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Schwörer F, Trapp M, Silvi L, Gutfreund P, Steitz R, Dahint R. Location of Polyelectrolytes in Swollen Lipid Oligobilayers. Langmuir 2023; 39:14958-14968. [PMID: 37815275 DOI: 10.1021/acs.langmuir.3c01792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/11/2023]
Abstract
Osteoarthritis is caused by degeneration of the cartilage, which covers the bone ends of the joints and is decorated with an oligolamellar phospholipid (PL) bilayer. The gap between the bone ends is filled with synovial fluid mainly containing hyaluronic acid (HA). HA and PLs are supposed to reduce friction and protect the cartilage from wear in joint movement. However, a detailed understanding of the molecular mechanisms of joint lubrication is still missing. Previously, we found that aqueous solutions of HA and poly(allylamine hydrochloride) (PAH), the latter serving as a polymeric analogue to HA, adsorb onto the headgroups of surface-bound 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) oligobilayers and significantly enhance their stability with respect to shear forces, typically occurring in joint movement. We now investigated the precise location of PAH chains across the lipid films in neutron reflectivity measurements, as bridging of the oligobilayers by polyelectrolytes (PEs) might be the cause for their improved mechanical stability. In a first set of experiments, we used hydrogenated PAH and chain-deuterated DMPC (DMPC-d54) to improve the contrast between the lipids and potentially intruding PAH. However, due to difficulties in distinguishing between incorporation of water and PAH, penetration into the lipid chain region could hardly be proven quantitatively. Therefore, we designed a more elaborate experiment based on mixed films of DMPC-d54 and hydrogenated DMPC, which is insensitive to water penetration into the films. Beside facilitating a detailed structural characterization of the oligolamellar system, this elaborate approach showed that PAH adsorbs to the DMPC heads and penetrates the lipid tail strata. No PAH was found in the lipid head strata, which excludes bridging of several lipid bilayers by the PE chains. The data are consistent with the assumption that PAH bridges are formed between the headgroups of two adjacent bilayers and contribute to the enhanced mechanical stability.
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Affiliation(s)
- Felicitas Schwörer
- Applied Physical Chemistry, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 253, Heidelberg 69120, Germany
| | - Marcus Trapp
- Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, Berlin 14109, Germany
| | - Luca Silvi
- Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, Berlin 14109, Germany
| | | | - Roland Steitz
- Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, Berlin 14109, Germany
| | - Reiner Dahint
- Applied Physical Chemistry, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 253, Heidelberg 69120, Germany
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Weissenfeld F, Wesenberg L, Nakahata M, Müller M, Tanaka M. Modulation of wetting of stimulus responsive polymer brushes by lipid vesicles: experiments and simulations. Soft Matter 2023; 19:2491-2504. [PMID: 36942886 DOI: 10.1039/d2sm01673g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The interactions between vesicle and substrate have been studied by simulation and experiment. We grafted polyacrylic acid brushes containing cysteine side chains at a defined area density on planar lipid membranes. Specular X-ray reflectivity data indicated that the addition of Cd2+ ions induces the compaction of the polymer brush layer and modulates the adhesion of lipid vesicles. Using microinterferometry imaging, we determined the onset level, [CdCl2] = 0.25 mM, at which the wetting of the vesicle emerges. The characteristics of the interactions between vesicle and brush were quantitatively evaluated by the shape of the vesicle near the substrate and height fluctuations of the membrane in contact with brushes. To analyze these experiments, we have systematically studied the shape and adhesion of axially symmetric vesicles for finite-range membrane-substrate interaction, i.e., a relevant experimental characteristic, through simulations. The wetting of vesicles sensitively depends on the interaction range and the approximate estimates of the capillary length change significantly, depending on the adhesion strength. We found, however, that the local transversality condition that relates the maximal curvature at the edge of the adhesion zone to the adhesion strength remains rather accurate even for a finite interaction range as long as the vesicle is large compared to the interaction range.
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Affiliation(s)
- Felix Weissenfeld
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, Heidelberg University, 69120 Heidelberg, Germany.
| | - Lucia Wesenberg
- Institute for Theoretical Physics, Georg-August University, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany.
| | - Masaki Nakahata
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 560-8531 Osaka, Japan
- Department of Macromolecular Science, Graduate School of Science, Osaka University, 560-8531 Osaka, Japan
| | - Marcus Müller
- Institute for Theoretical Physics, Georg-August University, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany.
| | - Motomu Tanaka
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, Heidelberg University, 69120 Heidelberg, Germany.
- Center for Advanced Study, Institute for Advanced Study, Kyoto University, 606-8501 Kyoto, Japan
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He G, Wen G, Skandalis A, Pispas S, Liu D. Effects of ionic strength and ion-specificity on the interface behavior of PDMAEMA-b-PLMA-b-POEGMA triblock terpolymer. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.130659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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He G, Wen G, Skandalis A, Pispas S, Liu D, Zhang W. Interfacial aggregation behavior of triblock terpolymers. J Polym Res 2022. [DOI: 10.1007/s10965-022-03244-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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Chen H, Wen G, Chrysostomou V, Pispas S, Li H, Sun Z. Effects of Ionic Strength and Ion Specificity on the Interface Behavior of Poly(dimethylaminoethyl methacrylate)-Poly(lauryl methacrylate). Langmuir 2021; 37:2419-2425. [PMID: 33570943 DOI: 10.1021/acs.langmuir.0c03424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The ion specificity effect on the water solubility of poly(N-isopropylacrylamide)-containing copolymers complies with the Hofmeister series, which is applicable to other copolymers or not need to be explored. In this work, effects of ionic strength under acidic conditions and ion specificity under alkaline conditions on the air/water interface behavior of two amphiphilic diblock copolymers poly(dimethylaminoethyl methacrylate)-poly(lauryl methacrylate) (PDMAEMA-PLMA) were systematically studied. Under acidic conditions, the surface pressure-area isotherms of a predominantly hydrophilic copolymer are insensitive to ionic strength. In contrast, the isotherms of a predominantly hydrophobic copolymer successively shift to the large, small, and large molecular area with the increase of ionic strength. Under alkaline conditions, the interfacial stretch degrees of PDMAEMA chains of two copolymers change with salt species and concentrations, which do not comply with the Hofmeister series. All of the Langmuir-Blodgett films of the former copolymer exhibit separate circular micelles. Nevertheless, those of the latter copolymer obtained under alkaline conditions exhibit various distinctive morphologies such as separate circular micelles, large separate PLMA cores within large PDMAEMA domains, and large PLMA domains/aggregates surrounded by short PDMAEMA shells. It can be attributed to the high deformability of PLMA chains, the ion specificity effect on the stretch degree of PDMAEMA blocks, and their underwater solubility upon compression.
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Affiliation(s)
- Hongxu Chen
- School of Material Science and Engineering, Harbin University of Science and Technology, Harbin 150040, China
| | - Gangyao Wen
- School of Material Science and Engineering, Harbin University of Science and Technology, Harbin 150040, China
| | - Varvara Chrysostomou
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Athens 11635, Greece
| | - Stergios Pispas
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Athens 11635, Greece
| | - Hongfei Li
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Zhaoyan Sun
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
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Li R, Qian F, Ren X. Amphiphilic Copolymers PDMAEMA
m
‐
b
‐PAA
n
and Their Complexes with Surfactants at the Air/Water Interface. J SURFACTANTS DETERG 2019. [DOI: 10.1002/jsde.12317] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Rong Li
- Key Laboratory of Eco‐textiles of Ministry of Education, College of Textiles and ClothingJiangnan University Wuxi Jiangsu 214122 China
| | - Fengyi Qian
- Key Laboratory of Eco‐textiles of Ministry of Education, College of Textiles and ClothingJiangnan University Wuxi Jiangsu 214122 China
| | - Xuehong Ren
- Key Laboratory of Eco‐textiles of Ministry of Education, College of Textiles and ClothingJiangnan University Wuxi Jiangsu 214122 China
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Zhao H, Xu K, Zhu P, Wang C, Chi Q. Smart hydrogels with high tunability of stiffness as a biomimetic cell carrier. Cell Biol Int 2019; 43:84-97. [DOI: 10.1002/cbin.11091] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Accepted: 12/23/2018] [Indexed: 12/23/2022]
Affiliation(s)
- Han Zhao
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences; University of Science and Technology of China; Hefei China
| | - Kang Xu
- Department of Cardiovascular Surgery; Union Hospital; Tongji Medical College, Huazhong University of Science and Technology; Wuhan China
| | - Peng Zhu
- Department of Cardiovascular Surgery; Union Hospital; Tongji Medical College, Huazhong University of Science and Technology; Wuhan China
| | - Chunli Wang
- “111 ” Project Laboratory of Biomechanics and Tissue Repair; Bioengineering College; Chongqing University; Chongqing China
| | - Qingjia Chi
- Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics; Department of Mechanics and Engineering Structure; Wuhan University of Technology; Wuhan China
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Palivan CG, Goers R, Najer A, Zhang X, Car A, Meier W. Bioinspired polymer vesicles and membranes for biological and medical applications. Chem Soc Rev 2016; 45:377-411. [DOI: 10.1039/c5cs00569h] [Citation(s) in RCA: 413] [Impact Index Per Article: 51.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Biological membranes play an essential role in living organisms by providing stable and functional compartments, supporting signalling and selective transport. Combining synthetic polymer membranes with biological molecules promises to be an effective strategy to mimic the functions of cell membranes and apply them in artificial systems.
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Affiliation(s)
| | - Roland Goers
- Department of Chemistry
- University of Basel
- CH-4056 Basel
- Switzerland
- Department of Biosystems Science and Engineering
| | - Adrian Najer
- Department of Chemistry
- University of Basel
- CH-4056 Basel
- Switzerland
| | - Xiaoyan Zhang
- Department of Chemistry
- University of Basel
- CH-4056 Basel
- Switzerland
| | - Anja Car
- Department of Chemistry
- University of Basel
- CH-4056 Basel
- Switzerland
| | - Wolfgang Meier
- Department of Chemistry
- University of Basel
- CH-4056 Basel
- Switzerland
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10
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Steinschulte AA, Xu W, Draber F, Hebbeker P, Jung A, Bogdanovski D, Schneider S, Tsukruk VV, Plamper FA. Interface-enforced complexation between copolymer blocks. Soft Matter 2015; 11:3559-3565. [PMID: 25807174 DOI: 10.1039/c5sm00242g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Binary diblock copolymers and corresponding ternary miktoarm stars are studied at oil-water interfaces. All polymers contain oil-soluble poly(propylene oxide) PPO, water-soluble poly(dimethylaminoethyl methacrylate) PDMAEMA and/or poly(ethylene oxide) PEO. The features of their Langmuir compression isotherms are well related to the ones of the corresponding homopolymers. Within the Langmuir-trough, PEO-b-PPO acts as the most effective amphiphile compared to the other PPO-containing copolymers. In contrast, the compression isotherms show a complexation of PPO and PDMAEMA for PPO-b-PDMAEMA and the star, reducing their overall amphiphilicity. Such complex formation between the blocks of PPO-b-PDMAEMA is prevented in bulk water but facilitated at the interface. The weakly-interacting blocks of PPO-b-PDMAEMA form a complex due to their enhanced proximity in such confined environments. Scanning force microscopy and Monte Carlo simulations with varying confinement support our results, which are regarded as compliant with the mathematical random walk theorem by Pólya. Finally, the results are expected to be of relevance for e.g. emulsion formulation and macromolecular engineering.
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11
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Schneck E, Berts I, Halperin A, Daillant J, Fragneto G. Neutron reflectometry from poly (ethylene-glycol) brushes binding anti-PEG antibodies: evidence of ternary adsorption. Biomaterials 2015; 46:95-104. [PMID: 25678119 DOI: 10.1016/j.biomaterials.2014.12.041] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 12/15/2014] [Accepted: 12/20/2014] [Indexed: 12/12/2022]
Abstract
Neutron reflectometry provides evidence of ternary protein adsorption within polyethylene glycol (PEG) brushes. Anti-PEG Immunoglobulin G antibodies (Abs) binding the methoxy terminated PEG chain segment specifically adsorb onto PEG brushes grafted to lipid monolayers on a solid support. The Abs adsorb at the outer edge of the brush. The thickness and density of the adsorbed Ab layer, as well as its distance from the grafting surface grow with increasing brush density. At high densities most of the protein is excluded from the brush. The results are consistent with an inverted "Y" configuration with the two FAB segments facing the brush. They suggest that increasing the grafting density favors narrowing of the angle between the FAB segments as well as overall orientation of the bound Abs perpendicular to the surface.
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12
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Hentrich D, Junginger M, Bruns M, Börner HG, Brandt J, Brezesinski G, Taubert A. Interface-controlled calcium phosphate mineralization: effect of oligo(aspartic acid)-rich interfaces. CrystEngComm 2015. [DOI: 10.1039/c4ce02274b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The phase behavior of an amphiphilic block copolymer based on a poly(aspartic acid) hydrophilic block and a poly(n-butyl acrylate) hydrophobic block was investigated at the air–water and air–buffer interface.
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Affiliation(s)
- Doreen Hentrich
- Institute of Chemistry
- University of Potsdam
- D-14476 Potsdam, Germany
| | | | - Michael Bruns
- Institute for Applied Materials and Karlsruhe Nano Micro Facility (KNMF)
- Karlsruhe Institute of Technology
- D-76344 Eggenstein-Leopoldshafen, Germany
| | - Hans G. Börner
- Max Planck Institute of Colloids and Interfaces
- D-14476 Potsdam, Germany
- Department of Chemistry
- Humboldt Universität zu Berlin
- D-12489 Berlin, Germany
| | - Jessica Brandt
- Max Planck Institute of Colloids and Interfaces
- D-14476 Potsdam, Germany
| | | | - Andreas Taubert
- Institute of Chemistry
- University of Potsdam
- D-14476 Potsdam, Germany
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13
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Coustet M, Irigoyen J, Garcia TA, Murray RA, Romero G, Susana Cortizo M, Knoll W, Azzaroni O, Moya SE. Layer-by-layer assembly of polymersomes and polyelectrolytes on planar surfaces and microsized colloidal particles. J Colloid Interface Sci 2014; 421:132-40. [PMID: 24594041 DOI: 10.1016/j.jcis.2014.01.038] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 01/28/2014] [Accepted: 01/29/2014] [Indexed: 01/22/2023]
Abstract
Hybrid polyelectrolyte multilayer systems were fabricated on top of planar surfaces and colloidal particles via layer by layer (LbL) assembly of polystyrene sulphonate (PSS) and polybenzyl methacrylate-block-poly(dimethylamino)ethyl methacrylate (PBzMA-b-PDMAEMA) polymersomes. Polymersomes were prepared by self assembly of PBzMA-b-PDMAEMA copolymer, synthesised by group transfer polymerisation. Polymersomes display a diameter of 270 nm and a shell thickness of 11nm. Assembly on planar surfaces was followed by means of the Quartz Crystal Microbalance with Dissipation (QCM-D) and Atomic Force Microscopy (AFM). Detailed information on the assembly mechanism and surface topology of the polymersome/polyelectrolyte films was thereby obtained. The assembly of polymersomes and PSS on top of silica particles of 500 nm in diameter was confirmed by ζ-potential measurements. Confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that polymersome/PSS coated silica particles increase in total diameter up to 3-5μm. This hints toward the formation of densely packed polymersome layers. In addition, CLSM showed that polymersome/PSS films exhibit a high loading capacity that could potentially be used for encapsulation and delivery of diverse chemical species. These results provide an insight into the formation of multilayered films with compartmentalised hydrophilic/hydrophobic domains and may lead to the successful application of polymersomes in surface-engineered colloidal systems.
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Affiliation(s)
- Marcos Coustet
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), CONICET, Diagonal 113 y 64 (1900), La Plata, Argentina
| | - Joseba Irigoyen
- CIC BiomaGUNE, 182 Paseo Miramón, 20009 San Sebastián, Spain
| | | | | | - Gabriela Romero
- CIC BiomaGUNE, 182 Paseo Miramón, 20009 San Sebastián, Spain
| | - M Susana Cortizo
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), CONICET, Diagonal 113 y 64 (1900), La Plata, Argentina
| | - Wolfgang Knoll
- Austrian Institute of Technology (AIT), Donau-City-Strasse 1, 1220 Vienna, Austria
| | - Omar Azzaroni
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), CONICET, Diagonal 113 y 64 (1900), La Plata, Argentina.
| | - Sergio E Moya
- CIC BiomaGUNE, 182 Paseo Miramón, 20009 San Sebastián, Spain.
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Bleek K, Taubert A. New developments in polymer-controlled, bioinspired calcium phosphate mineralization from aqueous solution. Acta Biomater 2013; 9:6283-321. [PMID: 23291492 DOI: 10.1016/j.actbio.2012.12.027] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 11/13/2012] [Accepted: 12/21/2012] [Indexed: 11/19/2022]
Abstract
The polymer-controlled and bioinspired precipitation of inorganic minerals from aqueous solution at near-ambient or physiological conditions avoiding high temperatures or organic solvents is a key research area in materials science. Polymer-controlled mineralization has been studied as a model for biomineralization and for the synthesis of (bioinspired and biocompatible) hybrid materials for a virtually unlimited number of applications. Calcium phosphate mineralization is of particular interest for bone and dental repair. Numerous studies have therefore addressed the mineralization of calcium phosphate using a wide variety of low- and high-molecular-weight additives. In spite of the growing interest and increasing number of experimental and theoretical data, the mechanisms of polymer-controlled calcium phosphate mineralization are not entirely clear to date, although the field has made significant progress in the last years. A set of elegant experiments and calculations has shed light on some details of mineral formation, but it is currently not possible to preprogram a mineralization reaction to yield a desired product for a specific application. The current article therefore summarizes and discusses the influence of (macro)molecular entities such as polymers, peptides, proteins and gels on biomimetic calcium phosphate mineralization from aqueous solution. It focuses on strategies to tune the kinetics, morphologies, final dimensions and crystal phases of calcium phosphate, as well as on mechanistic considerations.
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Affiliation(s)
- Katrin Bleek
- Institute of Chemistry, University of Potsdam, D-14476 Potsdam, Germany
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Shen HH, Lithgow T, Martin LL. Reconstitution of membrane proteins into model membranes: seeking better ways to retain protein activities. Int J Mol Sci 2013; 14:1589-607. [PMID: 23344058 PMCID: PMC3565336 DOI: 10.3390/ijms14011589] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 01/09/2013] [Accepted: 01/10/2013] [Indexed: 02/01/2023] Open
Abstract
The function of any given biological membrane is determined largely by the specific set of integral membrane proteins embedded in it, and the peripheral membrane proteins attached to the membrane surface. The activity of these proteins, in turn, can be modulated by the phospholipid composition of the membrane. The reconstitution of membrane proteins into a model membrane allows investigation of individual features and activities of a given cell membrane component. However, the activity of membrane proteins is often difficult to sustain following reconstitution, since the composition of the model phospholipid bilayer differs from that of the native cell membrane. This review will discuss the reconstitution of membrane protein activities in four different types of model membrane - monolayers, supported lipid bilayers, liposomes and nanodiscs, comparing their advantages in membrane protein reconstitution. Variation in the surrounding model environments for these four different types of membrane layer can affect the three-dimensional structure of reconstituted proteins and may possibly lead to loss of the proteins activity. We also discuss examples where the same membrane proteins have been successfully reconstituted into two or more model membrane systems with comparison of the observed activity in each system. Understanding of the behavioral changes for proteins in model membrane systems after membrane reconstitution is often a prerequisite to protein research. It is essential to find better solutions for retaining membrane protein activities for measurement and characterization in vitro.
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Affiliation(s)
- Hsin-Hui Shen
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne 3800, Australia; E-Mail:
- School of Chemistry, Monash University, Clayton, VIC 3800, Australia; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +61-3-9545-8159
| | - Trevor Lithgow
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne 3800, Australia; E-Mail:
| | - Lisandra L. Martin
- School of Chemistry, Monash University, Clayton, VIC 3800, Australia; E-Mail:
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Dante S, Hauß T, Steitz R, Canale C, Dencher NA. Nanoscale structural and mechanical effects of beta-amyloid (1–42) on polymer cushioned membranes: A combined study by neutron reflectometry and AFM Force Spectroscopy. Biochimica et Biophysica Acta (BBA) - Biomembranes 2011; 1808:2646-55. [DOI: 10.1016/j.bbamem.2011.07.024] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2011] [Revised: 07/06/2011] [Accepted: 07/19/2011] [Indexed: 11/20/2022]
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17
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Shen Y, Qi L, Wei X, Zhang R, Mao L. Preparation of well-defined environmentally responsive polymer brushes on monolithic surface by two-step atom transfer radical polymerization method for HPLC. POLYMER 2011. [DOI: 10.1016/j.polymer.2011.06.041] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Tanaka M, Schneck E, Yoshikawa HY, Rossetti FF. Physical chemistry of biological interfaces: generic and specific roles of soft interlayers. Chem Asian J 2011; 6:1728-38. [PMID: 21548102 DOI: 10.1002/asia.201100112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2011] [Indexed: 11/09/2022]
Abstract
Nature defines the spatial boundaries between different phases using membranes, and the interfacial interactions are mediated by soft biopolymer interlayers that contain various carbohydrates. This Review provides a comprehensive overview on the interplay of generic and specific interactions at cell-cell and cell-tissue interfaces. A focus will be put on the combination of defined model systems, experimental techniques in real- and reciprocal space, and theoretical simulations.
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Affiliation(s)
- Motomu Tanaka
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120 Heidelberg, Germany.
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Yoshikawa HY, Rossetti FF, Kaufmann S, Kaindl T, Madsen J, Engel U, Lewis AL, Armes SP, Tanaka M. Quantitative evaluation of mechanosensing of cells on dynamically tunable hydrogels. J Am Chem Soc 2011; 133:1367-74. [PMID: 21218794 DOI: 10.1021/ja1060615] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Thin hydrogel films based on an ABA triblock copolymer gelator [where A is pH-sensitive poly(2-(diisopropylamino)ethyl methacrylate) (PDPA) and B is biocompatible poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC)] were used as a stimulus-responsive substrate that allows fine adjustment of the mechanical environment experienced by mouse myoblast cells. The hydrogel film elasticity could be reversibly modulated by a factor of 40 via careful pH adjustment without adversely affecting cell viability. Myoblast cells exhibited pronounced stress fiber formation and flattening on increasing the hydrogel elasticity. As a new tool to evaluate the strength of cell adhesion, we combined a picosecond laser with an inverted microscope and utilized the strong shock wave created by the laser pulse to determine the critical pressure required for cell detachment. Furthermore, we demonstrate that an abrupt jump in the hydrogel elasticity can be utilized to monitor how cells adapt their morphology to changes in their mechanical environment.
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Affiliation(s)
- Hiroshi Y Yoshikawa
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, D69120 Heidelberg, Germany
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Junginger M, Kita-Tokarczyk K, Schuster T, Reiche J, Schacher F, Müller AHE, Cölfen H, Taubert A. Calcium phosphate mineralization beneath a polycationic monolayer at the air-water interface. Macromol Biosci 2010; 10:1084-92. [PMID: 20718053 DOI: 10.1002/mabi.201000093] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The self-assembly of the amphiphilic block copolymer poly(n-butyl methacrylate)-block-poly[2-(dimethylamino)ethyl methacrylate] at the air-water interface has been investigated at different pH values. Similar to Rehfeldt et al. (J. Phys. Chem. B 2006, 110, 9171), the subphase pH strongly affects the monolayer properties. The formation of calcium phosphate beneath the monolayer can be tuned by the subphase pH and hence the monolayer charge. After 12 h of mineralization at pH 5, the polymer monolayers are still transparent, but transmission electron microscopy (TEM) shows that very thin calcium phosphate fibers form, which aggregate into cotton ball-like features with diameters of 20 to 50 nm. In contrast, after 12 h of mineralization at pH 8, the polymer film is very slightly turbid and TEM shows dense aggregates with sizes between 200 and 700 nm. The formation of calcium phosphate is further confirmed by Raman and energy dispersive X-ray spectroscopy. The calcium phosphate architectures can be assigned to the monolayer charge, which is high at low pH and low at high pH. The study demonstrates that the effects of polycations should not be ignored if attempting to understand the colloid chemistry of biomimetic mineralization. It also shows that basic block copolymers are useful complementary systems to the much more commonly studied acidic block copolymer templates.
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Affiliation(s)
- Mathias Junginger
- University of Potsdam, Institute of Chemistry, 14476 Potsdam, Germany
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Junginger M, Bleek K, Kita-Tokarczyk K, Reiche J, Shkilnyy A, Schacher F, Müller AHE, Taubert A. Calcium phosphate growth beneath a polycationic monolayer at the air-water interface: effects of oscillating surface pressure on mineralization. Nanoscale 2010; 2:2440-2446. [PMID: 20835481 DOI: 10.1039/c0nr00380h] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The self-assembly of the amphiphilic block copolymer poly(butadiene)-block-poly[2-(dimethylamino)ethyl methacrylate] at the air-water interface and the mineralization of the monolayers with calcium phosphate was investigated at different pH values. As expected for polyelectrolytes, the subphase pH strongly affects the monolayer properties. The focus of the current study, however, is on the effect of an oscillating (instead of a static) polymer monolayer on calcium phosphate mineralization. Monitoring of the surface pressure vs. mineralization time shows that the monolayer is quite stable if the mineralization is performed at pH 8. In contrast, the monolayer at pH 5 shows a measurable decrease of the surface pressure already after ca. 2 h of mineralization. Transmission electron microscopy reveals that mineralization at low pH under constant oscillation leads to small particles, which are arranged in circular features and larger entities with holes of ca. 200 nm. The larger features with the holes disappear as the mineralization is continued in favor of the smaller particles. These grow with time and form necklace-like architectures of spherical particles with a uniform diameter. In contrast, mineralization at pH 8 leads to very uniform particle morphologies already after 2 h. The mineralization products consist of a circular feature with a dark dot in the center. The increasing contrast of the precipitates in the electron micrographs with mineralization time indicates an increasing degree of mineralization vs. reaction time. The study therefore shows that mechanical effects on mineralization at interfaces are quite complex.
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Seitz PC, Reif MD, Konovalov OV, Jordan R, Tanaka M. Modulation of Substrate-Membrane Interactions by Linear Poly(2-methyl-2-oxazoline) Spacers Revealed by X-ray Reflectivity and Ellipsometry. Chemphyschem 2009; 10:2876-83. [DOI: 10.1002/cphc.200900553] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Schneck E, Papp-Szabo E, Quinn BE, Konovalov OV, Beveridge TJ, Pink DA, Tanaka M. Calcium ions induce collapse of charged O-side chains of lipopolysaccharides from Pseudomonas aeruginosa. J R Soc Interface 2009; 6 Suppl 5:S671-8. [PMID: 19605401 DOI: 10.1098/rsif.2009.0190.focus] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Lipopolysaccharide (LPS) monolayers deposited on planar, hydrophobic substrates were used as a defined model of outer membranes of Pseudomonas aeruginosa strain dps 89. To investigate the influence of ions on the (out-of-plane) monolayer structure, we measured specular X-ray reflectivity at high energy (22 keV) to ensure transmission through water. Electron density profiles were reconstructed from the reflectivity curves, and they indicate that the presence of Ca(2+) ions induces a significant change in the conformation of the charged polysaccharide head groups (O-side chains). Monte Carlo simulations based on a minimal computer model of LPS molecules allow for the modelling of 100 or more molecules over 10(-3) s and theoretically explained the tendency found by experiments.
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Affiliation(s)
- Emanuel Schneck
- Biophysical Chemistry II, Institute of Physical Chemistry and BIOQUANT, University of Heidelberg, 69120 Heidelberg, Germany
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Kang H, Peng B, Liang Y, Han X, Liu H. Study of the interaction between a diblock polyelectrolyte PDMA-b-PAA and a gemini surfactant 12-6-12 in basic media. J Colloid Interface Sci 2009; 333:135-40. [DOI: 10.1016/j.jcis.2008.12.072] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Revised: 12/24/2008] [Accepted: 12/28/2008] [Indexed: 10/21/2022]
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Affiliation(s)
- Kevin N. Witte
- School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907
| | - Jaehyun Hur
- School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907
| | - Wei Sun
- School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907
| | - Sangtae Kim
- School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907
| | - You-Yeon Won
- School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907
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Schubert T, Seitz PC, Schneck E, Nakamura M, Shibakami M, Funari SS, Konovalov O, Tanaka M. Structure of synthetic transmembrane lipid membranes at the solid/liquid interface studied by specular X-ray reflectivity. J Phys Chem B 2008; 112:10041-4. [PMID: 18630946 DOI: 10.1021/jp803937m] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We fabricated a new class of supported membranes based on monolayers of artificial bola (transmembrane) lipids. The lipids used in this study are symmetric bola lipids with two phosphocholine head groups, which resemble natural archaea lipids. To prevent bending of the hydrocarbon chains, stiff triple bonds are inserted in the middle of the hydrocarbon cores. The formation of homogeneous "monolayers" of transmembrane lipids over macroscopic areas can be monitored with fluorescence microscopy. Structures of such supported monolayers in bulk water were characterized with specular X-ray reflectivity using high energy X-ray radiation, which guarantees a high transmission through bulk water. Here, the vertical structure of single monolayers could be resolved from reconstructed electron density profiles. To verify the structural model suggested by the specular reflectivity, we also performed small- and wide-angle X-ray scattering of transmembrane lipid suspensions. The wide-angle patterns reflect a distorted chain-chain correlation, while the small-angle scattering allowed us to model an electron density profile which is consistent with the profile calculated from specular reflectivity.
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Affiliation(s)
- Thomas Schubert
- Biophysical Chemistry II, Institute of Physical Chemistry and BIOQUANT, University of Heidelberg, INF 253, D-69120 Heidelberg, Germany
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Tanaka M, Rossetti FF, Kaufmann S. Native supported membranes: Creation of two-dimensional cell membranes on polymer supports (Review). Biointerphases 2008; 3:FA12-6. [DOI: 10.1116/1.2905233] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Liu G, Wu D, Ma C, Zhang G, Wang H, Yang S. Insight into the Origin of the Thermosensitivity of Poly[2-(dimethylamino)ethyl methacrylate]. Chemphyschem 2007; 8:2254-9. [PMID: 17879258 DOI: 10.1002/cphc.200700464] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We investigate the effects of pH and temperature on the conformational changes of poly[2-(dimethylamino)ethyl methacrylate] (PDEM) chains at the air/water interface by using Langmuir balance and sum frequency generation vibrational spectroscopy. At pH 4, the tertiary amine groups are fully charged and the PDEM chains are so hydrophilic that they completely enter into the water phase and do not exhibit thermosensitivity. At pH 7, these groups are only partially charged, and the accompanying hydration/dehydration--followed by repartitioning into the water and air phases--gives rise to a marked thermosensitivty. Finally, at pH 10, the tertiary amine groups become uncharged and thus preferentially stay in the hydrophobic air phase, devoid of associated water molecules, which results in the surface-pressure change (DeltaPi) being nearly independent of the temperature. Our Langmuir-balance experiments, coupled with surface-sensitive spectroscopy, demonstrate that: 1) the thermosensitivity of the PDEM chains relates to the hydration/dehydration of the tertiary amine groups, 2) the phase transition of thermosensitive polymers is most likely initiated by the dehydration of the chains, and 3) the phase transition of thermosensitive polymers at the air/water interface is markedly different from that in aqueous solution because of the redistribution of the macromolecular segments induced by the asymmetric forces at the air/water interface.
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Affiliation(s)
- Guangming Liu
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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Rehfeldt F, Steitz R, Armes SP, von Klitzing R, Gast AP, Tanaka M. Reversible Activation of Diblock Copolymer Monolayers at the Interface by pH Modulation, 2: Membrane Interactions at the Solid/Liquid Interface. J Phys Chem B 2006; 110:9177-82. [PMID: 16671731 DOI: 10.1021/jp054533b] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A monolayer of the pH-responsive poly[2-(dimethylamino)ethyl methacrylate-block-methyl methacrylate] diblock copolymer [PDMAEMA-PMMA] was transferred from the air/water interface to a silicon substrate for evaluation as a tunable interlayer between biological material and solid substrates. Specular neutron reflectivity experiments revealed that the weak polyelectrolyte PDMAEMA chains at the solid/liquid interface can be reversibly activated by pH modulation. The thickness, scattering length density, and surface roughness of the polymer film can be systematically controlled by pH titration. As a simple model of plasma membranes, a lipid bilayer was deposited onto the polymer film. The membrane-substrate interaction was characterized by neutron reflectivity experiments, demonstrating that the membrane-substrate distance could be reversibly regulated by pH titration. These results confirm the potential of stimuli-responsive polymers for precise control of cell-surface interactions.
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Affiliation(s)
- Florian Rehfeldt
- Physik Department E22, Technische Universität München, James-Franck-Str., D-85748 Garching, Germany.
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