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Miller EJ, Phan MD, Shah J, Honerkamp-Smith AR. Passive and reversible area regulation of supported lipid bilayers in response to fluid flow. Biophys J 2023; 122:2242-2255. [PMID: 36639867 PMCID: PMC10257118 DOI: 10.1016/j.bpj.2023.01.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 12/21/2022] [Accepted: 01/09/2023] [Indexed: 01/14/2023] Open
Abstract
Biological and model membranes are frequently subjected to fluid shear stress. However, membrane mechanical responses to flow remain incompletely described. This is particularly true of membranes supported on a solid substrate, and the influences of membrane composition and substrate roughness on membrane flow responses remain poorly understood. Here, we combine microfluidics, fluorescence microscopy, and neutron reflectivity to explore how supported lipid bilayer patches respond to controlled shear stress. We demonstrate that lipid membranes undergo a significant, passive, and partially reversible increase in membrane area due to flow. We show that these fluctuations in membrane area can be constrained, but not prevented, by increasing substrate roughness. Similar flow-induced changes to membrane structure may contribute to the ability of living cells to sense and respond to flow.
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Affiliation(s)
| | - Minh D Phan
- Large-Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee; Center for Neutron Science, Department of Chemical & Biomolecular Engineering, University of Delaware, Newark, Delaware
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Abstract
Langmuir monolayers at gas/liquid interfaces provide a rich framework to investigate the interplay between multiscale geometry and mechanics. Monolayer collapse is investigated at a topological and geometric level by building a scale space M from experimental imaging data. We present a general lipid monolayer collapse phase diagram, which shows that wrinkling, folding, crumpling, shear banding, and vesiculation are a continuous set of mechanical states that can be approached by either tuning monolayer composition or temperature. The origin of the different mechanical states can be understood by investigating the monolayer geometry at two scales: fluorescent vs atomic force microscopy imaging. We show that an interesting switch in continuity occurs in passing between the two scales, CAFM∈MAFM≠CFM∈M. Studying the difference between monolayers that fold vs shear band, we show that shear banding is correlated to the persistence of a multi-length scale microstructure within the monolayer at all surface pressures. A detailed analytical geometric formalism to describe this microstructure is developed using the theory of structured deformations. Lastly, we provide the first ever finite element simulation of lipid monolayer collapse utilizing a direct mapping from the experimental image space M into a simulation domain P. We show that elastic dissipation in the form of bielasticity is a necessary and sufficient condition to capture loss of in-plane stability and shear banding.
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Böhm P, Koutsioubas A, Moulin JF, Rädler JO, Sackmann E, Nickel B. Probing the Interface Structure of Adhering Cells by Contrast Variation Neutron Reflectometry. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:513-521. [PMID: 30518215 DOI: 10.1021/acs.langmuir.8b02228] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Cellular adhesion is a central element in tissue mechanics, biological cell-cell signaling, and cell motility. In this context, the cell-substrate distance has been investigated in the past by studying natural cells and biomimetic cell models adhering on solid substrates. The amount of water in the membrane substrate gap, however, is difficult to determine. Here, we present a neutron reflectivity (NR) structural study of confluent epithelial cell monolayers on silicon substrates. In order to ensure valid in vitro conditions, we developed a cell culture sample chamber allowing us to grow and cultivate cells under proper cell culture conditions while performing in vitro neutron reflectivity measurements. The cell chamber also enabled perfusion with cell medium and hence allowed for contrast variation in situ by sterile exchange of buffer with different H2O-to-D2O ratio. Contrast variation reduces the ambiguity of data modeling for determining the thickness and degree of hydration of the interfacial cleft between the adherent cells and the substrate. Our data suggest a three-layer interfacial organization. The first layer bound to the silicon surface interface is in agreement with a very dense protein film with a thickness of 9 ± 2 nm, followed by a highly hydrated 24 ± 4 nm thick layer, and a several tens of nanometers thick layer attributed to the composite membrane. Hence, the results provide clear evidence of a highly hydrated intermediate region between the composite cell membrane and the substrate, reminiscent of the basal lamina.
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Affiliation(s)
- Philip Böhm
- Fakultät für Physik and Center for NanoScience , Ludwig-Maximilians-Universität , Geschwister-Scholl-Platz 1 , 80539 München , Germany
- Nanosystems Initiative Munich , Schellingstraße 4 , 80799 München , Germany
| | - Alexandros Koutsioubas
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ) , Forschungszentrum Jülich GmbH , Lichtenbergstr. 1 , 85748 Garching , Germany
| | - Jean-François Moulin
- Helmholtz-Zentrum Geesthacht, Zentrum für Material und Küstenforschung , Außenstelle am MLZ in Garching bei München , Lichtenbergstraße 1 , 85748 Garching , Germany
| | - Joachim O Rädler
- Fakultät für Physik and Center for NanoScience , Ludwig-Maximilians-Universität , Geschwister-Scholl-Platz 1 , 80539 München , Germany
- Nanosystems Initiative Munich , Schellingstraße 4 , 80799 München , Germany
| | - Erich Sackmann
- Physikdepartment E22 , Technische Universität München , James-Franck-Str.1 , 85748 Garching , Germany
| | - Bert Nickel
- Fakultät für Physik and Center for NanoScience , Ludwig-Maximilians-Universität , Geschwister-Scholl-Platz 1 , 80539 München , Germany
- Nanosystems Initiative Munich , Schellingstraße 4 , 80799 München , Germany
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Analysis of biosurfaces by neutron reflectometry: from simple to complex interfaces. Biointerphases 2015; 10:019014. [PMID: 25779088 DOI: 10.1116/1.4914948] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Because of its high sensitivity for light elements and the scattering contrast manipulation via isotopic substitutions, neutron reflectometry (NR) is an excellent tool for studying the structure of soft-condensed material. These materials include model biophysical systems as well as in situ living tissue at the solid-liquid interface. The penetrability of neutrons makes NR suitable for probing thin films with thicknesses of 5-5000 Å at various buried, for example, solid-liquid, interfaces [J. Daillant and A. Gibaud, Lect. Notes Phys. 770, 133 (2009); G. Fragneto-Cusani, J. Phys.: Condens. Matter 13, 4973 (2001); J. Penfold, Curr. Opin. Colloid Interface Sci. 7, 139 (2002)]. Over the past two decades, NR has evolved to become a key tool in the characterization of biological and biomimetic thin films. In the current report, the authors would like to highlight some of our recent accomplishments in utilizing NR to study highly complex systems, including in-situ experiments. Such studies will result in a much better understanding of complex biological problems, have significant medical impact by suggesting innovative treatment, and advance the development of highly functionalized biomimetic materials.
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JUNGHANS ANN, WALTMAN MARYJO, SMITH HILLARYL, POCIVAVSEK LUKA, ZEBDA NOUREDDINE, BIRUKOV KONSTANTIN, VIAPIANO MARIANO, MAJEWSKI JAROSLAW. Understanding dynamic changes in live cell adhesion with neutron reflectometry. MODERN PHYSICS LETTERS. B, CONDENSED MATTER PHYSICS, STATISTICAL PHYSICS, APPLIED PHYSICS 2014; 28:1430015. [PMID: 25705067 PMCID: PMC4334466 DOI: 10.1142/s0217984914300154] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Neutron reflectometry (NR) was used to examine various live cells adhesion to quartz substrates under different environmental conditions, including flow stress. To the best of our knowledge, these measurements represent the first successful visualization and quantization of the interface between live cells and a substrate with sub-nanometer resolution. In our first experiments, we examined live mouse fibroblast cells as opposed to past experiments using supported lipids, proteins, or peptide layers with no associated cells. We continued the NR studies of cell adhesion by investigating endothelial monolayers and glioblastoma cells under dynamic flow conditions. We demonstrated that neutron reflectometry is a powerful tool to study the strength of cellular layer adhesion in living tissues, which is a key factor in understanding the physiology of cell interactions and conditions leading to abnormal or disease circumstances. Continuative measurements, such as investigating changes in tumor cell - surface contact of various glioblastomas, could impact advancements in tumor treatments. In principle, this can help us to identify changes that correlate with tumor invasiveness. Pursuit of these studies can have significant medical impact on the understanding of complex biological problems and their effective treatment, e.g. for the development of targeted anti-invasive therapies.
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Affiliation(s)
- ANN JUNGHANS
- MPA-CINT/Lujan Neutron Scattering Center, Los Alamos Neutron Science Center, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA
| | - MARY JO WALTMAN
- Biosciences Division, Bioenergy and Biome Sciences, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA
| | - HILLARY L. SMITH
- Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, CA 91125, USA
| | - LUKA POCIVAVSEK
- Department of Surgery, University of Pittsburgh Medical Center, 200 Lothrop St, Pittsburgh, PA 15213, USA
| | - NOUREDDINE ZEBDA
- NDA Analytics, Woolley Road, Huntingdon, Cambridgeshire, PE28 4HS, UK
| | - KONSTANTIN BIRUKOV
- Lung Injury Center, Department of Medicine, The University of Chicag; 5841 S. Maryland Ave., Chicago, IL 60637, USA
| | - MARIANO VIAPIANO
- Department of Neurosurgery, Brigham and Women’s Hospital and Harvard Medical School 4 Blackfan Circle, Boston, MA 02115, USA
| | - JAROSLAW MAJEWSKI
- MPA-CINT/Lujan Neutron Scattering Center, Los Alamos Neutron Science Center, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA
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Nanda H, Heinrich F, Lösche M. Membrane association of the PTEN tumor suppressor: neutron scattering and MD simulations reveal the structure of protein-membrane complexes. Methods 2014; 77-78:136-46. [PMID: 25461777 DOI: 10.1016/j.ymeth.2014.10.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Revised: 10/10/2014] [Accepted: 10/14/2014] [Indexed: 12/31/2022] Open
Abstract
Neutron reflection (NR) from planar interfaces is an emerging technology that provides unique and otherwise inaccessible structural information on disordered molecular systems such as membrane proteins associated with fluid bilayers, thus addressing one of the remaining challenges of structural biology. Although intrinsically a low-resolution technique, using structural information from crystallography or NMR allows the construction of NR models that describe the architecture of protein-membrane complexes at high resolution. In addition, a combination of these methods with molecular dynamics (MD) simulations has the potential to reveal the dynamics of protein interactions with the bilayer in atomistic detail. We review recent advances in this area by discussing the application of these techniques to the complex formed by the PTEN phosphatase with the plasma membrane. These studies provide insights in the cellular regulation of PTEN, its interaction with PI(4,5)P2 in the inner plasma membrane and the pathway by which its substrate, PI(3,4,5)P3, accesses the PTEN catalytic site.
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Affiliation(s)
- Hirsh Nanda
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA; NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Frank Heinrich
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA; NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Mathias Lösche
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA; Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA; NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
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Röttgermann PJF, Hertrich S, Berts I, Albert M, Segerer FJ, Moulin JF, Nickel B, Rädler JO. Cell Motility on Polyethylene Glycol Block Copolymers Correlates to Fibronectin Surface Adsorption. Macromol Biosci 2014; 14:1755-63. [DOI: 10.1002/mabi.201400246] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 08/13/2014] [Indexed: 01/27/2023]
Affiliation(s)
- Peter J. F. Röttgermann
- Faculty of Physics and Center for NanoScience (CeNS); Ludwig-Maximilians-University; Geschwister-Scholl-Platz 1 80539 Munich Germany
| | - Samira Hertrich
- Faculty of Physics and Center for NanoScience (CeNS); Ludwig-Maximilians-University; Geschwister-Scholl-Platz 1 80539 Munich Germany
| | - Ida Berts
- Faculty of Physics and Center for NanoScience (CeNS); Ludwig-Maximilians-University; Geschwister-Scholl-Platz 1 80539 Munich Germany
| | - Max Albert
- Faculty of Physics and Center for NanoScience (CeNS); Ludwig-Maximilians-University; Geschwister-Scholl-Platz 1 80539 Munich Germany
| | - Felix J. Segerer
- Faculty of Physics and Center for NanoScience (CeNS); Ludwig-Maximilians-University; Geschwister-Scholl-Platz 1 80539 Munich Germany
| | - Jean-François Moulin
- Helmholtz Zentrum Geesthacht; Institut für Werkstoffforschung; FRM II; Lichtenbergstr. 1 85747 Garching Germany
| | - Bert Nickel
- Faculty of Physics and Center for NanoScience (CeNS); Ludwig-Maximilians-University; Geschwister-Scholl-Platz 1 80539 Munich Germany
| | - Joachim O. Rädler
- Faculty of Physics and Center for NanoScience (CeNS); Ludwig-Maximilians-University; Geschwister-Scholl-Platz 1 80539 Munich Germany
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