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Akdeniz B, Wood JA, Lammertink RGH. Diffusiophoretic Behavior of Polyelectrolyte-Coated Particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:5934-5944. [PMID: 38451220 PMCID: PMC10956496 DOI: 10.1021/acs.langmuir.3c03916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 02/21/2024] [Accepted: 02/23/2024] [Indexed: 03/08/2024]
Abstract
Diffusiophoresis, the movement of particles under a solute concentration gradient, has practical implications in a number of applications, such as particle sorting, focusing, and sensing. For diffusiophoresis in an electrolyte solution, the particle velocity is described by the electrolyte relative concentration gradient and the diffusiophoretic mobility of the particle. The electrolyte concentration, which typically varies throughout the system in space and time, can also influence the zeta potential of particles in space and time. This variation affects the diffusiophoretic behavior, especially when the zeta potential is highly dependent on the electrolyte concentration. In this work, we show that adsorbing a single bilayer (or 4 bilayers) of a polyelectrolyte pair (PDADMAC/PSS) on the surface of microparticles resulted in effectively constant zeta potential values with respect to salt concentration throughout the experimental range of salt concentrations. This allowed a constant potential model for diffusiophoretic transport to describe the experimental observations, which was not the case for uncoated particles in the same electrolyte system. This work highlights the use of simple polyelectrolyte pairs to tune the zeta potential and maintain constant values for precise control of diffusiophoretic transport.
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Affiliation(s)
- Burak Akdeniz
- Soft Matter, Fluidics and Interfaces,
MESA+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, Enschede 7500 AE, The Netherlands
| | - Jeffery A. Wood
- Soft Matter, Fluidics and Interfaces,
MESA+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, Enschede 7500 AE, The Netherlands
| | - Rob G. H. Lammertink
- Soft Matter, Fluidics and Interfaces,
MESA+ Institute for Nanotechnology, University
of Twente, P.O. Box 217, Enschede 7500 AE, The Netherlands
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2
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Kolman K, Poggi G, Baglioni M, Chelazzi D, Baglioni P, Persson M, Holmberg K, Bordes R. pH-Controlled assembly of polyelectrolyte layers on silica nanoparticles in concentrated suspension. J Colloid Interface Sci 2022; 615:265-272. [DOI: 10.1016/j.jcis.2022.01.120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 01/18/2023]
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3
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Molotkovsky RJ, Galimzyanov TR, Ermakov YA. Heterogeneity in Lateral Distribution of Polycations at the Surface of Lipid Membrane: From the Experimental Data to the Theoretical Model. MATERIALS (BASEL, SWITZERLAND) 2021; 14:6623. [PMID: 34772149 PMCID: PMC8585412 DOI: 10.3390/ma14216623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/26/2021] [Accepted: 10/29/2021] [Indexed: 11/16/2022]
Abstract
Natural and synthetic polycations of different kinds attract substantial attention due to an increasing number of their applications in the biomedical industry and in pharmacology. The key characteristic determining the effectiveness of the majority of these applications is the number of macromolecules adsorbed on the surface of biological cells or their lipid models. Their study is complicated by a possible heterogeneity of polymer layer adsorbed on the membrane. Experimental methods reflecting the structure of the layer include the electrokinetic measurements in liposome suspension and the boundary potential of planar bilayer lipid membranes (BLM) and lipid monolayers with a mixed composition of lipids and the ionic media. In the review, we systematically analyze the methods of experimental registration and theoretical description of the laterally heterogeneous structures in the polymer layer published in the literature and in our previous studies. In particular, we consider a model based on classical theory of the electrical double layer, used to analyze the available data of the electrokinetic measurements in liposome suspension with polylysines of varying molecular mass. This model suggests a few parameters related to the heterogeneity of the polymer layer and allows determining the conditions for its appearance at the membrane surface. A further development of this theoretical approach is discussed.
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Affiliation(s)
- Rodion J. Molotkovsky
- Laboratory of Bioelectrochemistry, A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy Prospekt, 119071 Moscow, Russia;
| | | | - Yury A. Ermakov
- Laboratory of Bioelectrochemistry, A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy Prospekt, 119071 Moscow, Russia;
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4
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Temporal Changes of Adsorbed Layer Thickness and Electrophoresis of Polystyrene Sulfate Latex Particles after Long Incubation of Oppositely Charged Polyelectrolytes with Different Charge Densities. Polymers (Basel) 2021; 13:polym13152394. [PMID: 34371997 PMCID: PMC8348772 DOI: 10.3390/polym13152394] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/18/2021] [Accepted: 07/18/2021] [Indexed: 11/17/2022] Open
Abstract
The different desorption concepts of the two polyelectrolytes PTMA5M and PTMC5M, which have similar molecular weights and differ in the charge density on the polystyrene sulfate latex (PSL) particles by 25 times, and with various charge densities in a long incubation, were systematically investigated based on hydrodynamic adsorbed layer thickness (δH) and electrophoretic mobility (EPM) under two ionic strengths in the present study. Herein, in the case of highly charged polyelectrolyte PTMA5M, desorption continued for 4 h and re-adsorbing proceeded after a longer incubation time higher than 4 h. Meanwhile, in the case of lowly charged polyelectrolyte PTMC5M, an adsorption-desorption equilibrium was suggested to take into account the unchanging of both δH and EPM.
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5
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Chivu A, Chindera K, Mendes G, An A, Davidson B, Good L, Song W. Cellular gene delivery via poly(hexamethylene biguanide)/pDNA self-assembled nanoparticles. Eur J Pharm Biopharm 2020; 158:62-71. [PMID: 33176193 DOI: 10.1016/j.ejpb.2020.11.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 10/17/2020] [Accepted: 11/02/2020] [Indexed: 10/23/2022]
Abstract
Cellular gene delivery via polycations has wide implications for the potential of gene therapy, but it has remained a challenge due to the plethora of pre- and post-uptake barriers that must be overcome to reach desired efficiency. Herein we report poly(hexamethylene biguanide) (PHMB) as a nano-vector for intracellular delivery of plasmid DNA (pDNA) and oligodeoxynucleotides (ODNs). PHMB and pDNA or ODNs self-assembled into complex nanoparticles at different pH values (7.4 and 12). Their size, charge, cellular uptake, and gene-expression efficiency are assessed and compared to PEI analogues. The systematic results show that the nanoparticles are effective in delivering plasmid DNA and ODNs to model cell lines in culture (HepG2, HEK293T, HeLa), with measurable changes in gene expression levels, comparable to and, in some conditions, even higher than PEI. The well-accepted safety profile of PHMB makes it a valuable candidate for consideration as an effective intracellular DNA vector for further study and potential clinical translation.
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Affiliation(s)
- Alexandru Chivu
- Centre for Biomaterials in Surgical Reconstruction and Regeneration, Division of Surgery & Interventional Science, University College London, Rowland Hill Street, London NW3 2PF, United Kingdom
| | - Kantaraja Chindera
- Department of Pathology and Population Sciences, Royal Veterinary College, Royal College Street, London NW1 0TU, United Kingdom
| | - Graça Mendes
- Centre for Biomaterials in Surgical Reconstruction and Regeneration, Division of Surgery & Interventional Science, University College London, Rowland Hill Street, London NW3 2PF, United Kingdom
| | - Angela An
- Centre for Biomaterials in Surgical Reconstruction and Regeneration, Division of Surgery & Interventional Science, University College London, Rowland Hill Street, London NW3 2PF, United Kingdom
| | - Brian Davidson
- Centre for Biomaterials in Surgical Reconstruction and Regeneration, Division of Surgery & Interventional Science, University College London, Rowland Hill Street, London NW3 2PF, United Kingdom
| | - Liam Good
- Department of Pathology and Population Sciences, Royal Veterinary College, Royal College Street, London NW1 0TU, United Kingdom.
| | - Wenhui Song
- Centre for Biomaterials in Surgical Reconstruction and Regeneration, Division of Surgery & Interventional Science, University College London, Rowland Hill Street, London NW3 2PF, United Kingdom.
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6
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Morrissey KL, Fairbanks BD, Bull DS, Stoykovich MP, Bowman CN. Flocculation behavior and mechanisms of block copolymer architectures on silica microparticle and Chlorella vulgaris systems. J Colloid Interface Sci 2020; 567:316-327. [DOI: 10.1016/j.jcis.2020.02.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Revised: 01/31/2020] [Accepted: 02/01/2020] [Indexed: 11/15/2022]
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7
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PDADMAC/PSS Oligoelectrolyte Multilayers: Internal Structure and Hydration Properties at Early Growth Stages from Atomistic Simulations. Molecules 2020; 25:molecules25081848. [PMID: 32316422 PMCID: PMC7222011 DOI: 10.3390/molecules25081848] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/06/2020] [Accepted: 04/14/2020] [Indexed: 11/17/2022] Open
Abstract
We analyze the internal structure and hydration properties of poly(diallyl dimethyl ammonium chloride)/poly(styrene sulfonate sodium salt) oligoelectrolyte multilayers at early stages of their layer-by-layer growth process. Our study is based on large-scale molecular dynamics simulations with atomistic resolution that we presented recently [Sánchez et al., Soft Matter2019, 15, 9437], in which we produced the first four deposition cycles of a multilayer obtained by alternate exposure of a flat silica substrate to aqueous electrolyte solutions of such polymers at 0.1M of NaCl. In contrast to any previous work, here we perform a local structural analysis that allows us to determine the dependence of the multilayer properties on the distance to the substrate. We prove that the large accumulation of water and ions next to the substrate observed in previous overall measurements actually decreases the degree of intrinsic charge compensation, but this remains as the main mechanism within the interface region. We show that the range of influence of the substrate reaches approximately 3 nm, whereas the structure of the outer region is rather independent from the position. This detailed characterization is essential for the development of accurate mesoscale models able to reach length and time scales of technological interest.
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Ergün A, Tümer EH, Cengiz HY, Deligöz H. Monitoring the Salt Stability of Layer‐by‐Layer Self‐Assembled Films From Polyelectrolyte Blends by Quartz Crystal Microbalance‐Dissipation and Their Ion Separation Performances. POLYM ENG SCI 2020. [DOI: 10.1002/pen.25356] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Ayça Ergün
- Chemical Engineeringİstanbul University‐Cerrahpaşa, Engineering Faculty 34320 Avcılar, İstanbul Turkey
| | - Eda Hazal Tümer
- Engineering Faculty, Chemical EngineeringGebze Technical University 41400 Gebze Kocaeli Turkey
| | - Hacer Yeşim Cengiz
- Chemical Engineeringİstanbul University‐Cerrahpaşa, Engineering Faculty 34320 Avcılar, İstanbul Turkey
| | - Hüseyin Deligöz
- Chemical Engineeringİstanbul University‐Cerrahpaşa, Engineering Faculty 34320 Avcılar, İstanbul Turkey
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9
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Abdullahi W, Crossman M, Griffiths PC. Surfactant-Modulation of the Cationic-Polymer-Induced Aggregation of Anionic Particulate Dispersions. Polymers (Basel) 2020; 12:polym12020287. [PMID: 32024169 PMCID: PMC7077465 DOI: 10.3390/polym12020287] [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: 12/23/2019] [Accepted: 01/08/2020] [Indexed: 11/16/2022] Open
Abstract
Commodity formulations contain many chemically distinct components and their mutual interactions define the beneficial characteristics of the formulation. Mixing oppositely charged polymers and surfactants invariably induces macroscopic phase separation, to a degree dependent on the prevailing polymer and surface charge densities, and the interaction can be modulated by added ionic surfactants. Here, it is shown that a general universality exists between the charge present on a series of cationic-modified cellulose polymers—the charge being controlled either by the degree of cationic modification of the polymer itself or through the subsequent level of anionic surfactant binding—and its capacity to remove anionic colloidal material from solution, be that silica particles or polystyrene-butadiene lattices. Particulate material not removed from solution bears no adsorbed polymer, i.e., the particle surface is bare. Addition of nonionic surfactant does not negate this universality, implying that the nonionic surfactant is largely a spectator molecule or structure (micelle) in these systems, and that the dominant force is an electrostatic one.
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Affiliation(s)
- Wasiu Abdullahi
- School of Science, Faculty of Engineering and Science, University of Greenwich, Chatham Maritime, Kent ME4 4TB, UK;
| | - Martin Crossman
- Unilever Research, Port Sunlight, Quarry Road East, Bebington, Wirral CH63 3JW, UK;
| | - Peter Charles Griffiths
- School of Science, Faculty of Engineering and Science, University of Greenwich, Chatham Maritime, Kent ME4 4TB, UK;
- Correspondence: ; Tel.: +44-208-331-9549
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10
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Sánchez PA, Vögele M, Smiatek J, Qiao B, Sega M, Holm C. Atomistic simulation of PDADMAC/PSS oligoelectrolyte multilayers: overall comparison of tri- and tetra-layer systems. SOFT MATTER 2019; 15:9437-9451. [PMID: 31720676 DOI: 10.1039/c9sm02010a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
By employing large-scale molecular dynamics simulations of atomistically resolved oligoelectrolytes in aqueous solutions, we study in detail the first four layer-by-layer deposition cycles of an oligoelectrolyte multilayer made of poly(diallyl dimethyl ammonium chloride)/poly(styrene sulfonate sodium salt) (PDADMAC/PSS). The multilayers are grown on a silica substrate in 0.1 M NaCl electrolyte solutions and the swollen structures are then subsequently exposed to varying added salt concentration. We investigated the microscopic properties of the films, analyzing in detail the differences between three- and four-layer systems. Our simulations provide insights into the early stages of growth of a multilayer, which are particularly challenging for experimental observations. We found rather strong complexation of the oligoelectrolytes, with fuzzy layering of the film structure. The main charge compensation mechanism is for all cases intrinsic, whereas extrinsic compensation is relatively enhanced for the layer of the last deposition cycle. In addition, we quantified other fundamental observables of these systems, such as the film thickness, water uptake, and overcharge fractions for each deposition layer.
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Affiliation(s)
- Pedro A Sánchez
- Ural Federal University, 51 Lenin av., Ekaterinburg, 620000, Russian Federation. and Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden, Germany
| | - Martin Vögele
- Department of Computer Science, Stanford University, Stanford, California, USA
| | - Jens Smiatek
- Institut für Computerphysik, Universität Stuttgart, 70569 Stuttgart, Germany
| | - Baofu Qiao
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois, USA
| | - Marcello Sega
- Forschungszentrum Jülich, Helmholtz Institute Erlangen-Nuremberg, Nuremberg, Germany
| | - Christian Holm
- Institut für Computerphysik, Universität Stuttgart, 70569 Stuttgart, Germany
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11
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Alipoormazandarani N, Fatehi P. Adsorption Characteristics of Carboxymethylated Lignin on Rigid and Soft Surfaces Probed by Quartz Crystal Microbalance. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:15293-15303. [PMID: 30468388 DOI: 10.1021/acs.langmuir.8b02694] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Limited information is available on the interaction of anionically charged lignin and cationic particles, despite the promising use of anionic lignin as a coagulant and dispersant for suspension systems. The main objective of this study was to discover the fate of lignin on its interaction with rigid and soft surfaces. In this work, carboxymethylated lignin (CML) with two different charge densities were produced, and their adsorption performance on gold and poly(diallydimethylammonium chloride) (PDADMAC)-coated gold surfaces was comprehensively studied. The viscoelastic properties of adsorbed CML on the gold surface were investigated by means of quartz crystal microbalance with dissipation. A higher adsorbed amount and compact layer were observed for the adsorption of CML with a lower charge density of -1.16 meq/g (CML1). CML with a higher charge density (-2.92 meq/g), CML2, yielded a lower surface excess density of 2.31 × 10-6 mol/m2 and a higher occupied area per molecule (71.84 Å2) at the interface of water and gold sensor. Below and at equilibrium, CML2 generated a bulkier adsorption layer than did CML1 on the gold sensor and on the PDADMAC-coated sensor. Studies on the layer-by-layer (LBL) assembly of CML and PDADMAC revealed that CML1 adsorbed more greatly than CML2 on PDADMAC, and it generated a thicker but less viscoelastic layer. In this system, the greater loss to storage modulus ( G″/ G') value was achieved for CML2, indicating its looser structure in the LBL system. Studies on the LBL assembly of carboxymethylated xylan/PDADMAC and CML/PDADMAC provided concrete evidence for the fate of three-dimensional structure of CML on its adsorption performance.
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Affiliation(s)
| | - Pedram Fatehi
- Chemical Engineering Department , Lakehead University , 955 Oliver Road , Thunder Bay , ON , Canada P7B 5E1
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12
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Yu G, Zhou J. Understanding the curvature effect of silica nanoparticles on lysozyme adsorption orientation and conformation: a mesoscopic coarse-grained simulation study. Phys Chem Chem Phys 2018; 18:23500-7. [PMID: 27465065 DOI: 10.1039/c6cp01478j] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In nanobiotechnology applications, curvature of nanoparticles has a significant effect on protein activities. In this work, lysozyme adsorption on different-sized silica nanoparticles (SNPs) was simulated at the microsecond timescale by using mesoscopic coarse-grained molecular dynamics simulations. It is found that, with the increase of nanoparticle size, which indicates a decrease of surface curvature, adsorbed lysozyme shows a narrower orientation distribution and a greater conformation change, as the electrostatic attraction dominates lysozyme adsorption, and this trend is more pronounced on larger SNPs. Interestingly, the effect induced by different SNP surface curvatures is not related to the direct contact area between lysozyme and SNPs, but to the interfacial hydration layer above the silica surface, since a smaller curvature can lead to a stronger interfacial hydration and make the distribution of interfacial water molecules more ordered. Besides, at higher ionic strength, lysozyme conformation is less affected by strongly negatively charged SNPs, especially for larger nanoparticles. This work might shed some light on how to prepare protein coronas with higher bioactivities in nanobiotechnology.
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Affiliation(s)
- Gaobo Yu
- School of Chemistry and Chemical Engineering, Guangdong Provincial Key Lab for Green Chemical Product Technology, South China University of Technology, Guangzhou, 510640, P. R. China.
| | - Jian Zhou
- School of Chemistry and Chemical Engineering, Guangdong Provincial Key Lab for Green Chemical Product Technology, South China University of Technology, Guangzhou, 510640, P. R. China.
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13
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Iselau F, Phan Xuan T, Trefalt G, Matic A, Holmberg K, Bordes R. Formation and relaxation kinetics of starch-particle complexes. SOFT MATTER 2016; 12:9509-9519. [PMID: 27853795 DOI: 10.1039/c6sm01312k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The formation and relaxation kinetics of starch-particle complexes were investigated in this study. The combination of cationic nanoparticles in suspension and anionic starch in solution gave rise to aggregate formation which was studied by dynamic light scattering, revealing the initial adsorption of the starch molecules on the particle surface. By examining the stability ratio, W, it was found that even in the most destabilized state, i.e. at charge neutralization, the starch chains had induced steric stabilization to the system. At higher particle and starch concentrations relaxation of the aggregates could be seen, as monitored by a decrease in turbidity with time. This relaxation was evaluated by fitting the data to the Kohlrausch-Williams-Watts function. It was found that irrespective of the starch to particle charge ratio the relaxation time was similar. Moreover, a molecular weight dependence on the relaxation time was found, as well as a more pronounced initial aggregated state for the higher molecular weight starch. This initial aggregate state could be due to bridging flocculation. With time, as the starch chains have relaxed into a final conformation on the particle surface, bridging will be less important and is gradually replaced by patches that will cause patchwise flocculation. After an equilibration time no molecular weight dependence on aggregation could be seen, which confirms the patchwise flocculation mechanism.
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Affiliation(s)
- Frida Iselau
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Göteborg, Sweden. and Kemira Kemi AB, 44240 Kungälv, Sweden
| | - Tuan Phan Xuan
- Department of Physics, Chalmers University of Technology, 41296 Göteborg, Sweden
| | - Gregor Trefalt
- Department of Inorganic and Analytical Chemistry, University of Geneva, Switzerland
| | - Aleksandar Matic
- Department of Physics, Chalmers University of Technology, 41296 Göteborg, Sweden
| | - Krister Holmberg
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Göteborg, Sweden.
| | - Romain Bordes
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Göteborg, Sweden. and Vinn Excellence Center SuMo Biomaterials, Chalmers University of Technology, 41296 Göteborg, Sweden.
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14
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Iselau F, Phan Xuan T, Matic A, Persson M, Holmberg K, Bordes R. Competitive adsorption of amylopectin and amylose on cationic nanoparticles: a study on the aggregation mechanism. SOFT MATTER 2016; 12:3388-3397. [PMID: 26931418 DOI: 10.1039/c6sm00165c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this study we investigate the interactions between cationic nanoparticles and anionic starch, where the starch was composed of 20 wt% of amylose, a linear polymer, and 80 wt% of amylopectin, a branched polymer. The mechanism of aggregation was investigated by scattering techniques. It was found that the cationic particles formed large aggregates with the starch as a result of selective adsorption of the amylopectin. Amylose did not participate significantly in the aggregate formation even when the charge ratio of starch to particles was <1. For starch to particle ratio >1 stabilization was recovered mostly due to the large hindrance brought about by the highly branched amylopectin. This results in a shift of the stabilization mechanism from electrostatic to electrosteric. The internal structure of the aggregates was composed of primary particles with starch coils adsorbed on the surface. This information supports the proposed aggregation mechanism, which is based on adsorption of the negatively charged starch in patches on the positively charged nanoparticles causing attractive interaction between the particles.
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Affiliation(s)
- Frida Iselau
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Göteborg, Sweden.
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15
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Guzmán E, Maestro A, Llamas S, Álvarez-Rodríguez J, Ortega F, Maroto-Valiente Á, Rubio RG. 3D solid supported inter-polyelectrolyte complexes obtained by the alternate deposition of poly(diallyldimethylammonium chloride) and poly(sodium 4-styrenesulfonate). BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2016; 7:197-208. [PMID: 26977377 PMCID: PMC4778508 DOI: 10.3762/bjnano.7.18] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 01/19/2016] [Indexed: 05/17/2023]
Abstract
This work addresses the formation and the internal morphology of polyelectrolyte layers obtained by the layer-by-layer method. A multimodal characterization showed the absence of stratification of the films formed by the alternate deposition of poly(diallyldimethylammonium chloride) and poly(sodium 4-styrenesulfonate). Indeed the final organization might be regarded as three-dimensional solid-supported inter-polyelectrolyte films. The growth mechanism of the multilayers, followed using a quartz crystal microbalance, evidences two different growth trends, which show a dependency on the ionic strength due to its influence onto the polymer conformation. The hydration state does not modify the multilayer growth, but it contributes to the total adsorbed mass of the film. The water associated with the polyelectrolyte films leads to their swelling and plastification. The use of X-ray photoelectron spectroscopy has allowed for deeper insights on the internal structure and composition of the polyelectrolyte multilayers.
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Affiliation(s)
- Eduardo Guzmán
- Departamento de Química Física I-Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
| | - Armando Maestro
- Department of Physics - Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, CB3 0HE Cambridge, United Kingdom
| | - Sara Llamas
- Istituto per l’Energetica e le Interfasi - U.O.S. Genova, Consiglio Nazionale delle Ricerche, Via De Marini 6, 16149 Genova, Italy
| | - Jesús Álvarez-Rodríguez
- Departamento de Química Inorgánica y Química Técnica - Facultad de Ciencias Universidad Nacional de Educación a Distancia, C/ Senda del Rey 9, 28040 Madrid
| | - Francisco Ortega
- Departamento de Química Física I-Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
| | - Ángel Maroto-Valiente
- Departamento de Química Inorgánica y Química Técnica - Facultad de Ciencias Universidad Nacional de Educación a Distancia, C/ Senda del Rey 9, 28040 Madrid
| | - Ramón G Rubio
- Departamento de Química Física I-Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
- Instituto Pluridisciplinar, Universidad Complutense de Madrid Avda. Juan XXIII 1, 28040 Madrid, Spain
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16
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Menne D, Kamp J, Erik Wong J, Wessling M. Precise tuning of salt retention of backwashable polyelectrolyte multilayer hollow fiber nanofiltration membranes. J Memb Sci 2016. [DOI: 10.1016/j.memsci.2015.10.058] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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17
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Llamas S, Guzmán E, Ortega F, Baghdadli N, Cazeneuve C, Rubio RG, Luengo GS. Adsorption of polyelectrolytes and polyelectrolytes-surfactant mixtures at surfaces: a physico-chemical approach to a cosmetic challenge. Adv Colloid Interface Sci 2015; 222:461-87. [PMID: 24954878 DOI: 10.1016/j.cis.2014.05.007] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 05/30/2014] [Indexed: 10/25/2022]
Abstract
The use of polymer and polymer - surfactant mixtures for designing and developing textile and personal care cosmetic formulations is associated with various physico-chemical aspects, e.g. detergency and conditioning in the case of hair or wool, that determine their correct performances in preserving and improving the appearance and properties of the surface where they are applied. In this work, special attention is paid to the systems combining polycations and negatively charged surfactants. The paper introduces the hair surface and presents a comprehensive review of the adsorption properties of these systems at solid-water interfaces mimicking the negative charge and surface energy of hair. These model surfaces include mixtures of thiols that confer various charge densities to the surface. The kinetics and factors that govern the adsorption are discussed from the angle of those used in shampoos and conditioners developed by the cosmetic industry. Finally, systems able to adsorb onto negatively charged surfaces regardless of the anionic character are presented, opening new ways of depositing conditioning polymers onto keratin substrates such as hair.
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Affiliation(s)
- Sara Llamas
- Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040-Madrid, Spain
| | - Eduardo Guzmán
- Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040-Madrid, Spain; CNR-Istituto per l'Energetica e le Interfasi-U.O.S. Genova, Via de Marini 6, 16149-Genova, Italy
| | - Francisco Ortega
- Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040-Madrid, Spain
| | | | | | - Ramón G Rubio
- Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040-Madrid, Spain.
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18
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Kalasin S, Santore MM. Engineering nanoscale surface features to sustain microparticle rolling in flow. ACS NANO 2015; 9:4706-4716. [PMID: 25774448 DOI: 10.1021/nn505322m] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Nanoscopic features of channel walls are often engineered to facilitate microfluidic transport, for instance when surface charge enables electro-osmosis or when grooves drive mixing. The dynamic or rolling adhesion of flowing microparticles on a channel wall holds potential to accomplish particle sorting or to selectively transfer reactive species or signals between the wall and flowing particles. Inspired by cell rolling under the direction of adhesion molecules called selectins, we present an engineered platform in which the rolling of flowing microparticles is sustained through the incorporation of entirely synthetic, discrete, nanoscale, attractive features into the nonadhesive (electrostatically repulsive) surface of a flow channel. Focusing on one example or type of nanoscale feature and probing the impact of broad systematic variations in surface feature loading and processing parameters, this study demonstrates how relatively flat, weakly adhesive nanoscale features, positioned with average spacings on the order of tens of nanometers, can produce sustained microparticle rolling. We further demonstrate how the rolling velocity and travel distance depend on flow and surface design. We identify classes of related surfaces that fail to support rolling and present a state space that identifies combinations of surface and processing variables corresponding to transitions between rolling, free particle motion, and arrest. Finally we identify combinations of parameters (surface length scales, particle size, flow rates) where particles can be manipulated with size-selectivity.
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Affiliation(s)
- Surachate Kalasin
- Department of Polymer Science and Engineering, University of Massachusetts Amherst, 120 Governors Drive, Amherst, Massachusetts 01003, United States
| | - Maria M Santore
- Department of Polymer Science and Engineering, University of Massachusetts Amherst, 120 Governors Drive, Amherst, Massachusetts 01003, United States
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19
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Dhopatkar N, Park JH, Chari K, Dhinojwala A. Adsorption and viscoelastic analysis of polyelectrolyte-surfactant complexes on charged hydrophilic surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:1026-1037. [PMID: 25555062 DOI: 10.1021/la5043052] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The aggregation of surfactants around oppositely charged polyelectrolytes brings about a peculiar bulk phase behavior of the complex, known as coacervation, and can control the extent of adsorption of the polyelectrolyte at an aqueous-solid interface. Adsorption kinetics from turbid premixed polyelectrolyte-surfactant mixtures have been difficult to measure using optical techniques such as ellipsometry and reflectometry, thus limiting the correlation between bulk phases and interfacial adsorption. Here, we investigated the adsorption from premixed solutions of a cationic polysaccharide (PQ10) and the anionic surfactant sodium dodecyl sulfate (SDS) on an amphoteric alumina surface using quartz crystal microbalance with dissipation (QCMD). The surface charge on the alumina was tuned by changing the pH of the premixed solutions, allowing us to assess the role of electrostatic interactions by studying the adsorption on both negatively and positively charged surfaces. We observed a maximum extent of adsorption on both negatively and positively charged surfaces from a solution corresponding to the maximum turbidity. Enhanced adsorption upon diluting the redissolved complexes at a high SDS concentration was seen only on the negatively charged surface, and not on the positively charged one, confirming the importance of electrostatic interactions in controlling the adsorption on a hydrophilic charged surface. Using the Voight based viscoelastic model, QCMD also provided information on the effective viscosity, effective shear modulus, and thickness of the adsorbed polymeric complex. The findings of viscoelastic analysis, corroborated by atomic force microscopy measurements, suggest that PQ10 by itself forms a flat, uniform layer, rigidly attached to the surface. The PQ10-SDS complex shows a heterogeneous surface structure, where the underlayer is relatively compact and tightly attached and the top is a loosely bound diffused overlayer, accounting for most of the adsorbate, which gets washed away upon rinsing. Understanding of the surface structure will have important implications toward understanding lubrication.
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Affiliation(s)
- Nishad Dhopatkar
- Department of Polymer Science, The University of Akron , Akron, Ohio 44325, United States
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20
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Zhu X, Jańczewski D, Guo S, Lee SSC, Parra Velandia FJ, Teo SLM, He T, Puniredd SR, Vancso GJ. Polyion multilayers with precise surface charge control for antifouling. ACS APPLIED MATERIALS & INTERFACES 2015; 7:852-861. [PMID: 25485625 DOI: 10.1021/am507371a] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report on a molecular fabrication approach to precisely control surface ζ potentials of polymeric thin layers constructed by electrostatic layer-by-layer (LbL) assembly methods. The protocol established allows us to achieve surface isoelectric points (IEP) in the pH range of 6-10. Poly(acrylic acid) (PAA, a weak polyanion) and poly(diallyldimethylammonium chloride) (PDADMAC, a strong polycation) were chosen to build up the bulk films. The weak polycation polyethylenimine (PEI) was applied as a top layer. A unique feature of this approach is that the chemical composition of the top layer is not affected by the manipulation of the ζ potential of the films. Surface charge tuning is achieved by controlling the degree of ionization of the weak polyelectrolytes at various pH values and subsequent manipulation of the amount of polyelectrolyte deposited in the penultimate and last layers, respectively. Following assembly and characterization, the films were used as candidates for antifouling surfaces. The fouling behavior of barnacle cyprids and bacteria on the LbL films with similar hydrophilicity and roughness but different surface charge densities were studied. We found that more cyprids of Amphibalanus amphitrite settled on the negatively charged LbL film compared to the neutral or positively charged LbL film. In bacterial adhesion tests employing Pseudomonas, Escherichia coli, and Staphylococcus aureus, more bacteria were observed on the positively charged LbL film compared with the neutral and negatively charged LbL films, possibly as a result of the negative potential of the bacterial cell wall. The procedures proposed allow one to adjust surface isoelectric points of LbL architectures to achieve optimal antifouling performance of a given material taking into account specific pH values of the environment and the character of the fouler.
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Affiliation(s)
- Xiaoying Zhu
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology, and Research) , 3 Research Link, Singapore 117602
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21
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Wen Y, Guo X, Kalasin S, Santore MM. Capture of soft particles on electrostatically heterogeneous collectors: brushy particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:2019-2027. [PMID: 24559048 DOI: 10.1021/la404235g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This work investigated how particle softness can influence the initial adhesive capture of submicrometer colloidal particles from flow onto collecting surfaces. The study focused on the case dominated by potential attractions at the particle periphery (rather than, for instance, steric stabilization, requiring entropically costly deformations to access shorter-range van der Waals attractions.) The particles, "spherical polyelectrolyte brushes" with diameters in the range of 150-200 nm depending on the ionic strength, consisted of a polystyrene core and a corona of grafted poly(acrylic acid) chains, producing a relatively thick (20-40 nm) negative brushy layer. The adhesion of these particles was studied on electrostatically heterogeneous collecting surfaces: negatively charged substrates carrying flat polycationic patches made by irreversibly adsorbing the poly-l-lysine (PLL) polyelectrolyte. Variation in the amount of adsorbed PLL changed the net collector charge from completely negatively charged (repulsive) to positively charged (attractive). Adjustments in ionic strength varied the range of the electrostatic interactions. Comparing capture kinetics of soft brushy particles to those of similarly sized and similarly charged silica particles revealed nearly identical particle capture kinetics over the full range of collecting surface compositions at high ionic strengths. Even though the brushy particles contained an average of 5 vol % PAA in the brushy shell, with the rest being water under these conditions, their capture was indistinguishable from that of similarly charged rigid spheres. The brushy particles were, however, considerably less adherent at low ionic strengths where the brush was more extended, suggesting an influence of particle deformability or reduced interfacial charge. These findings, that the short time adhesion of brushy particles can resemble that of rigid particles, suggest that for bacteria and cell capture, modeling the cells as rigid particles can, in some instances, be a good approximation.
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Affiliation(s)
- Yicun Wen
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology , Shanghai 200237, People's Republic of China
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22
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Bharti B, Meissner J, Klapp SHL, Findenegg GH. Bridging interactions of proteins with silica nanoparticles: the influence of pH, ionic strength and protein concentration. SOFT MATTER 2014; 10:718-28. [PMID: 24835283 DOI: 10.1039/c3sm52401a] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Charge-driven bridging of nanoparticles by macromolecules represents a promising route for engineering functional structures, but the strong electrostatic interactions involved when using conventional polyelectrolytes impart irreversible complexation and ill-defined structures. Recently it was found that the electrostatic interaction of silica nanoparticles with small globular proteins leads to aggregate structures that can be controlled by pH. Here we study the combined influence of pH and electrolyte concentration on the bridging aggregation of silica nanoparticles with lysozyme in dilute aqueous dispersions. We find that protein binding to the silica particles is determined by pH irrespective of the ionic strength. The hetero-aggregate structures formed by the silica particles with the protein were studied by small-angle X-ray scattering (SAXS) and the structure factor data were analyzed on the basis of a short-range square-well attractive pair potential (close to the sticky-hard-sphere limit). It is found that the electrolyte concentration has a strong influence on the stickiness near pH 5, where the weakly charged silica particles are bridged by the strongly charged protein. An even stronger influence of the electrolyte is found in the vicinity of the isoelectric point of the protein (pI = 10.7) and is attributed to shielding of the repulsion between the highly charged silica particles and hydrophobic interactions between the bridging protein molecules.
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Affiliation(s)
- Bhuvnesh Bharti
- Institut für Chemie, Stranski Laboratorium, TC 7, Technische Universität Berlin, Strasse des 17. Juni 124, D-10623 Berlin, Germany.
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23
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Dussaud AD, Breen PC, Koczo K. Characterization of the deposition of silicone copolymers on keratin fibers by streaming potential measurements. Colloids Surf A Physicochem Eng Asp 2013. [DOI: 10.1016/j.colsurfa.2013.04.071] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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24
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Ngo YH, Li D, Simon GP, Garnier G. Formation of polyelectrolyte–gold nanoparticle necklaces on paper. J Colloid Interface Sci 2013; 405:71-7. [DOI: 10.1016/j.jcis.2013.05.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 04/25/2013] [Accepted: 05/04/2013] [Indexed: 11/16/2022]
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25
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Wang X, Lee S, Miller K, Welbourn R, Stocker I, Clarke S, Casford M, Gutfreund P, Skoda MA. Cation bridging studied by specular neutron reflection. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:5520-5527. [PMID: 23547891 PMCID: PMC3748452 DOI: 10.1021/la400767u] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 04/01/2013] [Indexed: 05/28/2023]
Abstract
The binding of an anionic surfactant onto an anionic surface by addition of divalent ions is reported based on experimental data from specular neutron reflection (NR) and attenuated total internal reflection IR spectroscopy (ATR-IR). Similar measurements using monovalent ions (sodium) do not show any evidence of such adsorption, even though the amount of surfactant can be much higher. This data is interpreted in terms of the so-called bridging mechanism of ion binding.
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Affiliation(s)
- Xiaofan Wang
- BP Institute
and Department
of Chemistry, University of Cambridge,
Cambridge, U.K
| | - Seung
Yeon Lee
- BP Institute
and Department
of Chemistry, University of Cambridge,
Cambridge, U.K
| | - Kathryn Miller
- BP Institute
and Department
of Chemistry, University of Cambridge,
Cambridge, U.K
| | - Rebecca Welbourn
- BP Institute
and Department
of Chemistry, University of Cambridge,
Cambridge, U.K
| | - Isabella Stocker
- BP Institute
and Department
of Chemistry, University of Cambridge,
Cambridge, U.K
| | - Stuart Clarke
- BP Institute
and Department
of Chemistry, University of Cambridge,
Cambridge, U.K
| | - Michael Casford
- Department
of Chemistry, University of Cambridge,
Cambridge, U.K
| | | | - Maximilian
W. A. Skoda
- ISIS, Rutherford
Appleton laboratory, Harwell Science and Innovation
Campus, Didcot, U.K
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26
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Effect of cationic polyacrylamide dissolution on the adsorption state of gold nanoparticles on paper and their Surface Enhanced Raman Scattering properties. Colloids Surf A Physicochem Eng Asp 2013. [DOI: 10.1016/j.colsurfa.2012.12.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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27
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Ngo YH, Li D, Simon GP, Garnier G. Effect of cationic polyacrylamides on the aggregation and SERS performance of gold nanoparticles-treated paper. J Colloid Interface Sci 2013; 392:237-246. [DOI: 10.1016/j.jcis.2012.09.080] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 09/29/2012] [Accepted: 09/29/2012] [Indexed: 12/22/2022]
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28
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Holland JG, Geiger FM. Y(III) interactions with guanine oligonucleotides covalently attached to aqueous/solid interfaces. J Phys Chem B 2013; 117:825-32. [PMID: 23231441 DOI: 10.1021/jp3105858] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The binding of Y(III) ions to surface-immobilized single-stranded 20-mers of guanine was studied using the Eisenthal χ((3)) technique and AFM. The free energy of binding for Y(III) to the G(20) sequence was found to be -39.5(8) kJ/mol. Furthermore, yttrium binds much more strongly to surface-immobilized oligonucleotides than the divalent metals previously reported. At maximum surface coverage, Y(III) ion densities range between one to three ions bound per strand. Comparatively, Mg(II) binds to the G(20)-functionalized interface in much higher ion densities. This result may be explained, in part, by the larger hydration sphere radius of Y(III) compared to that of Mg(II). The ion loading and binding free energy results, in conjunction with other surface and bulk aqueous phase studies, suggest that a fully hydrated +2 or +3 yttrium ion binds to the oligonucleotides through an outer-sphere mechanism. Tapping mode AFM results indicate that oligonucleotide height does not appreciably decrease following Y(III) binding. These results, together with the low ion densities for Y(III) ions, indicate that Y(III) strand loading may not significantly decrease the intrastrand Coulombic repulsions in order to cause a significant decrease in oligomer height.
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Affiliation(s)
- Joseph G Holland
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA
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29
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Peng P, Garnier G. Effect of cationic polyacrylamide on precipitated calcium carbonate flocculation: Kinetics, charge density and ionic strength. Colloids Surf A Physicochem Eng Asp 2012. [DOI: 10.1016/j.colsurfa.2012.05.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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30
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Tucker IM, Petkov JT, Penfold J, Thomas RK. How electrolyte and polyelectrolyte affect the adsorption of the anionic surfactant SDS onto the surface of a cellulose thin film and the structure of the cellulose film. 1. Hydrophobic cellulose. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:10773-80. [PMID: 22735050 DOI: 10.1021/la3019265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The nature of hydrophobic thin cellulose films, formed by Langmuir-Blodgett (LB) deposition on silica, has been studied using neutron reflectivity (NR). The impact of electrolyte and a polyelectrolyte, poly(dimethyldiallylammonium chloride) (polydmdaac), on the adsorption of the anionic surfactant sodium dodecyl sulfate (SDS) onto the surface of the hydrophobic cellulose film and upon the structure of the cellulose film has been investigated. The results show how a combination of polyelectrolytes and electrolyte can be used to manipulate surfactant adsorption onto hydrophobic cellulose surfaces and modify the structure of the cellulose film by swelling and penetration. The results illustrate how polyelectrolytes can be used to reverse adsorption and swelling of cellulose films which are not reversible simply by dilution in solvent.
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Affiliation(s)
- Ian M Tucker
- Unilever Research and Development Laboratory, Port Sunlight, Quarry Road East, Bebington, Wirral, UK
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31
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Tucker IM, Petkov JT, Penfold J, Thomas RK. Interaction of the anionic surfactant SDS with a cellulose thin film and the role of electrolyte and poyelectrolyte. 2 Hydrophilic cellulose. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:10223-9. [PMID: 22679930 DOI: 10.1021/la3019277] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The interaction of the anionic surfactant, sodium dodecylsulfate (SDS), with the hydrophilic surface of a thin cellulose film and the role of electrolyte (0.1 M NaCl) and the polyelectrolyte, poly(dimethyldiallyl ammonium chloride) [polydmdaac], have been studied by neutron reflectivity (NR). The thin cellulose films were prepared by Langmuir-Blodgett (LB) deposition of trimethylsilyl-cellulose (TMSC) on silicon, and the hydrophilic surface was produced by the cleaving of the terminal methyl groups of the TMSC by HCl vapor. Despite both the surfactant and cellulose surfaces being nominally anionic, SDS adsorption and swelling of the cellulose film occurred during adsorption. The results show that the nature of the adsorption and the extent of the penetration into the cellulose film can be controlled by the addition of electrolyte, NaCl, and cationic polyelectrolyte, polydmdaac.
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Affiliation(s)
- Ian M Tucker
- Unilever Research and Development Laboratory, Port Sunlight, Bebington, Wirral, United Kingdom
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32
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Porus M, Clerc F, Maroni P, Borkovec M. Ion-Specific Responsiveness of Polyamidoamine (PAMAM) Dendrimers Adsorbed on Silica Substrates. Macromolecules 2012. [DOI: 10.1021/ma3004295] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Maria Porus
- Department of Inorganic, Analytical
Chemistry, University of Geneva, 30, Quai
Ernest-Ansermet, 1205
Geneva, Switzerland
| | - Florent Clerc
- Department of Inorganic, Analytical
Chemistry, University of Geneva, 30, Quai
Ernest-Ansermet, 1205
Geneva, Switzerland
| | - Plinio Maroni
- Department of Inorganic, Analytical
Chemistry, University of Geneva, 30, Quai
Ernest-Ansermet, 1205
Geneva, Switzerland
| | - Michal Borkovec
- Department of Inorganic, Analytical
Chemistry, University of Geneva, 30, Quai
Ernest-Ansermet, 1205
Geneva, Switzerland
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33
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Milkova V, Kamburova K, Cameron R, Radeva T. Complexation of Ferric Oxide Particles with Pectins of Ordered and Random Distribution of Charged Units. Biomacromolecules 2011; 13:138-45. [DOI: 10.1021/bm201374p] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Viktoria Milkova
- Institute of Physical Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
| | - Kamelia Kamburova
- Institute of Physical Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
| | - Randall Cameron
- U.S. Department of Agriculture, Agricultural Research Service, Citrus
and Subtropical Products Laboratory, Winter Haven, Florida, United
States
| | - Tsetska Radeva
- Institute of Physical Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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34
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Adamczyk Z, Nattich M, Wasilewska M, Zaucha M. Colloid particle and protein deposition - electrokinetic studies. Adv Colloid Interface Sci 2011; 168:3-28. [PMID: 21621181 DOI: 10.1016/j.cis.2011.04.002] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 04/15/2011] [Accepted: 04/18/2011] [Indexed: 11/30/2022]
Abstract
Recent developments in the electrokinetic determination of particle, polyelectrolyte and protein deposition at solid/electrolyte interfaces, are reviewed. In the first section basic theoretical results are discussed enabling a quantitative interpretation of the streaming current/potential and microelectrophoretic measurements. Experimental results are presented, pertinent to electrokinetic characteristics of simple (homogeneous) surfaces such as mica, silica and various polymeric surfaces used in protein studies. The influence of the ionic strength, background electrolyte composition and pH is discussed, and the effective (electrokientic) charge of these interfaces is evaluated. In the next section, experimental data obtained by streaming potential measurements for colloid particle mono- and bilayers are presented and interpreted successfully in terms of available theoretical approaches. These results, obtained for model systems of monodisperse colloid particles are used as reference data for discussion of more complicated experiments performed for polyelectrolyte and protein covered surfaces. Results are discussed, obtained for cationic polyelectrolytes (PEI, PAH) and fibrinogen adsorbing on mica, interpreted quantitatively in terms of the theoretical approach postulating a heterogeneous 3D charge distribution. The Gouy-Chapman model, based on the continuous charge distribution proved inadequate. Interesting experimental data are also discussed, obtained by electrophoretic methods in the case of protein adsorption on colloid latex particles. In the last section, supplementary results on particle deposition on heterogeneous surfaces produced by controlled protein adsorption are discussed. Quantitative relationships between the amount of adsorbed protein, zeta potential of the interface and the particle coverage are specified. Possibility of evaluating the heterogeneity of protein charge distribution is pointed out. The anomalous deposition of colloid particles on protein molecules bearing the same sign of zeta potential, which contradicts classical DLVO theory, is interpreted in terms of the fluctuation theory. It is concluded that theoretical and experimental results obtained for model colloid systems and flat interfaces can be effectively used for interpretation of protein adsorption phenomena, studied by electrophoresis. In this way the universality of electrokinetic phenomena is underlined.
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Affiliation(s)
- Z Adamczyk
- J. Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Cracow, Poland.
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35
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Lyklema J, Deschênes L. The first step in layer-by-layer deposition: electrostatics and/or non-electrostatics? Adv Colloid Interface Sci 2011; 168:135-48. [PMID: 21545980 DOI: 10.1016/j.cis.2011.03.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 03/21/2011] [Accepted: 03/22/2011] [Indexed: 10/18/2022]
Abstract
A critical discussion is presented on the properties and prerequisites of adsorbed polyelectrolytes that have to function as substrates for further layer-by-layer deposition. The central theme is discriminating between the roles of electrostatic and non-electrostatic interactions. In order to emphasize this feature we refrain from discussing practical problems sometimes incurred in polyelectrolyte adsorption like freezing-in of non-equilibrium situations, patchwise attachment, unclear chemistry and only consider solid substrates. Although it is in principle ambiguous to discriminate between coulombic and non-coulombic or "chemical" interactions, it will be shown that, as a rule, non-coulombic contributions to the interactions cannot be neglected. They are responsible for the familiar overcharging. For obtaining more insight, it is recommended to consider electrometric techniques such as electrokinetics, conductometry and potentiometry, in combination with other analytical techniques applied to well-defined systems, for which various parameters can be modulated in a systematic way.
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36
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Sadeghpour A, Seyrek E, Szilágyi I, Hierrezuelo J, Borkovec M. Influence of the degree of ionization and molecular mass of weak polyelectrolytes on charging and stability behavior of oppositely charged colloidal particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:9270-9276. [PMID: 21707034 DOI: 10.1021/la201968b] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Positively charged amidine latex particles are studied in the presence of poly(acrylic acid) (PAA) with different molecular masses under neutral and acidic conditions by electrophoresis and time-resolved dynamic light scattering. Under neutral conditions, where PAA is highly charged, the system is governed by the charge reversal induced by the quantitatively adsorbing polyelectrolyte and attractive patch-charge interactions. Under acidic conditions, where PAA is more weakly charged, the following two effects come into play. First, the lateral structure of the adsorbed layers becomes more homogeneous, which weakens the attractive patch-charge interactions. Second, polyelectrolyte adsorption is no longer quantitative and partitioning into the solution phase is observed, especially for PAA of low molecular mass.
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Affiliation(s)
- Amin Sadeghpour
- Department of Inorganic, Analytical, and Applied Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland
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Kalasin S, Martwiset S, Coughlin EB, Santore MM. Particle capture via discrete binding elements: systematic variations in binding energy for randomly distributed nanoscale surface features. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:16865-16870. [PMID: 20961162 DOI: 10.1021/la103023t] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This work examines how the binding strength of surface-immobilized "stickers" (representative of receptors or, in nonbiological systems, chemical heterogeneities) influences the adhesion between surfaces that are otherwise repulsive. The study focuses on a series of surfaces designed with fixed average adhesive energy per unit area and demonstrates quantitatively how a redistribution of the adhesive functionality into progressively larger clusters (stronger stickers) increases the probability of adhesive events. The work employs an electrostatic model system: relatively uniform, negative 1 μm silica spheres flow gently over negative silica flats. The flats contain small amounts of randomly positioned nanoscale cationic patches. The silica-silica interaction is repulsive; however, the cationic patches (present at sufficiently low levels that the overall surface charge remains substantially negative) produce local attractions. In this study, the attractions are relatively weak so that multiple patches engage to capture flowing particles. Experiments reveal an adhesion signature characteristic of a renormalized random distribution when the sticker strength is increased at an overall fixed binding strength per unit area of surface. The form of the particle capture curves are in good quantitative agreement with a simple model that assumes only a fixed adhesion energy needed for particle capture. Aside from the quantitative details that provide a simple formalism for anticipating particle adhesion, this work demonstrates how increasing the heterogeneities in the surface functionality can cause a system to go from being nonadhesive to becoming strongly adhesive. Indeed, systems containing small amounts of discretized adhesive functionality are always more adhesive than systems in which the same functionality is distributed uniformly over the surface (the mean field scenario).
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Affiliation(s)
- Surachate Kalasin
- Department of Polymer Science and Engineering, University of Massachusetts, 120 Governor's Drive, Amherst, Massachusetts 01003, United States
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Kalasin S, Dabkowski J, Nüsslein K, Santore MM. The role of nano-scale heterogeneous electrostatic interactions in initial bacterial adhesion from flow: A case study with Staphylococcus aureus. Colloids Surf B Biointerfaces 2010; 76:489-95. [DOI: 10.1016/j.colsurfb.2009.12.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2009] [Revised: 12/13/2009] [Accepted: 12/15/2009] [Indexed: 11/25/2022]
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Kalasin S, Santore MM. Sustained rolling of microparticles in shear flow over an electrostatically patchy surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:2317-2324. [PMID: 20141198 DOI: 10.1021/la9027404] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This paper explores the particle-level dynamics involved in the capture of gently flowing microparticles on adhesive planar surfaces, governed by electrostatic interactions. The work focuses on conditions which produce sustained microparticle rolling, useful for the development of microfluidic devices which steer analyte particles and cells for manipulation and separation. In the regime where particle-surface interactions dominate particle-particle interactions, capture of individual negative silica microspheres, for thousands of microspheres, is studied on three model surfaces: negative silica, a flat polycation layer adsorbed on silica producing a strong positive charge, and an electrostatically patchy surface containing 6% areal coverage of flat 10 nm polycation coils. The patchy surface possesses a net negative charge close to that of bare silica. On the patchy surface, sustained rolling is observed for a substantial population of 1 microm silica particles, the ones which happened to diffuse close to the surface. Here, the velocity is near 2 microm/s (for a wall shear of 22 s(-1).) Run lengths for particle rolling exceed several hundred micrometers (usually exceeding the length of the microscopic field of view), with more particles escaping diffusively from the interface than permanently arresting. By contrast, firm particle arrest, with very few instances of rolling and a short run length when rolling did occur, was observed on the fully cationic surface. On the bare silica surface, a small rolling population was observed; however, the average run length was shorter than on the patchy surface. This study demonstrated how a patchy surface that produces adhesion through localized attractions can facilitate rolling in a shear field. The physicochemical heterogeneity acts like a surface roughness or a rapidly binding ligand-receptor pair, transferring stress and imparting torque across the interface.
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Affiliation(s)
- Surachate Kalasin
- Department of Physics, University of Massachusetts at Amherst, Amherst, Massachusetts 01003, USA
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Adamczyk Z, Sadlej K, Wajnryb E, Nattich M, Ekiel-Jeżewska M, Bławzdziewicz J. Streaming potential studies of colloid, polyelectrolyte and protein deposition. Adv Colloid Interface Sci 2010; 153:1-29. [PMID: 19926067 DOI: 10.1016/j.cis.2009.09.004] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 09/24/2009] [Accepted: 09/26/2009] [Indexed: 10/20/2022]
Abstract
Recent developments in the electrokinetic determination of particle, protein and polyelectrolyte monolayers at solid/electrolyte interfaces, are reviewed. Illustrative theoretical results characterizing particle transport to interfaces are presented, especially analytical formulae for the limiting flux under various deposition regimes and expressions for diffusion coefficients of various particle shapes. Then, blocking effects appearing for higher surface coverage of particles are characterized in terms of the random sequential adsorption model. These theoretical predictions are used for interpretation of experimental results obtained for colloid particles and proteins under convection and diffusion transport conditions. The kinetics of particle deposition and the structure of monolayers are analyzed quantitatively in terms of the generalized random sequential adsorption (RSA) model, considering the coupling of the bulk and surface transport steps. Experimental results are also discussed, showing the dependence of the jamming coverage of monolayers on the ionic strength of particle suspensions. In the next section, theoretical and experimental results pertaining to electrokinetics of particle covered surfaces are presented. Theoretical models are discussed, enabling a quantitative evaluation of the streaming current and the streaming potential as a function of particle coverage and their surface properties (zeta potential). Experimental data related to electrokinetic characteristics of particle monolayers, mostly streaming potential measurements, are presented and interpreted in terms of the above theoretical approaches. These results, obtained for model systems of monodisperse colloid particles are used as reference data for discussion of experiments performed for polyelectrolyte and protein covered surfaces. The utility of the electrokinetic measurements for a precise, in situ determination of particle and protein monolayers at various interfaces is pointed out.
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Kalasin S, Santore MM. Non-specific adhesion on biomaterial surfaces driven by small amounts of protein adsorption. Colloids Surf B Biointerfaces 2009; 73:229-36. [DOI: 10.1016/j.colsurfb.2009.05.028] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 05/05/2009] [Accepted: 05/25/2009] [Indexed: 01/07/2023]
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Duffadar R, Kalasin S, Davis JM, Santore MM. The impact of nanoscale chemical features on micron-scale adhesion: Crossover from heterogeneity-dominated to mean-field behavior. J Colloid Interface Sci 2009; 337:396-407. [DOI: 10.1016/j.jcis.2009.05.046] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Revised: 04/30/2009] [Accepted: 05/20/2009] [Indexed: 01/08/2023]
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Bordi F, Sennato S, Truzzolillo D. Polyelectrolyte-induced aggregation of liposomes: a new cluster phase with interesting applications. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:203102. [PMID: 21825508 DOI: 10.1088/0953-8984/21/20/203102] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Different charged colloidal particles have been shown to be able to self-assemble, when mixed in an aqueous solvent with oppositely charged linear polyelectrolytes, forming long-lived finite-size mesoscopic aggregates. On increasing the polyelectrolyte content, with the progressive reduction of the net charge of the primary polyelectrolyte-decorated particles, larger and larger clusters are observed. Close to the isoelectric point, where the charge of the adsorbed polyelectrolytes neutralizes the original charge of the particles' surface, the aggregates reach their maximum size, while beyond this point any further increase of the polyelectrolyte-particle charge ratio causes the formation of aggregates whose size is progressively reduced. This re-entrant condensation behavior is accompanied by a significant overcharging. Overcharging, or charge inversion, occurs when more polyelectrolyte chains adsorb on a particle than are needed to neutralize its original charge so that, eventually, the sign of the net charge of the polymer-decorated particle is inverted. The stability of the finite-size long-lived clusters that this aggregation process yields results from a fine balance between long-range repulsive and short-range attractive interactions, both of electrostatic nature. For the latter, besides the ubiquitous dispersion forces, whose supply becomes relevant only at high ionic strength, the main contribution appears due to the non-uniform correlated distribution of the charge on the surface of the polyelectrolyte-decorated particles ('charge-patch' attraction). The interesting phenomenology shown by these system has a high potential for biotechnological applications, particularly when the primary colloidal particles are bio-compatible lipid vesicles. Possible applications of these systems as multi-compartment vectors for the simultaneous intra-cellular delivery of different pharmacologically active substances will be briefly discussed.
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Affiliation(s)
- F Bordi
- Dipartimento di Fisica, Università di Roma 'La Sapienza', Piazzale Aldo Moro 5, I-00185 Rome, Italy. CRS CNR-INFM 'SOFT', Università di Roma 'La Sapienza', Piazzale Aldo Moro 5, I-00185-Rome, Italy
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Adamczyk Z, Nattich M, Barbasz J. Deposition of colloid particles at heterogeneous and patterned surfaces. Adv Colloid Interface Sci 2009; 147-148:2-17. [PMID: 19193360 DOI: 10.1016/j.cis.2008.12.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Theoretical and experimental results pertinent to irreversible adsorption (deposition) of particles at heterogeneous and patterned surfaces were reviewed. Three main deposition regimes are distinguished: (i) the quasi continuous surface regime, (ii) the random site surface (RSS) regime and (iii) the patterned surface regime. Theoretical results obtained for the RSS and the patterned surface regime were presented, in particular the topology of particle monolayers, the jamming (maximum) coverage, the averaged number of particles adsorbed and particle distribution density over various surface patterns. Special attention was focused on rectangular surface features (stripes). These results were obtained using the random sequential adsorption (RSA) approach, whose range of validity is assessed using the limiting analytical solutions. These theoretical predictions were used for interpretation of experimental results obtained mostly for monodisperse latex particles adsorbing on random site surfaces created by controlled colloid particle or polyelectrolyte adsorption. The structure of monolayers was analyzed adsorption probability as a function of site coverage and the jamming coverage limit for various particle to site size ratio. Finally, recent results were discussed, obtained for surface features of regular shape like circles and rectangles. It was concluded that these experimental data confirmed the validity of the RSA model for describing particle deposition at heterogeneous and patterned surfaces. It was also concluded that theoretical and experimental results obtained for model colloid systems can be effectively used as useful reference states for analyzing protein and macromolecule adsorption at heterogeneous surfaces.
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Olsen C, Van Tassel PR. Polyelectrolyte adsorption kinetics under an applied electric potential: Strongly versus weakly charged polymers. J Colloid Interface Sci 2009; 329:222-7. [DOI: 10.1016/j.jcis.2008.10.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Revised: 10/03/2008] [Accepted: 10/06/2008] [Indexed: 11/30/2022]
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Zhao X, Pan F, Coffey P, Lu JR. Cationic copolymer-mediated DNA immobilization: interfacial structure and composition as determined by ellipsometry, dual polarization interferometry, and neutron reflection. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:13556-13564. [PMID: 18986183 DOI: 10.1021/la8024974] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
DNA immobilization onto support surfaces is required in biotechnological applications such as microarrays and gene delivery. This important interfacial molecular process can be mediated from a preadsobred cationic polymer. There is, however, a lack of understanding over the control of the interfacial composition and structural distribution of the DNA immobilized. We have used a combined approach of spectroscopic ellipsometry (SE), dual polarization interferometry (DPI) and neutron reflection (NR) to determine the interfacial polymer adsorption and the subsequent DNA binding. Cationic diblock copolymers incorporating 30 phosphorylcholine (PC) groups and different diethylaminoethyl groups, referred to as MPC30-DEAn, were chosen because of their well-defined molecular architecture. While our studies revealed different effects of surface charge and hydrophobicity, the amount of copolymers adsorbed on both model surfaces showed a broad trend of increase with solution pH, indicating a strong effect arising from pH-dependent charge density on the copolymers. In contrast, the copolymer structure and solution concentration showed a weak effect under the conditions studied. The subsequent DNA binding at pH 7 showed that on both surfaces the amount of DNA immobilized followed an approximate 1:1 charge interaction for all different DNA samples studied, irrespective of single or double strand, or different DNA size, indicating the dominant effect of electrostatic interaction between the two species. Both DPI and NR revealed consistent thickness increase upon DNA binding. Furthermore, with increasing DNA size, the interfacial layer became much thicker, and charge interaction drove more extensive interfacial mixing between the two species. Our results show that the amount of DNA immobilized is controlled by the amount of cationic copolymer preadsorbed that is in turn controlled by the solution pH and surface chemistry but that is barely affected by the type and concentration of DNA or cationic copolymer.
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Affiliation(s)
- XiuBo Zhao
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Schuster Building, Manchester M13 9PL, UK
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Milkova V, Kamburova K, Petkanchin I, Radeva T. Complexation of ferric oxide particles with pectins of different charge density. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:9495-9499. [PMID: 18652496 DOI: 10.1021/la8012602] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The effect of polyelectrolyte charge density on the electrical properties and stability of suspensions of oppositely charged oxide particles is followed by means of electro-optics and electrophoresis. Variations in the electro-optical effect and the electrophoretic mobility are examined at conditions where fully ionized pectins of different charge density adsorb onto particles with ionizable surfaces. The charge neutralization point coincides with the maximum of particle aggregation in all suspensions. We find that the concentration of polyelectrolyte, needed to neutralize the particle charge, decreases with increasing charge density of the pectin. The most highly charged pectin presents an exception to this order, which is explained with a reduction of the effective charge density of this pectin due to condensation of counterions. The presence of condensed counterions, remaining bound to the pectin during its adsorption on the particle surface, is proved by investigation of the frequency behavior of the electro-optical effect at charge reversal of the particle surface.
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Affiliation(s)
- Viktoria Milkova
- Institute of Physical Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Comparative study of electrokinetic potentials and binding affinity of lipopolysaccharides–chitosan complexes. Biophys Chem 2008; 136:1-6. [DOI: 10.1016/j.bpc.2008.03.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Accepted: 03/22/2008] [Indexed: 11/19/2022]
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Bratskaya SY, Schwarz S, Liebert T, Heinze T. Flocculation and binding properties of highly substituted cationic starches. RUSS J APPL CHEM+ 2008. [DOI: 10.1134/s1070427208050273] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Rakhmatullina E, Meier W. Solid-supported block copolymer membranes through interfacial adsorption of charged block copolymer vesicles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:6254-6261. [PMID: 18481881 DOI: 10.1021/la8003068] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The properties of amphiphilic block copolymer membranes can be tailored within a wide range of physical parameters. This makes them promising candidates for the development of new (bio)sensors based on solid-supported biomimetic membranes. Here we investigated the interfacial adsorption of polyelectrolyte vesicles on three different model substrates to find the optimum conditions for formation of planar membranes. The polymer vesicles were made from amphiphilic ABA triblock copolymers with short, positively charged poly(2,2-dimethylaminoethyl methacrylate) (PDMAEMA) end blocks and a hydrophobic poly( n-butyl methacrylate) (PBMA) middle block. We observed reorganization of the amphiphilic copolymer chains from vesicular structures into a 1.5+/-0.04 nm thick layer on the hydrophobic HOPG surface. However, this film starts disrupting and dewetting upon drying. In contrast, adsorption of the vesicles on the negatively charged SiO2 and mica substrates induced vesicle fusion and formation of planar, supported block copolymer films. This process seems to be controlled by the surface charge density of the substrate and concentration of the block copolymers in solution. The thickness of the copolymer membrane on mica was comparable to the thickness of phospholipid bilayers.
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Affiliation(s)
- Ekaterina Rakhmatullina
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland
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