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Hmam O, Côté-Dubuc F, Badia A. Gold-Supported Lipid Membranes Formed by Redox-Triggered Vesicle Fusion on Binary Self-Assembled Monolayers: Ion-Pairing Association and Surface Hydrophilicity. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 37223998 DOI: 10.1021/acsami.3c03526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The assembly of biomimetic, planar supported lipid bilayers (SLBs) by the popular vesicle fusion method, which relies on the spontaneous adsorption and rupture of small unilamellar vesicles from aqueous solution on a solid surface, typically works with a limited range of support materials and lipid systems. We previously reported a conceptual advance in the formation of SLBs from vesicles in the gel or fluid phase using the interfacial ion-pairing association of charged phospholipid headgroups with electrochemically generated cationic ferroceniums bound to a self-assembled monolayer (SAM) chemisorbed to gold. This redox-driven approach lays down a single bilayer membrane on the SAM-modified gold surface at room temperature within minutes and is compatible with both anionic and zwitterionic phospholipids. The present work explores the effects of the surface ferrocene concentration and hydrophobicity/hydrophilicity on the formation of continuous SLBs of dialkyl phosphatidylserine, dialkyl phosphatidylglycerol, and dialkyl phosphatidylcholine using binary SAMs of ferrocenylundecanethiolate (FcC11S) and dodecanethiolate (CH3C11S) or hydroxylundecanethiolate (HOC11S) comprising different surface mole fractions of ferrocene (χFcsurf). An increase in the surface hydrophilicity and surface free energy of the FcC11S/HOC11S SAM mitigates the decrease in the attractive ion-pairing interactions resulting from a reduced χFcsurf. SLBs of ≳80% area coverage form on the FcC11S/HOC11S SAM for all the phospholipid types down to χFcsurf of at least 0.2, composition yielding a water contact angle (θW) of 44 ± 4°. By contrast, a greater number of ion-pairing interactions is required on the hydrophobic FcC11S/CH3C11S surface to drive the vesicle fusion process; bilayers or bilayer patches form at χFcsurf ≳ 0.6 (θW = 97 ± 3°). These findings will aid in tailoring the surface chemistry of redox-active modified surfaces to widen the conditions that yield supported lipid membranes.
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Affiliation(s)
- Ons Hmam
- Département de chimie, Quebec Centre for Advanced Materials and Regroupement québécois sur les matériaux de pointe, Université de Montréal, Complexe des sciences, C.P. 6128, succursale Centre-ville, Montréal, Quebec H3C 3J7, Canada
| | - Félix Côté-Dubuc
- Département de chimie, Quebec Centre for Advanced Materials and Regroupement québécois sur les matériaux de pointe, Université de Montréal, Complexe des sciences, C.P. 6128, succursale Centre-ville, Montréal, Quebec H3C 3J7, Canada
| | - Antonella Badia
- Département de chimie, Quebec Centre for Advanced Materials and Regroupement québécois sur les matériaux de pointe, Université de Montréal, Complexe des sciences, C.P. 6128, succursale Centre-ville, Montréal, Quebec H3C 3J7, Canada
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Vega M, Lurio L, Lal J, Karapetrova EA, Gaillard ER. Structure of supported DPPC/cholesterol bilayers studied via X-ray reflectivity. Phys Chem Chem Phys 2020; 22:19089-19099. [PMID: 32807995 DOI: 10.1039/d0cp01834a] [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 electron density profile of bilayers of DPPC/cholesterol mixtures supported on semiconductor grade silicon substrates were studied with the objective of determining how the proximity of a solid interface modifies the phase diagram of mixed bilayers. The bilayers were studied in situ immersed in water via synchrotron X-ray reflectivity (XRR). Measurements were performed as a function of temperature through the main phase transition and cholesterol mole fractions up to 40%. Analysis of XRR yields the bilayer thickness, roughness and leaflet asymmetry. We find that the structure of the pure DPPC bilayers in the gel phase is in agreement with previous X-ray measurements of supported bilayers deposited via vesicle fusion and multilamellar vesicles but show more clearly defined features than measurements made on films formed using Langmuir-Blodget Langmuir-Shaffer (LB) deposition. Examination of bilayer thickness vs. temperature shows that the melting temperature for supported bilayers is shifted upwards by approximately 4 °C relative to multilamellar vesicles and that the melting temperature decreases with increasing cholesterol content up to 20%. For pure DPPC bilayers the leaflets melt in two stages with the distal leaflet melting first. For cholesterol concentrations of 10% and 20% there is no clear indication of separate melting. For 33% and 40% cholesterol content no clear transition is seen in the bilayer thickness, but an abrupt change in roughness indicates possible microdomain formation in the 40% cholesterol sample.
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Affiliation(s)
- Michael Vega
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL 60115, USA.
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Richard-Lacroix M, Umuhire KN, Lister E, Pellerin C, Badia A. Selective Isotopic Labeling Resolves the Gel-to-Fluid Phase Transitions of the Individual Leaflets of a Planar-Supported Phospholipid Bilayer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:9912-9922. [PMID: 31277548 DOI: 10.1021/acs.langmuir.9b00747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Knowledge of the thermotropic phase behavior of solid-supported bilayer lipid assemblies is essential to mimick the molecular organization and lateral fluidity of cell membranes. The gel-to-fluid phase transitions in a homologous series of single phospholipid bilayers supported on planar silicon substrates were investigated by temperature-controlled atomic force microscopy and attenuated total reflection infrared spectroscopy to obtain complementary information at the mesoscopic and molecular scales. Symmetric bilayers of dipalmitoylphosphatidylcholine (DPPC) and vertically asymmetric bilayers composed of a leaflet of DPPC and another of acyl-chain-deuterated DPPC (DPPC-d62) were prepared by the Langmuir-Blodgett technique. The selective deuteration of one of the bilayer leaflets enabled the simultaneous monitoring by IR spectroscopy of the acyl chain melting in each leaflet via the spectrally isolated CH2 and CD2 stretching vibrations. Two gel-to-fluid transitions were discerned for both the symmetric and asymmetric bilayers in ultrapure water. The deuterium isotope effect observed in free-standing membranes was maintained for the supported bilayers. IR spectroscopy revealed that the melting of one leaflet promotes the disordering of the acyl chains in the adjacent one. The findings suggest that the two leaflet phase transitions do not evolve in isolation. This work sheds insight into the nature of leaflet-leaflet interactions and the thermodynamic properties of surface-confined phospholipid bilayers.
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Affiliation(s)
- Marie Richard-Lacroix
- Département de chimie, Centre québécois sur les matériaux fonctionnels , Université de Montréal , C.P. 6128, succursale Centre-ville , Montréal , QC H3C 3J7 , Canada
| | - Kayiganwa Natyvella Umuhire
- Département de chimie, Centre québécois sur les matériaux fonctionnels , Université de Montréal , C.P. 6128, succursale Centre-ville , Montréal , QC H3C 3J7 , Canada
| | - Eugénie Lister
- Département de chimie, Centre québécois sur les matériaux fonctionnels , Université de Montréal , C.P. 6128, succursale Centre-ville , Montréal , QC H3C 3J7 , Canada
| | - Christian Pellerin
- Département de chimie, Centre québécois sur les matériaux fonctionnels , Université de Montréal , C.P. 6128, succursale Centre-ville , Montréal , QC H3C 3J7 , Canada
| | - Antonella Badia
- Département de chimie, Centre québécois sur les matériaux fonctionnels , Université de Montréal , C.P. 6128, succursale Centre-ville , Montréal , QC H3C 3J7 , Canada
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Poursoroush A, Sperotto MM, Laradji M. Phase behavior of supported lipid bilayers: A systematic study by coarse-grained molecular dynamics simulations. J Chem Phys 2018; 146:154902. [PMID: 28433014 DOI: 10.1063/1.4981008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Solid-supported lipid bilayers are utilized by experimental scientists as models for biological membranes because of their stability. However, compared to free standing bilayers, their close proximity to the substrate may affect their phase behavior. As this is still poorly understood, and few computational studies have been performed on such systems thus far, here we present the results from a systematic study based on molecular dynamics simulations of an implicit-solvent model for solid-supported lipid bilayers with varying lipid-substrate interactions. The attractive interaction between the substrate and the lipid head groups that are closest to the substrate leads to an increased translocation of the lipids from the distal to the proximal bilayer-leaflet. This thereby leads to a transbilayer imbalance of the lipid density, with the lipid density of the proximal leaflet higher than that of the distal leaflet. Consequently, the order parameter of the proximal leaflet is found to be higher than that of the distal leaflet, the higher the strength of lipid interaction is, the stronger the effect. The proximal leaflet exhibits gel and fluid phases with an abrupt melting transition between the two phases. In contrast, below the melting temperature of the proximal leaflet, the distal leaflet is inhomogeneous with coexisting gel and fluid domains. The size of the fluid domains increases with increasing the strength of the lipid interaction. At low temperatures, the inhomogeneity of the distal leaflet is due to its reduced lipid density.
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Affiliation(s)
- Asma Poursoroush
- Department of Physics and Materials Science, The University of Memphis, Memphis, Tennessee 38152, USA
| | - Maria Maddalena Sperotto
- DTU Bioinformatics, Department of Bio and Health Informatics, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Mohamed Laradji
- Department of Physics and Materials Science, The University of Memphis, Memphis, Tennessee 38152, USA
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Paige MF, Eftaiha AF. Phase-separated surfactant monolayers: Exploiting immiscibility of fluorocarbons and hydrocarbons to pattern interfaces. Adv Colloid Interface Sci 2017; 248:129-146. [PMID: 28756970 DOI: 10.1016/j.cis.2017.07.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 04/21/2017] [Accepted: 07/17/2017] [Indexed: 10/19/2022]
Abstract
The mutual immiscibility of hydrogenated and fluorinated surfactants at interfaces frequently leads to phase-separation, which provides a useful and flexible method for patterning air-water and solid-air interfaces. In this article, we review recent advances in the use of hydrogenated-fluorinated surfactant mixtures to achieve interfacial patterning. For even relatively simple systems comprised of binary mixed monolayers of hydrogenated and perfluorinated fatty acids, a diverse range of film morphologies can be generated at the air-water interface and successfully transferred onto solid substrates. Systematic investigations reported over the past several years have allowed for correlation between the chemical structure of the film constituents with the gross film morphology and underlying crystalline structure of the films. Early thermodynamic models based on the interplay between dipole-dipole repulsion forces between charged headgroups balanced by line tension between phases that were formulated to describe phase-behavior in simple phospholipid monolayer systems have proven highly useful to describe morphologies for the immiscible surfactant blends. Beyond simple binary fatty acid mixtures, highly-structured films have also been reported in mixed phospholipid systems, which have found important application in controlling the physical, compositional and performance properties of lung surfactant mixtures, as well as in semifluorinated alkane monolayers which form unique, hemimicellar structures at both liquid and solid interfaces. We also describe advances in using these approaches to pattern photopolymerizable, luminescent surfactants, which have found extensive use in colorimetric and fluorometric sensing devices. The long-term outlook for this field, with an emphasis on potential applications and future research directions are discussed.
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Thermal Response Analysis of Phospholipid Bilayers Using Ellipsometric Techniques. BIOSENSORS-BASEL 2017; 7:bios7030034. [PMID: 28820461 PMCID: PMC5618040 DOI: 10.3390/bios7030034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 08/15/2017] [Accepted: 08/16/2017] [Indexed: 12/29/2022]
Abstract
Biomimetic planar artificial membranes have been widely studied due to their multiple applications in several research fields. Their humectation and thermal response are crucial for reaching stability; these characteristics are related to the molecular organization inside the bilayer, which is affected by the aliphatic chain length, saturations, and molecule polarity, among others. Bilayer stability becomes a fundamental factor when technological devices are developed—like biosensors—based on those systems. Thermal studies were performed for different types of phosphatidylcholine (PC) molecules: two pure PC bilayers and four binary PC mixtures. These analyses were carried out through the detection of slight changes in their optical and structural parameters via Ellipsometry and Surface Plasmon Resonance (SPR) techniques. Phospholipid bilayers were prepared by Langmuir-Blodgett technique and deposited over a hydrophilic silicon wafer. Their molecular inclination degree, mobility, and stability of the different phases were detected and analyzed through bilayer thickness changes and their optical phase-amplitude response. Results show that certain binary lipid mixtures—with differences in its aliphatic chain length—present a co-existence of two thermal responses due to non-ideal mixing.
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González-Henríquez CM, Sarabia-Vallejos MA. Electrospinning deposition of hydrogel fibers used as scaffold for biomembranes. Thermal stability of DPPC corroborated by ellipsometry. Chem Phys Lipids 2015. [PMID: 26206414 DOI: 10.1016/j.chemphyslip.2015.07.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
DPPC bilayers were deposited over thin hydrogel scaffolds using the Langmuir-Blodgett technique (with DPPC thickness ∼ 6.2 nm). Wrinkled hydrogels films were used to maintain a moist environment in order to enhance DPPC bilayer stability. Polymer mixtures were prepared using HEMA (as a base monomer) and DEGDMA, PEGDA575, PEGDA700 or AAm (as crosslinking agents); a thermal initiator was added to obtain a final pre-hydrogel (oligomer) with an adequate viscosity for thin film formation. This mixture was deposited as wrinkled film/fibers over hydrophilic silicon wafers using an electrospinning technique. Later, these samples were exposed to UV light to trigger photopolymerization, generating crosslinking bonds between hydrogel chains; this process also generated remnant surface stresses in the films that favored wrinkle formation. In the cases where DEGDMA and AAm were used as crosslinking agents, HEMA was added in higher amounts. The resultant polymer film surface showed homogenous layering with some small isolated clusters. If PEGDA575/700 was used as the crosslinking agent, we observed the formation of polymer wrinkled thin films, composed by main and secondary chains (with different dimensions). Moreover, water absorption and release was found to be mediated through surface morphology, ordering and film thickness. The thermal behavior of biomembranes was examined using ellipsometry techniques under controlled heating cycles, allowing phases and phase transitions to be detected through slight thickness variations with respect to temperature. Atomic force microscopy was used to determinate surface roughness changes according to temperature variation, temperature was varied sufficiently for the detection and recording of DPPC phase limits. Contact angle measurements corroborated and quantified system wettability, supporting the theory that wrinkled hydrogel films act to enhance DPPC bilayer stability during thermal cycles.
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Affiliation(s)
- C M González-Henríquez
- Departamento de Química, Universidad Tecnológica Metropolitana, Las Palmeras #3360, Santiago, Chile.
| | - M A Sarabia-Vallejos
- Instituto de Física, Pontificia Universidad Católica de Chile, Avda. Vicuña Mackenna #4860, Santiago, Chile
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Wang L, Roth JS, Han X, Evans SD. Photosynthetic Proteins in Supported Lipid Bilayers: Towards a Biokleptic Approach for Energy Capture. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:3306-3318. [PMID: 25727786 DOI: 10.1002/smll.201403469] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 01/11/2015] [Indexed: 06/04/2023]
Abstract
In nature, plants and some bacteria have evolved an ability to convert solar energy into chemical energy usable by the organism. This process involves several proteins and the creation of a chemical gradient across the cell membrane. To transfer this process to a laboratory environment, several conditions have to be met: i) proteins need to be reconstituted into a lipid membrane, ii) the proteins need to be correctly oriented and functional and, finally, iii) the lipid membrane should be capable of maintaining chemical and electrical gradients. Investigating the processes of photosynthesis and energy generation in vivo is a difficult task due to the complexity of the membrane and its associated proteins. Solid, supported lipid bilayers provide a good model system for the systematic investigation of the different components involved in the photosynthetic pathway. In this review, the progress made to date in the development of supported lipid bilayer systems suitable for the investigation of membrane proteins is described; in particular, there is a focus on those used for the reconstitution of proteins involved in light capture.
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Affiliation(s)
- Lei Wang
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
- State Key Laboratory of Urban Water Resource and Environment, School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin, 150001, China
| | - Johannes S Roth
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Xiaojun Han
- State Key Laboratory of Urban Water Resource and Environment, School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin, 150001, China
| | - Stephen D Evans
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
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Mangiarotti A, Wilke N. Energetics of the Phase Transition in Free-Standing versus Supported Lipid Membranes. J Phys Chem B 2015; 119:8718-24. [DOI: 10.1021/acs.jpcb.5b04397] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Agustín Mangiarotti
- Centro
de Investigaciones
en Química Biológica de Córdoba (CIQUIBIC, UNC−CONICET),
Departamento de Química Biológica, Facultad de Ciencias
Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina
Allende, Ciudad Universitaria, X5000HUA Córdoba, Argentina
| | - Natalia Wilke
- Centro
de Investigaciones
en Química Biológica de Córdoba (CIQUIBIC, UNC−CONICET),
Departamento de Química Biológica, Facultad de Ciencias
Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina
Allende, Ciudad Universitaria, X5000HUA Córdoba, Argentina
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Takahashi M, Mohan P, Nakade A, Higashimine K, Mott D, Hamada T, Matsumura K, Taguchi T, Maenosono S. Ag/FeCo/Ag core/shell/shell magnetic nanoparticles with plasmonic imaging capability. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:2228-2236. [PMID: 25614919 DOI: 10.1021/la5046805] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Magnetic nanoparticles (NPs) have been used to separate various species such as bacteria, cells, and proteins. In this study, we synthesized Ag/FeCo/Ag core/shell/shell NPs designed for magnetic separation of subcellular components like intracellular vesicles. A benefit of these NPs is that their silver metal content allows plasmon scattering to be used as a tool to observe detection by the NPs easily and semipermanently. Therefore, these NPs are considered a potential alternative to existing fluorescent probes like dye molecules and colloidal quantum dots. In addition, the Ag core inside the NPs suppresses the oxidation of FeCo because of electron transfer from the Ag core to the FeCo shell, even though FeCo is typically susceptible to oxidation. The surfaces of the Ag/FeCo/Ag NPs were functionalized with ε-poly-L-lysine-based hydrophilic polymers to make them water-soluble and biocompatible. The imaging capability of the polymer-functionalized NPs induced by plasmon scattering from the Ag core was investigated. The response of the NPs to a magnetic field using liposomes as platforms and applying a magnetic field during observation by confocal laser scanning microscopy was assessed. The results of the magnetophoresis experiments of liposomes allowed us to calculate the magnetic force to which each liposome was subjected.
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Affiliation(s)
- Mari Takahashi
- School of Materials Science, Japan Advanced Institute of Science and Technology , 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan
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