecular weight distribution data of the polymers present on the surface indicate that the RAFT chain extension proceeds linearly with time up to high conversions. The current study thus adds SMFS as a valuable tool for the investigation of SI-RAFT polymerizations.
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Affiliation(s)
| | | | - Vanessa Trouillet
- Institute
for Applied Materials (IAM), Karlsruhe Institute of Technology (KIT) and Karlsruhe Nano Micro Facility (KNMF), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | | | - Christopher Barner-Kowollik
- Preparative
Macromolecular Chemistry, Institut für Technische Chemie und
Polymerchemie, Karlsruhe Institute of Technology (KIT), Engesserstr. 18, 76131 Karlsruhe, Germany
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15
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Luo Z, Cheng B, Cui S. Effects of Water on the Single-Chain Elasticity of Poly(U) RNA. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:6107-6113. [PMID: 25989243 DOI: 10.1021/acs.langmuir.5b01313] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Water, the dominant component under the physiological condition, is a complicated solvent which greatly affects the properties of solute molecules. Here, we utilize atomic force microscope-based single-molecule force spectroscopy to study the influence of water on the single-molecule elasticity of an unstructured single-stranded RNA (poly(U)). In nonpolar solvents, RNA presents its inherent elasticity, which is consistent with the theoretical single-chain elasticity calculated by quantum mechanics calculations. In aqueous buffers, however, an additional energy of 1.88 kJ/mol·base is needed for the stretching of the ssRNA chain. This energy is consumed by the bound water rearrangement (Ew) during chain elongation. Further experimental results indicate that the Ew value is uncorrelated to the salt concentrations and stretching velocity. The results obtained in an 8 M guanidine·HCl solution provide more evidence that the bound water molecules around RNA give rise to the observed deviation between aqueous and nonaqueous environments. Compared to synthetic water-soluble polymers, the value of Ew of RNA is much lower. The weak interference of water is supposed to be the precondition for the RNA secondary structure to exist in aqueous solution.
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Affiliation(s)
- Zhonglong Luo
- Key Lab of Advanced Technologies of Materials, Ministry of Education of China, Southwest Jiaotong University, Chengdu 610031, China
| | - Bo Cheng
- Key Lab of Advanced Technologies of Materials, Ministry of Education of China, Southwest Jiaotong University, Chengdu 610031, China
| | - Shuxun Cui
- Key Lab of Advanced Technologies of Materials, Ministry of Education of China, Southwest Jiaotong University, Chengdu 610031, China
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