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Tero R, Hagiwara Y, Saito S. Domain Localization by Graphene Oxide in Supported Lipid Bilayers. Int J Mol Sci 2023; 24:ijms24097999. [PMID: 37175707 PMCID: PMC10178265 DOI: 10.3390/ijms24097999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 04/13/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023] Open
Abstract
The gel-phase domains in a binary supported lipid bilayer (SLB) comprising dioleoylphosphatidylcholine (DOPC) and dipalmitoylphosphatidylcholine (DPPC) were localized on graphene oxide (GO) deposited on a SiO2/Si substrate. We investigated the distribution of the gel-phase domains and the liquid crystalline (Lα) phase regions in DOPC+DPPC-SLB on thermally oxidized SiO2/Si substrates with GO flakes to understand the mechanism of the domain localization on GO. Fluorescence microscopy and atomic force microscopy revealed that the gel-phase domains preferably distributed on GO flakes, whereas the fraction of the Lα-phase increased on the bare SiO2 surface which was not covered with the GO flakes. The gel-phase domain was condensed on GO more effectively at the lower cooling rate. We propose that nucleation of the gel-phase domain preferentially occurred on GO, whose surface has amphiphilic property, during the gel-phase domain formation. The domains of the liquid ordered (Lo) phase were also condensed on GO in a ternary bilayer containing cholesterol that was phase-separated to the Lo phase and the liquid disordered phase. Rigid domains segregates on GO during their formation process, leaving fluid components to the surrounding region of GO.
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Affiliation(s)
- Ryugo Tero
- Department of Applied Chemistry and Life Science, Toyohashi University of Technology, Toyohashi 441-8580, Japan
| | - Yoshi Hagiwara
- Department of Applied Chemistry and Life Science, Toyohashi University of Technology, Toyohashi 441-8580, Japan
| | - Shun Saito
- Department of Applied Chemistry and Life Science, Toyohashi University of Technology, Toyohashi 441-8580, Japan
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Sannigrahi A, Rai VH, Chalil MV, Chakraborty D, Meher SK, Roy R. A Versatile Suspended Lipid Membrane System for Probing Membrane Remodeling and Disruption. MEMBRANES 2022; 12:1190. [PMID: 36557095 PMCID: PMC9784602 DOI: 10.3390/membranes12121190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/12/2022] [Accepted: 10/18/2022] [Indexed: 06/17/2023]
Abstract
Artificial membrane systems can serve as models to investigate molecular mechanisms of different cellular processes, including transport, pore formation, and viral fusion. However, the current, such as SUVs, GUVs, and the supported lipid bilayers suffer from issues, namely high curvature, heterogeneity, and surface artefacts, respectively. Freestanding membranes provide a facile solution to these issues, but current systems developed by various groups use silicon or aluminum oxide wafers for fabrication that involves access to a dedicated nanolithography facility and high cost while conferring poor membrane stability. Here, we report the development, characterization and applications of an easy-to-fabricate suspended lipid bilayer (SULB) membrane platform leveraging commercial track-etched porous filters (PCTE) with defined microwell size. Our SULB system offers a platform to study the lipid composition-dependent structural and functional properties of membranes with exceptional stability. With dye entrapped in PCTE microwells by SULB, we show that sphingomyelin significantly augments the activity of pore-forming toxin, Cytolysin A (ClyA) and the pore formation induces lipid exchange between the bilayer leaflets. Further, we demonstrate high efficiency and rapid kinetics of membrane fusion by dengue virus in our SULB platform. Our suspended bilayer membrane mimetic offers a novel platform to investigate a large class of biomembrane interactions and processes.
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3
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Capability of Polyunsaturated Phosphatidylcholine for Non-raft Domain Formation in Cholesterol-containing Lipid Bilayers. E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY 2022. [DOI: 10.1380/ejssnt.2022-015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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4
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Lateral organization of biomimetic cell membranes in varying pH conditions. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.117907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Non-raft submicron domain formation in cholesterol-containing lipid bilayers induced by polyunsaturated phosphatidylethanolamine. Colloids Surf B Biointerfaces 2021; 210:112235. [PMID: 34891064 DOI: 10.1016/j.colsurfb.2021.112235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 11/08/2021] [Accepted: 11/16/2021] [Indexed: 12/13/2022]
Abstract
Domain formation in "HLC" ternary lipid bilayers, comprising a high transition temperature (High-Tm) lipid, a Low-Tm lipid, and cholesterol (Chol), has been extensively studied as raft-resembling systems. Recently, we reported the formation of submicron domains in an "LLC" lipid bilayer, encompassing Low-Tm phosphatidylethanolamine (PE), Low-Tm phosphatidylcholine (PC), and Chol. We hypothesized that the formation of this unique domain is driven by polyunsaturated PE. In this study, we explored the effects of the degree of PE unsaturation and the double bond distribution at the sn-position on the mechanism of formation and the composition of submicron domains. Supported lipid bilayers (SLBs), comprising PE with various degrees of unsaturation, monounsaturated PC (POPC), and Chol, were investigated using fluorescence microscopy, atomic force microscopy, and the force-distance curve measurement. The area fraction of submicron domains in PE+POPC+Chol-SLB increased with the PE concentration and degree of unsaturation of the PE acyl chain. The results indicated that the submicron domains were enriched with polyunsaturated PE and were in the liquid-disordered-like state, whereas their surrounding regions were in the liquid-ordered-like state. Segregation of polyunsaturated PE from the Chol-containing region generated submicron domains in the LLC lipid bilayer. We propose a mechanism for the formation of these submicron domains based on molecular interactions involving the hydrophobic and hydrophilic parts of the bilayer membrane.
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Goh MWS, Tero R. Cholesterol-induced microdomain formation in lipid bilayer membranes consisting of completely miscible lipids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183626. [PMID: 33901442 DOI: 10.1016/j.bbamem.2021.183626] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 11/19/2022]
Abstract
Recently, we reported that a ternary lipid bilayer comprising phosphatidylethanolamine (PE), phosphatidylcholine (PC), which were both derived from chicken egg, and cholesterol (Chol) generates microdomains that function as specific fusion sites for proteoliposomes. Chol-induced microdomain formation in a completely miscible lipid bilayer is an exceptional phenomenon. Numerous studies have elucidated the formation of domains in liquid ordered (Lo) and liquid disordered (Ld) phases of ternary bilayers, which comprise two partially miscible lipids and Chol. Herein, we investigated the composition and mechanism of formation of these unique microdomains in supported lipid bilayers (SLBs) using a fluorescence microscope and an atomic force microscope (AFM). We prepared ternary SLBs using egg-derived PC (eggPC), Chol and three different types of PE: egg-derived PE, 1-palmitoyl-2-oleoyl-PE, and 1,2-didocosahexaenoyl-PE (diDHPE). Fluorescence microscopy observations revealed that fluid and continuous SLBs were formed at PE concentrations (CPE) of ≥6 mol%. Fluorescence recovery after photobleaching measurement revealed that the microdomain was more fluid than the surrounding region that showed typical diffusion coefficient of the Lo phase. The microdomains were observed as depressions in the AFM topographies. Their area fraction (θ) increased with CPE, and diDHPE produced a significantly large θ among the three PEs. The microdomains in the PE+eggPC+Chol-SLBs were rich in polyunsaturated PE and were in the Ld-like phase. Associating eggPC and Chol caused polyunsaturated PE to segregate, resulting in a microdomain formation by conferring the umbrella effect on Chol, entropic effect of disordered acyl chains, and π-π interactions in the hydrophobic core.
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Affiliation(s)
- Melvin Wei Shern Goh
- Department of Applied Chemistry and Life Science, Toyohashi University of Technology, Toyohashi, Aichi 441-8580, Japan
| | - Ryugo Tero
- Department of Applied Chemistry and Life Science, Toyohashi University of Technology, Toyohashi, Aichi 441-8580, Japan.
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Kataoka-Hamai C, Kawakami K. Domain Sorting in Giant Unilamellar Vesicles Adsorbed on Glass. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:1082-1088. [PMID: 33440115 DOI: 10.1021/acs.langmuir.0c02843] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Giant unilamellar vesicles (GUVs) adsorb to a solid surface and rupture to form a planar bilayer patch. These bilayer patches are used to investigate the properties and functions of biological membranes. Therefore, it is crucial to understand the mechanisms of GUV adsorption. In this study, we investigate the adsorption of phase-separated GUVs on glass using fluorescence microscopy. GUVs containing liquid-ordered (Lo) and liquid-disordered (Ld) phases underwent domain sorting after adsorption. The Ld domain in the unbound region migrated to the highly curved region near the edge of the adsorbed region. Additionally, the Lo phase grew linearly along the edge of the adsorbed region, creating a thin ring-like domain. After the domain sorting event, the GUV ruptured to form a planar bilayer patch with circular-patterned domains in the initially adsorbed area. We found that domain sorting was promoted by increasing the extent of GUV deformation. These results suggest that both the Ld and Lo domains are reorganized for stabilizing the curved bilayer region in adsorbed GUVs.
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Affiliation(s)
- Chiho Kataoka-Hamai
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Kohsaku Kawakami
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
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Páez-Pérez M, López-Duarte I, Vyšniauskas A, Brooks NJ, Kuimova MK. Imaging non-classical mechanical responses of lipid membranes using molecular rotors. Chem Sci 2020; 12:2604-2613. [PMID: 34164028 PMCID: PMC8179291 DOI: 10.1039/d0sc05874b] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 12/22/2020] [Indexed: 12/15/2022] Open
Abstract
Lipid packing in cellular membranes has a direct effect on membrane tension and microviscosity, and plays a central role in cellular adaptation, homeostasis and disease. According to conventional mechanical descriptions, viscosity and tension are directly interconnected, with increased tension leading to decreased membrane microviscosity. However, the intricate molecular interactions that combine to build the structure and function of a cell membrane suggest a more complex relationship between these parameters. In this work, a viscosity-sensitive fluorophore ('molecular rotor') is used to map changes in microviscosity in model membranes under conditions of osmotic stress. Our results suggest that the relationship between membrane tension and microviscosity is strongly influenced by the bilayer's lipid composition. In particular, we show that the effects of increasing tension are minimised for membranes that exhibit liquid disordered (Ld) - liquid ordered (Lo) phase coexistence; while, surprisingly, membranes in pure gel and Lo phases exhibit a negative compressibility behaviour, i.e. they soften upon compression.
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Affiliation(s)
- Miguel Páez-Pérez
- MSRH, Department of Chemistry, Imperial College London Wood Lane London W12 0BZ UK
| | - Ismael López-Duarte
- MSRH, Department of Chemistry, Imperial College London Wood Lane London W12 0BZ UK
- Departamento de Química Orgánica, Universidad Autónoma de Madrid Cantoblanco 28049 Madrid Spain
| | - Aurimas Vyšniauskas
- MSRH, Department of Chemistry, Imperial College London Wood Lane London W12 0BZ UK
- Center of Physical Sciences and Technology Saulėtekio av. 3 Vilnius Lithuania
| | - Nicholas J Brooks
- MSRH, Department of Chemistry, Imperial College London Wood Lane London W12 0BZ UK
| | - Marina K Kuimova
- MSRH, Department of Chemistry, Imperial College London Wood Lane London W12 0BZ UK
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Cisternas MA, Palacios-Coddou F, Molina S, Retamal MJ, Gomez-Vierling N, Moraga N, Zelada H, Soto-Arriaza MA, Corrales TP, Volkmann UG. Dry Two-Step Self-Assembly of Stable Supported Lipid Bilayers on Silicon Substrates. Int J Mol Sci 2020; 21:E6819. [PMID: 32957654 PMCID: PMC7555443 DOI: 10.3390/ijms21186819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/13/2020] [Accepted: 09/16/2020] [Indexed: 11/17/2022] Open
Abstract
Artificial membranes are models for biological systems and are important for applications. We introduce a dry two-step self-assembly method consisting of the high-vacuum evaporation of phospholipid molecules over silicon, followed by a subsequent annealing step in air. We evaporate dipalmitoylphosphatidylcholine (DPPC) molecules over bare silicon without the use of polymer cushions or solvents. High-resolution ellipsometry and AFM temperature-dependent measurements are performed in air to detect the characteristic phase transitions of DPPC bilayers. Complementary AFM force-spectroscopy breakthrough events are induced to detect single- and multi-bilayer formation. These combined experimental methods confirm the formation of stable non-hydrated supported lipid bilayers with phase transitions gel to ripple at 311.5 ± 0.9 K, ripple to liquid crystalline at 323.8 ± 2.5 K and liquid crystalline to fluid disordered at 330.4 ± 0.9 K, consistent with such structures reported in wet environments. We find that the AFM tip induces a restructuring or intercalation of the bilayer that is strongly related to the applied tip-force. These dry supported lipid bilayers show long-term stability. These findings are relevant for the development of functional biointerfaces, specifically for fabrication of biosensors and membrane protein platforms. The observed stability is relevant in the context of lifetimes of systems protected by bilayers in dry environments.
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Affiliation(s)
- Marcelo A. Cisternas
- Instituto de Fisica, Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile; (M.A.C.); (F.P.-C.); (S.M.); (N.G.-V.); (N.M.); (H.Z.)
- Centro de Investigacion en Nanotecnologia y Materiales Avanzados (CIEN-UC), Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile; (M.J.R.); (M.A.S.-A.)
| | - Francisca Palacios-Coddou
- Instituto de Fisica, Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile; (M.A.C.); (F.P.-C.); (S.M.); (N.G.-V.); (N.M.); (H.Z.)
- Centro de Investigacion en Nanotecnologia y Materiales Avanzados (CIEN-UC), Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile; (M.J.R.); (M.A.S.-A.)
| | - Sebastian Molina
- Instituto de Fisica, Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile; (M.A.C.); (F.P.-C.); (S.M.); (N.G.-V.); (N.M.); (H.Z.)
- Centro de Investigacion en Nanotecnologia y Materiales Avanzados (CIEN-UC), Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile; (M.J.R.); (M.A.S.-A.)
| | - Maria Jose Retamal
- Centro de Investigacion en Nanotecnologia y Materiales Avanzados (CIEN-UC), Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile; (M.J.R.); (M.A.S.-A.)
- Departamento de Química-Física, Facultad de Quimica y de Farmacia, Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile
| | - Nancy Gomez-Vierling
- Instituto de Fisica, Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile; (M.A.C.); (F.P.-C.); (S.M.); (N.G.-V.); (N.M.); (H.Z.)
- Centro de Investigacion en Nanotecnologia y Materiales Avanzados (CIEN-UC), Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile; (M.J.R.); (M.A.S.-A.)
| | - Nicolas Moraga
- Instituto de Fisica, Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile; (M.A.C.); (F.P.-C.); (S.M.); (N.G.-V.); (N.M.); (H.Z.)
- Centro de Investigacion en Nanotecnologia y Materiales Avanzados (CIEN-UC), Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile; (M.J.R.); (M.A.S.-A.)
| | - Hugo Zelada
- Instituto de Fisica, Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile; (M.A.C.); (F.P.-C.); (S.M.); (N.G.-V.); (N.M.); (H.Z.)
- Centro de Investigacion en Nanotecnologia y Materiales Avanzados (CIEN-UC), Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile; (M.J.R.); (M.A.S.-A.)
| | - Marco A. Soto-Arriaza
- Centro de Investigacion en Nanotecnologia y Materiales Avanzados (CIEN-UC), Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile; (M.J.R.); (M.A.S.-A.)
- Departamento de Química-Física, Facultad de Quimica y de Farmacia, Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile
| | - Tomas P. Corrales
- Departamento de Fisica, Universidad Técnica Federico Santa María, Valparaíso 2390123, Chile;
| | - Ulrich G. Volkmann
- Instituto de Fisica, Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile; (M.A.C.); (F.P.-C.); (S.M.); (N.G.-V.); (N.M.); (H.Z.)
- Centro de Investigacion en Nanotecnologia y Materiales Avanzados (CIEN-UC), Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile; (M.J.R.); (M.A.S.-A.)
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Sibold J, Tewaag VE, Vagedes T, Mey I, Steinem C. Phase separation in pore-spanning membranes induced by differences in surface adhesion. Phys Chem Chem Phys 2020; 22:9308-9315. [DOI: 10.1039/d0cp00335b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A porous scaffold providing different adhesion energies alters the behaviour of coexisting phases in lipid membranes considerably.
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Affiliation(s)
- Jeremias Sibold
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Vera E. Tewaag
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Thomas Vagedes
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Ingo Mey
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Claudia Steinem
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
- Max Planck Institute for Dynamics and Self-Organization
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11
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Oshima A, Nakashima H, Sumitomo K. Evaluation of Lateral Diffusion of Lipids in Continuous Membranes between Freestanding and Supported Areas by Fluorescence Recovery after Photobleaching. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:11725-11734. [PMID: 31407907 DOI: 10.1021/acs.langmuir.9b01595] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The lateral diffusion of lipids is a key factor when functionalizing artificial planar bilayer lipid membranes (BLMs). Fluorescence recovery after photobleaching (FRAP) is an established method for evaluating the fluidity of BLMs by the quantitative determination of the diffusion coefficient. However, a BLM with a uniform diffusion coefficient is usually assumed for analysis. In addition, when the BLM to be evaluated is small, the spread of a bleached circle caused by lateral diffusion during the bleaching process and the divergence of the laser used for bleaching interfere with the quantitative analysis. In this study, a numerical calculation was adopted to make it possible to analyze the continuous BLM between freestanding and supported areas, where the diffusion coefficients change depending on the presence or absence of an interaction with the substrate. A quantitative evaluation independent of such bleaching conditions as the bleaching diameter was also ensured by incorporating the spreading effect of the bleached circle in the calculation, which was employed to analyze a freestanding BLM with a diameter of only a few micrometers. By comparing calculations and experiments on FRAP recovery curves, we found that there are multiple diffusion elements and high diffusion barriers at the boundary between the freestanding and supported areas in a BLM over a SiO2/Si microwell substrate.
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Affiliation(s)
- Azusa Oshima
- NTT Basic Research Laboratories , NTT Corporation , 3-1 Morinosato Wakamiya , Atsugi , Kanagawa 243-0198 , Japan
| | - Hiroshi Nakashima
- NTT Basic Research Laboratories , NTT Corporation , 3-1 Morinosato Wakamiya , Atsugi , Kanagawa 243-0198 , Japan
| | - Koji Sumitomo
- University of Hyogo , 2167 Shosha , Himeji , Hyogo 671-2280 , Japan
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OSHIMA A, SUMITOMO K. Vesicle Fusion with Artificial Bilayer Lipid Membrane Induced by Electrostatic Interaction. BUNSEKI KAGAKU 2019. [DOI: 10.2116/bunsekikagaku.68.23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Azusa OSHIMA
- NTT Basic Research Laboratories, NTT Corporation
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13
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Evolution and development of model membranes for physicochemical and functional studies of the membrane lateral heterogeneity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:2012-2017. [DOI: 10.1016/j.bbamem.2018.03.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 03/08/2018] [Accepted: 03/11/2018] [Indexed: 12/19/2022]
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14
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Kakimoto Y, Tachihara Y, Okamoto Y, Miyazawa K, Fukuma T, Tero R. Morphology and Physical Properties of Hydrophilic-Polymer-Modified Lipids in Supported Lipid Bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:7201-7209. [PMID: 29788718 DOI: 10.1021/acs.langmuir.8b00870] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Lipid molecules such as glycolipids that are modified with hydrophilic biopolymers participate in the biochemical reactions occurring on cell membranes. Their functions and efficiency are determined by the formation of microdomains and their physical properties. We investigated the morphology and properties of domains induced by the hydrophilic-polymer-modified lipid applying a polyethylene glycol (PEG)-modified lipid as a model modified lipid. We formed supported lipid bilayers (SLBs) using a 0-10 mol % range of PEG-modified lipid concentration ( CPEG). We studied their morphology and fluidity by fluorescence microscopy, the fluorescence recovery after photobleaching method, and atomic force microscopy (AFM). Fluorescence images showed that domains rich in the PEG-modified lipid appeared and SLB fluidity decreased when CPEG ≥ 5%. AFM topographies showed that clusters of the PEG-modified lipid appeared prior to domain formation and the PEG-lipid-rich domains were observed as depressions. Frequency-modulation AFM revealed a force-dependent appearance of the PEG-lipid-rich domain.
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Affiliation(s)
- Yasuhiro Kakimoto
- Department of Environmental and Life Sciences , Toyohashi University of Technology , Toyohashi , Aichi 441-8580 , Japan
| | - Yoshihiro Tachihara
- Department of Environmental and Life Sciences , Toyohashi University of Technology , Toyohashi , Aichi 441-8580 , Japan
| | - Yoshiaki Okamoto
- Department of Environmental and Life Sciences , Toyohashi University of Technology , Toyohashi , Aichi 441-8580 , Japan
| | - Keisuke Miyazawa
- Division of Electrical Engineering and Computer Science , Kanazawa University , Kakuma-machi, Kanazawa 920-1192 , Japan
| | - Takeshi Fukuma
- Division of Electrical Engineering and Computer Science , Kanazawa University , Kakuma-machi, Kanazawa 920-1192 , Japan
- Nano Life Science Institute (WPI-NanoLSI) , Kakuma-machi, Kanazawa 920-1192 , Japan
| | - Ryugo Tero
- Department of Environmental and Life Sciences , Toyohashi University of Technology , Toyohashi , Aichi 441-8580 , Japan
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