1
|
Song X, Man J, Qiu Y, Wang J, Liu J, Li R, Zhang Y, Li J, Li J, Chen Y. Design, preparation, and characterization of lubricating polymer brushes for biomedical applications. Acta Biomater 2024; 175:76-105. [PMID: 38128641 DOI: 10.1016/j.actbio.2023.12.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 11/21/2023] [Accepted: 12/14/2023] [Indexed: 12/23/2023]
Abstract
The lubrication modification of biomedical devices significantly enhances the functionality of implanted interventional medical devices, thereby providing additional benefits for patients. Polymer brush coating provides a convenient and efficient method for surface modification while ensuring the preservation of the substrate's original properties. The current research has focused on a "trial and error" method to finding polymer brushes with superior lubricity qualities, which is time-consuming and expensive, as obtaining effective and long-lasting lubricity properties for polymer brushes is difficult. This review summarizes recent research advances in the biomedical field in the design, material selection, preparation, and characterization of lubricating and antifouling polymer brushes, which follow the polymer brush development process. This review begins by examining various approaches to polymer brush design, including molecular dynamics simulation and machine learning, from the fundamentals of polymer brush lubrication. Recent advancements in polymer brush design are then synthesized and potential avenues for future research are explored. Emphasis is placed on the burgeoning field of zwitterionic polymer brushes, and highlighting the broad prospects of supramolecular polymer brushes based on host-guest interactions in the field of self-repairing polymer brush applications. The review culminates by providing a summary of methodologies for characterizing the structural and functional attributes of polymer brushes. It is believed that a development approach for polymer brushes based on "design-material selection-preparation-characterization" can be created, easing the challenge of creating polymer brushes with high-performance lubricating qualities and enabling the on-demand creation of coatings. STATEMENT OF SIGNIFICANCE: Biomedical devices have severe lubrication modification needs, and surface lubrication modification by polymer brush coating is currently the most promising means. However, the design and preparation of polymer brushes often involves "iterative testing" to find polymer brushes with excellent lubrication properties, which is both time-consuming and expensive. This review proposes a polymer brush development process based on the "design-material selection-preparation-characterization" strategy and summarizes recent research advances and trends in the design, material selection, preparation, and characterization of polymer brushes. This review will help polymer brush researchers by alleviating the challenges of creating polymer brushes with high-performance lubricity and promises to enable the on-demand construction of polymer brush lubrication coatings.
Collapse
Affiliation(s)
- Xinzhong Song
- Key Laboratory of High Efficiency and Clean Mechanicalanufacture of Ministry of Education, School of Mechanical Engineering, Shandong University, Jinan 250061, PR China; Key National Demonstration Center for Experimental Mechanical Engineering Education, Shandong University, Jinan 250061, PR China
| | - Jia Man
- Key Laboratory of High Efficiency and Clean Mechanicalanufacture of Ministry of Education, School of Mechanical Engineering, Shandong University, Jinan 250061, PR China; Key National Demonstration Center for Experimental Mechanical Engineering Education, Shandong University, Jinan 250061, PR China.
| | - Yinghua Qiu
- Key Laboratory of High Efficiency and Clean Mechanicalanufacture of Ministry of Education, School of Mechanical Engineering, Shandong University, Jinan 250061, PR China; Key National Demonstration Center for Experimental Mechanical Engineering Education, Shandong University, Jinan 250061, PR China
| | - Jiali Wang
- Qilu Hospital of Shandong University, Jinan 250012, PR China
| | - Jianing Liu
- Qilu Hospital of Shandong University, Jinan 250012, PR China
| | - Ruijian Li
- Qilu Hospital of Shandong University, Jinan 250012, PR China
| | - Yongqi Zhang
- Key Laboratory of High Efficiency and Clean Mechanicalanufacture of Ministry of Education, School of Mechanical Engineering, Shandong University, Jinan 250061, PR China; Key National Demonstration Center for Experimental Mechanical Engineering Education, Shandong University, Jinan 250061, PR China
| | - Jianyong Li
- Key Laboratory of High Efficiency and Clean Mechanicalanufacture of Ministry of Education, School of Mechanical Engineering, Shandong University, Jinan 250061, PR China; Key National Demonstration Center for Experimental Mechanical Engineering Education, Shandong University, Jinan 250061, PR China
| | - Jianfeng Li
- Key Laboratory of High Efficiency and Clean Mechanicalanufacture of Ministry of Education, School of Mechanical Engineering, Shandong University, Jinan 250061, PR China; Key National Demonstration Center for Experimental Mechanical Engineering Education, Shandong University, Jinan 250061, PR China
| | - Yuguo Chen
- Qilu Hospital of Shandong University, Jinan 250012, PR China
| |
Collapse
|
2
|
Popova TO, Borisov OV, Zhulina EB. Polyelectrolyte Brushes with Protein-Like Nanocolloids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:1232-1246. [PMID: 38176061 DOI: 10.1021/acs.langmuir.3c02556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
Electrostatic interaction of ampholytic nanocolloidal particles (NPs), which mimic globular proteins, with polyelectrolyte brushes is analyzed within mean-field Poisson-Boltzmann approximation. In accordance with experimental findings, the theory predicts that an electrostatic driving force for the particle uptake by the brush may emerge when the net charge of the particle in the buffer and the charge of the brush are of the same sign. The origin of this driving force is change in the ionization state of weak cationic and anionic groups on the NP surface provoked by interaction with the brush. In experimental systems, the ionic interactions are complemented by excluded-volume, hydrophobic, and other types of interactions that all together control NP uptake by or expulsion from the brush. Here, we focus on the NP-brush ionic interactions. It is demonstrated that deviation between the buffer pH and the NP isoelectric point, considered usually as the key control parameter, does not uniquely determine the insertion free energy patterns. The latter depends also on the proportion of cationic and anionic groups in the NPs and their specific ionization constants as well as on salt concentration in the buffer. The analysis of the free energy landscape proves that a local minimum in the free energy inside the brush appears, provided the NP charge reversal occurs upon insertion into the brush. This minimum corresponds either to a thermodynamically stable or to a metastable state, depending on the pH offset from the IEP and salt concentration, and is separated from the bulk of the solution by a free energy barrier. The latter, being fairly independent of salt concentration in height, may strongly impede the NP absorption kinetically even when it is thermodynamically favorable. Hence, change reversal is a necessary but insufficient condition for the uptake of the NPs by similarly charged polyelectrolyte brushes.
Collapse
Affiliation(s)
- Tatiana O Popova
- ITMO University, 197101 St. Petersburg, Russia
- Institute of Macromolecular Compounds of the Russian Academy of Sciences, 199004 St. Petersburg, Russia
| | - Oleg V Borisov
- ITMO University, 197101 St. Petersburg, Russia
- Institute of Macromolecular Compounds of the Russian Academy of Sciences, 199004 St. Petersburg, Russia
- Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux, CNRS, Université de Pau et des Pays de l'Adour UMR 5254, Pau 64053, France
| | - Ekaterina B Zhulina
- Institute of Macromolecular Compounds of the Russian Academy of Sciences, 199004 St. Petersburg, Russia
| |
Collapse
|
3
|
Milchev A, Petkov P. Concave polymer brushes inwardly grafted in spherical cavities. J Chem Phys 2023; 158:094903. [PMID: 36889952 DOI: 10.1063/5.0141450] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
The structure and scaling properties of inwardly curved polymer brushes, tethered under good solvent conditions to the inner surface of spherical shells such as membranes and vesicles, are studied by extensive molecular dynamics simulations and compared with earlier scaling and self-consistent field theory predictions for different molecular weights of the polymer chains N and grafting densities σg in the case of strong surface curvature, R-1. We examine the variation of the critical radius R*(σg), separating the regimes of weak concave brushes and compressed brushes, predicted earlier by Manghi et al. [Eur. Phys. J. E 5, 519-530 (2001)], as well as various structural properties such as the radial monomer- and chain-end density profiles, orientation of bonds, and brush thickness. The impact of chain stiffness, κ, on concave brush conformations is briefly considered as well. Eventually, we present the radial profiles of the local pressure normal, PN, and tangential, PT, to the grafting surface, and the surface tension γ(σg), for soft and rigid brushes, and find a new scaling relationship PN(R)∝σg 4, independent of the degree of chain stiffness.
Collapse
Affiliation(s)
- Andrey Milchev
- Institute of Physical Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
| | - Peicho Petkov
- Sofia University St. Kliment Ohridski, Faculty of Physics, Sofia, Bulgaria
| |
Collapse
|
4
|
Hegaard F, Biro R, Ehtiati K, Thormann E. Ion-Specific Antipolyelectrolyte Effect on the Swelling Behavior of Polyzwitterionic Layers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:1456-1464. [PMID: 36656651 DOI: 10.1021/acs.langmuir.2c02798] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
In this study, we systematically investigate the interactions between mobile ions generated from added salts and immobile charges within a sulfobetaine-based polyzwitterionic film in the presence of five salts (KCl, KBr, KSCN, LiCl, and CsCl). The sulfobetaine groups contain quaternary alkylammonium and sulfonate groups, giving the positive and negative charges. The swelling of the zwitterionic film in the presence of different salts is compared with the swelling behavior of a polycationic or polyanionic film containing the same charged groups. For such a comparative study, we design cross-linked terpolymer films with similar thicknesses, cross-link densities, and charge fractions, but with varying charged moieties. While the addition of salt in general leads to a collapse of both cationic and anionic films, the presence of specific types of mobile anions (Cl-, Br-, and SCN-) considerably influences the swelling behavior of polycationic films. We attribute this observation to a different degree of ion-pair formations between the different types of anionic counterions and the immobile cationic quaternary alkylammonium groups in the films where highly polarizable counterions such as SCN- lead to a high degree of ion pairing and less polarizable counterions, such as Cl-, cause a low degree of ion pairing. Conversely, we do not observe any substantial effect of varying the type of cationic counterions (K+, Li+, and Cs+), which we assign to the lack of ion pairing between the weakly polarizable cations and the immobile anionic sulfonate groups in the films. In addition, we observe that the zwitterionic films swell with increasing ionic strength and the degree of swelling is anion dependent, which is in agreement with previous reports on the "antipolyelectrolyte effect". Herein, we explain this ion-specific swelling behavior with the different cation and anion abilities to form ion pairs with quaternary alkylammonium and sulfonate in the sulfobetaine groups.
Collapse
Affiliation(s)
- Frederik Hegaard
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Robert Biro
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Koosha Ehtiati
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Esben Thormann
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| |
Collapse
|
5
|
Abstract
I review experimental developments in the growth and application of surface-grafted weak polyelectrolytes (brushes), concentrating on their surface, tribological, and adhesive and bioadhesive properties, and their role as actuators.
Collapse
Affiliation(s)
- Mark Geoghegan
- School of Engineering, Newcastle University, Merz Court, Newcastle-upon-Tyne NE1 7RU, UK.
| |
Collapse
|
6
|
Zhang BY, Luo HN, Zhang W, Liu Y. Research progress in self-oscillating polymer brushes. RSC Adv 2022; 12:1366-1374. [PMID: 35425176 PMCID: PMC8979042 DOI: 10.1039/d1ra07374e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 12/22/2021] [Indexed: 12/02/2022] Open
Abstract
Polymer brushes possess unique changes in physical and chemical properties when they are exposed to external stimuli and have a wide range of applications. Self-oscillating polymers are anchored on surfaces of certain materials and are coupled with some self-oscillating reactions (with the Belousov–Zhabotinsky (BZ) reaction as an example) to form self-oscillating polymer brushes. As an independent field of stimulus response functional surface research, the development of new intelligent bionic materials has good potential. This article reviews the oscillation mechanisms of self-oscillating polymer brushes and their classifications. First, the oscillation mechanisms of self-oscillating polymer brushes are introduced. Second, the research progress in self-oscillating polymers is discussed in terms of the type of self-oscillation reactions. Finally, possible future developments of self-oscillating polymer brushes are prospected. Polymer brushes possess unique changes in physical and chemical properties when they are exposed to external stimuli and have a wide range of applications.![]()
Collapse
Affiliation(s)
- Bao-Ying Zhang
- School of Chemical Engineering, China University of Mining and Technology Xuzhou Jiangsu 221116 China .,School of Chemistry, Chemical Engineering and Materials Science, Zaozhuang University Zaozhuang Shandong 277160 China
| | - Hai-Nan Luo
- School of Chemistry, Chemical Engineering and Materials Science, Zaozhuang University Zaozhuang Shandong 277160 China
| | - Wei Zhang
- School of Chemistry, Chemical Engineering and Materials Science, Zaozhuang University Zaozhuang Shandong 277160 China
| | - Yang Liu
- School of Chemistry, Chemical Engineering and Materials Science, Zaozhuang University Zaozhuang Shandong 277160 China
| |
Collapse
|
7
|
Polymer Brush in a Nanopore: Effects of Solvent Strength and Macromolecular Architecture Studied by Self-Consistent Field and Scaling Theory. Polymers (Basel) 2021; 13:polym13223929. [PMID: 34833228 PMCID: PMC8618684 DOI: 10.3390/polym13223929] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/06/2021] [Accepted: 11/08/2021] [Indexed: 12/02/2022] Open
Abstract
To study conformational transition occuring upon inferior solvent strength in a brush formed by linear or dendritically branched macromolecules tethered to the inner surface of cylindrical or planar (slit-like) pore, a self-consistent field analytical approach is employed. Variations in the internal brush structure as a function of variable solvent strength and pore radius, and the onset of formation of a hollow channel in the pore center are analysed. The predictions of analytical theory are supported and complemented by numerical modelling by a self-consistent field Scheutjens–Fleer method. Scaling arguments are used to study microphase segregation under poor solvent conditions leading to formation of a laterally and longitudinally patterned structure in planar and cylindrical pores, respectively, and the effects of confinement on "octopus-like" clusters in the pores of different geometries.
Collapse
|
8
|
Flemming P, Münch AS, Fery A, Uhlmann P. Constrained thermoresponsive polymers - new insights into fundamentals and applications. Beilstein J Org Chem 2021; 17:2123-2163. [PMID: 34476018 PMCID: PMC8381851 DOI: 10.3762/bjoc.17.138] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 08/10/2021] [Indexed: 12/15/2022] Open
Abstract
In the last decades, numerous stimuli-responsive polymers have been developed and investigated regarding their switching properties. In particular, thermoresponsive polymers, which form a miscibility gap with the ambient solvent with a lower or upper critical demixing point depending on the temperature, have been intensively studied in solution. For the application of such polymers in novel sensors, drug delivery systems or as multifunctional coatings, they typically have to be transferred into specific arrangements, such as micelles, polymer films or grafted nanoparticles. However, it turns out that the thermodynamic concept for the phase transition of free polymer chains fails, when thermoresponsive polymers are assembled into such sterically confined architectures. Whereas many published studies focus on synthetic aspects as well as individual applications of thermoresponsive polymers, the underlying structure-property relationships governing the thermoresponse of sterically constrained assemblies, are still poorly understood. Furthermore, the clear majority of publications deals with polymers that exhibit a lower critical solution temperature (LCST) behavior, with PNIPAAM as their main representative. In contrast, for polymer arrangements with an upper critical solution temperature (UCST), there is only limited knowledge about preparation, application and precise physical understanding of the phase transition. This review article provides an overview about the current knowledge of thermoresponsive polymers with limited mobility focusing on UCST behavior and the possibilities for influencing their thermoresponsive switching characteristics. It comprises star polymers, micelles as well as polymer chains grafted to flat substrates and particulate inorganic surfaces. The elaboration of the physicochemical interplay between the architecture of the polymer assembly and the resulting thermoresponsive switching behavior will be in the foreground of this consideration.
Collapse
Affiliation(s)
- Patricia Flemming
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
- Technische Universität Dresden, 01062 Dresden, Germany
| | - Alexander S Münch
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
| | - Andreas Fery
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
- Technische Universität Dresden, 01062 Dresden, Germany
| | - Petra Uhlmann
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
- University of Nebraska-Lincoln, NE 68588, Lincoln, USA
| |
Collapse
|
9
|
Chen N, Davydovich O, McConnell C, Sidorenko A, Moore PB. Densely Packed Tethered Polymer Nanoislands: A Simulation Study. Polymers (Basel) 2021; 13:polym13152570. [PMID: 34372173 PMCID: PMC8348327 DOI: 10.3390/polym13152570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/22/2021] [Accepted: 07/22/2021] [Indexed: 11/29/2022] Open
Abstract
COordinated Responsive Arrays of Surface-Linked polymer islands (CORALS) allow for the creation of molecular surfaces with novel and switchable properties. Critical components of CORALs are the uniformly distributed islands of densely grafted polymer chains (nanoislands) separated by regions of bare surface. The grafting footprint and separation distances of nanoislands are comparable to that of the constituent polymer chains themselves. Herein, we characterize the structural features of the nanoislands and semiflexible polymers within to better understand this critical constituent of CORALs. We observe different characteristics of grafted semiflexible polymers depending on the polymer island’s size and distance from the center of the island. Specifically, the characteristics of the chains at the island periphery are similar to isolated tethered polymer chains (full flexible chains), while chains in the center of the island experience the neighbor effect such as chains in the classic polymer brush. Chains close to the edge of the islands exhibit unique structural features between these two regimes. These results can be used in the rational design of CORALs with specific interfacial characteristics and predictable responses to external stimuli. It is hoped that this the discussion of the different morphologies of the polymers as a function of distance from the edge of the polymer will find applications in a wide variety of systems.
Collapse
Affiliation(s)
- Nicolas Chen
- Department of Chemistry & Biochemistry, University of the Sciences in Philadelphia, Philadelphia, PA 19104, USA; (N.C.); (C.M.); (A.S.)
| | - Oleg Davydovich
- 2720 Beckman Institute, 405 North Mathews Avenue, Urbana, IL 61801, USA;
| | - Caitlyn McConnell
- Department of Chemistry & Biochemistry, University of the Sciences in Philadelphia, Philadelphia, PA 19104, USA; (N.C.); (C.M.); (A.S.)
| | - Alexander Sidorenko
- Department of Chemistry & Biochemistry, University of the Sciences in Philadelphia, Philadelphia, PA 19104, USA; (N.C.); (C.M.); (A.S.)
| | - Preston B. Moore
- Department of Chemistry & Biochemistry, University of the Sciences in Philadelphia, Philadelphia, PA 19104, USA; (N.C.); (C.M.); (A.S.)
- Correspondence:
| |
Collapse
|
10
|
Ehtiati K, Z. Moghaddam S, Daugaard AE, Thormann E. Crucial Nonelectrostatic Effects on Polyelectrolyte Brush Behavior. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c02526] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Koosha Ehtiati
- Department of Chemistry, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
| | - Saeed Z. Moghaddam
- Department of Chemistry, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
| | - Anders E. Daugaard
- Danish Polymer Center, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
| | - Esben Thormann
- Department of Chemistry, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
| |
Collapse
|
11
|
Kandhasamy DM, Selvaraju C, Dharuman V. Structure and dynamics of poly(methacrylic acid) and its interpolymer complex probed by covalently bound rhodamine-123. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 248:119166. [PMID: 33310609 DOI: 10.1016/j.saa.2020.119166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 10/19/2020] [Accepted: 10/28/2020] [Indexed: 06/12/2023]
Abstract
The dynamics and structural characteristics of polymethacrylic acid bound rhodamine-123 (PMAA-R123) and its interpolymer complex formed through hydrogen bonding between the monomeric units with poly(vinylpyrrolidone) were investigated using single molecular fluorescence studies. The time resolved fluorescence anisotropy decay of PMAA-R123 under acidic pH exhibits an associated anisotropy decay behavior characteristic of two different environments experienced by the fluorophore with one shorter and another longer rotational correlation time. The anisotropy decay retains normal bi-exponential behavior under neutral pH. Fluorescence correlation spectroscopic investigation reveals that the attached fluorophore undergoes hydrolysis under basic condition which results in the release of the fluorophore from the polymer backbone. Shrinkage in the hydrodynamic radius of PMAA is observed on addition of the complementary polymer PVP which is attributed to the formation compact solubilized nanoparticle like aggregates. The size of particle further decreases on the addition of NaCl. The detailed results show that these complexes have potential for use as drug-delivery system under physiological conditions.
Collapse
Affiliation(s)
| | - Chellappan Selvaraju
- National Centre for Ultrafast Processes, University of Madras, Sekkizhar Campus, Taramani, Chennai 600113, India
| | - Venkataraman Dharuman
- Department of Bioelectronics and Biosensors, Alagappa University, Karaikudi 630003, India
| |
Collapse
|
12
|
Boyd H, Gonzalez-Martinez JF, Welbourn RJL, Gutfreund P, Klechikov A, Robertsson C, Wickström C, Arnebrant T, Barker R, Sotres J. A comparison between the structures of reconstituted salivary pellicles and oral mucin (MUC5B) films. J Colloid Interface Sci 2020; 584:660-668. [PMID: 33198975 DOI: 10.1016/j.jcis.2020.10.124] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 10/06/2020] [Accepted: 10/27/2020] [Indexed: 01/01/2023]
Abstract
HYPOTHESIS Salivary pellicles i.e., thin films formed upon selective adsorption of saliva, protect oral surfaces against chemical and mechanical insults. Pellicles are also excellent aqueous lubricants. It is generally accepted that reconstituted pellicles have a two-layer structure, where the outer layer is mainly composed of MUC5B mucins. We hypothesized that by comparing the effect of ionic strength on reconstituted pellicles and MUC5B films we could gain further insight into the pellicle structure. EXPERIMENTS Salivary pellicles and MUC5B films reconstituted on solid surfaces were investigated at different ionic strengths by Force Spectroscopy, Quartz Crystal Microbalance with Dissipation, Null Ellipsometry and Neutron Reflectometry. FINDINGS Our results support the two-layer structure for reconstituted salivary pellicles. The outer layer swelled when ionic strength decreased, indicating a weak polyelectrolyte behavior. While initially the MUC5B films exhibited a similar tendency, this was followed by a drastic collapse indicating an interaction between exposed hydrophobic domains. This suggests that mucins in the pellicle outer layer form complexes with other salivary components that prevent this interaction. Lowering ionic strength below physiological values also led to a partial removal of the pellicle inner layer. Overall, our results highlight the importance that the interactions of mucins with other pellicle components play on their structure.
Collapse
Affiliation(s)
- Hannah Boyd
- Department of Biomedical Science & Biofilms-Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden.
| | - Juan F Gonzalez-Martinez
- Department of Biomedical Science & Biofilms-Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden
| | - Rebecca J L Welbourn
- ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, UK
| | - Philipp Gutfreund
- Institut Laue Langevin, 71 avenue des Martyrs, Grenoble 38000, France
| | - Alexey Klechikov
- Institut Laue Langevin, 71 avenue des Martyrs, Grenoble 38000, France; Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden
| | - Carolina Robertsson
- Department of Oral Biology and Pathology & Biofilms-Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden
| | - Claes Wickström
- Department of Oral Biology and Pathology & Biofilms-Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden
| | - Thomas Arnebrant
- Department of Biomedical Science & Biofilms-Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden
| | - Robert Barker
- School of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH, UK
| | - Javier Sotres
- Department of Biomedical Science & Biofilms-Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden.
| |
Collapse
|
13
|
Okrugin BM, Richter RP, Leermakers FAM, Neelov IM, Zhulina EB, Borisov OV. Electroresponsive Polyelectrolyte Brushes Studied by Self-Consistent Field Theory. Polymers (Basel) 2020; 12:polym12040898. [PMID: 32295011 PMCID: PMC7240567 DOI: 10.3390/polym12040898] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 04/06/2020] [Accepted: 04/07/2020] [Indexed: 11/16/2022] Open
Abstract
End-grafting of polyelectrolyte chains to conducting substrates offers an opportunity to fabricate electro-responsive surfaces capable of changing their physical/chemical properties (adhesion, wettability) in response to applied electrical voltage. We use a self-consistent field numerical approach to compare the equilibrium properties of tethered strong and weak (pH-sensitive) polyelectrolytes to applied electrical field in both salt-free and salt-containing solutions. We demonstrate that both strong and weak polyelectrolyte brushes exhibit segregation of polyions in two populations if the surface is oppositely charged with respect to the brush. This segregation gives rise to complex patterns in the dependence of the brush thickness on salt concentration. We demonstrate that adjustable ionization of weak polyelectrolytes weakens their conformational response in terms of the dependence of brush thickness on the amplitude of the applied voltage.
Collapse
Affiliation(s)
- Boris M. Okrugin
- CIC biomaGUNE, Biosurface Lab, Paseo Miramon 182, 20014 San Sebastian, Spain; (B.M.O.); (R.P.R.)
- Institut des Sciences Analytiques et de Physico-Chimie pour l’Environnement et les Matériaux, UMR 5254 CNRS UPPA, 64053 Pau, France
| | - Ralf P. Richter
- CIC biomaGUNE, Biosurface Lab, Paseo Miramon 182, 20014 San Sebastian, Spain; (B.M.O.); (R.P.R.)
- School of Biomedical Sciences, Faculty of Biological Sciences, School of Physics and Astronomy, Faculty of Engineering and Physical Sciences, Astbury Centre for Structural Molecular Biology, and Bragg Center for Materials Research, University of Leeds, Leeds LS2 9JT, UK
| | - Frans A. M. Leermakers
- Physical Chemistry and Soft Matter, Wageningen University, 6703 NB Wageningen, The Netherlands;
| | - Igor M. Neelov
- St. Petersburg National University of Informational Technologies, Mechanics and Optics, 197101 St.Petersburg, Russia; (I.M.N.); (E.B.Z.)
| | - Ekaterina B. Zhulina
- St. Petersburg National University of Informational Technologies, Mechanics and Optics, 197101 St.Petersburg, Russia; (I.M.N.); (E.B.Z.)
- Institute of Macromolecular Compounds of the Russian Academy of Sciences, 199004 St. Petersburg, Russia
| | - Oleg V. Borisov
- Institut des Sciences Analytiques et de Physico-Chimie pour l’Environnement et les Matériaux, UMR 5254 CNRS UPPA, 64053 Pau, France
- St. Petersburg National University of Informational Technologies, Mechanics and Optics, 197101 St.Petersburg, Russia; (I.M.N.); (E.B.Z.)
- Institute of Macromolecular Compounds of the Russian Academy of Sciences, 199004 St. Petersburg, Russia
- Correspondence:
| |
Collapse
|
14
|
Sudre G, Siband E, Gallas B, Cousin F, Hourdet D, Tran Y. Responsive Adsorption of N-Isopropylacrylamide Based Copolymers on Polymer Brushes. Polymers (Basel) 2020; 12:polym12010153. [PMID: 31936092 PMCID: PMC7022643 DOI: 10.3390/polym12010153] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 01/01/2020] [Accepted: 01/02/2020] [Indexed: 01/12/2023] Open
Abstract
We investigate the adsorption of pH- or temperature-responsive polymer systems by ellipsometry and neutron reflectivity. To this end, temperature-responsive poly (N-isopropylacrylamide) (PNIPAM) brushes and pH-responsive poly (acrylic acid) (PAA) brushes have been prepared using the "grafting onto" method to investigate the adsorption process of polymers and its reversibility under controlled environment. To that purpose, macromolecular brushes were designed with various chain lengths and a wide range of grafting density. Below the transition temperature (LCST), the characterization of PNIPAM brushes by neutron reflectivity shows that the swelling behavior of brushes is in good agreement with the scaling models before they collapse above the LCST. The reversible adsorption on PNIPAM brushes was carried out with linear copolymers of N-isopropylacrylamide and acrylic acid, P(NIPAM-co-AA). While these copolymers remain fully soluble in water over the whole range of temperature investigated, a quantitative adsorption driven by solvophobic interactions was shown to proceed only above the LCST of the brush and to be totally reversible upon cooling. Similarly, the pH-responsive adsorption driven by electrostatic interactions on PAA brushes was studied with copolymers of NIPAM and N,N-dimethylaminopropylmethacrylamide, P(NIPAM-co-MADAP). In this case, the adsorption of weak polycations was shown to increase with the ionization of the PAA brush with interactions mainly located in the upper part of the brush at pH 7 and more deeply adsorbed within the brush at pH 9.
Collapse
Affiliation(s)
- Guillaume Sudre
- Ingénierie des Matériaux Polymères, Université Claude Bernard Lyon 1, Université de Lyon, CNRS UMR 5223, 69100 Villeurbanne, France
- Correspondence: (G.S.); (Y.T.)
| | - Elodie Siband
- Soft Matter Sciences and Engineering, ESPCI Paris, PSL Université, Sorbonne Université, CNRS, 10 rue Vauquelin, F-75005 Paris, France; (E.S.); (D.H.)
| | - Bruno Gallas
- Sorbonne Université, CNRS-UMR 7588, Institut des NanoSciences de Paris, INSP, 4 place Jussieu, F-75005 Paris, France;
| | - Fabrice Cousin
- Laboratoire Léon Brillouin, Université Paris-Saclay, CEA-CNRS, Saclay, 91191 Gif-sur-Yvette CEDEX, France;
| | - Dominique Hourdet
- Soft Matter Sciences and Engineering, ESPCI Paris, PSL Université, Sorbonne Université, CNRS, 10 rue Vauquelin, F-75005 Paris, France; (E.S.); (D.H.)
| | - Yvette Tran
- Soft Matter Sciences and Engineering, ESPCI Paris, PSL Université, Sorbonne Université, CNRS, 10 rue Vauquelin, F-75005 Paris, France; (E.S.); (D.H.)
- Correspondence: (G.S.); (Y.T.)
| |
Collapse
|
15
|
Lebedeva IO, Shavykin OV, Neelov IM, Zhulina EB, Leermakers FAM, Borisov OV. Non-linear elasticity effects and stratification in brushes of branched polyelectrolytes. J Chem Phys 2019; 151:214902. [PMID: 31822102 DOI: 10.1063/1.5130580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Brushes formed by arm-tethered starlike polyelectrolytes may exhibit internal segregation into weakly and strongly extended populations (stratified two-layer structure) when strong ionic intermolecular repulsions induce stretching of the tethers up to the limit of their extensibility. We propose an approximate Poisson-Boltzmann theory for analysis of the structure of the stratified brush and compare it with results of numerical self-consistent field modeling. Both analytical and numerical models point to the formation of a narrow cloud of counterions (internal double electrical layer) localized inside a stratified brush at the boundary between the layers.
Collapse
Affiliation(s)
- Inna O Lebedeva
- Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et Les Matériaux, UMR 5254 CNRS UPPA, 64053 Pau, France
| | - Oleg V Shavykin
- St. Petersburg National University of Informational Technologies, Mechanics and Optics, 197101 St. Petersburg, Russia
| | - Igor M Neelov
- St. Petersburg National University of Informational Technologies, Mechanics and Optics, 197101 St. Petersburg, Russia
| | - Ekaterina B Zhulina
- St. Petersburg National University of Informational Technologies, Mechanics and Optics, 197101 St. Petersburg, Russia
| | - Frans A M Leermakers
- Physical Chemistry and Soft Matter, Wageningen University, 6703 HB Wageningen, The Netherlands
| | - Oleg V Borisov
- Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et Les Matériaux, UMR 5254 CNRS UPPA, 64053 Pau, France
| |
Collapse
|
16
|
A grazing incidence neutron spin echo study of near surface dynamics in p(MEO2MA-co-OEGMA) copolymer brushes. Colloid Polym Sci 2018. [DOI: 10.1007/s00396-018-4421-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
17
|
Xu X, Billing M, Ruths M, Klok HA, Yu J. Structure and Functionality of Polyelectrolyte Brushes: A Surface Force Perspective. Chem Asian J 2018; 13:3411-3436. [PMID: 30080310 DOI: 10.1002/asia.201800920] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Indexed: 11/11/2022]
Abstract
The unique functionality of polyelectrolyte brushes depends on several types of specific interactions, including solvent structure effects, hydrophobic forces, electrostatic interactions, and specific ion interactions. Subtle variations in the solution environment can lead to conformational and surface structural changes of the polyelectrolyte brushes, which are mainly discussed from a surface-interaction perspective in this Focus Review. A brief overview is given of recent theoretical and experimental progress in the structure of polyelectrolyte brushes in various environments. Two important techniques for surface-force measurements are described, the surface forces apparatus (SFA) and atomic force microscopy (AFM), and some recent results on polyelectrolyte brushes are shown. Lastly, this Focus Review highlights the use of these surface-grafted polyelectrolyte brushes in the creation of functional surfaces for various applications, including nonfouling surfaces, boundary lubricants, and stimuli-responsive surfaces.
Collapse
Affiliation(s)
- Xin Xu
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore.,Department of Chemistry, University of Massachusetts Lowell, Lowell, MA, 01854, USA
| | - Mark Billing
- Institut des Matériaux et Institut des Sciences et Ingénierie Chimiques, Laboratoire des Polymères, École Polytechnique Fédérale de Lausanne (EPFL), Bâtiment MXD, Station 12, CH-1015, Lausanne, Switzerland
| | - Marina Ruths
- Department of Chemistry, University of Massachusetts Lowell, Lowell, MA, 01854, USA
| | - Harm-Anton Klok
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore.,Institut des Matériaux et Institut des Sciences et Ingénierie Chimiques, Laboratoire des Polymères, École Polytechnique Fédérale de Lausanne (EPFL), Bâtiment MXD, Station 12, CH-1015, Lausanne, Switzerland
| | - Jing Yu
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| |
Collapse
|
18
|
Microencapsulated self-healing polymers via controlled, surface initiated atom transfer radical polymerization from the surface of graphene oxide. JOURNAL OF POLYMER RESEARCH 2018. [DOI: 10.1007/s10965-018-1603-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
19
|
Okrugin BM, Richter RP, Leermakers FAM, Neelov IM, Borisov OV, Zhulina EB. Structure and properties of polydisperse polyelectrolyte brushes studied by self-consistent field theory. SOFT MATTER 2018; 14:6230-6242. [PMID: 30027975 DOI: 10.1039/c8sm01138a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Two complementary self-consistent field theoretical approaches are used to analyze the equilibrium structure of binary and ternary brushes of polyions with different degrees of polymerization. Stratification in binary brushes is predicted: the shorter chains are entirely embedded in the proximal sublayer depleted of end-points of longer chains while the peripheral sublayer contains exclusively terminal segments of longer chains. The boundary between sublayers is enriched with counterions that neutralize the residual charge of the proximal sublayer. These analytical predictions for binary brushes are confirmed and extended to ternary brushes using the numerical Scheutjens-Fleer approach.
Collapse
Affiliation(s)
- Boris M Okrugin
- CIC biomaGUNE, Biosurface Lab, Paseo Miramon 182, 20014 San Sebastian, Spain
| | | | | | | | | | | |
Collapse
|
20
|
Li L, Cao Q, Zuo C. Effect of Counterion Valence on Conformational Behavior of Spherical Polyelectrolyte Brushes Confined between Two Parallel Walls. Polymers (Basel) 2018; 10:E363. [PMID: 30966398 PMCID: PMC6415134 DOI: 10.3390/polym10040363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 03/21/2018] [Accepted: 03/22/2018] [Indexed: 11/16/2022] Open
Abstract
We study the conformational behavior of spherical polyelectrolyte brushes in the presence of monovalent and trivalent counterions in a confined environment. The confinement is exerted by two parallel walls on the brushes. The enhancement of the confinement induces the extension of grafted chains. For the monovalent case, the increase of the charge fraction leads to extended brush conformation for different slit width (distance between two walls) but collapsed brush in the presence of trivalent counterions is observed. The confinement does not affect electrostatic correlation between trivalent counterions and charged monomers. However, it was found that narrow slit width contributes to stronger electrostatic correlation for the monovalent case. This is because more monovalent counterions are inside the brush at strong confinement, but almost all trivalent counterions are trapped into the brush independently of the slit width. The diffusion of counterions under the confinement is related to the electrostatic correlation. Our simulations also reveal that the brush thickness depends on the slit width nonlinearly.
Collapse
Affiliation(s)
- Lujuan Li
- College of Mechanical and Electrical Engineering, Jiaxing University, Jiaxing 314001, China.
- China-Australia Institute for Advanced Materials and Manufacturing, Jiaxing University, Jiaxing 314001, China.
| | - Qianqian Cao
- College of Mechanical and Electrical Engineering, Jiaxing University, Jiaxing 314001, China.
| | - Chuncheng Zuo
- College of Mechanical and Electrical Engineering, Jiaxing University, Jiaxing 314001, China.
| |
Collapse
|
21
|
Davydovich O, Chu E, Friar Z, Smilgies DM, Moore P, Sidorenko A. Coordinated Responsive Arrays of Surface-Linked Polymer Islands-CORALs. ACS APPLIED MATERIALS & INTERFACES 2018; 10:7459-7468. [PMID: 29405063 DOI: 10.1021/acsami.7b18305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The concept of co-ordinated responsive arrays of surface-linked islands (polymer CORALs) is introduced. This study targets a responsive system capable of revealing or covering the substrate surface in response to environmental changes in a reversible way. A convenient method of fabrication of polymer CORALs is proposed. It is based on microphase separation that occurs in thin films of supramolecular assemblies of block copolymers with reactive blocks. Such blocks form nanometer-size domains that may serve as anchors for surface-linked polymer islands. Two characteristics of the islands are critically important for the switching function: high grafting density within the islands and small lateral separation that allows interactions between polymer chains grafted to the neighboring islands. This combination permits complete coverage of the substrate surface upon exposure to a good solvent (relaxed state). In a weak solvent, the chains collapse within the islands, thus revealing the substrate (compact state). The morphology of the CORALs in both states and some details of the switching process were studied with atomic force microscopy, grazing incidence small-angle scattering, and coarse-grained molecular dynamic simulations.
Collapse
Affiliation(s)
- Oleg Davydovich
- Department of Chemistry & Biochemistry, University of the Sciences , Philadelphia, Pennsylvania 19104, United States
| | - Elza Chu
- Department of Chemistry & Biochemistry, University of the Sciences , Philadelphia, Pennsylvania 19104, United States
| | - Zachary Friar
- Department of Chemistry & Biochemistry, University of the Sciences , Philadelphia, Pennsylvania 19104, United States
| | - Detlef-M Smilgies
- Cornell High Energy Synchrotron Source , Ithaca, New York 14853, United States
| | - Preston Moore
- Department of Chemistry & Biochemistry, University of the Sciences , Philadelphia, Pennsylvania 19104, United States
| | - Alexander Sidorenko
- Department of Chemistry & Biochemistry, University of the Sciences , Philadelphia, Pennsylvania 19104, United States
| |
Collapse
|
22
|
Lebedeva IO, Zhulina EB, Borisov OV. Self-consistent field theory of polyelectrolyte brushes with finite chain extensibility. J Chem Phys 2017; 146:214901. [PMID: 28595404 PMCID: PMC5459626 DOI: 10.1063/1.4984101] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 05/12/2017] [Indexed: 11/14/2022] Open
Abstract
Polyelectrolyte brushes are formed by charged macromolecules tethered by the end segment to a solid-liquid interface. At low ionic strength of the solution, the intermolecular electrostatic interactions lead to strong stretching of the macromolecules that may, as a result, approach the limit of their extensibility (the contour length). Here, we present an analytical theory of polyelectrolyte brushes developed within the Poisson-Boltzmann approximation which explicitly accounts for finite extensibility of the brush-forming chains. In contrast to earlier theories based on the approximation of Gaussian elasticity of the brush-forming chains, the current approach enables avoiding artificial result of stretching of the chains beyond the contour length at high degrees of ionization or/and large grafting densities.
Collapse
Affiliation(s)
- Inna O Lebedeva
- Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux, UMR 5254 CNRS UPPA, Pau, France
| | - Ekaterina B Zhulina
- Institute of Macromolecular Compounds of the Russian Academy of Sciences, St. Petersburg, Russia
| | - Oleg V Borisov
- Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux, UMR 5254 CNRS UPPA, Pau, France
| |
Collapse
|
23
|
Yamazoe K, Higaki Y, Inutsuka Y, Miyawaki J, Cui YT, Takahara A, Harada Y. Enhancement of the Hydrogen-Bonding Network of Water Confined in a Polyelectrolyte Brush. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:3954-3959. [PMID: 28359152 DOI: 10.1021/acs.langmuir.7b00243] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Water existing in the vicinity of polyelectrolytes exhibits unique structural properties, which demonstrate key roles in chemistry, biology, and geoscience. In this study, X-ray absorption and emission spectroscopy was employed to observe the local hydrogen-bonding structure of water confined in a charged polyelectrolyte brush. Even at room temperature, a majority of the water molecules confined in the polyelectrolyte brush exhibited one type of hydrogen-bonding configuration: a slightly distorted, albeit ordered, configuration. The findings from this study provide new insight in terms of the correlation between the function and local structure of water at the interface of biological materials under physiological conditions.
Collapse
Affiliation(s)
- Kosuke Yamazoe
- Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo , 5-1-5, Kashiwanoha, Kashiwa-shi, Chiba 277-8561, Japan
| | | | | | - Jun Miyawaki
- Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo , 5-1-5, Kashiwanoha, Kashiwa-shi, Chiba 277-8561, Japan
- Institute for Solid State Physics, The University of Tokyo , 5-1-5, Kashiwanoha, Kashiwa-shi, Chiba 277-0882, Japan
- Synchrotron Radiation Research Organization, The University of Tokyo , 1-490-2, Kouto, Shingu-cho, Tatsuno, Hyogo 679-5165, Japan
| | - Yi-Tao Cui
- Synchrotron Radiation Research Organization, The University of Tokyo , 1-490-2, Kouto, Shingu-cho, Tatsuno, Hyogo 679-5165, Japan
| | | | - Yoshihisa Harada
- Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo , 5-1-5, Kashiwanoha, Kashiwa-shi, Chiba 277-8561, Japan
- Institute for Solid State Physics, The University of Tokyo , 5-1-5, Kashiwanoha, Kashiwa-shi, Chiba 277-0882, Japan
- Synchrotron Radiation Research Organization, The University of Tokyo , 1-490-2, Kouto, Shingu-cho, Tatsuno, Hyogo 679-5165, Japan
| |
Collapse
|
24
|
Willott JD, Murdoch TJ, Webber GB, Wanless EJ. Physicochemical behaviour of cationic polyelectrolyte brushes. Prog Polym Sci 2017. [DOI: 10.1016/j.progpolymsci.2016.09.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
25
|
Lu Y, Ballauff M. Spherical polyelectrolyte brushes as nanoreactors for the generation of metallic and oxidic nanoparticles: Synthesis and application in catalysis. Prog Polym Sci 2016. [DOI: 10.1016/j.progpolymsci.2016.03.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
26
|
Yu J, Mao J, Yuan G, Satija S, Chen W, Tirrell M. The effect of multivalent counterions to the structure of highly dense polystyrene sulfonate brushes. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.02.053] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
27
|
|
28
|
Chen G, Das S. Anomalous Shrinking–Swelling of Nanoconfined End-Charged Polyelectrolyte Brushes: Interplay of Confinement and Electrostatic Effects. J Phys Chem B 2016; 120:6848-57. [DOI: 10.1021/acs.jpcb.6b04636] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Guang Chen
- Department
of Mechanical
Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - Siddhartha Das
- Department
of Mechanical
Engineering, University of Maryland, College Park, Maryland 20742, United States
| |
Collapse
|
29
|
Micciulla S, Soltwedel O, Löhmann O, von Klitzing R. Temperature responsive behavior of polymer brush/polyelectrolyte multilayer composites. SOFT MATTER 2016; 12:1176-83. [PMID: 26612742 DOI: 10.1039/c5sm02256h] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The complex interaction of polyelectrolyte multilayers (PEMs) physisorbed onto end-grafted polymer brushes with focus on the temperature-responsive behavior of the system is addressed in this work. The investigated brush/multilayer composite consists of a poly(styrene sulfonate)/poly(diallyldimethylammonium chloride) (PSS/PDADMAC) multilayer deposited onto the poly(N-isopropylacrylamide-b-dimethylaminoethyl methacrylate) P(NIPAM-b-DMAEMA) brush. Ellipsometry and neutron reflectometry were used to monitor the brush collapse with the thickness decrease as a function of temperature and the change in the monomer distribution perpendicular to the substrate at temperatures below, across and above the phase transition, respectively. It was found that the adsorption of PEMs onto polymer brushes had a hydrophobization effect on PDMAEMA, inducing the shift of its phase transition to lower temperatures, but without suppressing its temperature-responsiveness. Moreover, the diffusion of the free polyelectrolyte chains inside the charged brush was proved by comparing the neutron scattering length density profile of pure and the corresponding PEM-capped brushes, eased by the enhanced contrast between hydrogenated brushes and deuterated PSS chains. The results presented herein demonstrate the possibility of combining a temperature-responsive brush with polyelectrolyte multilayers without quenching the responsive behavior, even though significant interpolyelectrolyte interactions are present. This is of importance for the design of multicompartment coatings, where the brush can be used as a reservoir for the controlled release of substances and the multilayer on the top as a membrane to control the diffusion in/out by applying different stimuli.
Collapse
Affiliation(s)
- Samantha Micciulla
- Stranski-Laboratorium, Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 124, D-10623 Berlin, Germany.
| | - Olaf Soltwedel
- Max-Planck-Institute for Solid State Research, Outstation at MLZ, Lichtenbergstr. 1, 85747 Garching, Germany
| | - Oliver Löhmann
- Stranski-Laboratorium, Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 124, D-10623 Berlin, Germany.
| | - Regine von Klitzing
- Stranski-Laboratorium, Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 124, D-10623 Berlin, Germany.
| |
Collapse
|
30
|
Kim HC, Lee H, Khetan J, Won YY. Surface Mechanical and Rheological Behaviors of Biocompatible Poly((D,L-lactic acid-ran-glycolic acid)-block-ethylene glycol) (PLGA-PEG) and Poly((D,L-lactic acid-ran-glycolic acid-ran-ε-caprolactone)-block-ethylene glycol) (PLGACL-PEG) Block Copolymers at the Air-Water Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:13821-13833. [PMID: 26633595 DOI: 10.1021/acs.langmuir.5b03622] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Air-water interfacial monolayers of poly((D,L-lactic acid-ran-glycolic acid)-block-ethylene glycol) (PLGA-PEG) exhibit an exponential increase in surface pressure under high monolayer compression. In order to understand the molecular origin of this behavior, a combined experimental and theoretical investigation (including surface pressure-area isotherm, X-ray reflectivity (XR) and interfacial rheological measurements, and a self-consistent field (SCF) theoretical analysis) was performed on air-water monolayers formed by a PLGA-PEG diblock copolymer and also by a nonglassy analogue of this diblock copolymer, poly((D,L-lactic acid-ran-glycolic acid-ran-caprolactone)-block-ethylene glycol) (PLGACL-PEG). The combined results of this study show that the two mechanisms, i.e., the glass transition of the collapsed PLGA film and the lateral repulsion of the PEG brush chains that occur simultaneously under lateral compression of the monolayer, are both responsible for the observed PLGA-PEG isotherm behavior. Upon cessation of compression, the high surface pressure of the PLGA-PEG monolayer typically relaxes over time with a stretched exponential decay, suggesting that in this diblock copolymer situation, the hydrophobic domain formed by the PLGA blocks undergoes glass transition in the high lateral compression state, analogously to the PLGA homopolymer monolayer. In the high PEG grafting density regime, the contribution of the PEG brush chains to the high monolayer surface pressure is significantly lower than what is predicted by the SCF model because of the many-body attraction among PEG segments (referred to in the literature as the "n-cluster" effects). The end-grafted PEG chains were found to be protein resistant even under the influence of the "n-cluster" effects.
Collapse
Affiliation(s)
- Hyun Chang Kim
- School of Chemical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| | - Hoyoung Lee
- School of Chemical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| | - Jawahar Khetan
- School of Chemical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| | - You-Yeon Won
- School of Chemical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| |
Collapse
|
31
|
Utilizing vapor swelling of surface-initiated polymer brushes to develop quantitative measurements of brush thermodynamics and grafting density. POLYMER 2015. [DOI: 10.1016/j.polymer.2015.05.030] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
32
|
Application of polymeric macroporous supports for temperature-responsive chromatography of pharmaceuticals. J Chromatogr A 2015; 1407:90-9. [DOI: 10.1016/j.chroma.2015.06.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 06/01/2015] [Accepted: 06/10/2015] [Indexed: 01/29/2023]
|
33
|
Kroning A, Furchner A, Aulich D, Bittrich E, Rauch S, Uhlmann P, Eichhorn KJ, Seeber M, Luzinov I, Kilbey SM, Lokitz BS, Minko S, Hinrichs K. In Situ Infrared Ellipsometry for Protein Adsorption Studies on Ultrathin Smart Polymer Brushes in Aqueous Environment. ACS APPLIED MATERIALS & INTERFACES 2015; 7:12430-12439. [PMID: 25668395 DOI: 10.1021/am5075997] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The protein-adsorbing and -repelling properties of various smart nanometer-thin polymer brushes containing poly(N-isopropylacrylamide) and poly(acrylic acid) with high potential for biosensing and biomedical applications are studied by in situ infrared-spectroscopic ellipsometry (IRSE). IRSE is a highly sensitive nondestructive technique that allows protein adsorption on polymer brushes to be investigated in an aqueous environment as external stimuli, such as temperature and pH, are varied. These changes are relevant to conditions for regulation of protein adsorption and desorption for biotechnology, biocatalysis, and bioanalytical applications. Here brushes are used as model surfaces for controlling protein adsorption of human serum albumin and human fibrinogen. The important finding of this work is that IRSE in the in situ experiments in protein solutions can distinguish between contributions of polymer brushes and proteins. The vibrational bands of the polymers provide insights into the hydration state of the brushes, whereas the protein-specific amide bands are related to changes of the protein secondary structure.
Collapse
Affiliation(s)
- Annika Kroning
- ‡Leibniz-Institut für Analytische Wissenschaften - ISAS - e. V., Schwarzschildstraße 8, 12489 Berlin, Germany
| | - Andreas Furchner
- ‡Leibniz-Institut für Analytische Wissenschaften - ISAS - e. V., Schwarzschildstraße 8, 12489 Berlin, Germany
| | - Dennis Aulich
- ‡Leibniz-Institut für Analytische Wissenschaften - ISAS - e. V., Schwarzschildstraße 8, 12489 Berlin, Germany
| | - Eva Bittrich
- §Leibniz-Institut für Polymerforschung Dresden e. V., Hohe Straße 6, 01069 Dresden, Germany
| | - Sebastian Rauch
- §Leibniz-Institut für Polymerforschung Dresden e. V., Hohe Straße 6, 01069 Dresden, Germany
| | - Petra Uhlmann
- §Leibniz-Institut für Polymerforschung Dresden e. V., Hohe Straße 6, 01069 Dresden, Germany
| | - Klaus-Jochen Eichhorn
- §Leibniz-Institut für Polymerforschung Dresden e. V., Hohe Straße 6, 01069 Dresden, Germany
| | - Michael Seeber
- ⊥School of Materials Science and Engineering Clemson University, 161 Sirrine Hall, Clemson, South Carolina 29634-0971, United States
| | - Igor Luzinov
- ⊥School of Materials Science and Engineering Clemson University, 161 Sirrine Hall, Clemson, South Carolina 29634-0971, United States
| | - S Michael Kilbey
- ∥Departments of Chemistry and of Chemical Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Bradley S Lokitz
- #Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Sergiy Minko
- ∇Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Karsten Hinrichs
- ‡Leibniz-Institut für Analytische Wissenschaften - ISAS - e. V., Schwarzschildstraße 8, 12489 Berlin, Germany
| |
Collapse
|
34
|
Watson S, Nie M, Wang L, Stokes K. Challenges and developments of self-assembled monolayers and polymer brushes as a green lubrication solution for tribological applications. RSC Adv 2015. [DOI: 10.1039/c5ra17468f] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Surface initiated polymer brushes, grafted from self-assembled initiating monolayers on a contact surface, provide opportunities to develop innovative solutions for friction reduction in tribological systems.
Collapse
Affiliation(s)
- Simon Watson
- National Centre for Advanced Tribology at Southampton (nCATS)
- University of Southampton
- Southampton SO17 1BJ
- UK
| | - Mengyan Nie
- National Centre for Advanced Tribology at Southampton (nCATS)
- University of Southampton
- Southampton SO17 1BJ
- UK
| | - Ling Wang
- National Centre for Advanced Tribology at Southampton (nCATS)
- University of Southampton
- Southampton SO17 1BJ
- UK
| | - Keith Stokes
- National Centre for Advanced Tribology at Southampton (nCATS)
- University of Southampton
- Southampton SO17 1BJ
- UK
- Platform Systems Division
| |
Collapse
|
35
|
Zhu PW. Effects of Sodium Dodecyl Sulfate on Structures of Poly(N-isopropylacrylamide) at the Particle Surface. J Phys Chem B 2014; 119:359-71. [DOI: 10.1021/jp510350w] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Peng Wei Zhu
- Department of Materials Engineering, Monash University, Clayton, VIC 3800, Australia
| |
Collapse
|
36
|
Galvin CJ, Dimitriou MD, Satija SK, Genzer J. Swelling of polyelectrolyte and polyzwitterion brushes by humid vapors. J Am Chem Soc 2014; 136:12737-45. [PMID: 25134061 DOI: 10.1021/ja5065334] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Swelling behavior of polyelectrolyte and polyzwitterion brushes derived from poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) in water vapor is investigated using a combination of neutron and X-ray reflectivity and spectroscopic ellipsometry over a wide range of relative humidity (RH) levels. The extent of swelling depends strongly on the nature of the side-chain chemistry. For parent PDMAEMA, there is an apparent enrichment of water vapor at the polymer/air interface. Despite extensive swelling at high humidity level, no evidence of charge repulsion is found in weak or strong polyelectrolyte brushes. Polyzwitterionic brushes swell to a greater extent than the quaternized brushes studied. However, for RH levels beyond 70%, the polyzwitterionic brushes take up less water molecules, leading to a decline in water volume fraction from the maximum of ~0.30 down to ~0.10. Using a gradient in polymer chain grafting density (σ), we provide evidence that this behavior stems from the formation of inter- and intramolecular zwitterionic complexes.
Collapse
Affiliation(s)
- Casey J Galvin
- Department of Chemical and Biomolecular Engineering, North Carolina State University , Raleigh, North Carolina 27695-7905, United States
| | | | | | | |
Collapse
|
37
|
Bhairamadgi NS, Pujari SP, Leermakers FAM, van Rijn CJM, Zuilhof H. Adhesion and friction properties of polymer brushes: fluoro versus nonfluoro polymer brushes at varying thickness. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:2068-2076. [PMID: 24555721 DOI: 10.1021/la404915k] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A series of different thicknesses of fluoro poly(2,2,2-trifluoroethyl methacrylate) and its analogous nonfluoro poly(ethyl methacrylate) polymer brushes were prepared via surface-initiated ATRP (SI-ATRP) on Si(111) surfaces. The thiol-yne click reaction was used to immobilize the SI-ATRP initiator with a high surface coverage, in order to achieve denser polymer brushes (grafting density from ~0.1 to 0.8 chains/nm(2)). All polymer brushes were characterized by static water contact angle measurements, infrared absorption reflection spectroscopy, and X-ray photoelectron spectroscopy. Adhesion and friction force measurements were conducted with silica colloidal probe atomic force microscopy (CP-AFM) under ambient and dry (argon) conditions. The fluoro poly(2,2,2-trifluoroethyl methacrylate) polymer showed a decrease in adhesion and friction with increasing thickness. The analogous nonfluoro poly(ethyl methacrylate) polymer brushes showed high adhesion and friction under ambient conditions. Friction coefficients down to 0.0057 (ambient conditions) and 0.0031 (dry argon) were obtained for poly(2,2,2-trifluoroethyl methacrylate) polymer brushes with 140 nm thickness, which are the lowest among these types of polymer brushes.
Collapse
Affiliation(s)
- Nagendra S Bhairamadgi
- Laboratory of Organic Chemistry and ‡Laboratory of Physical Chemistry and Colloid Science, Wageningen University and Research Center , Dreijenplein 8, 6703 HB Wageningen, The Netherlands
| | | | | | | | | |
Collapse
|
38
|
Alswieleh A, Cheng N, Leggett GJ, Armes SP. Spatial control over cross-linking dictates the pH-responsive behavior of poly(2-(tert-butylamino)ethyl methacrylate) brushes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:1391-400. [PMID: 24417283 PMCID: PMC4190050 DOI: 10.1021/la403666y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 01/13/2014] [Indexed: 05/12/2023]
Abstract
Surface-initiated atom transfer radical polymerization (ATRP) of 2-(tert-butylamino)ethyl methacrylate (TBAEMA) produced pH-responsive secondary amine-functionalized polymer brushes with dry thicknesses ranging from 4 to 28 nm, as determined by ellipsometry. At low pH, linear PTBAEMA brushes became protonated and highly swollen; brush collapse occurred when the solution pH was increased to ca. 7.7 due to deprotonation. PTBAEMA brushes were subsequently cross-linked using tolylene-2,4-diisocyanate-terminated poly(propylene glycol) (PPG-TGI) in either THF (a good solvent for PTBAEMA) or n-hexane (a poor solvent). The intensity of the C-C-O component (286.5 eV) in the C1s X-ray photoelectron spectrum increased after reaction with PPG-TDI, suggesting that cross-linking was successful in both solvents. Ellipsometry studies indicated that the pH-responsive behavior of these cross-linked brushes is dictated by the spatial location of the PPG-TDI cross-linker. Thus, uniformly cross-linked brushes prepared in THF became appreciably less swollen at a given (low) pH than surface-cross-linked brushes prepared in n-hexane. Micro- and nanopatterned PTBAEMA brushes were prepared via UV irradiation and interference lithography, respectively, and characterized by atomic force microscopy. The change in brush height was determined as a function of pH, and these AFM observations correlated closely with the ellipsometric studies.
Collapse
Affiliation(s)
| | | | - Graham J. Leggett
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
| | - Steven P. Armes
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
| |
Collapse
|
39
|
Choi BC, Choi S, Leckband DE. Poly(N-isopropyl acrylamide) brush topography: dependence on grafting conditions and temperature. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:5841-5850. [PMID: 23600842 DOI: 10.1021/la400066d] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The topography of poly (N-isopropyl acrylamide) brushes end-grafted from initiator-terminated monolayers was imaged by atomic force microscopy, as a function of the area per chain and of solvent quality. Measurements were done in air and in water, below and above the lower critical solution temperature. At low grafting densities and molecular weights, area-averaged ellipsometry measurements did not detect changes in the volume of water-swollen, end-grafted polymer films above the lower critical solution temperature. However, atomic force microscopy images revealed surface features that suggest the formation of lateral aggregates or "octopus micelles". At high grafting densities and molecular weights, the films collapsed uniformly, as detected by both AFM imaging and ellipsometry. These findings reconcile in part prior results suggesting that some poly(N-isopropyl acrylamide) chains do not collapse in poor solvent, and they also reveal more complex collapse behavior above the lower critical solution temperature than is commonly assumed. This behavior would influence the ability to tune the functional properties of poly(N-isopropyl acrylamide) coatings.
Collapse
Affiliation(s)
- B-C Choi
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, Illinois 61801, United States
| | | | | |
Collapse
|
40
|
Zhao Y, Qin Y, Liang Y, Zou H, Peng X, Huang H, Lu M, Feng M. Salt-induced stability and serum-resistance of polyglutamate polyelectrolyte brushes/nuclear factor-κB p65 siRNA Polyplex enhance the apoptosis and efficacy of doxorubicin. Biomacromolecules 2013; 14:1777-86. [PMID: 23617546 DOI: 10.1021/bm400177q] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Short interfering RNAs (siRNAs) as chemotherapeutic RNAi agents hold great promise for a significant improvement in cancer therapy. Despite the promise, effective transport of siRNA with minimal side effects remains a challenge. The common problem associated with the low delivery efficiencies of current polycation-based gene delivery systems is their low stability in the presence of salt and serum. In the present study we developed the polyglutamate derivatives (PGS) polyelectrolyte brushes for NF-κB p65 siRNA delivery. The PGS polyelectrolyte brushes/siRNA polyplex was colloidally stable (150 nm diameter) in physiological saline (150 mM NaCl), likely due to the osmotic brushes of PGS. The size-controlled siRNA/PGS polyplex also showed the serum resistance resulting in their efficient cellular uptake was not negatively influenced by the presence of serum. The endothermic profile of ITC, their low values of Gibbs free energy and binding constants Kb under salt conditions provided the direct evidence that PGS polyelectrolyte brushes had a much lower binding affinity for serum proteins, compared with PEI 25KDa. PGS polyelectrolyte brushes delivering NF-κB p65 siRNA achieved efficient down-regulation of NF-κB p65 protein in HeLa cells. The NF-κB p65 down-regulation mediated by PGS polyelectrolyte brushes was more significant than PEI 25KDa and comparable to Lipofectamine 2000. Furthermore, the combination treatment with PGS polyelectrolyte brushes/NF-κB p65 siRNA polyplex and doxorubicin demonstrated synergistic apoptotic and cytotoxic effects on HeLa cancer cells. The high stability in physiological saline and salt-induced serum resistance of PGS polyelectrolyte brushes/siRNA polyplex has potential applications together with standard chemotherapies such as doxorubicin to be a viable method to improve the clinical outcomes in cancer therapies.
Collapse
Affiliation(s)
- Yuefang Zhao
- Department of Pharmacy, School of Pharmaceutical Sciences, Sun Yat-sen University , University Town, Guangzhou, People's Republic of China 510006
| | | | | | | | | | | | | | | |
Collapse
|
41
|
Abstract
Cell-free gene expression in localized DNA brushes on a biochip has been shown to depend on gene density and orientation, suggesting that brushes form compartments with partitioned conditions. At high density, the interplay of DNA entropic elasticity, electrostatics, and excluded volume interactions leads to collective conformations that affect the function of DNA-associated proteins. Hence, measuring the collective interactions in dense DNA, free of proteins, is essential for understanding crowded cellular environments and for the design of cell-free synthetic biochips. Here, we assembled dense DNA polymer brushes on a biochip along a density gradient and directly measured the collective extension of DNA using evanescent fluorescence. DNA of 1 kbp in a brush undergoes major conformational changes, from a relaxed random coil to a stretched configuration, following a universal function of density to ionic strength ratio with scaling exponent of 1/3. DNA extends because of the swelling force induced by the osmotic pressure of ions, which are trapped in the brush to maintain local charge neutrality, in competition with the restoring force of DNA entropic elasticity. The measurements reveal in DNA crossover between regimes of osmotic, salted, mushroom, and quasineutral brush. It is surprising to note that, at physiological ionic strength, DNA density does not induce collective stretch despite significant chain overlap, which implies that excluded volume interactions in DNA are weak.
Collapse
|
42
|
Halperin A, Kröger M. Thermoresponsive cell culture substrates based on PNIPAM brushes functionalized with adhesion peptides: theoretical considerations of mechanism and design. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:16623-16637. [PMID: 23121235 DOI: 10.1021/la303443t] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Thermoresponsive tissue culture substrates based on PNIPAM brushes are used to harvest confluent cell sheets for tissue engineering. The prospect of clinical use imposes the utilization of culture medium free of bovine serum, thus suggesting conjugation with adhesion peptides containing the RGD minimal recognition sequence. The optimum position of the RGD along the chain should ensure both cell adhesion at 37 °C and cell detachment at T(L) below the lower critical solution temperature of PNIPAM. Design guidelines are formulated from considerations of brush confinement by the cells: (i) Cell adhesion at 37 °C is controlled by the RGDs accessible without brush compression. (ii) Cell detachment at T(L) is driven by a disjoining force due to confinement of the swollen brush by cells retaining integrin-RGD bonds formed at 37 °C. These suggest placing the RGDs at the grafting surface or its vicinity. Randomly placed RGDs do not enable efficient detachment because a large fraction of the integrin-RGD bonds are not sufficiently tensioned at T(L), in line with experimental observations (Ebara, M.; Yamato, M.; Aoyagi, T.; Kikuchi, A.; Sakai, K.; Okano, T. Immobilization of celladhesive peptides to temperature-responsive surfaces facilitates both serum-free cell adhesion and noninvasive cell harvest. Tissue Eng. 2004, 10, 1125-1135). The theory framework enables analysis of culture media based on polymer brushes conjugated with adhesion peptides in general.
Collapse
Affiliation(s)
- Avraham Halperin
- University of Grenoble 1/CNRS, LIPhy UMR 5588, BP 87, 38041 Grenoble, France.
| | | |
Collapse
|
43
|
Abstract
Research advancements for magnetically guided drug delivery encompass not only the improvement of the design, synthesis and evaluation of more selective nanomaterials bearing magnetic properties, but also the optimization of the transport and delivery of magnetic agents. Such versatile platforms can be utilized for simultaneously carrying therapeutics and diagnostics.
Collapse
|
44
|
Lau KHA, Ren C, Sileika TS, Park SH, Szleifer I, Messersmith PB. Surface-grafted polysarcosine as a peptoid antifouling polymer brush. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:16099-107. [PMID: 23101930 PMCID: PMC3530414 DOI: 10.1021/la302131n] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Poly(N-substituted glycine) "peptoids" are a class of peptidomimetic molecules receiving significant interest as engineered biomolecules. Sarcosine (i.e., poly(N-methyl glycine)) has the simplest side chain chemical structure of this family. In this Article, we demonstrate that surface-grafted polysarcosine (PSAR) brushes exhibit excellent resistance to nonspecific protein adsorption and cell attachment. Polysarcosine was coupled to a mussel adhesive protein-inspired DOPA-Lys pentapeptide, which enabled solution grafting and control of the surface chain density of the PSAR brushes. Protein adsorption was found to decrease monotonically with increasing grafted chain densities, and protein adsorption could be completely inhibited above certain critical chain densities specific to different polysarcosine chain lengths. The dependence of protein adsorption on chain length and density was also investigated by a molecular theory. PSAR brushes at high chain length and density were shown to resist fibroblast cell attachment over a 7 week period, as well as resist the attachment of some clinically relevant bacterial strains. The excellent antifouling performance of PSAR may be related to the highly hydrophilic character of polysarcosine, which was evident from high-pressure liquid chromatography measurements of polysarcosine and water contact angle measurements of the PSAR brushes. Peptoids have been shown to resist proteolytic degradation, and polysarcosine could be produced in large quantities by N-carboxy anhydride polymerization. In summary, surface-grafted polysarcosine peptoid brushes hold great promise for antifouling applications.
Collapse
Affiliation(s)
- King Hang Aaron Lau
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, USA
- Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208, USA
| | - Chunlai Ren
- National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
| | - Tadas S. Sileika
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, USA
- Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208, USA
| | - Sung Hyun Park
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, USA
- Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208, USA
| | - Igal Szleifer
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, USA
- Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208, USA
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Evanston, Illinois 60208, USA
| | - Phillip B. Messersmith
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, USA
- Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208, USA
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| |
Collapse
|
45
|
Beers KM, Balsara NP. Design of Cluster-free Polymer Electrolyte Membranes and Implications on Proton Conductivity. ACS Macro Lett 2012; 1:1155-1160. [PMID: 35607186 DOI: 10.1021/mz300389f] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nanoscale ionic aggregates are ubiquitous in copolymers containing charged and uncharged monomers. In most cases, these clusters persist when these polymers are hydrated and ion-conducting channels percolate through the sample. We argue that these clusters impede ion motion due to (1) the requirement that ions must hop across ion-free regions in the channels as they are transported from one cluster to the next, and (2) increased counterion condensation due to proximity of fixed acid groups in the clusters. Block copolymers wherein the size of the ion-containing microphase is 6 nm or less provides one approach for eliminating the clusters.
Collapse
Affiliation(s)
- Keith M. Beers
- Department of Chemical
Engineering, University of California, Berkeley, California 94720, United States
| | - Nitash P. Balsara
- Department of Chemical
Engineering, University of California, Berkeley, California 94720, United States
| |
Collapse
|
46
|
Qin S, Tang X, Zhu L, Wei Y, Du X, Zhu DM. Viscoelastic signature of physisorbed macromolecules at the solid–liquid interface. J Colloid Interface Sci 2012; 383:208-14. [DOI: 10.1016/j.jcis.2012.06.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 06/15/2012] [Accepted: 06/16/2012] [Indexed: 10/28/2022]
|
47
|
Zhu PW. Nonequilibrium polymer chains induced by conformational transitions in densely interfacial layers. J Chem Phys 2012; 137:104903. [PMID: 22979886 DOI: 10.1063/1.4751479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Nonequilibrium poly(N-isopropylacrylamide) (PNIPAM) chains are generated by temperature-induced conformational transitions in the densely interfacial PNIPAM layer at high adsorbed amounts in aqueous solution. The interleaving chains relax in a spatially heterogeneous space of adsorbed layer which is filled with the domains via the hydrogen bonding and hydrophobic interactions. The relaxation dynamics of interleaving chains is changed from the weekly stretched exponential behaviour at the lower adsorbed amount to the strongly stretched exponential behaviour at the higher adsorbed amount. The kinetic constraints for the relaxation dynamics depend on the segment density of the adsorbed layer which is controlled by the temperature. The stretched exponential relaxation is related to an ensemble of relaxations confined in the domains with different physical origins for the heterogeneous dynamics. The range of energy barriers for the relaxation is estimated from the stretched exponent based on the random first order transition theory.
Collapse
Affiliation(s)
- Peng-Wei Zhu
- Cooperative Research Centre for Polymers, Melbourne, Australia
| |
Collapse
|
48
|
Bakandritsos A, Papagiannopoulos A, Anagnostou EN, Avgoustakis K, Zboril R, Pispas S, Tucek J, Ryukhtin V, Bouropoulos N, Kolokithas-Ntoukas A, Steriotis TA, Keiderling U, Winnefeld F. Merging high doxorubicin loading with pronounced magnetic response and bio-repellent properties in hybrid drug nanocarriers. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2012; 8:2381-2393. [PMID: 22549909 DOI: 10.1002/smll.201102525] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 02/15/2012] [Indexed: 05/31/2023]
Abstract
Hybrid magnetic drug nanocarriers are prepared via a self-assembly process of poly(methacrylic acid)-graft-poly(ethyleneglycol methacrylate) (p(MAA-g-EGMA)) on growing iron oxide nanocrystallites. The nanocarriers successfully merge together bio-repellent properties, pronounced magnetic response, and high loading capacity for the potent anticancer drug doxorubicin (adriamicin), in a manner not observed before in such hybrid colloids. High magnetic responses are accomplished by engineering the size of the magnetic nanocrystallites (∼13.5 nm) following an aqueous single-ferrous precursor route, and through adjustment of the number of cores in each colloidal assembly. Complementing conventional magnetometry, the magnetic response of the nanocarriers is evaluated by magnetophoretic experiments providing insight into their internal organization and on their response to magnetic manipulation. The structural organization of the graft-copolymer, locked on the surface of the nanocrystallites, is further probed by small-angle neutron scattering on single-core colloids. Analysis showed that the MAA segments selectively populate the area around the magnetic nanocrystallites, while the poly(ethylene glycol)-grafted chains are arranged as protrusions, pointing towards the aqueous environment. These nanocarriers are screened at various pHs and in highly salted media by light scattering and electrokinetic measurements. According to the results, their stability is dramatically enhanced, as compared to uncoated nanocrystallites, owing to the presence of the external protective PEG canopy. The nanocarriers are also endowed with bio-repellent properties, as evidenced by stability assays using human blood plasma as the medium.
Collapse
|
49
|
Galvin CJ, Genzer J. Applications of surface-grafted macromolecules derived from post-polymerization modification reactions. Prog Polym Sci 2012. [DOI: 10.1016/j.progpolymsci.2011.12.001] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|
50
|
Theoretical considerations on mechanisms of harvesting cells cultured on thermoresponsive polymer brushes. Biomaterials 2012; 33:4975-87. [DOI: 10.1016/j.biomaterials.2012.03.060] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 03/17/2012] [Indexed: 11/20/2022]
|