1
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Luo ZH, Chen C, Zhao QH, Deng NN. Functional metal-phenolic cortical cytoskeleton for artificial cells. SCIENCE ADVANCES 2024; 10:eadj4047. [PMID: 38363847 PMCID: PMC10871533 DOI: 10.1126/sciadv.adj4047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 01/16/2024] [Indexed: 02/18/2024]
Abstract
Cortex-like cytoskeleton, a thin layer of cross-linked cytoplasmic proteins underlying the cell membrane, plays an essential role in modulating membrane behavior and cell surface properties. However, bottom-up construction of functional cortex-like cytoskeleton in artificial cells remains a challenge. Here, we present metal-phenolic networks as artificial cortical cytoskeletons in liposome-based artificial cells. The metal-phenolic cytoskeleton-reinforced artificial cells exhibit long-term stability, enhanced resistance to a variety of harsh environments, tunable permeability, and well-controlled morphologies. We anticipate that our stable artificial cell models will stride forward to practical applications of liposome-based microsystem.
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Affiliation(s)
- Zhen-Hong Luo
- Shanghai Jiao Tong University, School of Chemistry and Chemical Engineering, Shanghai 200240, China
| | - Chen Chen
- Shanghai Jiao Tong University, School of Chemistry and Chemical Engineering, Shanghai 200240, China
| | - Qi-Hong Zhao
- Shanghai Jiao Tong University, School of Chemistry and Chemical Engineering, Shanghai 200240, China
| | - Nan-Nan Deng
- Shanghai Jiao Tong University, School of Chemistry and Chemical Engineering, Shanghai 200240, China
- Shanghai Jiao Tong University Sichuan Research Institute, Chengdu 610213, Sichuan, China
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2
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Chen Q, Yang H, Liu Y, Yu K, Zhao D. Toward an improved understanding of emulsion stabilization at elevated temperatures by direct visualization and reversibility analysis. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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3
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Pinon L, Ruyssen N, Pineau J, Mesdjian O, Cuvelier D, Chipont A, Allena R, Guerin CL, Asnacios S, Asnacios A, Pierobon P, Fattaccioli J. Phenotyping polarization dynamics of immune cells using a lipid droplet-cell pairing microfluidic platform. CELL REPORTS METHODS 2022; 2:100335. [PMID: 36452873 PMCID: PMC9701611 DOI: 10.1016/j.crmeth.2022.100335] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 09/20/2022] [Accepted: 10/19/2022] [Indexed: 05/12/2023]
Abstract
The immune synapse is the tight contact zone between a lymphocyte and a cell presenting its cognate antigen. This structure serves as a signaling platform and entails a polarization of intracellular components necessary to the immunological function of the cell. While the surface properties of the presenting cell are known to control the formation of the synapse, their impact on polarization has not yet been studied. Using functional lipid droplets as tunable artificial presenting cells combined with a microfluidic pairing device, we simultaneously observe synchronized synapses and dynamically quantify polarization patterns of individual B cells. By assessing how ligand concentration, surface fluidity, and substrate rigidity impact lysosome polarization, we show that its onset and kinetics depend on the local antigen concentration at the synapse and on substrate rigidity. Our experimental system enables a fine phenotyping of monoclonal cell populations based on their synaptic readout.
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Affiliation(s)
- Léa Pinon
- École Normale Supérieure, UMR 8640, Laboratoire PASTEUR, Département de Chimie, PSL Research University, Sorbonne Université, CNRS, 75005 Paris, France
- Institut Curie, U932, Immunology and Cancer, INSERM, 75005 Paris, France
- Institut Pierre-Gilles de Gennes pour la Microfluidique, 75005 Paris, France
| | - Nicolas Ruyssen
- Arts et Métiers Institute of Technology, Université Paris 13, Sorbonne Paris Cité, IBHGC, HESAM Université, 75013 Paris, France
| | - Judith Pineau
- Institut Curie, U932, Immunology and Cancer, INSERM, 75005 Paris, France
| | - Olivier Mesdjian
- École Normale Supérieure, UMR 8640, Laboratoire PASTEUR, Département de Chimie, PSL Research University, Sorbonne Université, CNRS, 75005 Paris, France
- Institut Pierre-Gilles de Gennes pour la Microfluidique, 75005 Paris, France
| | - Damien Cuvelier
- Institut Pierre-Gilles de Gennes pour la Microfluidique, 75005 Paris, France
- Institut Curie, UMR 144, PSL Research University, CNRS, Paris, France
- Sorbonne Université, Faculté des Sciences et Ingénierie, UFR 926 Chemistry, 75005 Paris, France
| | - Anna Chipont
- Institut Curie, Cytometry Platform, 75005 Paris, France
| | - Rachele Allena
- Arts et Métiers Institute of Technology, Université Paris 13, Sorbonne Paris Cité, IBHGC, HESAM Université, 75013 Paris, France
- LJAD, UMR 7351, Université Côte d’Azur, 06100 Nice, France
| | - Coralie L. Guerin
- Institut Curie, Cytometry Platform, 75005 Paris, France
- Université Paris Cité, INSERM, Innovative Therapies in Haemostasis, 75006 Paris, France
| | - Sophie Asnacios
- Université de Paris, CNRS, Laboratoire Matière et Systèmes Complexes, UMR 7057, 75013 Paris, France
- Sorbonne Université, Faculté des Sciences et Ingénierie, UFR 925 Physics, 75005 Paris, France
| | - Atef Asnacios
- Université de Paris, CNRS, Laboratoire Matière et Systèmes Complexes, UMR 7057, 75013 Paris, France
| | - Paolo Pierobon
- Institut Curie, U932, Immunology and Cancer, INSERM, 75005 Paris, France
| | - Jacques Fattaccioli
- École Normale Supérieure, UMR 8640, Laboratoire PASTEUR, Département de Chimie, PSL Research University, Sorbonne Université, CNRS, 75005 Paris, France
- Institut Pierre-Gilles de Gennes pour la Microfluidique, 75005 Paris, France
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4
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Ma J, Yao M, Yang Y, Zhang X. Comprehensive review on stability and demulsification of unconventional heavy oil-water emulsions. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118510] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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5
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Ho TM, Razzaghi A, Ramachandran A, Mikkonen KS. Emulsion characterization via microfluidic devices: A review on interfacial tension and stability to coalescence. Adv Colloid Interface Sci 2022; 299:102541. [PMID: 34920366 DOI: 10.1016/j.cis.2021.102541] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 09/22/2021] [Accepted: 10/03/2021] [Indexed: 01/29/2023]
Abstract
Emulsions have gained significant importance in many industries including foods, pharmaceuticals, cosmetics, health care formulations, paints, polymer blends and oils. During emulsion generation, collisions can occur between newly-generated droplets, which may lead to coalescence between the droplets. The extent of coalescence is driven by the properties of the dispersed and continuous phases (e.g. density, viscosity, ion strength and pH), and system conditions (e.g. temperature, pressure or any external applied forces). In addition, the diffusion and adsorption behaviors of emulsifiers which govern the dynamic interfacial tension of the forming droplets, the surface potential, and the duration and frequency of the droplet collisions, contribute to the overall rate of coalescence. An understanding of these complex behaviors, particularly those of interfacial tension and droplet coalescence during emulsion generation, is critical for the design of an emulsion with desirable properties, and for the optimization of the processing conditions. However, in many cases, the time scales over which these phenomena occur are extremely short, typically a fraction of a second, which makes their accurate determination by conventional analytical methods extremely challenging. In the past few years, with advances in microfluidic technology, many attempts have demonstrated that microfluidic systems, characterized by micrometer-size channels, can be successfully employed to precisely characterize these properties of emulsions. In this review, current applications of microfluidic devices to determine the equilibrium and dynamic interfacial tension during droplet formation, and to investigate the coalescence stability of dispersed droplets applicable to the processing and storage of emulsions, are discussed.
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6
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Hristova E(J, Tchoukov P, Stoyanov SR. Coalescence inhibition and agglomeration initiation near the critical dilution of asphaltene precipitation. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.127400] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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7
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Sun C, Liu L, Vasudevan HN, Chang KC, Abate AR. Accurate Bulk Quantitation of Droplet Digital Polymerase Chain Reaction. Anal Chem 2021; 93:9974-9979. [PMID: 34252272 PMCID: PMC8829825 DOI: 10.1021/acs.analchem.1c00877] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Droplet digital PCR
provides superior accuracy for nucleic acid
quantitation. The requirement of microfluidics to generate and analyze
the emulsions, however, is a barrier to its adoption, particularly
in low resource settings or clinical laboratories. Here, we report
a novel method to prepare ddPCR droplets by vortexing and readout
of the results by bulk analysis of recovered amplicons. We demonstrate
the approach by accurately quantitating SARS-CoV-2 sequences using
entirely bulk processing and no microfluidics. Our approach for quantitating
reactions should extend to all digital assays that generate amplicons,
including digital PCR and LAMP conducted in droplets, microchambers,
or nanoliter wells. More broadly, our approach combines important
attributes of ddPCR, including enhanced accuracy and robustness to
inhibition, with the high-volume sample processing ability of quantitative
PCR.
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Affiliation(s)
- Chen Sun
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California 94158, United States
| | - Leqian Liu
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California 94158, United States
| | - Harish N Vasudevan
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California 94158, United States.,Department of Radiation Oncology, University of California San Francisco, San Francisco, California 94158, United States
| | - Kai-Chun Chang
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California 94158, United States
| | - Adam R Abate
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California 94158, United States.,California Institute for Quantitative Biosciences, University of California San Francisco, San Francisco, California 94158, United States.,Chan Zuckerberg Biohub, San Francisco, California 94158, United States
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8
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Sun C, Liu L, Vasudevan HN, Chang KC, Abate AR. Accurate bulk quantitation of droplet digital PCR. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2021:2021.01.13.424628. [PMID: 33469578 PMCID: PMC7814815 DOI: 10.1101/2021.01.13.424628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Droplet digital PCR provides superior accuracy in nucleic acid quantitation. The requirement of microfluidics to generate and analyze the emulsions, however, is a barrier to its adoption, particularly in low resource or clinical settings. Here, we report a novel method to prepare ddPCR droplets by vortexing and readout the results by bulk analysis of recovered amplicons. We demonstrate the approach by accurately quantitating SARS-CoV-2 sequences using entirely bulk processing and no microfluidics. Our approach for quantitating reactions should extend to all digital assays that generate amplicons, including digital PCR and LAMP conducted in droplets, microchambers, or nanoliter wells. More broadly, our approach combines important attributes of ddPCR, including enhanced accuracy and robustness to inhibition, with the high-volume sample processing ability of quantitative PCR.
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Affiliation(s)
- Chen Sun
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA 94158, USA
| | - Leqian Liu
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA 94158, USA
| | - Harish N. Vasudevan
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA 94158, USA
- Department of Radiation Oncology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Kai-Chun Chang
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA 94158, USA
| | - Adam R. Abate
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA 94158, USA
- California Institute for Quantitative Biosciences, University of California San Francisco, San Francisco, CA 94158, USA
- Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
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9
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Zhang Z, Song J, Lin YJ, Wang X, Biswal SL. Comparing the Coalescence Rate of Water-in-Oil Emulsions Stabilized with Asphaltenes and Asphaltene-like Molecules. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:7894-7900. [PMID: 32597186 DOI: 10.1021/acs.langmuir.0c00966] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Asphaltenes are a significant contributor to flow assurance problems related to crude oil production. Because of their polydispersity, model molecules such as coronene and violanthrone-79 (VO-79) have been used as mimics to represent the physiochemical properties of asphaltenes. This work aims to evaluate the emulsion-stabilization characteristics of fractionated asphaltenes and these two model molecules. Such evaluation is expected to better characterize the stabilizing mechanisms of asphaltenes on water-in-oil emulsions. The coalescence process of water-in-oil emulsion droplets is visualized using a microfluidic flow-focusing geometry. The rate of coalescence events is used as the parameter to assess emulsion stability. Interfacial tension (IFT) and oil/brine zeta potential are measured to help explain the differences in the rates of coalescence. VO-79 is found to be better at stabilizing emulsions as compared to coronene. Although VO-79 and asphaltenes have similar interfacial tension and oil/brine zeta potential values, the rate of coalescence differs significantly. This highlights the difficulty in using model molecules to mimic the transport dynamics of asphaltenes.
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Affiliation(s)
- Zhuqing Zhang
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Jin Song
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Yu-Jiun Lin
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Xinglin Wang
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Sibani Lisa Biswal
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
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10
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Cheng Y, Yuan S. Emulsification of Surfactant on Oil Droplets by Molecular Dynamics Simulation. Molecules 2020; 25:molecules25133008. [PMID: 32630093 PMCID: PMC7412001 DOI: 10.3390/molecules25133008] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/21/2020] [Accepted: 06/25/2020] [Indexed: 11/16/2022] Open
Abstract
Heavy oil in crude oil flooding is extremely difficult to extract due to its high viscosity and poor fluidity. In this paper, molecular dynamics simulation was used to study the emulsification behavior of sodium dodecyl sulfonate (SDSn) micelles on heavy oil droplets composed of asphaltenes (ASP) at the molecular level. Some analyzed techniques were used including root mean square displacement, hydrophile-hydrophobic area of an oil droplet, potential of mean force, and the number of hydrogen bonds between oil droplet and water phase. The simulated results showed that the asphaltene with carboxylate groups significantly enhances the hydration layer on the surface of oil droplets, and SDSn molecules can change the strength of the hydration layer around the surface of the oil droplets. The water bridge structure between both polar heads of the surfactant was commonly formed around the hydration layer of the emulsified oil droplet. During the emulsification of heavy oil, the ratio of hydrophilic hydrophobic surface area around an oil droplet is essential. Molecular dynamics method can be considered as a helpful tool for experimental techniques at the molecular level.
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11
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Liu S, Li X, Hu L, Deng S, Zhang W, Liu P, Zhang Y. Interfacial Instability of Emulsion Droplets Containing a Polymer and a Fatty Alcohol. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:3821-3825. [PMID: 32202117 DOI: 10.1021/acs.langmuir.0c00463] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We investigated the interfacial instability of emulsion droplets via in situ measuring the oil/water interfacial tension (IFT) using the capillary suction method. The discrete phase of the oil-in-water emulsion contains a hydrophobic polymer (polystyrene, PS) and a fatty alcohol cosurfactant n-cetyl alcohol (CA) or n-octadecanol (OD), both of which were dissolved in an organic solvent (chloroform). The continuous phase is an aqueous solution of surfactant (sodium dodecyl sulfate, SDS). Upon removal of the organic solvent, the concentrations of CA and PS increase gradually, which induce a continual decrease of the IFT until the occurrence of interfacial instability. Micropipette tensiometry performed on an evaporating emulsion droplet reveals that interfacial instability is triggered when the IFT decreases close to ∼0.17 mN/m. As a result, micron particles with wrinkled surfaces can be obtained after the complete removal of the organic solvent. The effect of the initial concentration and alkyl chain length of the cosurfactant on the interfacial instability and surface roughness of the formed particles was studied. This study provides theoretical guidance for the preparation of micrometer-sized polymer particles with diverse morphologies via the interfacial instability of emulsion droplets.
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Affiliation(s)
- Shanqin Liu
- School of Chemistry and Chemical Engineering, Henan Institute of Science and Technology, Xinxiang 453003, Henan, P. R. China
| | - Xuanhe Li
- School of Chemistry and Chemical Engineering, Henan Institute of Science and Technology, Xinxiang 453003, Henan, P. R. China
| | - Linfeng Hu
- School of Chemistry and Chemical Engineering, Henan Institute of Science and Technology, Xinxiang 453003, Henan, P. R. China
| | - Shaohuan Deng
- School of Chemistry and Chemical Engineering, Henan Institute of Science and Technology, Xinxiang 453003, Henan, P. R. China
| | - Wanqing Zhang
- School of Chemistry and Chemical Engineering, Henan Institute of Science and Technology, Xinxiang 453003, Henan, P. R. China
| | - Pengfei Liu
- School of Chemistry and Chemical Engineering, Henan Institute of Science and Technology, Xinxiang 453003, Henan, P. R. China
| | - Yuping Zhang
- School of Chemistry and Chemical Engineering, Henan Institute of Science and Technology, Xinxiang 453003, Henan, P. R. China
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12
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Interfacial properties pertinent to W/O and O/W emulsion systems prepared using polyaromatic compounds. Colloids Surf A Physicochem Eng Asp 2019. [DOI: 10.1016/j.colsurfa.2019.05.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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13
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Micro-Surface and -Interfacial Tensions Measured Using the Micropipette Technique: Applications in Ultrasound-Microbubbles, Oil-Recovery, Lung-Surfactants, Nanoprecipitation, and Microfluidics. MICROMACHINES 2019; 10:mi10020105. [PMID: 30717224 PMCID: PMC6413238 DOI: 10.3390/mi10020105] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/23/2019] [Accepted: 01/25/2019] [Indexed: 01/08/2023]
Abstract
This review presents a series of measurements of the surface and interfacial tensions we have been able to make using the micropipette technique. These include: equilibrium tensions at the air-water surface and oil-water interface, as well as equilibrium and dynamic adsorption of water-soluble surfactants and water-insoluble and lipids. At its essence, the micropipette technique is one of capillary-action, glass-wetting, and applied pressure. A micropipette, as a parallel or tapered shaft, is mounted horizontally in a microchamber and viewed in an inverted microscope. When filled with air or oil, and inserted into an aqueous-filled chamber, the position of the surface or interface meniscus is controlled by applied micropipette pressure. The position and hence radius of curvature of the meniscus can be moved in a controlled fashion from dimensions associated with the capillary tip (~5–10 μm), to back down the micropipette that can taper out to 450 μm. All measurements are therefore actually made at the microscale. Following the Young–Laplace equation and geometry of the capillary, the surface or interfacial tension value is simply obtained from the radius of the meniscus in the tapered pipette and the applied pressure to keep it there. Motivated by Franklin’s early experiments that demonstrated molecularity and monolayer formation, we also give a brief potted-historical perspective that includes fundamental surfactancy driven by margarine, the first use of a micropipette to circuitously measure bilayer membrane tensions and free energies of formation, and its basis for revolutionising the study and applications of membrane ion-channels in Droplet Interface Bilayers. Finally, we give five examples of where our measurements have had an impact on applications in micro-surfaces and microfluidics, including gas microbubbles for ultrasound contrast; interfacial tensions for micro-oil droplets in oil recovery; surface tensions and tensions-in-the surface for natural and synthetic lung surfactants; interfacial tension in nanoprecipitation; and micro-surface tensions in microfluidics.
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14
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Yang F, Tchoukov P, Qiao P, Ma X, Pensini E, Dabros T, Czarnecki J, Xu Z. Studying demulsification mechanisms of water-in-crude oil emulsions using a modified thin liquid film technique. Colloids Surf A Physicochem Eng Asp 2018. [DOI: 10.1016/j.colsurfa.2017.12.056] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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15
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Kurokawa C, Fujiwara K, Morita M, Kawamata I, Kawagishi Y, Sakai A, Murayama Y, Nomura SIM, Murata S, Takinoue M, Yanagisawa M. DNA cytoskeleton for stabilizing artificial cells. Proc Natl Acad Sci U S A 2017; 114:7228-7233. [PMID: 28652345 PMCID: PMC5514726 DOI: 10.1073/pnas.1702208114] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Cell-sized liposomes and droplets coated with lipid layers have been used as platforms for understanding live cells, constructing artificial cells, and implementing functional biomedical tools such as biosensing platforms and drug delivery systems. However, these systems are very fragile, which results from the absence of cytoskeletons in these systems. Here, we construct an artificial cytoskeleton using DNA nanostructures. The designed DNA oligomers form a Y-shaped nanostructure and connect to each other with their complementary sticky ends to form networks. To undercoat lipid membranes with this DNA network, we used cationic lipids that attract negatively charged DNA. By encapsulating the DNA into the droplets, we successfully created a DNA shell underneath the membrane. The DNA shells increased interfacial tension, elastic modulus, and shear modulus of the droplet surface, consequently stabilizing the lipid droplets. Such drastic changes in stability were detected only when the DNA shell was in the gel phase. Furthermore, we demonstrate that liposomes with the DNA gel shell are substantially tolerant against outer osmotic shock. These results clearly show the DNA gel shell is a stabilizer of the lipid membrane akin to the cytoskeleton in live cells.
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Affiliation(s)
- Chikako Kurokawa
- Department of Applied Physics, Tokyo University of Agriculture and Technology, Tokyo 184-8588 Japan
| | - Kei Fujiwara
- Department of Biosciences and Informatics, Keio University, Kanagawa 223-8522, Japan
| | - Masamune Morita
- Department of Computer Science, Tokyo Institute of Technology, Kanagawa 226-8502, Japan
| | - Ibuki Kawamata
- Department of Robotics, Tohoku University, Sendai 980-8579, Japan
| | - Yui Kawagishi
- Department of Robotics, Tohoku University, Sendai 980-8579, Japan
| | - Atsushi Sakai
- Department of Applied Physics, Tokyo University of Agriculture and Technology, Tokyo 184-8588 Japan
| | - Yoshihiro Murayama
- Department of Applied Physics, Tokyo University of Agriculture and Technology, Tokyo 184-8588 Japan
| | | | - Satoshi Murata
- Department of Robotics, Tohoku University, Sendai 980-8579, Japan
| | - Masahiro Takinoue
- Department of Computer Science, Tokyo Institute of Technology, Kanagawa 226-8502, Japan;
| | - Miho Yanagisawa
- Department of Applied Physics, Tokyo University of Agriculture and Technology, Tokyo 184-8588 Japan;
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16
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Kinoshita K, Parra E, Needham D. Adsorption of ionic surfactants at microscopic air-water interfaces using the micropipette interfacial area-expansion method: Measurement of the diffusion coefficient and renormalization of the mean ionic activity for SDS. J Colloid Interface Sci 2017. [PMID: 28623702 DOI: 10.1016/j.jcis.2017.05.077] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The dynamic adsorption of ionic surfactants at air-water interfaces have been less-well studied than that of the simpler non-ionics since experimental limitations on dynamic surface tension (DST) measurements create inconsistencies in their kinetic analysis. Using our newly designed "Micropipette interfacial area-expansion method", we have measured and evaluated both equilibrium and dynamic adsorption of a well-known anionic surfactant, sodium dodecyl sulphate (SDS), in the absence or presence of 100mM NaCl. Our focus was to determine if and to what extent the inclusion of a new correction parameter for the "ideal ionic activity", A±i, can renormalize both equilibrium and dynamic surface tension measurements and provide better estimates of the diffusion coefficient of ionic surfactants in aqueous media obtained from electroneutral models, namely extended Frumkin isotherm and Ward-Tordai adsorption models. We found that the estimated value of the new parameter, A±i=0.29, is key to obtain the diffusion coefficient D=5.3±0.3×10-6cm2/s for SDS, in excellent agreement with the literature. These new technique and analyses can now be applied to study the interfacial adsorption of a range of both ionic and non-ionic surface-active molecules, including the potentially slower-diffusing polymers and biological materials like lipids, peptides, and proteins.
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Affiliation(s)
- Koji Kinoshita
- Center for Single Particle Science and Engineering, (SPSE), Department of Molecular Medicine, University of Southern Denmark, Campusvej 55, DK-5230 Odense, Denmark.
| | - Elisa Parra
- Center for Single Particle Science and Engineering, (SPSE), Department of Molecular Medicine, University of Southern Denmark, Campusvej 55, DK-5230 Odense, Denmark
| | - David Needham
- Center for Single Particle Science and Engineering, (SPSE), Department of Molecular Medicine, University of Southern Denmark, Campusvej 55, DK-5230 Odense, Denmark; Department of Mechanical Engineering and Material Science, Duke University, Durham, NC 27708, USA
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17
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Amrollahi Biyouki A, Hosseinpour N, Bahramian A, Vatani A. In-situ upgrading of reservoir oils by in-situ preparation of NiO nanoparticles in thermal enhanced oil recovery processes. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2017.01.089] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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18
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Xie L, Shi C, Cui X, Zeng H. Surface Forces and Interaction Mechanisms of Emulsion Drops and Gas Bubbles in Complex Fluids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:3911-3925. [PMID: 28178417 DOI: 10.1021/acs.langmuir.6b04669] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The interactions of emulsion drops and gas bubbles in complex fluids play important roles in a wide range of biological and technological applications, such as programmable drug and gene delivery, emulsion and foam formation, and froth flotation of mineral particles. In this feature article, we have reviewed our recent progress on the quantification of surface forces and interaction mechanisms of gas bubbles and emulsion drops in different material systems by using several complementary techniques, including the drop/bubble probe atomic force microscope (AFM), surface forces apparatus (SFA), and four-roll mill fluidic device. These material systems include the bubble-self-assembled monolayer (SAM), bubble-polymer, bubble-superhydrophobic surface, bubble-mineral, water-in-oil and oil-in-water emulsions with interface-active components in oil production, and oil/water wetting on polyelectrolyte surfaces. The bubble probe AFM combined with reflection interference contrast microscopy (RICM) was applied for the first time to simultaneously quantify the interaction forces and spatiotemporal evolution of a confined thin liquid film between gas bubbles and solid surfaces with varying hydrophobicity. The nanomechanical results have provided useful insights into the fundamental interaction mechanisms (e.g., hydrophobic interaction in aqueous media) at gas/water/solid interfaces, the stabilization/destabilization mechanisms of emulsion drops, and oil/water wetting mechanisms on solid surfaces. A long-range hydrophilic attraction was found between water and polyelectrolyte surfaces in oil, with the strongest attraction for polyzwitterions, contributing to their superior water wettability in oil and self-cleaning capability of oil contamination. Some remaining challenges and future research directions are discussed and provided.
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Affiliation(s)
- Lei Xie
- Department of Chemical and Materials Engineering, University of Alberta , Edmonton, Alberta T6G 1H9, Canada
| | - Chen Shi
- Department of Chemical and Materials Engineering, University of Alberta , Edmonton, Alberta T6G 1H9, Canada
| | - Xin Cui
- Department of Chemical and Materials Engineering, University of Alberta , Edmonton, Alberta T6G 1H9, Canada
| | - Hongbo Zeng
- Department of Chemical and Materials Engineering, University of Alberta , Edmonton, Alberta T6G 1H9, Canada
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From Single Microparticles to Microfluidic Emulsification: Fundamental Properties (Solubility, Density, Phase Separation) from Micropipette Manipulation of Solvent, Drug and Polymer Microspheres. Processes (Basel) 2016. [DOI: 10.3390/pr4040049] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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20
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Molino D, Quignard S, Gruget C, Pincet F, Chen Y, Piel M, Fattaccioli J. On-Chip Quantitative Measurement of Mechanical Stresses During Cell Migration with Emulsion Droplets. Sci Rep 2016; 6:29113. [PMID: 27373558 PMCID: PMC4931467 DOI: 10.1038/srep29113] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 06/15/2016] [Indexed: 02/01/2023] Open
Abstract
The ability of immune cells to migrate within narrow and crowded spaces is a critical feature involved in various physiological processes from immune response to metastasis. Several in-vitro techniques have been developed so far to study the behaviour of migrating cells, the most recent being based on the fabrication of microchannels within which cells move. To address the question of the mechanical stress a cell is able to produce during the encounter of an obstacle while migrating, we developed a hybrid microchip made of parallel PDMS channels in which oil droplets are sparsely distributed and serve as deformable obstacles. We thus show that cells strongly deform droplets while passing them. Then, we show that the microdevice can be used to study the influence of drugs on migration at the population level. Finally, we describe a quantitative analysis method of the droplet deformation that allows measuring in real-time the mechanical stress exerted by a single cell. The method presented herein thus constitutes a powerful analytical tool for cell migration studies under confinement.
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Affiliation(s)
- D. Molino
- École Normale Supérieure - PSL Research University, Département de Chimie, 24 rue Lhomond, F-75005 Paris, France
- Sorbonne Universités, UPMC Univ. Paris 06, PASTEUR, F-75005, Paris, France
- CNRS, UMR 8640 PASTEUR, F-75005, Paris, France
| | - S. Quignard
- École Normale Supérieure - PSL Research University, Département de Chimie, 24 rue Lhomond, F-75005 Paris, France
- Sorbonne Universités, UPMC Univ. Paris 06, PASTEUR, F-75005, Paris, France
- CNRS, UMR 8640 PASTEUR, F-75005, Paris, France
| | - C. Gruget
- Laboratoire de Physique Statistique, Ecole Normale Supérieure, Université Pierre et Marie Curie, Université Paris Diderot, Centre National de la Recherche Scientifique UMR8550, 24 rue Lhomond, Paris 75005, France
| | - F. Pincet
- Laboratoire de Physique Statistique, Ecole Normale Supérieure, Université Pierre et Marie Curie, Université Paris Diderot, Centre National de la Recherche Scientifique UMR8550, 24 rue Lhomond, Paris 75005, France
| | - Y. Chen
- École Normale Supérieure - PSL Research University, Département de Chimie, 24 rue Lhomond, F-75005 Paris, France
- Sorbonne Universités, UPMC Univ. Paris 06, PASTEUR, F-75005, Paris, France
- CNRS, UMR 8640 PASTEUR, F-75005, Paris, France
| | - M. Piel
- Institut Curie, CNRS UMR 144, 26 rue d’Ulm, 75005, Paris, France
| | - J. Fattaccioli
- École Normale Supérieure - PSL Research University, Département de Chimie, 24 rue Lhomond, F-75005 Paris, France
- Sorbonne Universités, UPMC Univ. Paris 06, PASTEUR, F-75005, Paris, France
- CNRS, UMR 8640 PASTEUR, F-75005, Paris, France
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21
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Zhang L, Shi C, Lu Q, Liu Q, Zeng H. Probing Molecular Interactions of Asphaltenes in Heptol Using a Surface Forces Apparatus: Implications on Stability of Water-in-Oil Emulsions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:4886-4895. [PMID: 27128395 DOI: 10.1021/acs.langmuir.6b01000] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The behaviors and molecular interactions of asphaltenes are related to many challenging issues in oil production. In this study, the molecular interaction mechanism of asphaltenes in Heptol solvents of varying toluene/n-heptane ratio were directly measured using a surface forces apparatus (SFA). The results showed that the interactions between asphaltene surfaces gradually changed from pure repulsion to weak adhesion as the weight ratio of toluene (ω) in Heptol decreased from ω = 1 to 0. The measured repulsion was mainly due to the steric interactions between swelling asphaltene molecules and/aggregates. The micropipet technique was applied to test the stability of two water-in-oil emulsion droplets attached to glass pipettes. A computer-controlled 4-roll mill fluidic device was also built in-house to investigate the interaction of free-suspending water-in-oil emulsions under dynamic flow conditions. Both micropipet and 4-roll mill fluidic tests demonstrate that asphaltenes adsorbed at oil/water interfaces play a critical role in stabilizing the emulsion drops, in agreement with the repulsion measured between asphaltene surfaces in toluene using SFA, and that interfacial sliding or shearing is generally required to destabilize the protective interfacial apshaltene layers which facilitates the coalescence of emulsion drops. Our results provide insights into the fundamental understanding of molecular interaction mechanisms of asphaltenes in organic solvents and stabilization/destabilization behaviors of water-in-oil emulsions with asphaltenes.
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Affiliation(s)
- Ling Zhang
- Department of Chemical and Materials Engineering, University of Alberta , Edmonton, AB T6G 2V4, Canada
| | - Chen Shi
- Department of Chemical and Materials Engineering, University of Alberta , Edmonton, AB T6G 2V4, Canada
| | - Qingye Lu
- Department of Chemical and Materials Engineering, University of Alberta , Edmonton, AB T6G 2V4, Canada
| | - Qingxia Liu
- Department of Chemical and Materials Engineering, University of Alberta , Edmonton, AB T6G 2V4, Canada
| | - Hongbo Zeng
- Department of Chemical and Materials Engineering, University of Alberta , Edmonton, AB T6G 2V4, Canada
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Khan A, Redelius P, Kringos N. Toward a new experimental method for measuring coalescence in bitumen emulsions: A study of two bitumen droplets. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2016.01.045] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Pradilla D, Simon S, Sjöblom J, Samaniuk J, Skrzypiec M, Vermant J. Sorption and Interfacial Rheology Study of Model Asphaltene Compounds. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:2900-2911. [PMID: 26949974 DOI: 10.1021/acs.langmuir.6b00195] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The sorption and rheological properties of an acidic polyaromatic compound (C5PeC11), which can be used to further our understanding of the behavior of asphaltenes, are determined experimentally. The results show that C5PeC11 exhibits the type of pH-dependent surface activity and interfacial shear rheology observed in C6-asphaltenes with a decrease in the interfacial tension concomitant with the elastic modulus when the pH increases. Surface pressure-area (Π-A) isotherms show evidence of aggregation behavior and π-π stacking at both the air/water and oil/water interfaces. Similarly, interactions between adsorbed C5PeC11 compounds are evidenced through desorption experiments at the oil/water interface. Contrary to indigenous asphaltenes, adsorption is reversible, but desorption is slower than for noninteracting species. The reversibility enables us to create layers reproducibly, whereas the presence of interactions between the compounds enables us to mimic the key aspects of interfacial activity in asphaltenes. Shear and dilatational rheology show that C5PeC11 forms a predominantly elastic film both at the liquid/air and the liquid/liquid interfaces. Furthermore, a soft glassy rheology model (SGR) fits the data obtained at the liquid/liquid interface. However, it is shown that the effective noise temperature determined from the SGR model for C5PeC11 is higher than for indigenous asphaltenes measured under similar conditions. Finally, from a colloidal and rheological standpoint, the results highlight the importance of adequately addressing the distinction between the material functions and true elasticity extracted from a shear measurement and the apparent elasticity measured in dilatational-pendant drop setups.
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Affiliation(s)
- Diego Pradilla
- Ugelstad Laboratory, Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU) , NO-7491 Trondheim, Norway
| | - Sébastien Simon
- Ugelstad Laboratory, Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU) , NO-7491 Trondheim, Norway
| | - Johan Sjöblom
- Ugelstad Laboratory, Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU) , NO-7491 Trondheim, Norway
| | - Joseph Samaniuk
- Soft Materials Laboratory, Department of Materials, ETH Zürich , Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland
| | - Marta Skrzypiec
- Institute of Chemical Technology and Engineering, Poznan University of Technology , Berdychowo 4, 60-965 Poznan, Poland
| | - Jan Vermant
- Soft Materials Laboratory, Department of Materials, ETH Zürich , Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland
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24
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Li Y, Sarıyer OS, Ramachandran A, Panyukov S, Rubinstein M, Kumacheva E. Universal behavior of hydrogels confined to narrow capillaries. Sci Rep 2015; 5:17017. [PMID: 26596468 PMCID: PMC4657056 DOI: 10.1038/srep17017] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 10/23/2015] [Indexed: 11/22/2022] Open
Abstract
Flow of soft matter objects through one-dimensional environments is important in industrial, biological and biomedical systems. Establishing the underlying principles of the behavior of soft matter in confinement can shed light on its performance in many man-made and biological systems. Here, we report an experimental and theoretical study of translocation of micrometer-size hydrogels (microgels) through microfluidic channels with a diameter smaller than an unperturbed microgel size. For microgels with different dimensions and mechanical properties, under a range of applied pressures, we established the universal principles of microgel entrance and passage through microchannels with different geometries, as well as the reduction in microgel volume in confinement. We also show a non-monotonic change in the flow rate of liquid through the constrained microgel, governed by its progressive confinement. The experimental results were in agreement with the theory developed for non-linear biaxial deformation of unentangled polymer gels. Our work has implications for a broad range of phenomena, including occlusion of blood vessels by thrombi and needle-assisted hydrogel injection in tissue engineering.
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Affiliation(s)
- Yang Li
- Department of Chemical Engineering & Applied Chemistry,
University of Toronto, Toronto
| | - Ozan S. Sarıyer
- Department of Chemistry, University of North Carolina,
Chapel Hill, North Carolina
27599-3290
| | - Arun Ramachandran
- Department of Chemical Engineering & Applied Chemistry,
University of Toronto, Toronto
| | - Sergey Panyukov
- P. N. Lebedev Physics Institute, Russian Academy of
Sciences, Moscow
117924
| | - Michael Rubinstein
- Department of Chemistry, University of North Carolina,
Chapel Hill, North Carolina
27599-3290
| | - Eugenia Kumacheva
- Department of Chemical Engineering & Applied Chemistry,
University of Toronto, Toronto
- Department of Chemistry, University of Toronto,
Toronto
- Institute of Biomaterials & Biomedical Engineering,
University of Toronto, Toronto
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25
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Abstract
As a major actor of cellular trafficking, COPI coat proteins assemble on membranes and locally bend them to bud 60 nm-size coated particles. Budding requires the energy of the coat assembly to overcome the one necessary to deform the membrane which primarily depends on the bending modulus and surface tension, γ. Using a COPI-induced oil nanodroplet formation approach, we modulated the budding of nanodroplets using various amounts and types of surfactant. We found a Heaviside-like dependence between the budding efficiency and γ: budding was only dependent on γ and occurred beneath 1.3 mN/m. With the sole contribution of γ to the membrane deformation energy, we assessed that COPI supplies ~1500 kBT for budding particles from membranes, which is consistent with common membrane deformation energies. Our results highlight how a simple remodeling of the composition of membranes could mechanically modulate budding in cells.
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26
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Studying bubble–particle interactions by zeta potential distribution analysis. J Colloid Interface Sci 2015; 449:399-408. [DOI: 10.1016/j.jcis.2015.01.040] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 01/14/2015] [Accepted: 01/15/2015] [Indexed: 11/19/2022]
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27
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Rozairo DP, Croll AB. Using the sessile drop geometry to measure fluid and elastic block copolymer interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:1303-1311. [PMID: 25565303 DOI: 10.1021/la504183g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
There is considerable interest in the fabrication and mechanics of soft spheres and capsules because of their use in a large number of applications ranging from targeted drug delivery to cosmetically active agents. Many systems, such as lipid and block copolymer vesicles, are already finding considerable industrial use where the performance of soft spheres depends intimately on their mechanics. New advanced features such as fast cargo delivery can be realized only if they fit into the existing mechanical niche of the system in question. Here we present a model system to demonstrate how a capsule structure can be fundamentally changed while maintaining its overall mechanical response as well as a simple, universal method to measure the resulting capsule material properties. Specifically, we use confocal microscopy to adapt the sessile drop geometry to a measurement of the static properties of an ensemble of polystyrene-b-poly(ethylene oxide) (PS-PEO)-stabilized oil droplets. We then synthesize a polystyrene-b-poly(acrylic acid)-b-polystyrene (PS-PAA-PS) elastic-shell-coated emulsion drop that shows an identical deformation to the fluidlike PS-PEO droplets. Both systems, in sessile geometry, can be related to their basic material properties through appropriate modeling. We find that the elastic shell is dominated by its surface tension, easily enabling it to match the static response of a purely fluid drop.
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Affiliation(s)
- Damith P Rozairo
- Materials and Nanotechnology and ‡Department of Physics, North Dakota State University , Fargo, North Dakota 58108, United States
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28
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He L, Lin F, Li X, Sui H, Xu Z. Interfacial sciences in unconventional petroleum production: from fundamentals to applications. Chem Soc Rev 2015; 44:5446-94. [DOI: 10.1039/c5cs00102a] [Citation(s) in RCA: 203] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
With the ever increasing demand for energy to meet the needs of growth in population and improvement in the living standards, in particular in developing countries, the abundant unconventional oil reserves (about 70% of total world oil), such as heavy oil, oil/tar sands and shale oil, are playing an increasingly important role in securing global energy supply.
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Affiliation(s)
- Lin He
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin
- P. R. China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin)
| | - Feng Lin
- Department of Chemical and Materials Engineering
- University of Alberta
- Edmonton
- Canada
| | - Xingang Li
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin
- P. R. China
- National Engineering Research Centre of Distillation Technology
| | - Hong Sui
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin
- P. R. China
- National Engineering Research Centre of Distillation Technology
| | - Zhenghe Xu
- Department of Chemical and Materials Engineering
- University of Alberta
- Edmonton
- Canada
- Institute of Nuclear and New Energy Technology
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29
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Benmekhbi M, Simon S, Sjöblom J. Dynamic and Rheological Properties of Span 80 at Liquid–Liquid Interfaces. J DISPER SCI TECHNOL 2014. [DOI: 10.1080/01932691.2013.811573] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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30
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Interfacial pressure and phospholipid density at emulsion droplet interface using fluorescence microscopy. Colloids Surf B Biointerfaces 2013; 117:545-8. [PMID: 24373642 DOI: 10.1016/j.colsurfb.2013.11.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 11/14/2013] [Accepted: 11/15/2013] [Indexed: 11/22/2022]
Abstract
Phospholipids are widely used to stabilize oil in water micron size emulsion droplets; the interfacial phospholipid density and tension of such droplets are difficult to estimate. In the present paper, we describe a simple approach by which the measurement of a micron size oil droplet interface fluorescence intensity provides directly both the interfacial phospholipid density and the interfacial tension. This method relies on two prior calibration steps: (i) the quantitative variation of the interfacial tension with fluorescence intensity at droplets interface through micro-manipulation techniques; (ii) the variation of interfacial tension with phospholipid density through monolayer isotherm. Here, we show the validity of this approach with the example of micron size oil droplets stabilized with a phosphatidylcholine phospholipid, in aqueous buffer.
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31
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COPI buds 60-nm lipid droplets from reconstituted water-phospholipid-triacylglyceride interfaces, suggesting a tension clamp function. Proc Natl Acad Sci U S A 2013; 110:13244-9. [PMID: 23901109 DOI: 10.1073/pnas.1307685110] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Intracellular trafficking between organelles is achieved by coat protein complexes, coat protomers, that bud vesicles from bilayer membranes. Lipid droplets are protected by a monolayer and thus seem unsuitable targets for coatomers. Unexpectedly, coat protein complex I (COPI) is required for lipid droplet targeting of some proteins, suggesting a possible direct interaction between COPI and lipid droplets. Here, we find that COPI coat components can bud 60-nm triacylglycerol nanodroplets from artificial lipid droplet (LD) interfaces. This budding decreases phospholipid packing of the monolayer decorating the mother LD. As a result, hydrophobic triacylglycerol molecules become more exposed to the aqueous environment, increasing LD surface tension. In vivo, this surface tension increase may prime lipid droplets for reactions with neighboring proteins or membranes. It provides a mechanism fundamentally different from transport vesicle formation by COPI, likely responsible for the diverse lipid droplet phenotypes associated with depletion of COPI subunits.
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32
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Kupai MM, Yang F, Harbottle D, Moran K, Masliyah J, Xu Z. Characterising rag-forming solids. CAN J CHEM ENG 2013. [DOI: 10.1002/cjce.21842] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Morvarid Madjlessi Kupai
- Department of Chemical and Materials Engineering; University of Alberta; Edmonton, Alberta; Canada; T6G 2V4
| | - Fan Yang
- Department of Chemical and Materials Engineering; University of Alberta; Edmonton, Alberta; Canada; T6G 2V4
| | - David Harbottle
- Department of Chemical and Materials Engineering; University of Alberta; Edmonton, Alberta; Canada; T6G 2V4
| | - Kevin Moran
- Titanium Corporation; Suite 1400, Baker Centre, 10025-106 Street; Edmonton, Alberta; Canada
| | - Jacob Masliyah
- Department of Chemical and Materials Engineering; University of Alberta; Edmonton, Alberta; Canada; T6G 2V4
| | - Zhenghe Xu
- Department of Chemical and Materials Engineering; University of Alberta; Edmonton, Alberta; Canada; T6G 2V4
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Thiam AR, Bremond N, Bibette J. From stability to permeability of adhesive emulsion bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:6291-8. [PMID: 22439743 DOI: 10.1021/la3003349] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Water drops dispersed in chloroform and stabilized with phospholipids become adhesive if a bad solvent for lipids, such as silicone oil, is added to the continuous phase. In this way, two sticking drops are separated by a bilayer of phospholipids. By using microfluidic technologies, we probe the stability and properties of such membranes likewise encountered in foams or vesicles. We first establish the stability diagram of adhering drop pairs as a function of the continuous phase composition. We found two regimes of destabilization of the bilayer. The first one concerns a competition between the dynamics of adhesion and the transport of surfactants toward the interfaces that leads to a dilute surfactant coverage. The second one corresponds to a dense surface coverage where the lifetime distribution of the bilayer exponentially decreases as a signature of a nucleation process. In the stable regime, we observe the propagation of adhesion among a concentrated collection of drops. This is another remarkable illustration of the suction consequence when two close deformable objects are pulled apart. Moreover, the present experimental strategy offers a novel way to study the phase diagrams of bilayers from a single phospholipid to a mixture of phospholipids. Indeed, we detect phase transitions at a liquid-liquid interface that are ruled by the amount of bad solvent. Finally, we probe the transport of water molecules through the bilayer and show that its permeability is linked to the adhesion energy that reflects its fluidity.
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Affiliation(s)
- Abdou R Thiam
- UPMC Universite Paris 06, CNRS UMR 7195, ESPCI ParisTech, 10 rue Vauquelin, 75231 Paris, France.
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Esmaeili P, Lin F, Yeung A. Stability of emulsified heavy oil: the combined effects of deterministic DLVO forces and random surface charges. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:4948-4954. [PMID: 22369363 DOI: 10.1021/la204254m] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
When dispersed in aqueous solution, droplets of bitumen (extra heavy oil) are known to acquire negative surface charges. The resulting electrostatic repulsion, according to traditional DLVO theory, is far too strong for any droplet coalescence to occur. However, from experience it is known that bitumen droplets do coalesce in aqueous suspensions. Furthermore, the process appears to be random, with the probability of coalescence increasing sharply with the drop size. To explain these facts, we modeled the bitumen-water interface as a heterogeneous surface comprising charged "patches"; the zeta potentials of the patches constitute a random variable that is assumed to be Gaussian. The traditional DLVO theory, according to this model, remains sound on the local scale (i.e., for patches interacting across an intervening water layer). Such a theory can predict the probabilities of coalescence in remarkable detail. A parameter central to this theory is the lateral extent of the charged patches, which was estimated to be in the neighborhood of 0.6 μm.
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Affiliation(s)
- Payman Esmaeili
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, Canada
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35
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Interfacial tension of evaporating emulsion droplets containing amphiphilic block copolymers: Effects of solvent and polymer composition. J Colloid Interface Sci 2012; 365:275-9. [DOI: 10.1016/j.jcis.2011.09.020] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 09/07/2011] [Accepted: 09/10/2011] [Indexed: 11/21/2022]
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36
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Study of water-in-oil thin liquid films: Implications for the stability of petroleum emulsions. Colloids Surf A Physicochem Eng Asp 2010. [DOI: 10.1016/j.colsurfa.2010.09.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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37
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Feng X, Mussone P, Gao S, Wang S, Wu SY, Masliyah JH, Xu Z. Mechanistic study on demulsification of water-in-diluted bitumen emulsions by ethylcellulose. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:3050-3057. [PMID: 20175568 DOI: 10.1021/la9029563] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In our previous study, ethylcellulose (EC), an effective, nontoxic, and biodegradable natural polymer, was found effective in dewatering water-in-diluted bitumen emulsions. In this study, the demulsification mechanism of water-in-diluted bitumen emulsions by EC is investigated. In situ experiments using a micropipet apparatus provided direct evidence on both flocculation and coalescence of water droplets in diluted bitumen by EC. The addition of EC was found to decrease naphtha-diluted bitumen-water interfacial tension significantly. At the molecular level, AFM imaging revealed disruption of the continuous interfacial films formed from surface-active components of bitumen by EC. Our study clearly indicates that the demulsification by EC is through both flocculation and coalescence of water droplets, attained by competitive adsorption of EC at the oil-water interface and disruption of the original protective interfacial films formed from the surface-active components of bitumen.
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Affiliation(s)
- Xianhua Feng
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2G6, Canada
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Kang Z, Yeung A, Foght JM, Gray MR. Hydrophobic bacteria at the hexadecane–water interface: Examination of micrometre-scale interfacial properties. Colloids Surf B Biointerfaces 2008; 67:59-66. [DOI: 10.1016/j.colsurfb.2008.07.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 07/24/2008] [Accepted: 07/27/2008] [Indexed: 11/29/2022]
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Masliyah J, Zhou ZJ, Xu Z, Czarnecki J, Hamza H. Understanding Water-Based Bitumen Extraction from Athabasca Oil Sands. CAN J CHEM ENG 2008. [DOI: 10.1002/cjce.5450820403] [Citation(s) in RCA: 311] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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A microfluidic electrochemical detection technique for assessing stability of thin films and emulsions. J Colloid Interface Sci 2008; 317:593-603. [DOI: 10.1016/j.jcis.2007.09.068] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Revised: 09/22/2007] [Accepted: 09/24/2007] [Indexed: 11/20/2022]
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Tsamantakis C, Masliyah J, Yeung A, Gentzis T. Investigation of the interfacial properties of water-in-diluted-bitumen emulsions using micropipette techniques. J Colloid Interface Sci 2006; 284:176-83. [PMID: 15752799 DOI: 10.1016/j.jcis.2004.10.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2004] [Accepted: 10/07/2004] [Indexed: 11/25/2022]
Abstract
The interfacial properties of water-in-diluted bitumen emulsions were studied using micropipette techniques. It was observed that, as bitumen concentration in the bulk phase (C0) increased, the interfacial tension on the water droplet surfaces decreased. In addition, there was a small effect on the interfacial tension when different solvent mixtures were used. Mixtures of toluene and heptane in different ratios were used as solvents for bitumen dilution. Crumpling of the interface was influenced by bitumen concentration and type of solvent. No crumpling was found for bitumen content less than 0.01% for all solvents used. Crumpling was observed at higher bitumen concentrations when deionized water (pH 5.4-5.6) was used. Setting "heptol[A]" to be the mixture of toluene and heptane, with the volume percent of toluene being A, the following were concluded. Crumpling disappeared at C0 > 1% and when heptol[100] was used, and also at C0 > 10% and when heptol[30] was used. Crumpling was strongly affected by the water pH. In the case of heptol[50], at a higher pH, the crumpling region that normally occurred at C0 > 0.01% disappeared. The micropipette technique proved to be useful in studying the interfacial properties of micrometer-sized emulsion drops.
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Affiliation(s)
- Christina Tsamantakis
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Canada
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Goual L, Horváth-Szabó G, Masliyah JH, Xu Z. Adsorption of bituminous components at oil/water interfaces investigated by quartz crystal microbalance: implications to the stability of water-in-oil emulsions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:8278-89. [PMID: 16114932 DOI: 10.1021/la050333f] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Silica-gel-coated QCM crystals oscillating in a thickness shear mode are used to measure adsorption of bituminous components in water-saturated heptol (1/1 vol ratio of a heptane/toluene mixture) at the oil/water interface. In addition to the viscoelasticity of the adsorbed film, the effects of the bulk liquid density and viscosity as well as the liquid trapped in interfacial cavities are taken into account for the calculation of adsorbed mass. Asphaltenes in heptol adsorb continuously at the oil/water interface, while resins (the surface-active species in maltenes) show adsorption saturation in the same solvent. For Athabasca bitumen in heptol, two adsorption regimes are observed depending on concentration. At low concentrations, a slow, non-steady-state, and irreversible adsorption takes place. At high concentrations, a steady-state adsorption with limited reversibility results in a quick adsorption saturation. The threshold concentration between these adsorption regimes is 1.5 wt % and 8 wt % for oil/water and oil/gold interfaces, respectively. The threshold concentration, the total adsorbed amount, and the flux of non-steady-state adsorption depend on the resin-to-asphaltene ratio. The threshold concentration is related to the earlier reported critical bitumen concentration characterizing the rigid-to-flexible transition of the interfacial film. We propose a new mechanism based on the change of the effective resin-to-asphaltene ratio with dilution to explain both the adsorption behavior and emulsion stability.
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Affiliation(s)
- Lamia Goual
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton AB T6G 2G6, Canada
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Horváth-Szabó G, Masliyah JH, Elliott JAW, Yarranton HW, Czarnecki J. Adsorption isotherms of associating asphaltenes at oil/water interfaces based on the dependence of interfacial tension on solvent activity. J Colloid Interface Sci 2005; 283:5-17. [PMID: 15694419 DOI: 10.1016/j.jcis.2004.08.174] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2003] [Accepted: 08/26/2004] [Indexed: 10/26/2022]
Abstract
In the Gibbs adsorption equation, the application of solvent activity for the calculation of the surface/interfacial excess is proposed for nonideal or associating or pseudocomponents such as asphaltenes. For the aforementioned systems, only the mass-based phenomenological interfacial excess can be determined based on interfacial tension versus activity data. The use of the mole fraction is compared to the use of the activity when the adsorbed amount of associating asphaltenes is calculated at a water/toluene interface. Langmuir-type isotherms describe the adsorption of asphaltenes at toluene/water interfaces. Asphaltenes were treated to remove the resins and natural surfactants using cyclic precipitation and dissolution of asphaltenes at a fixed aliphatic/aromatic ratio. Different fractions of asphaltenes were obtained by changing the aliphatic/aromatic ratio of the precipitating solvent. The limiting molar masses of asphaltenes measured by vapor pressure osmometry are different for fractions precipitated at different heptane to toluene ratios. The mass-based adsorbed amounts at the water/toluene interface, at a 0.1 asphaltene-to-toluene mass-ratio, varied in the range of 0.8-2.8 mg/m(2), depending on the molar mass of asphaltenes.
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Affiliation(s)
- Géza Horváth-Szabó
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2G6, Canada.
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Dorobantu LS, Yeung AKC, Foght JM, Gray MR. Stabilization of oil-water emulsions by hydrophobic bacteria. Appl Environ Microbiol 2004; 70:6333-6. [PMID: 15466587 PMCID: PMC522095 DOI: 10.1128/aem.70.10.6333-6336.2004] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Formation of oil-water emulsions during bacterial growth on hydrocarbons is often attributed to biosurfactants. Here we report the ability of certain intact bacterial cells to stabilize oil-in-water and water-in-oil emulsions without changing the interfacial tension, by inhibition of droplet coalescence as observed in emulsion stabilization by solid particles like silica.
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Affiliation(s)
- Loredana S Dorobantu
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 2G6, Canada
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Jorgensen L, Kim DH, Vermehren C, Bjerregaard S, Frokjaer S. Micropipette manipulation: A technique to evaluate the stability of water‐in‐oil emulsions containing proteins. J Pharm Sci 2004; 93:2994-3003. [PMID: 15468333 DOI: 10.1002/jps.20205] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The interfacial properties and stability of water-in-oil emulsions containing protein were studied using micromanipulation. Micropipettes were used to produce individual water droplets in oil in a controlled manner on the micron scale. The pipettes were then used to bring two droplets into contact in order to observe fusion. The occurrence of fusion was investigated as a function of the compositions of both the continuous (oil) and dispersed (aqueous) phases. Various proteins, i.e., insulin, growth hormone, or serum albumin, were dissolved in the dispersed phase. When low concentrations of surfactants or no surfactant were present in the oil phase, a condensed protein film was formed at the surface of the droplets, which was revealed by the irregular topology of the droplet surface viewed with contrast microscopy. At higher surfactant concentrations, this topology was not observed nor was the stability apparently affected; emulsion droplets coalesce immediately upon contact with each other. There seems to be a limiting surfactant concentration, which stabilizes the droplets toward fusion and prevents formation of a condensed surface film, when the droplets contain protein. The technique exhibits potential for examination of the effects of various excipients on the coalescence stability of emulsion droplets.
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Affiliation(s)
- Lene Jorgensen
- Department of Pharmaceutics, the Danish University of Pharmaceutical Sciences, Universitetsparken 2, DK-2100 Copenhagen O, Denmark.
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Abstract
The shape relaxation of a distorted viscous drop suspended in a quiescent immiscible liquid is analyzed in the creeping flow limit. The shape of the drop is axisymmetric, but otherwise arbitrary. The relaxation process is assumed to be driven by a constant interfacial tension and rate-limited by the Newtonian viscosities of the dispersed and continuous phases. For analysis, a least squares technique is developed which, compared to the more common boundary integral methods, is simpler to implement and especially suited for systems where one liquid is much more viscous than the other (i.e., when the viscosity ratio lambda, defined as the ratio of the dispersed to continuous phase viscosities, approaches either zero or infinity). To demonstrate the validity of the proposed least squares technique, its results are shown to agree well with boundary integral calculations for moderate values of lambda, and with experimental data when lambda is much larger than unity (approximately 10(6)). Predictions at infinite viscosity ratio--the regime in which the least squares technique is most useful--are then used to evaluate interfacial tensions associated with a system of practical importance, namely, the dispersion of heavy crude oil in an aqueous environment. This amounts to a novel and accurate technique for determining interfacial tensions--especially those of low values (1 mN/m or less)--between density-matched liquids where at least one of the phases is highly viscous. The experimental part of this study involves the use of suction pipettes to manipulate the shapes of individual micrometer-sized droplets, thus avoiding the need for complex flow-generating devices to create drop deformations.
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Affiliation(s)
- K Moran
- Syncrude Canada Ltd., Edmonton Research Centre, 9421, 17th Avenue, Edmonton, Alberta T6N 1H4, Canada
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Yeung A, Moran K, Masliyah J, Czarnecki J. Shear-induced coalescence of emulsified oil drops. J Colloid Interface Sci 2003; 265:439-43. [PMID: 12962680 DOI: 10.1016/s0021-9797(03)00531-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Crude oil droplets, when suspended in water, possess negative surface charges which give rise to double-layer repulsive forces between the drops. According to conventional DLVO theory, the magnitude of this repulsion (based on the measured zeta potential) is more than sufficient to prevent coalescence of the droplets. Indeed, when two such droplets were brought together on direct (i.e., "head-on") approach, coalescence was rarely observed. Upon oblique approach, however, the same droplets were seen to coalesce readily. An oblique encounter must necessarily give rise to lateral relative motion-or shearing-between the droplet surfaces. It is speculated that, if the charge distributions at the droplet surfaces were heterogeneous, lateral shearing would facilitate many encounters between surface patches of different zeta potentials across the intervening water film. If the repulsion across any local region were sufficiently weak to allow formation of an oil bridge across the water film, coalescence of the drops would follow inevitably. With the hypothesis of surface heterogeneity, it is not necessary to invoke any additional colloidal interactions (such as "hydrophobic forces") to account for the observed droplet-droplet coalescence. This finding may have important implications for the underlying mechanisms of emulsion stability in general and the commercial extraction of bitumen from oil sands in particular.
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Affiliation(s)
- A Yeung
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 2G6, Canada.
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Bauget F, Langevin D, Lenormand R. Dynamic Surface Properties of Asphaltenes and Resins at the Oil-Air Interface. J Colloid Interface Sci 2001; 239:501-508. [PMID: 11427016 DOI: 10.1006/jcis.2001.7566] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Because of the existence of large reserves, the production of heavy oils is presently the object of much interest. Some heavy oil reservoirs show anomalous behavior in primary production, with rates of production better than predicted. In Canada and Venezuela some heavy oils are produced in the form of "bubbly" oil, which is stable for several hours in open vessels. These crude oils are therefore commonly called "foamy oils". Since the presence of bubbles could be responsible for an enhanced rate of production, a better knowledge of the properties of the gas-oil interface is desirable. We have experimentally studied the effect of concentration of asphaltenes and resins on static and dynamic properties of oil-air interfaces and also on bulk viscosity. The experiments include surface tension measurements using the pendant-drop method, surface viscosity by the oscillating-drop method, foamability by continuous gas injection, and film lifetime. All the experiments were performed using resins and asphaltenes in toluene solutions at 20 degrees C. At first asphaltenes enhance foamability and film lifetime. All the experiments performed showed a change in regime for asphaltene concentrations around 10% by weight, possibly due to clustering. At the studied concentrations, the adsorption process at the air-oil interface is not diffusion controlled but rather involves a reorganization of asphaltene molecules in a network structure. The formation of a solid skin is well identified by the increase of the elastic modulus. This elastic modulus is also an important property for foam stability, since a rigid interface limits bubble rupture. The interface rigidity at long times decreases with increases in resin fraction, which could decrease foam stability as well as emulsion stability. Copyright 2001 Academic Press.
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Affiliation(s)
- Fabrice Bauget
- Institut Franais du Pétrole. 1 & 4, avenue de Bois-Préau, Rueil-Malmaison Cedex, 92852, France
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