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Zhang Y, Marlow JB, Millar W, Silvester DS, Warr GG, Li H, Atkin R. Effect of ion structure on the nanostructure and electrochemistry of surface active ionic liquids. J Colloid Interface Sci 2023; 630:931-939. [DOI: 10.1016/j.jcis.2022.10.074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 09/29/2022] [Accepted: 10/16/2022] [Indexed: 11/05/2022]
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2
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Qiu Y, Chien CC, Maroulis B, Bei J, Gaitas A, Gong B. Extending applications of AFM to fluidic AFM in single living cell studies. J Cell Physiol 2022; 237:3222-3238. [PMID: 35696489 PMCID: PMC9378449 DOI: 10.1002/jcp.30809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 05/25/2022] [Indexed: 12/30/2022]
Abstract
In this article, a review of a series of applications of atomic force microscopy (AFM) and fluidic Atomic Force Microscopy (fluidic AFM, hereafter fluidFM) in single-cell studies is presented. AFM applications involving single-cell and extracellular vesicle (EV) studies, colloidal force spectroscopy, and single-cell adhesion measurements are discussed. FluidFM is an offshoot of AFM that combines a microfluidic cantilever with AFM and has enabled the research community to conduct biological, pathological, and pharmacological studies on cells at the single-cell level in a liquid environment. In this review, capacities of fluidFM are discussed to illustrate (1) the speed with which sequential measurements of adhesion using coated colloid beads can be done, (2) the ability to assess lateral binding forces of endothelial or epithelial cells in a confluent cell monolayer in an appropriate physiological environment, and (3) the ease of measurement of vertical binding forces of intercellular adhesion between heterogeneous cells. Furthermore, key applications of fluidFM are reviewed regarding to EV absorption, manipulation of a single living cell by intracellular injection, sampling of cellular fluid from a single living cell, patch clamping, and mass measurements of a single living cell.
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Affiliation(s)
- Yuan Qiu
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Chen-Chi Chien
- The Estelle and Daniel Maggin Department of Neurology, Icahn School of Medicine at Mount Sinai, New York City, New York, USA
| | - Basile Maroulis
- The Estelle and Daniel Maggin Department of Neurology, Icahn School of Medicine at Mount Sinai, New York City, New York, USA
| | - Jiani Bei
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Angelo Gaitas
- The Estelle and Daniel Maggin Department of Neurology, Icahn School of Medicine at Mount Sinai, New York City, New York, USA.,BioMedical Engineering & Imaging Institute, Leon and Norma Hess Center for Science and Medicine, New York City, New York, USA
| | - Bin Gong
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, USA.,Sealy Center for Vector Borne and Zoonotic Diseases, University of Texas Medical Branch, Galveston, Texas, USA.,Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas, USA.,Institute for Human Infectious and Immunity, University of Texas Medical Branch, Galveston, Texas, USA
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Zhang Y, Marlow JB, Millar W, Aman ZM, Silvester DS, Warr GG, Atkin R, Li H. Nanostructure, electrochemistry and potential-dependent lubricity of the catanionic surface-active ionic liquid [P 6,6,6,14] [AOT]. J Colloid Interface Sci 2022; 608:2120-2130. [PMID: 34752982 DOI: 10.1016/j.jcis.2021.10.120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 10/14/2021] [Accepted: 10/20/2021] [Indexed: 10/20/2022]
Abstract
HYPOTHESIS A catanionic surface-active ionic liquid (SAIL) trihexyltetradecylphosphonium 1,4-bis(2-ethylhexoxy)-1,4-dioxobutane-2-sulfonate ([P6,6,6,14] [AOT]) is nanostructured in the bulk and at the interface. The interfacial nanostructure and lubricity may be changed by applying a potential. EXPERIMENTS The bulk structure and viscosity have been investigated using small angle X-ray scattering (SAXS) and rheometry. The interfacial structure and lubricity as a function of potential have been investigated using atomic force microscopy (AFM). The electrochemistry has been investigated using cyclic voltammetry. FINDINGS [P6,6,6,14] [AOT] shows sponge-like bulk nanostructure with distinct interdigitation of cation-anion alkyl chains. Shear-thinning occurs at 293 K and below, but becomes less obvious on heating up to 313 K. Voltammetric analysis reveals that the electrochemical window of [P6,6,6,14] [AOT] on a gold micro disk electrode exceeds the potential range of the AFM experiments and that negligible redox activity occurs in this range. The interfacial layered structure of [P6,6,6,14] [AOT] is weaker than conventional ILs and SAILs, whereas lubricity is better, confirming the inverse correlation between the near-surface structure and lubricity. The adhesive forces of [P6,6,6,14] [AOT] are lower at -1.0 V than at open circuit potential and +1.0 V, likely due to reduced electrostatic interactions caused by shielding of charge centres via long alkyl chains.
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Affiliation(s)
- Yunxiao Zhang
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Joshua B Marlow
- School of Chemistry and Sydney Nano Institute, The University of Sydney, Sydney, NSW 2006, Australia
| | - Wade Millar
- School of Molecular and Life Sciences, Curtin University, GPO Box U1987, Perth 6845, Western Australia, Australia
| | - Zachary M Aman
- Fluid Science and Resources Division, School of Engineering, The University of Western Australia, Perth, Western Australia, Australia
| | - Debbie S Silvester
- School of Molecular and Life Sciences, Curtin University, GPO Box U1987, Perth 6845, Western Australia, Australia
| | - Gregory G Warr
- School of Chemistry and Sydney Nano Institute, The University of Sydney, Sydney, NSW 2006, Australia
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia.
| | - Hua Li
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia; Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia, Australia.
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4
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Li H, Zhang Y, Jones S, Segalman R, Warr GG, Atkin R. Interfacial nanostructure and friction of a polymeric ionic liquid-ionic liquid mixture as a function of potential at Au(111) electrode interface. J Colloid Interface Sci 2022; 606:1170-1178. [PMID: 34487936 DOI: 10.1016/j.jcis.2021.08.067] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/09/2021] [Accepted: 08/09/2021] [Indexed: 11/28/2022]
Abstract
HYPOTHESIS The polymeric cations of polymeric ionic liquids (PILs) can adsorb from the bulk of a conventional ionic liquid (IL) to the Au(111) electrode interface and form a boundary layer. The interfacial properties of the PIL boundary layer may be tuned by potential. EXPERIMENTS Atomic force microscopy has been used to investigate the changes of surface morphology, normal and lateral forces of a 5 wt% PIL/IL mixture as a function of potential. FINDINGS Polymeric cations adsorb strongly to Au(111) and form a polymeric cation-enriched boundary layer at -1.0 V. This boundary layer binds less strongly to the surface at open circuit potential (OCP) and weakly at + 1.0 V. The polymeric cation chains are compressed at -1.0 V and OCP owing to electrical attractions with the electrode surface, but fully stretched at + 1.0 V due to electrical repulsions. The lateral forces of the 5 wt% PIL/IL mixture at -1.0 V and OCP are higher than at + 1.0 V as the polymeric cation-enriched boundary layer is rougher and has stronger interactions with the AFM probe; at + 1.0 V, the lateral force is low and comparable to pure conventional IL due to displacement of polymeric cations with conventional anions in the boundary layer.
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Affiliation(s)
- Hua Li
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia; Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia, Australia.
| | - Yunxiao Zhang
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Seamus Jones
- Department of Chemical Engineering and Materials Department, University of California, Santa Barbara, Santa Barbara, CA 93106, United States
| | - Rachel Segalman
- Department of Chemical Engineering and Materials Department, University of California, Santa Barbara, Santa Barbara, CA 93106, United States
| | - Gregory G Warr
- School of Chemistry and Sydney Nano Institute, The University of Sydney, NSW 2006, Australia
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia.
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5
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Wojas NA, Dobryden I, Wallqvist V, Swerin A, Järn M, Schoelkopf J, Gane PAC, Claesson PM. Nanoscale Wear and Mechanical Properties of Calcite: Effects of Stearic Acid Modification and Water Vapor. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:9826-9837. [PMID: 34355909 PMCID: PMC8397405 DOI: 10.1021/acs.langmuir.1c01390] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 07/26/2021] [Indexed: 06/13/2023]
Abstract
Understanding the wear of mineral fillers is crucial for controlling industrial processes, and in the present work, we examine the wear resistance and nanomechanical properties of bare calcite and stearic acid-modified calcite surfaces under dry and humid conditions at the nanoscale. Measurements under different loads allow us to probe the situation in the absence and presence of abrasive wear. The sliding motion is in general characterized by irregular stick-slip events that at higher loads lead to abrasion of the brittle calcite surface. Bare calcite is hydrophilic, and under humid conditions, a thin water layer is present on the surface. This water layer does not affect the friction force. However, it slightly decreases the wear depth and strongly influences the distribution of wear particles. In contrast, stearic acid-modified surfaces are hydrophobic. Nevertheless, humidity affects the wear characteristics by decreasing the binding strength of stearic acid at higher humidity. A complete monolayer coverage of calcite by stearic acid results in a significant reduction in wear but only a moderate reduction in friction forces at low humidity and no reduction at 75% relative humidity (RH). Thus, our data suggest that the wear reduction does not result from a lowering of the friction force but rather from an increased ductility of the surface region as offered by the stearic acid layer. An incomplete monolayer of stearic acid on the calcite surface provides no reduction in wear regardless of the RH investigated. Clearly, the wear properties of modified calcite surfaces depend crucially on the packing density of the surface modifier and also on the air humidity.
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Affiliation(s)
- Natalia A. Wojas
- Bioeconomy
and Health Division, Department of Materials and Surface Design, RISE Research Institutes of Sweden, Box 5607, SE-114 86 Stockholm, Sweden
- Division
of Surface Chemistry and Corrosion Science, Department of Chemistry,
School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden
| | - Illia Dobryden
- Division
of Surface Chemistry and Corrosion Science, Department of Chemistry,
School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden
- Division
of Materials Science, Department of Engineering Sciences and Mathematics, Luleå University of Technology, SE−971 87 Luleå, Sweden
| | - Viveca Wallqvist
- Bioeconomy
and Health Division, Department of Materials and Surface Design, RISE Research Institutes of Sweden, Box 5607, SE-114 86 Stockholm, Sweden
| | - Agne Swerin
- Department
of Engineering and Chemical Sciences: Chemical Engineering, Faculty
of Health, Science and Technology, Karlstad
University, SE-651 88 Karlstad, Sweden
| | - Mikael Järn
- Bioeconomy
and Health Division, Department of Materials and Surface Design, RISE Research Institutes of Sweden, Box 5607, SE-114 86 Stockholm, Sweden
| | | | - Patrick A. C. Gane
- Department
of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O.
Box 16300, FI-00076 Aalto, Finland
| | - Per M. Claesson
- Bioeconomy
and Health Division, Department of Materials and Surface Design, RISE Research Institutes of Sweden, Box 5607, SE-114 86 Stockholm, Sweden
- Division
of Surface Chemistry and Corrosion Science, Department of Chemistry,
School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden
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6
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Pilkington GA, Welbourn R, Oleshkevych A, Watanabe S, Pedraz P, Radiom M, Glavatskih S, Rutland MW. Effect of water on the electroresponsive structuring and friction in dilute and concentrated ionic liquid lubricant mixtures. Phys Chem Chem Phys 2020; 22:28191-28201. [PMID: 33295339 DOI: 10.1039/d0cp05110a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effect of water on the electroactive structuring of a tribologically relevant ionic liquid (IL) when dispersed in a polar solvent has been investigated at a gold electrode interface using neutron reflectivity (NR). For all solutions studied, the addition of small amounts of water led to clear changes in electroactive structuring of the IL at the electrode interface, which was largely determined by the bulk IL concentration. At a dilute IL concentration, the presence of water gave rise to a swollen interfacial structuring, which exhibited a greater degree of electroresponsivity with applied potential compared to an equivalent dry solution. Conversely, for a concentrated IL solution, the presence of water led to an overall thinning of the interfacial region and a crowding-like structuring, within which the composition of the inner layer IL layers varied systematically with applied potential. Complementary nanotribotronic atomic force microscopy (AFM) measurements performed for the same IL concentration, in dry and ambient conditions, show that the presence of water reduces the lubricity of the IL boundary layers. However, consistent with the observed changes in the IL layers observed by NR, reversible and systematic control of the friction coefficient with applied potential was still achievable. Combined, these measurements provide valuable insight into the implications of water on the interfacial properties of ILs at electrified interfaces, which inevitably will determine their applicability in tribotronic and electrochemical contexts.
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Affiliation(s)
- Georgia A Pilkington
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
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7
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Erben A, Hörning M, Hartmann B, Becke T, Eisler SA, Southan A, Cranz S, Hayden O, Kneidinger N, Königshoff M, Lindner M, Tovar GEM, Burgstaller G, Clausen‐Schaumann H, Sudhop S, Heymann M. Precision 3D-Printed Cell Scaffolds Mimicking Native Tissue Composition and Mechanics. Adv Healthc Mater 2020; 9:e2000918. [PMID: 33025765 DOI: 10.1002/adhm.202000918] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 08/29/2020] [Indexed: 12/20/2022]
Abstract
Cellular dynamics are modeled by the 3D architecture and mechanics of the extracellular matrix (ECM) and vice versa. These bidirectional cell-ECM interactions are the basis for all vital tissues, many of which have been investigated in 2D environments over the last decades. Experimental approaches to mimic in vivo cell niches in 3D with the highest biological conformity and resolution can enable new insights into these cell-ECM interactions including proliferation, differentiation, migration, and invasion assays. Here, two-photon stereolithography is adopted to print up to mm-sized high-precision 3D cell scaffolds at micrometer resolution with defined mechanical properties from protein-based resins, such as bovine serum albumin or gelatin methacryloyl. By modifying the manufacturing process including two-pass printing or post-print crosslinking, high precision scaffolds with varying Young's moduli ranging from 7-300 kPa are printed and quantified through atomic force microscopy. The impact of varying scaffold topographies on the dynamics of colonizing cells is observed using mouse myoblast cells and a 3D-lung microtissue replica colonized with primary human lung fibroblast. This approach will allow for a systematic investigation of single-cell and tissue dynamics in response to defined mechanical and bio-molecular cues and is ultimately scalable to full organs.
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Affiliation(s)
- Amelie Erben
- Center for Applied Tissue Engineering and Regenerative Medicine Munich University of Applied Sciences Lothstr. 34 Munich 80533 Germany
- Heinz‐Nixdorf‐Chair of Biomedical Electronics, TranslaTUM, Campus Klinikum rechts der Isar Technical University of Munich Einsteinstraße 25 Munich 81675 Germany
- Center for NanoScience (CeNS) Ludwig‐Maximilians‐University Geschwister‐Scholl Platz 1 Munich 80539 Germany
| | - Marcel Hörning
- Institute of Biomaterials and Biomolecular Systems University of Stuttgart Pfaffenwaldring 57 Stuttgart 70569 Germany
| | - Bastian Hartmann
- Center for Applied Tissue Engineering and Regenerative Medicine Munich University of Applied Sciences Lothstr. 34 Munich 80533 Germany
- Center for NanoScience (CeNS) Ludwig‐Maximilians‐University Geschwister‐Scholl Platz 1 Munich 80539 Germany
| | - Tanja Becke
- Center for Applied Tissue Engineering and Regenerative Medicine Munich University of Applied Sciences Lothstr. 34 Munich 80533 Germany
- Center for NanoScience (CeNS) Ludwig‐Maximilians‐University Geschwister‐Scholl Platz 1 Munich 80539 Germany
| | - Stephan A. Eisler
- Stuttgart Research Center Systems Biology University of Stuttgart Nobelstr. 15 Stuttgart 70569 Germany
| | - Alexander Southan
- Institute of Interfacial Process Engineering and Plasma Technology IGVP University of Stuttgart Nobelstr. 12 Stuttgart 70569 Germany
| | - Séverine Cranz
- Institute of Lung Biology and Disease and Comprehensive Pneumology Center with the CPC‐M bioArchive, Helmholtz Zentrum München Member of the German Center for Lung Research (DZL) Max‐Lebsche‐Platz 31 Munich 81377 Germany
- Research Unit Lung Repair and Regeneration Helmholtz Zentrum München Max‐Lebsche‐Platz 31 Munich 81377 Germany
| | - Oliver Hayden
- Heinz‐Nixdorf‐Chair of Biomedical Electronics, TranslaTUM, Campus Klinikum rechts der Isar Technical University of Munich Einsteinstraße 25 Munich 81675 Germany
| | - Nikolaus Kneidinger
- Institute of Lung Biology and Disease and Comprehensive Pneumology Center with the CPC‐M bioArchive, Helmholtz Zentrum München Member of the German Center for Lung Research (DZL) Max‐Lebsche‐Platz 31 Munich 81377 Germany
- Department of Internal Medicine V Ludwig‐Maximillians‐University Munich Marchioninistr. 15 Munich 81377 Germany
| | - Melanie Königshoff
- Institute of Lung Biology and Disease and Comprehensive Pneumology Center with the CPC‐M bioArchive, Helmholtz Zentrum München Member of the German Center for Lung Research (DZL) Max‐Lebsche‐Platz 31 Munich 81377 Germany
- Research Unit Lung Repair and Regeneration Helmholtz Zentrum München Max‐Lebsche‐Platz 31 Munich 81377 Germany
- University of Colorado Department of Pulmonary Sciences and Critical Care Medicine 13001 E. 17th Pl. Aurora CO 80045 USA
| | - Michael Lindner
- Institute of Lung Biology and Disease and Comprehensive Pneumology Center with the CPC‐M bioArchive, Helmholtz Zentrum München Member of the German Center for Lung Research (DZL) Max‐Lebsche‐Platz 31 Munich 81377 Germany
- University Department of Visceral and Thoracic Surgery Salzburg Paracelsus Medical University Müllner Hauptstraße 48 Salzburg A‐5020 Austria
| | - Günter E. M. Tovar
- Institute of Interfacial Process Engineering and Plasma Technology IGVP University of Stuttgart Nobelstr. 12 Stuttgart 70569 Germany
| | - Gerald Burgstaller
- Institute of Lung Biology and Disease and Comprehensive Pneumology Center with the CPC‐M bioArchive, Helmholtz Zentrum München Member of the German Center for Lung Research (DZL) Max‐Lebsche‐Platz 31 Munich 81377 Germany
- Institute of Lung Biology and Disease (ILBD) Helmholtz Zentrum München Max‐Lebsche‐Platz 31 Munich 81377 Germany
| | - Hauke Clausen‐Schaumann
- Center for Applied Tissue Engineering and Regenerative Medicine Munich University of Applied Sciences Lothstr. 34 Munich 80533 Germany
- Center for NanoScience (CeNS) Ludwig‐Maximilians‐University Geschwister‐Scholl Platz 1 Munich 80539 Germany
| | - Stefanie Sudhop
- Center for Applied Tissue Engineering and Regenerative Medicine Munich University of Applied Sciences Lothstr. 34 Munich 80533 Germany
- Center for NanoScience (CeNS) Ludwig‐Maximilians‐University Geschwister‐Scholl Platz 1 Munich 80539 Germany
| | - Michael Heymann
- Center for NanoScience (CeNS) Ludwig‐Maximilians‐University Geschwister‐Scholl Platz 1 Munich 80539 Germany
- Institute of Biomaterials and Biomolecular Systems University of Stuttgart Pfaffenwaldring 57 Stuttgart 70569 Germany
- Department of Cellular and Molecular Biophysics MPI of Biochemistry Martinsried Am Klopferspitz 18 Planegg 82152 Germany
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8
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Pilkington GA, Oleshkevych A, Pedraz P, Watanabe S, Radiom M, Reddy AB, Vorobiev A, Glavatskih S, Rutland MW. Electroresponsive structuring and friction of a non-halogenated ionic liquid in a polar solvent: effect of concentration. Phys Chem Chem Phys 2020; 22:19162-19171. [PMID: 32812565 DOI: 10.1039/d0cp02736g] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Neutron reflectivity (NR) measurements have been employed to study the interfacial structuring and composition of electroresponsive boundary layers formed by an ionic liquid (IL) lubricant at an electrified gold interface when dispersed in a polar solvent. The results reveal that both the composition and extent of the IL boundary layers intricately depend on the bulk IL concentration and the applied surface potential. At the lowest concentration (5% w/w), a preferential adsorption of the IL cation at the gold electrode is observed, which hinders the ability to electro-induce changes in the boundary layers. In contrast, at higher IL bulk concentrations (10 and 20% w/w), the NR results reveal a significantly larger concentration of the IL ions at the gold interface that exhibit significantly greater electroresponsivity, with clear changes in the layer composition and layer thickness observed for different potentials. In complementary atomic force microscopy (AFM) measurements on an electrified gold surface, such IL boundary layers are demonstrated to provide excellent friction reduction and electroactive friction (known as tribotronics). In agreement with the NR results obtained, clear concentration effects are also observed. Together such results provide valuable molecular insight into the electroactive structuring of ILs in solvent mixtures, as well as provide mechanistic understanding of their tribotronic behaviours.
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Affiliation(s)
- Georgia A Pilkington
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
| | - Anna Oleshkevych
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
| | - Patricia Pedraz
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
| | - Seiya Watanabe
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
| | - Milad Radiom
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
| | - Akepati Bhaskar Reddy
- System and Component Design, Department of Machine Design, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Alexei Vorobiev
- Department of Physics and Astronomy, Division of Materials Physics, Uppsala University, Uppsala, Sweden
| | - Sergei Glavatskih
- System and Component Design, Department of Machine Design, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden and Department of Electromechanical, Systems and Metal Engineering, Ghent University, B-9052 Ghent, Belgium
| | - Mark W Rutland
- Division of Surface and Corrosion Science, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden. and Surfaces, Processes and Formulation, RISE Research Institutes of Sweden, SE-100 44 Stockholm, Sweden
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9
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Li H, Niemann T, Ludwig R, Atkin R. Effect of Hydrogen Bonding between Ions of Like Charge on the Boundary Layer Friction of Hydroxy-Functionalized Ionic Liquids. J Phys Chem Lett 2020; 11:3905-3910. [PMID: 32338913 DOI: 10.1021/acs.jpclett.0c00689] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Atomic force microscopy has been used to measure the lubricity of a series of ionic liquids (ILs) at mica surfaces in the boundary friction regime. A previously unreported cation bilayer structure is detected at the IL-mica interface due to the formation of H-bonds between the hydroxy-functionalized cations [(c-c) H-bonds], which enhances the ordering of the ions in the boundary layer and improves the lubrication. The strength of the cation bilayer structure is controlled by altering the strength of (c-c) H-bonding via changes in the hydroxyalkyl chain length, the cation charge polarizability, and the coordination strength of the anions. This reveals a new means of controlling IL boundary nanostructure via H-bonding between ions of the same charge, which can impact diverse applications, including surface catalysis, particle stability, electrochemistry, etc.
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Affiliation(s)
- Hua Li
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia 6009, Australia
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia 6009, Australia
| | - Thomas Niemann
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr.-Lorenz-Weg 2, 18059 Rostock, Germany
- Department LL&M, University of Rostock, Albert-Einstein-Strasse 25, 18059 Rostock, Germany
| | - Ralf Ludwig
- Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr.-Lorenz-Weg 2, 18059 Rostock, Germany
- Department LL&M, University of Rostock, Albert-Einstein-Strasse 25, 18059 Rostock, Germany
- Leibniz-Institut für Katalyse an der Universität Rostock e.V., Albert-Einstein-Strasse 29a, 18059 Rostock, Germany
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia 6009, Australia
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10
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Yin H, Strunz F, Yan Z, Lu J, Brochhausen C, Kiderlen S, Clausen-Schaumann H, Wang X, Gomes ME, Alt V, Docheva D. Three-dimensional self-assembling nanofiber matrix rejuvenates aged/degenerative human tendon stem/progenitor cells. Biomaterials 2020; 236:119802. [PMID: 32014804 DOI: 10.1016/j.biomaterials.2020.119802] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 01/14/2020] [Accepted: 01/18/2020] [Indexed: 12/29/2022]
Abstract
The poor healing capacity of tendons is known to worsen in the elderly. During tendon aging and degeneration, endogenous human tendon stem/progenitor cells (hTSPCs) experience profound pathological changes. Here, we explored a rejuvenation strategy for hTSPCs derived from aged/degenerated Achilles tendons (A-TSPCs) by providing three-dimensional (3D) nanofiber hydrogels and comparing them to young/healthy TSPCs (Y-TSPCs). RADA peptide hydrogel has a self-assembling ability, forms a nanofibrous 3D niche and can be further functionalized by adding RGD motifs. Cell survival, apoptosis, and proliferation assays demonstrated that RADA and RADA/RGD hydrogels support A-TSPCs in a comparable manner to Y-TSPCs. Moreover, they rejuvenated A-TSPCs to a phenotype similar to that of Y-TSPCs, as evidenced by restored cell morphology and cytoskeletal architecture. Transmission electron, confocal laser scanning and atomic force microscopies demonstrated comparable ultrastructure, surface roughness and elastic modulus of A- and Y-TSPC-loaded hydrogels. Lastly, quantitative PCR revealed similar expression profiles, as well a significant upregulation of genes related to tenogenesis and multipotency. Taken together, the RADA-based hydrogels exert a rejuvenating effect by recapitulating in vitro specific features of the natural microenvironment of human TSPCs, which strongly indicates their potential to direct cell behaviour and overcome the challenge of cell aging and degeneration in tendon repair.
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Affiliation(s)
- Heyong Yin
- Experimental Trauma Surgery, Department of Trauma Surgery, University Regensburg Medical Centre, Regensburg, Germany; Department of Orthopedics, Beijing Friendship Hospital, Capital Medical University, Beijing, China.
| | - Franziska Strunz
- Experimental Trauma Surgery, Department of Trauma Surgery, University Regensburg Medical Centre, Regensburg, Germany.
| | - Zexing Yan
- Experimental Trauma Surgery, Department of Trauma Surgery, University Regensburg Medical Centre, Regensburg, Germany.
| | - Jiaju Lu
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, China.
| | | | - Stefanie Kiderlen
- Center for Applied Tissue Engineering and Regenerative Medicine, Munich University of Applied Sciences, Munich, Germany; Center for NanoScience, Ludwig-Maximilians-University, Munich, Germany.
| | - Hauke Clausen-Schaumann
- Center for Applied Tissue Engineering and Regenerative Medicine, Munich University of Applied Sciences, Munich, Germany; Center for NanoScience, Ludwig-Maximilians-University, Munich, Germany.
| | - Xiumei Wang
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, China.
| | - Manuela E Gomes
- 3B's Research Group, I3Bs-Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Guimarães, Portugal.
| | - Volker Alt
- Experimental Trauma Surgery, Department of Trauma Surgery, University Regensburg Medical Centre, Regensburg, Germany.
| | - Denitsa Docheva
- Experimental Trauma Surgery, Department of Trauma Surgery, University Regensburg Medical Centre, Regensburg, Germany.
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11
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Boland MJ, Hempel JL, Ansary A, Nasseri M, Strachan DR. Graphene used as a lateral force microscopy calibration material in the low-load non-linear regime. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:113902. [PMID: 30501363 DOI: 10.1063/1.5044727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 11/01/2018] [Indexed: 06/09/2023]
Abstract
A lateral force microscopy (LFM) calibration technique utilizing a random low-profile surface is proposed that is successfully employed in the low-load non-linear frictional regime using a single layer of graphene on a supporting oxide substrate. This calibration at low loads and on low friction surfaces like graphene has the benefit of helping to limit the wear of the LFM tip during the calibration procedure. Moreover, the low-profiles of the calibration surface characteristic of these layered 2D materials, on standard polished oxide substrates, result in a nearly constant frictional, adhesive, and elastic response as the tip slides over the surface, making the determination of the calibration coefficient robust. Through a detailed calibration analysis that takes into account non-linear frictional response, it is found that the adhesion is best described by a nearly constant vertical orientation, rather than the more commonly encountered normally directed adhesion, as the single asperity passes over the low-profile graphene-coated oxide surface.
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Affiliation(s)
- Mathias J Boland
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
| | - Jacob L Hempel
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
| | - Armin Ansary
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
| | - Mohsen Nasseri
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
| | - Douglas R Strachan
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
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12
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Thorén PA, Borgani R, Forchheimer D, Haviland DB. Calibrating torsional eigenmodes of micro-cantilevers for dynamic measurement of frictional forces. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:075004. [PMID: 30068127 DOI: 10.1063/1.5038967] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 06/30/2018] [Indexed: 06/08/2023]
Abstract
Non-invasive thermal noise calibration of both torsional and flexural eigenmodes is performed on numerous cantilevers of 10 different types. We show that for all tipless and short-tipped cantilevers, the ratio of torsional to flexural mode stiffness is given by the ratio of their resonant frequency times a constant, unique to that cantilever type. By determining this constant, we enable a calibration of the torsional eigenmode, starting from a calibration of the flexural eigenmode. Our results are well motivated from beam theory, and we verify them with finite element simulation.
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Affiliation(s)
- Per-Anders Thorén
- Nanostructure Physics, Royal Institute of Technology (KTH), Albanova, SE-10791 Stockholm, Sweden
| | - Riccardo Borgani
- Nanostructure Physics, Royal Institute of Technology (KTH), Albanova, SE-10791 Stockholm, Sweden
| | - Daniel Forchheimer
- Nanostructure Physics, Royal Institute of Technology (KTH), Albanova, SE-10791 Stockholm, Sweden
| | - David B Haviland
- Nanostructure Physics, Royal Institute of Technology (KTH), Albanova, SE-10791 Stockholm, Sweden
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13
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Riley JK, Matyjaszewski K, Tilton RD. Friction and adhesion control between adsorbed layers of polyelectrolyte brush-grafted nanoparticles via pH-triggered bridging interactions. J Colloid Interface Sci 2018; 526:114-123. [PMID: 29723792 DOI: 10.1016/j.jcis.2018.04.082] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 04/18/2018] [Accepted: 04/21/2018] [Indexed: 11/19/2022]
Abstract
HYPOTHESIS Adsorption of polyelectrolyte brush-grafted nanoparticles (BGNPs) produces a heterogeneous interface with sub-monolayer surface coverage resulting from lateral electrostatic repulsions that limit packing. As a result, the interaction forces between opposing BGNP layers include an adhesive cross-surface BGNP-substrate bridging force that depends on the interparticle spacing, particle size, and strength of electrostatic interactions. We hypothesize that BGNPs with pH-responsive, annealed polyelectrolyte brushes can undergo controlled changes in surface area coverage through post-adsorption swelling or de-swelling into non-equilibrium layer conformations and that such changes in surface coverage can switch off or switch on particle intercalation, bridging attractions, and enhanced energy dissipation upon sliding. This work aims to characterize the nature of surface forces in heterogeneous BGNP adsorbed layers and to utilize pH-sensitive bridging forces as a mechanism to tune friction and adhesion. EXPERIMENTS Colloidal probe atomic force microscopy (CP-AFM) is used to measure normal and lateral forces between negatively charged silica surfaces with adsorbed pH-responsive cationic BGNPs. The BGNPs are poly(2-dimethylaminoethyl methacrylate) brush-grafted silica nanoparticles. Adhesion force and friction analysis is complemented by simultaneous quartz-crystal microbalance and ellipsometry measurements under conditions that render the particles strongly charged and swollen (acidic) or weakly charged and de-swollen (basic). FINDINGS Adsorbed BGNPs can be swollen or de-swollen via pH rinses, enabling direct control of surface coverage and bridging interactions. Transitions from adhesive bridging contacts with high friction to non-adhesive contacts with low friction forces occur when adsorbed BGNP layers are switched from a de-swollen/weakly charged state to a swollen/highly charged state. The ability to controllably shift the character of normal and lateral forces via coverage-mediated bridging interactions is a unique feature of adsorbed nanoparticulate brush constructs and highlights their potential to condition surfaces with additional functionality compared to dense, planar homopolymer brushes.
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Affiliation(s)
- John K Riley
- Department of Chemical Engineering, Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, United States
| | - Krzysztof Matyjaszewski
- Department of Chemistry, Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, United States
| | - Robert D Tilton
- Department of Chemical Engineering, Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, United States; Department of Biomedical Engineering, Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, United States.
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14
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Riley JK, Tilton RD. Sequential Adsorption of Nanoparticulate Polymer Brushes as a Strategy To Control Adhesion and Friction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:11440-11447. [PMID: 27734683 DOI: 10.1021/acs.langmuir.6b02963] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This work investigates surface forces that result from adsorbed layers of silica nanoparticles with grafted pH-responsive, cationic poly(2-(dimethylamino)ethyl methacrylate) brushes (SiO2-g-PDMAEMA) and how adhesive bridging forces can be suppressed and friction forces reduced by "backfilling" these heterogeneous adsorbed layers with nonionic poly(ethylene oxide) star copolymers (Star PEO45MA). Adsorption of SiO2-g-PDMAEMA and Star PEO45MA to silica is measured as a function of pH by quartz crystal microbalance with dissipation (QCM-D) in order to evaluate the electrostatically driven adsorption of SiO2-g-PDMAEMA and hydrogen-bonding-driven adsorption of Star PEO45MA. Force measurements performed using colloidal probe force microscopy show the strong role that limited surface coverage plays in adhesive bridging forces between silica with adsorbed SiO2-g-PDMAEMA, while Star PEO45MA adsorption produces purely repulsive steric interactions. Bridging between SiO2-g-PDMAEMA-coated surfaces produces frictional forces that tend to be larger than those acting between bare surfaces at similar normal loads, while friction is consistently decreased by Star PEO45MA adsorption. Sequential adsorption of SiO2-g-PDMAEMA and Star PEO45MA generates high-coverage mixed nanoparticulate brush layers with uniformly repulsive normal forces and reduced friction forces. Adsorption and force measurements reveal that Star PEO45MA not only adsorbs to silica but also binds to SiO2-g-PDMAEMA. The latter allows sequential adsorption of the two components to produce mixed multilayers. The mixed SiO2-g-PDMAEMA/Star PEO45MA multilayers exhibit larger layer thicknesses, no bridging, and sustained smooth friction, highlighting their potential usefulness as aqueous boundary lubricant layers.
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Affiliation(s)
- John K Riley
- Center for Complex Fluids Engineering, ‡Department of Chemical Engineering, and §Department of Biomedical Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Robert D Tilton
- Center for Complex Fluids Engineering, ‡Department of Chemical Engineering, and §Department of Biomedical Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
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15
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Hjalmarsson N, Atkin R, Rutland MW. Is the boundary layer of an ionic liquid equally lubricating at higher temperature? Phys Chem Chem Phys 2016; 18:9232-9. [PMID: 26976694 DOI: 10.1039/c5cp05837f] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Atomic force microscopy has been used to study the effect of temperature on normal forces and friction for the room temperature ionic liquid (IL) ethylammonium nitrate (EAN), confined between mica and a silica colloid probe at 25 °C, 50 °C, and 80 °C. Force curves revealed a strong fluid dynamic influence at room temperature, which was greatly reduced at elevated temperatures due to the reduced liquid viscosity. A fluid dynamic analysis reveals that bulk viscosity is manifested at large separation but that EAN displays a nonzero slip, indicating a region of different viscosity near the surface. At high temperatures, the reduction in fluid dynamic force reveals step-like force curves, similar to those found at room temperature using much lower scan rates. The ionic liquid boundary layer remains adsorbed to the solid surface even at high temperature, which provides a mechanism for lubrication when fluid dynamic lubrication is strongly reduced. The friction data reveals a decrease in absolute friction force with increasing temperature, which is associated with increased thermal motion and reduced viscosity of the near surface layers but, consistent with the normal force data, boundary layer lubrication was unaffected. The implications for ILs as lubricants are discussed in terms of the behaviour of this well characterised system.
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Affiliation(s)
- Nicklas Hjalmarsson
- Surface and Corrosion Science, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden.
| | - Rob Atkin
- Priority Research Centre for Advanced Fluids and Interfaces, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Mark W Rutland
- Surface and Corrosion Science, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden. and Chemistry, Materials and Surfaces, SP Technical Research Institute Sweden, SE-11428 Stockholm, Sweden
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16
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Sweeney J, Webber GB, Atkin R. Poly(ethylene oxide) Mushrooms Adsorbed at Silica-Ionic Liquid Interfaces Reduce Friction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:1947-1954. [PMID: 26844589 DOI: 10.1021/acs.langmuir.5b04503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The adsorbed layer conformation and lubricity of 35, 100, and 300 kDa PEO adsorbed to ionic liquid (IL)-silica interfaces from 0.01 wt % solutions have been investigated using colloid probe atomic force microscopy. The ILs used were propylammonium nitrate (PAN) and 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), which are protic and aprotic ILs, respectively. Normal force curves reveal steric interactions consistent with adsorbed polymer layers which are best fit using the mushroom model. Friction measurements show that the adsorbed polymer layer markedly reduces friction compared to surfaces sliding in the pure ILs and that lubricity increases with polymer length. When polymer is adsorbed to the sliding surfaces, friction is controlled by the creation and disruption of intermolecular interactions between entangled chains and the dragging of polymer chains through the interpenetration region. These experiments show that added polymer can reduce friction while maintaining the useful properties of ILs as lubricants.
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Affiliation(s)
- James Sweeney
- Priority Research Centre for Advanced Fluids and Interfaces, Newcastle Institute for Energy and Resources, The University of Newcastle , Callaghan, NSW 2308, Australia
| | - Grant B Webber
- Priority Research Centre for Advanced Fluids and Interfaces, Newcastle Institute for Energy and Resources, The University of Newcastle , Callaghan, NSW 2308, Australia
| | - Rob Atkin
- Priority Research Centre for Advanced Fluids and Interfaces, Newcastle Institute for Energy and Resources, The University of Newcastle , Callaghan, NSW 2308, Australia
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Kulik AJ, Lekka M, Lee K, Pyka-Fościak G, Nowak W. Probing fibronectin-antibody interactions using AFM force spectroscopy and lateral force microscopy. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2015; 6:1164-1175. [PMID: 26114080 PMCID: PMC4462853 DOI: 10.3762/bjnano.6.118] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 04/22/2015] [Indexed: 06/04/2023]
Abstract
The first experiment showing the effects of specific interaction forces using lateral force microscopy (LFM) was demonstrated for lectin-carbohydrate interactions some years ago. Such measurements are possible under the assumption that specific forces strongly dominate over the non-specific ones. However, obtaining quantitative results requires the complex and tedious calibration of a torsional force. Here, a new and relatively simple method for the calibration of the torsional force is presented. The proposed calibration method is validated through the measurement of the interaction forces between human fibronectin and its monoclonal antibody. The results obtained using LFM and AFM-based classical force spectroscopies showed similar unbinding forces recorded at similar loading rates. Our studies verify that the proposed lateral force calibration method can be applied to study single molecule interactions.
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Affiliation(s)
- Andrzej J Kulik
- Laboratoire de la Physique de la Matière Vivante, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Małgorzata Lekka
- Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Kraków, Poland
| | - Kyumin Lee
- Laboratoire de la Physique de la Matière Vivante, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Grazyna Pyka-Fościak
- Department of Histology, Jagiellonian University Medical College, Kopernika 7, 31-034 Kraków, Poland
| | - Wieslaw Nowak
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziądzka 5/7, 87-100 Toruń, Poland
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Sweeney J, Webber GB, Atkin R. Near surface properties of mixtures of propylammonium nitrate with n-alkanols 2. Nanotribology and fluid dynamics. Phys Chem Chem Phys 2015; 17:26629-37. [DOI: 10.1039/c5cp04787k] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Colloid probe friction force microscopy (FFM) has been used to study the lubricity of propylammonium nitrate (PAN) mixed with n-alkanols confined between sliding silica and mica surfaces.
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Affiliation(s)
- James Sweeney
- Centre for Advanced Particle Processing and Transport
- Newcastle Institute for Energy and Resources
- The University of Newcastle
- Callaghan
- Australia
| | - Grant B. Webber
- Centre for Advanced Particle Processing and Transport
- Newcastle Institute for Energy and Resources
- The University of Newcastle
- Callaghan
- Australia
| | - Rob Atkin
- Centre for Advanced Particle Processing and Transport
- Newcastle Institute for Energy and Resources
- The University of Newcastle
- Callaghan
- Australia
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19
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Jarząbek DM. Precise and direct method for the measurement of the torsion spring constant of the atomic force microscopy cantilevers. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:013701. [PMID: 25638084 DOI: 10.1063/1.4904866] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A direct method for the evaluation of the torsional spring constants of the atomic force microscope cantilevers is presented in this paper. The method uses a nanoindenter to apply forces at the long axis of the cantilever and in the certain distance from it. The torque vs torsion relation is then evaluated by the comparison of the results of the indentations experiments at different positions on the cantilever. Next, this relation is used for the precise determination of the torsional spring constant of the cantilever. The statistical analysis shows that the standard deviation of the calibration measurements is equal to approximately 1%. Furthermore, a simple method for calibration of the photodetector's lateral response is proposed. The overall procedure of the lateral calibration constant determination has the accuracy approximately equal to 10%.
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Affiliation(s)
- D M Jarząbek
- Institute of Fundamental Technological Research, Pawińskiego 5b, 02-106 Warsaw, Poland
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