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Chuduang K, Pholraksa P, Naumann CA. Capillary-Assisted Assembly of Polymer Gel-Supported Lipid Bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024. [PMID: 39255463 DOI: 10.1021/acs.langmuir.4c01750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2024]
Abstract
The polymer-supported lipid bilayer represents an attractive supramolecular assembly in numerous biophysical and bioanalytical applications. The assembly of polymer-supported membranes with a polymer layer thickness of just a few nanometers is now well-established, but bilayer properties in such a membrane architecture are still influenced by the nearby solid substrate. Polymer-supported lipid bilayer systems with a several micrometers thick polymer layer will overcome this shortcoming. However, formation of a fluid lipid bilayer on a fully hydrated, micrometer thick polymer film using traditional methods (e.g., vesicle fusion and lipid monolayer deposition techniques) remains a challenging task due to the rather unfavorable interfacial conditions for bilayer formation in such a system. Here, we report for the first time on the facile capillary-assisted formation of a lipid bilayer on the surface of a fully hydrated, several micrometers thick polyacrylamide (PAA) gel, in which forced molecular crowding of lipids at the air-water interface of the capillary results in monolayer instability and collapse, thereby forming a lipid bilayer on the top of the polymer gel inside the capillary. Stable bilayer attachment on the surface of the polymer gel can be achieved via physisorption or specific chemical linkages (tethering) on both cross-linked and non-cross-linked PAA films. Unlike the traditional solid-supported lipid bilayer (SLB), the lipid lateral diffusion in the polymer gel-supported lipid bilayer is not anymore perturbed by a solid substrate. Instead, more like a plasma membrane, it is mainly influenced by the properties of the underlying polymer and the nature/distribution of polymer-bilayer attachments. Polymer gel-supported lipid bilayers built using the capillary-assisted assembly approach show attractive self-healing properties, resulting in superior long-term stability relative to the SLB. We hypothesize that the described capillary-assisted assembly method can be applied to a wide range of polymeric materials and lipid compositions, opening exciting opportunities as an advanced model membrane system.
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Affiliation(s)
- Kridnut Chuduang
- Department of Chemistry and Chemical Biology, Indiana University Indianapolis, 402 N. Blackford Street, Indianapolis, Indiana 46202, United States
| | - Pornchanan Pholraksa
- Department of Biology, Indiana University Indianapolis, 402 N. Blackford Street, Indianapolis, Indiana 46202, United States
| | - Christoph A Naumann
- Department of Chemistry and Chemical Biology, Indiana University Indianapolis, 402 N. Blackford Street, Indianapolis, Indiana 46202, United States
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2
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Ge Y, Shi X, Boopathy S, McDonald J, Smith AW, Chao LH. Two forms of Opa1 cooperate to complete fusion of the mitochondrial inner-membrane. eLife 2020; 9:50973. [PMID: 31922487 PMCID: PMC7299343 DOI: 10.7554/elife.50973] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 01/10/2020] [Indexed: 12/24/2022] Open
Abstract
Mitochondrial membrane dynamics is a cellular rheostat that relates metabolic function and organelle morphology. Using an in vitro reconstitution system, we describe a mechanism for how mitochondrial inner-membrane fusion is regulated by the ratio of two forms of Opa1. We found that the long-form of Opa1 (l-Opa1) is sufficient for membrane docking, hemifusion and low levels of content release. However, stoichiometric levels of the processed, short form of Opa1 (s-Opa1) work together with l-Opa1 to mediate efficient and fast membrane pore opening. Additionally, we found that excess levels of s-Opa1 inhibit fusion activity, as seen under conditions of altered proteostasis. These observations describe a mechanism for gating membrane fusion.
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Affiliation(s)
- Yifan Ge
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States
| | - Xiaojun Shi
- Department of Chemistry, University of Akron, Akron, United States
| | - Sivakumar Boopathy
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States
| | - Julie McDonald
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States
| | - Adam W Smith
- Department of Chemistry, University of Akron, Akron, United States
| | - Luke H Chao
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States.,Department of Genetics, Harvard Medical School, Boston, United States
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3
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Tunable cell-surface mimetics as engineered cell substrates. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:2076-2093. [PMID: 29935145 DOI: 10.1016/j.bbamem.2018.06.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 05/18/2018] [Accepted: 06/08/2018] [Indexed: 12/21/2022]
Abstract
Most recent breakthroughs in understanding cell adhesion, cell migration, and cellular mechanosensitivity have been made possible by the development of engineered cell substrates of well-defined surface properties. Traditionally, these substrates mimic the extracellular matrix (ECM) environment by the use of ligand-functionalized polymeric gels of adjustable stiffness. However, such ECM mimetics are limited in their ability to replicate the rich dynamics found at cell-cell contacts. This review focuses on the application of cell surface mimetics, which are better suited for the analysis of cell adhesion, cell migration, and cellular mechanosensitivity across cell-cell interfaces. Functionalized supported lipid bilayer systems were first introduced as biomembrane-mimicking substrates to study processes of adhesion maturation during adhesion of functionalized vesicles (cell-free assay) and plated cells. However, while able to capture adhesion processes, the fluid lipid bilayer of such a relatively simple planar model membrane prevents adhering cells from transducing contractile forces to the underlying solid, making studies of cell migration and cellular mechanosensitivity largely impractical. Therefore, the main focus of this review is on polymer-tethered lipid bilayer architectures as biomembrane-mimicking cell substrate. Unlike supported lipid bilayers, these polymer-lipid composite materials enable the free assembly of linkers into linker clusters at cellular contacts without hindering cell spreading and migration and allow the controlled regulation of mechanical properties, enabling studies of cellular mechanosensitivity. The various polymer-tethered lipid bilayer architectures and their complementary properties as cell substrates are discussed.
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Glazier R, Salaita K. Supported lipid bilayer platforms to probe cell mechanobiology. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2017; 1859:1465-1482. [PMID: 28502789 PMCID: PMC5531615 DOI: 10.1016/j.bbamem.2017.05.005] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 05/09/2017] [Accepted: 05/09/2017] [Indexed: 12/15/2022]
Abstract
Mammalian and bacterial cells sense and exert mechanical forces through the process of mechanotransduction, which interconverts biochemical and physical signals. This is especially important in contact-dependent signaling, where ligand-receptor binding occurs at cell-cell or cell-ECM junctions. By virtue of occurring within these specialized junctions, receptors engaged in contact-dependent signaling undergo oligomerization and coupling with the cytoskeleton as part of their signaling mechanisms. While our ability to measure and map biochemical signaling within cell junctions has advanced over the past decades, physical cues remain difficult to map in space and time. Recently, supported lipid bilayer (SLB) technologies have emerged as a flexible platform to mimic and perturb cell-cell and cell-ECM junctions, allowing one to study membrane receptor mechanotransduction. Changing the lipid composition and underlying substrate tunes bilayer fluidity, and lipid and ligand micro- and nano-patterning spatially control positioning and clustering of receptors. Patterning metal gridlines within SLBs confines lipid mobility and introduces mechanical resistance. Here we review fundamental SLB mechanics and how SLBs can be engineered as tunable cell substrates for mechanotransduction studies. Finally, we highlight the impact of this work in understanding the biophysical mechanisms of cell adhesion. This article is part of a Special Issue entitled: Interactions between membrane receptors in cellular membranes edited by Kalina Hristova.
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Affiliation(s)
- Roxanne Glazier
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, and Emory University, Atlanta, GA 30322, United States
| | - Khalid Salaita
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, and Emory University, Atlanta, GA 30322, United States; Department of Chemistry, Emory University, Atlanta, GA 30322, United States..
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Agnarsson B, Wayment-Steele HK, Höök F, Kunze A. Monitoring of single and double lipid membrane formation with high spatiotemporal resolution using evanescent light scattering microscopy. NANOSCALE 2016; 8:19219-19223. [PMID: 27845799 DOI: 10.1039/c6nr06726c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Formation and quality of single solid supported lipid membranes and double lipid membranes were investigated with single vesicle resolution using label-free evanescence light scattering microscopy (EvSM). For the formation of double lipid membranes we made use of electrostatic interaction between charged lipids and oppositely charged cations.
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Affiliation(s)
- B Agnarsson
- Dept of Appl. Physics, Chalmers University of Technology, Göteborg, Sweden.
| | | | - F Höök
- Dept of Appl. Physics, Chalmers University of Technology, Göteborg, Sweden.
| | - A Kunze
- Dept of Appl. Physics, Chalmers University of Technology, Göteborg, Sweden. and Inst of Physical Chemistry, University of Göttingen, Göttingen, Germany
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6
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Ge Y, Lin YH, Lautscham LA, Goldmann WH, Fabry B, Naumann CA. N-cadherin-functionalized polymer-tethered multi-bilayer: a cell surface-mimicking substrate to probe cellular mechanosensitivity. SOFT MATTER 2016; 12:8274-8284. [PMID: 27731476 DOI: 10.1039/c6sm01673a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Fate and function of anchorage-dependent cells depend on a variety of environmental cues, including those of mechanical nature. Previous progress in the understanding of cellular mechanosensitivity has been closely linked to the availability of artificial cell substrates of adjustable viscoelasticity, allowing for a direct correlation between substrate stiffness and cell response. Exemplary, polymeric gel substrates with polymer-conjugated cell-substrate linkers provided valuable insight into the role of mechanical signals during cell migration in an extracellular matrix environment. In contrast, less is known about the role of external mechanical signals across cell-cell interfaces, in part, due to the limitations of traditional polymeric substrates to mimic the remarkable dynamics of cell-cell linkages. To overcome this shortcoming, we introduce a cell surface-mimicking cell substrate of adjustable stiffness, which is comprised of a polymer-tethered lipid multi-bilayer stack with N-cadherin linkers. Unlike traditional polymeric cell substrates with polymer-conjugated linkers, this novel artificial cell substrate is able to replicate the dynamic assembly/disassembly of cadherin linkers into linker clusters and the long-range movements of cadherin-based cell-substrate linkages observed at cell-cell interfaces. Moreover, substrate stiffness can be changed by adjusting the number of bilayers in the multi-bilayer stack, thus enabling the analysis of cellular mechanosensitivity in the presence of artificial cell-cell linkages. The presented biomembrane-mimicking cell substrate provides a valuable tool to explore the functional role of mechanical cues from neighboring cells.
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Affiliation(s)
- Y Ge
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University, Indianapolis, 46202 USA.
| | - Y H Lin
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University, Indianapolis, 46202 USA.
| | - L A Lautscham
- Department of Biophysics, University of Erlangen-Nuremberg, Erlangen, 91052, Germany
| | - W H Goldmann
- Department of Biophysics, University of Erlangen-Nuremberg, Erlangen, 91052, Germany
| | - B Fabry
- Department of Biophysics, University of Erlangen-Nuremberg, Erlangen, 91052, Germany
| | - C A Naumann
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University, Indianapolis, 46202 USA.
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Heath GR, Li M, Polignano IL, Richens JL, Catucci G, O’Shea P, Sadeghi SJ, Gilardi G, Butt JN, Jeuken LJC. Layer-by-Layer Assembly of Supported Lipid Bilayer Poly-l-Lysine Multilayers. Biomacromolecules 2015; 17:324-35. [DOI: 10.1021/acs.biomac.5b01434] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- George R. Heath
- School
of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Mengqiu Li
- School
of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | | | - Joanna L. Richens
- Cell
Biophysics Group, Institute of Biophysics, Imaging and Optical Science,
School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Gianluca Catucci
- Life
Sciences and Systems Biology, University of Torino, 10123, Turin, Italy
| | - Paul O’Shea
- Cell
Biophysics Group, Institute of Biophysics, Imaging and Optical Science,
School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Sheila J. Sadeghi
- Life
Sciences and Systems Biology, University of Torino, 10123, Turin, Italy
| | - Gianfranco Gilardi
- Life
Sciences and Systems Biology, University of Torino, 10123, Turin, Italy
| | - Julea N. Butt
- Centre
for Molecular and Structural Biochemistry, School of Biological Sciences,
and School of Chemistry, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Lars J. C. Jeuken
- School
of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
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Zhu Y, Negmi A, Moran-Mirabal J. Multi-Stacked Supported Lipid Bilayer Micropatterning through Polymer Stencil Lift-Off. MEMBRANES 2015; 5:385-98. [PMID: 26343733 PMCID: PMC4584287 DOI: 10.3390/membranes5030385] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 08/25/2015] [Indexed: 01/07/2023]
Abstract
Complex multi-lamellar structures play a critical role in biological systems, where they are present as lamellar bodies, and as part of biological assemblies that control energy transduction processes. Multi-lamellar lipid layers not only provide interesting systems for fundamental research on membrane structure and bilayer-associated polypeptides, but can also serve as components in bioinspired materials or devices. Although the ability to pattern stacked lipid bilayers at the micron scale is of importance for these purposes, limited work has been done in developing such patterning techniques. Here, we present a simple and direct approach to pattern stacked supported lipid bilayers (SLBs) using polymer stencil lift-off and the electrostatic interactions between cationic and anionic lipids. Both homogeneous and phase-segregated stacked SLB patterns were produced, demonstrating that the stacked lipid bilayers retain lateral diffusivity. We demonstrate patterned SLB stacks of up to four bilayers, where fluorescence resonance energy transfer (FRET) and quenching was used to probe the interactions between lipid bilayers. Furthermore, the study of lipid phase behaviour showed that gel phase domains align between adjacent layers. The proposed stacked SLB pattern platform provides a robust model for studying lipid behaviour with a controlled number of bilayers, and an attractive means towards building functional bioinspired materials or devices.
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Affiliation(s)
- Yujie Zhu
- Department of Chemistry and Chemical Biology, McMaster Univerisity, 1280 Main Street West,Hamilton, Ontario L8S 4M8, Canada
| | - Ahmed Negmi
- Department of Chemistry and Chemical Biology, McMaster Univerisity, 1280 Main Street West,Hamilton, Ontario L8S 4M8, Canada
| | - Jose Moran-Mirabal
- Department of Chemistry and Chemical Biology, McMaster Univerisity, 1280 Main Street West,Hamilton, Ontario L8S 4M8, Canada.
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9
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Hasan IY, Mechler A. Viscoelastic changes measured in partially suspended single bilayer membranes. SOFT MATTER 2015; 11:5571-5579. [PMID: 26073288 DOI: 10.1039/c5sm00278h] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
For studies involving biomimetic phospholipid membrane systems, such as membrane-protein interactions, it is crucial that the supported membrane is biomimetic in its physical properties as well as in its composition. Two often overlooked aspects of biomimicry are the need for unrestrained lipid mobility, reflected in the viscoelastic properties of the membrane, and sufficient space between the membrane and the support for the insertion of transmembrane proteins. Here we show for a series of DMPC-based membranes that a partially suspended single bilayer membrane can be formed on functionalized gold surface without tethering. These membranes exhibit sufficient freedom of motion to represent the viscoelastic properties of a free lamellar bilayer membrane as demonstrated by determining the phase transition temperatures of these single bilayer membranes from the viscosity change upon chain melting using the dissipation signal of a quartz crystal microbalance (QCM-D). Atomic force microscopy imaging confirmed confluent, smooth membrane coverage of the QCM-D sensor that completely obscured the roughness of the sputtered gold surface. High-force AFM imaging was able to push membrane patches into the valleys of the gold morphology, confirming the inherently suspended nature of the MPA supported membrane. We show that the correlation between frequency and dissipation changes in the QCM-D sensograms is a sensitive indicator of the morphology of the membrane.
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Affiliation(s)
- Imad Younus Hasan
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia.
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10
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Lautscham LA, Lin CY, Auernheimer V, Naumann CA, Goldmann WH, Fabry B. Biomembrane-mimicking lipid bilayer system as a mechanically tunable cell substrate. Biomaterials 2014; 35:3198-207. [PMID: 24439398 PMCID: PMC4026006 DOI: 10.1016/j.biomaterials.2013.12.091] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 12/22/2013] [Indexed: 11/26/2022]
Abstract
Cell behavior such as cell adhesion, spreading, and contraction critically depends on the elastic properties of the extracellular matrix. It is not known, however, how cells respond to viscoelastic or plastic material properties that more closely resemble the mechanical environment cells encounter in the body. In this report, we employ viscoelastic and plastic biomembrane-mimicking cell substrates. The compliance of the substrates can be tuned by increasing the number of polymer-tethered bilayers. This leaves the density and conformation of adhesive ligands on the top bilayer unaltered. We then observe the response of fibroblasts to these property changes. For comparison, we also study the cells on soft polyacrylamide and hard glass surfaces. Cell morphology, motility, cell stiffness, contractile forces and adhesive contact size all decrease on more compliant matrices but are less sensitive to changes in matrix dissipative properties. These data suggest that cells are able to feel and respond predominantly to the effective matrix compliance, which arises as a combination of substrate and adhesive ligand mechanical properties.
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Affiliation(s)
- Lena A Lautscham
- Department of Biophysics, University of Erlangen-Nuremberg, Erlangen 91052, Germany.
| | - Corey Y Lin
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University, Indianapolis 46202, USA
| | - Vera Auernheimer
- Department of Biophysics, University of Erlangen-Nuremberg, Erlangen 91052, Germany
| | - Christoph A Naumann
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University, Indianapolis 46202, USA
| | - Wolfgang H Goldmann
- Department of Biophysics, University of Erlangen-Nuremberg, Erlangen 91052, Germany
| | - Ben Fabry
- Department of Biophysics, University of Erlangen-Nuremberg, Erlangen 91052, Germany
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11
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Minner DE, Rauch P, Käs J, Naumann CA. Polymer-tethered lipid multi-bilayers: a biomembrane-mimicking cell substrate to probe cellular mechano-sensing. SOFT MATTER 2014; 10:1189-1198. [PMID: 24652490 DOI: 10.1039/c3sm52298a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Cells tiptoe through their environment forming highly localized and dynamic focal contacts. Experiments on polymeric gels of adjustable elasticity have shown that cells probe the viscoelasticity of their environment through an adaptive process of focal contact assembly/disassembly that critically affects cell adhesion, morphology, and motility. However, the specific mechanisms of this process have not yet been fully revealed. Here we report, for the first time, that fibroblast adhesion, morphology, and migration can also be controlled by altering the number of bilayers in a stack of multiple polymer-tethered lipid bilayers stabilized via maleimide-sulfhydral coupling chemistry. The observed changes in cell morphology, migration, and cytoskeletal organization in response to bilayer stacking correspond well with those previously observed on polymeric substrates of different polymer crosslinking density suggesting that variations in bilayer stacking are associated with changes in substrate viscoelasticity. This is in conceptual agreement with the existing knowledge about the structural, dynamic, and mechanical properties of polymer-lipid composite materials. Several distinct features, such as the lateral mobility of individual cell linkers and the immobilization of linker clusters, make the described substrates highly attractive tools for the study of dynamic, mechano-regulated cell linkages and cellular mechano-sensing.
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Affiliation(s)
- Daniel E Minner
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202-3274, USA.
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