1
|
Wu X, Xue H, Bordia G, Fink Z, Kim PY, Streubel R, Han J, Helms BA, Ashby PD, Omar AK, Russell TP. Self-Propulsion by Directed Explosive Emulsification. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2310435. [PMID: 38386499 DOI: 10.1002/adma.202310435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 02/15/2024] [Indexed: 02/24/2024]
Abstract
An active droplet system, programmed to repeatedly move autonomously at a specific velocity in a well-defined direction, is demonstrated. Coulombic energy is stored in oversaturated interfacial assemblies of charged nanoparticle-surfactants by an applied DC electric field and can be released on demand. Spontaneous emulsification is suppressed by an increase in the stiffness of the oversaturated assemblies. Rapidly removing the field releases the stored energy in an explosive event that propels the droplet, where thousands of charged microdroplets are ballistically ejected from the surface of the parent droplet. The ejection is made directional by a symmetry breaking of the interfacial assembly, and the combined interaction force of the microdroplet plume on one side of the droplet propels the droplet distances tens of times its size, making the droplet active. The propulsion is autonomous, repeatable, and agnostic to the chemical composition of the nanoparticles. The symmetry-breaking in the nanoparticle assembly controls the microdroplet velocity and direction of propulsion. This mechanism of droplet propulsion will advance soft micro-robotics, establishes a new type of active matter, and introduces new vehicles for compartmentalized delivery.
Collapse
Affiliation(s)
- Xuefei Wu
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Han Xue
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Gautam Bordia
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Zachary Fink
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Polymer Science and Engineering Department, University of Massachusetts, Amherst, MA, 01003, USA
| | - Paul Y Kim
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Robert Streubel
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Jiale Han
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Brett A Helms
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Paul D Ashby
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Ahmad K Omar
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Thomas P Russell
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Polymer Science and Engineering Department, University of Massachusetts, Amherst, MA, 01003, USA
| |
Collapse
|
2
|
Nagao M, Seto H. Neutron scattering studies on dynamics of lipid membranes. BIOPHYSICS REVIEWS 2023; 4:021306. [PMID: 38504928 PMCID: PMC10903442 DOI: 10.1063/5.0144544] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 05/01/2023] [Indexed: 03/21/2024]
Abstract
Neutron scattering methods are powerful tools for the study of the structure and dynamics of lipid bilayers in length scales from sub Å to tens to hundreds nm and the time scales from sub ps to μs. These techniques also are nondestructive and, perhaps most importantly, require no additives to label samples. Because the neutron scattering intensities are very different for hydrogen- and deuterium-containing molecules, one can replace the hydrogen atoms in a molecule with deuterium to prepare on demand neutron scattering contrast without significantly altering the physical properties of the samples. Moreover, recent advances in neutron scattering techniques, membrane dynamics theories, analysis tools, and sample preparation technologies allow researchers to study various aspects of lipid bilayer dynamics. In this review, we focus on the dynamics of individual lipids and collective membrane dynamics as well as the dynamics of hydration water.
Collapse
Affiliation(s)
| | - Hideki Seto
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan
| |
Collapse
|
3
|
Donina L, Porcar L, Cabral JT. Effect of salt on the lamellar L α-to-MLV transformation in SDS/octanol/water under microfluidic flow. SOFT MATTER 2022; 18:7010-7019. [PMID: 35912998 DOI: 10.1039/d2sm00643j] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We investigate the effect of added (NaCl) salt and varying flow rate on the phase behaviour and flow response of a model surfactant Lα phase, sodium dodecyl sulfate (SDS)/octanol/water, using small angle neutron scattering (SANS) and polarised optical microscopy in microfluidics, supported by NMR, viscosity, conductivity and zeta potential measurements. A long (∼3 m) tubular microchannel device is employed to quantify the spatiotemporal structural evolution of the system towards multilamellar vesicles (MLV). The effect of salt is rationalised in terms of changes in membrane bending rigidity and phase stability. It is shown that ∼1.8 w/w% NaCl addition results in MLV formation within the shortest time (or equivalent lengthscale) and yields near-centrosymmetric scattering profiles characteristic of MLVs (at a reference 1 mL h-1 flow rate and ≃90 s-1 shear rate). Further salt addition yields biphasic systems that remain strongly aligned under flow, while lower salt content also increases scattering anisotropy, accompanied by higher membrane rigidity and solution viscosity. Increasing flow rate causes greater initial Lα alignment, and thus flow anisotropy, but also faster evolution towards isotropy and MLV formation.
Collapse
Affiliation(s)
- Liva Donina
- Department of Chemical Engineering, Imperial College London, London, UK.
| | - Lionel Porcar
- Institut Laue-Langevin, 71 Avenue des Martyrs, B.P. 156, F-38042 Grenoble Cedex, France
| | - João T Cabral
- Department of Chemical Engineering, Imperial College London, London, UK.
| |
Collapse
|
4
|
Gilbert J, Ermilova I, Nagao M, Swenson J, Nylander T. Effect of encapsulated protein on the dynamics of lipid sponge phase: a neutron spin echo and molecular dynamics simulation study. NANOSCALE 2022; 14:6990-7002. [PMID: 35470842 DOI: 10.1039/d2nr00882c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Lipid membranes are highly mobile systems with hierarchical, time and length scale dependent, collective motions including thickness fluctuations, undulations, and topological membrane changes, which play an important role in membrane interactions. In this work we have characterised the effect of encapsulating two industrially important enzymes, β-galactosidase and aspartic protease, in lipid sponge phase nanoparticles on the dynamics of the lipid membrane using neutron spin echo (NSE) spectroscopy and molecular dynamics (MD) simulations. From NSE, reduced membrane dynamics were observed upon enzyme encapsulation, which were dependent on the enzyme concentration and type. By fitting the intermediate scattering functions (ISFs) with a modified Zilman and Granek model including nanoparticle diffusion, an increase in membrane bending rigidity was observed, with a larger effect for β-galactosidase than aspartic protease at the same concentration. MD simulations for the system with and without aspartic protease showed that the lipids relax more slowly in the system with protein due to the replacement of the lipid carbonyl-water hydrogen bonds with lipid-protein hydrogen bonds. This indicates that the most likely cause of the increase in membrane rigidity observed in the NSE measurements was dehydration of the lipid head groups. The dynamics of the protein itself were also studied, which showed a stable secondary structure of protein over the simulation, indicating no unfolding events occurred.
Collapse
Affiliation(s)
- Jennifer Gilbert
- Division of Physical Chemistry, Department of Chemistry, Naturvetarvägen 14, Lund University, 22362 Lund, Sweden.
- NanoLund, Lund University, Professorsgatan 1, 223 63 Lund, Sweden
| | - Inna Ermilova
- Department of Physics, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Michihiro Nagao
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA
| | - Jan Swenson
- Department of Physics, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Tommy Nylander
- Division of Physical Chemistry, Department of Chemistry, Naturvetarvägen 14, Lund University, 22362 Lund, Sweden.
- NanoLund, Lund University, Professorsgatan 1, 223 63 Lund, Sweden
- Lund Institute of Advanced Neutron and X-Ray Science, Scheelevägen 19, 223 70 Lund, Sweden
| |
Collapse
|
5
|
Allolio C, Harries D. Calcium Ions Promote Membrane Fusion by Forming Negative-Curvature Inducing Clusters on Specific Anionic Lipids. ACS NANO 2021; 15:12880-12887. [PMID: 34338519 DOI: 10.1021/acsnano.0c08614] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Vesicles enriched in certain negatively charged lipids, such as phosphatidylserine and PIP2, are known to undergo fusion in the presence of calcium ions without assistance from protein assemblies. Other lipids do not exhibit this propensity, even if they are negatively charged. Using our recently developed methodology, we extract elastic properties of a representative set of lipids. This allows us to trace the origin of lipid-calcium selectivity in membrane fusion to the formation of lipid clusters with long-range correlations that induce negative curvature on the membrane surface. Furthermore, the clusters generate lateral tension in the headgroup region at the membrane surface, concomitantly also stabilizing negative Gaussian curvature. Finally, calcium binding also reduces the orientational polarization of water around the membrane head groups, potentially reducing the hydration force acting between membranes. Binding calcium only weakly increases membrane bending rigidity and tilt moduli, in agreement with experiments. We show how the combined effects of calcium binding to membranes lower the barriers along the fusion pathway that lead to the formation of the fusion stalk as well as the fusion pore.
Collapse
Affiliation(s)
- Christoph Allolio
- Charles University, Faculty of Mathematics and Physics, Mathematical Institute, Sokolovská 83, 186 75 Prague 8, Czech Republic
- Institute of Chemistry, The Fritz Haber Center, and The Center for Nanoscience and Nanotechnology, The Hebrew University, E.J. Safra Campus, Jerusalem 9190401, Israel
| | - Daniel Harries
- Institute of Chemistry, The Fritz Haber Center, and The Center for Nanoscience and Nanotechnology, The Hebrew University, E.J. Safra Campus, Jerusalem 9190401, Israel
| |
Collapse
|
6
|
Nagao M, Kelley EG, Faraone A, Saito M, Yoda Y, Kurokuzu M, Takata S, Seto M, Butler PD. Relationship between Viscosity and Acyl Tail Dynamics in Lipid Bilayers. PHYSICAL REVIEW LETTERS 2021; 127:078102. [PMID: 34459628 DOI: 10.1103/physrevlett.127.078102] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 06/28/2021] [Indexed: 06/13/2023]
Abstract
Membrane viscosity is a fundamental property that controls molecular transport and structural rearrangements in lipid membranes. Given its importance in many cell processes, various experimental and computational methods have been developed to measure the membrane viscosity, yet the estimated values depend highly on the method and vary by orders of magnitude. Here we investigate the molecular origins of membrane viscosity by measuring the nanoscale dynamics of the lipid acyl tails using x-ray and neutron spectroscopy techniques. The results show that the membrane viscosity can be estimated from the structural relaxation times of the lipid tails.
Collapse
Affiliation(s)
- Michihiro Nagao
- National Institute of Standards and Technology Center for Neutron Research, Gaithersburg, Maryland 20899-6102, USA
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742-2115, USA
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA
| | - Elizabeth G Kelley
- National Institute of Standards and Technology Center for Neutron Research, Gaithersburg, Maryland 20899-6102, USA
| | - Antonio Faraone
- National Institute of Standards and Technology Center for Neutron Research, Gaithersburg, Maryland 20899-6102, USA
| | - Makina Saito
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Kumatori, Osaka, 590-0494, Japan
| | - Yoshitaka Yoda
- Japan Synchrotron Radiation Research Institute, Sayo, Hyogo, 679-5198, Japan
| | - Masayuki Kurokuzu
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Kumatori, Osaka, 590-0494, Japan
| | - Shinichi Takata
- J-PARC Center, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan
| | - Makoto Seto
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Kumatori, Osaka, 590-0494, Japan
| | - Paul D Butler
- National Institute of Standards and Technology Center for Neutron Research, Gaithersburg, Maryland 20899-6102, USA
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, USA
- Department of Chemistry, The University of Tennessee, Knoxville, Tennessee 37996, USA
| |
Collapse
|
7
|
Kumari P, Faraone A, Kelley EG, Benedetto A. Stiffening Effect of the [Bmim][Cl] Ionic Liquid on the Bending Dynamics of DMPC Lipid Vesicles. J Phys Chem B 2021; 125:7241-7250. [PMID: 34169716 PMCID: PMC8279542 DOI: 10.1021/acs.jpcb.1c01347] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The elastic properties of the cellular lipid membrane play a crucial role for life. Their alteration can lead to cell malfunction, and in turn, being able to control them holds the promise of effective therapeutic and diagnostic approaches. In this context, due to their proven strong interaction with lipid bilayers, ionic liquids (ILs)-a vast class of organic electrolytes-may play an important role. This work focuses on the effect of the model imidazolium-IL [bmim][Cl] on the bending modulus of DMPC lipid vesicles, a basic model of cellular lipid membranes. Here, by combining small-angle neutron scattering and neutron spin-echo spectroscopy, we show that the IL, dispersed at low concentrations at the bilayer-water interface, (i) diffuses into the lipid region, accounting for five IL-cations for every 11 lipids, and (ii) causes an increase of the lipid bilayer bending modulus, up to 60% compared to the neat lipid bilayer at 40 °C.
Collapse
Affiliation(s)
- Pallavi Kumari
- Department of Sciences, University of Roma Tre, 00146 Rome, Italy.,School of Physics and Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland
| | - Antonio Faraone
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Elizabeth G Kelley
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Antonio Benedetto
- Department of Sciences, University of Roma Tre, 00146 Rome, Italy.,School of Physics and Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland.,Laboratory for Neutron Scattering, Paul Scherrer Institute, 5232 Villigen, Switzerland
| |
Collapse
|
8
|
Christoff-Tempesta T, Cho Y, Kim DY, Geri M, Lamour G, Lew AJ, Zuo X, Lindemann WR, Ortony JH. Self-assembly of aramid amphiphiles into ultra-stable nanoribbons and aligned nanoribbon threads. NATURE NANOTECHNOLOGY 2021; 16:447-454. [PMID: 33462430 DOI: 10.1038/s41565-020-00840-w] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 12/10/2020] [Indexed: 06/12/2023]
Abstract
Small-molecule self-assembly is an established route for producing high-surface-area nanostructures with readily customizable chemistries and precise molecular organization. However, these structures are fragile, exhibiting molecular exchange, migration and rearrangement-among other dynamic instabilities-and are prone to dissociation upon drying. Here we show a small-molecule platform, the aramid amphiphile, that overcomes these dynamic instabilities by incorporating a Kevlar-inspired domain into the molecular structure. Strong, anisotropic interactions between aramid amphiphiles suppress molecular exchange and elicit spontaneous self-assembly in water to form nanoribbons with lengths of up to 20 micrometres. Individual nanoribbons have a Young's modulus of 1.7 GPa and tensile strength of 1.9 GPa. We exploit this stability to extend small-molecule self-assembly to hierarchically ordered macroscopic materials outside of solvated environments. Through an aqueous shear alignment process, we organize aramid amphiphile nanoribbons into arbitrarily long, flexible threads that support 200 times their weight when dried. Tensile tests of the dry threads provide a benchmark for Young's moduli (between ~400 and 600 MPa) and extensibilities (between ~0.6 and 1.1%) that depend on the counterion chemistry. This bottom-up approach to macroscopic materials could benefit solid-state applications historically inaccessible by self-assembled nanomaterials.
Collapse
Affiliation(s)
- Ty Christoff-Tempesta
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yukio Cho
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Dae-Yoon Kim
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Institute of Advanced Composite Materials, Korea Institute of Science and Technology, Bondong, Korea
| | - Michela Geri
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Guillaume Lamour
- LAMBE, Université Paris-Saclay, University of Evry, CNRS, Evry-Courcouronnes, France
| | - Andrew J Lew
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Xiaobing Zuo
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL, USA
| | - William R Lindemann
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Julia H Ortony
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
| |
Collapse
|
9
|
Nagao M, Bradbury R, Ansar SM, Kitchens CL. Effect of gold nanoparticle incorporation into oil-swollen surfactant lamellar membranes. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2020; 7:065102. [PMID: 33344674 PMCID: PMC7744122 DOI: 10.1063/4.0000041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 11/25/2020] [Indexed: 05/08/2023]
Abstract
An oil-swollen surfactant membrane is employed to measure the effects of incorporated hydrophobically functionalized gold nanoparticles (AuNPs) on the structure and dynamics of the membranes. While maintaining an average AuNP diameter of approximately 5 nm, the membrane thickness was varied from 5 nm to 7.5 nm by changing the amount of oil in the membrane. The membranes become softer as the proportion of oil is increased, while the thickness fluctuations become slower. We attribute this to an increased fluctuation wavelength. Incorporation of AuNPs in the membrane induces membrane thinning and softening. Oil molecules surround the nanoparticles in the membrane and help their relatively homogeneous distribution. AuNPs significantly alter the membrane's structure and dynamics through thinning of the membrane, increased compressibility, and possible diffusion of AuNPs inside the membrane.
Collapse
Affiliation(s)
| | | | - Siyam M. Ansar
- Department of Chemical and Biomolecular Engineering, Clemson University, Clemson, South Carolina 29634, USA
| | - Christopher L. Kitchens
- Department of Chemical and Biomolecular Engineering, Clemson University, Clemson, South Carolina 29634, USA
| |
Collapse
|
10
|
Kelley EG, Nagao M, Butler PD, Porcar L, Farago B. Enhanced dynamics in the anomalous melting regime of DMPG lipid membranes. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2020; 7:054704. [PMID: 33094128 PMCID: PMC7568673 DOI: 10.1063/4.0000031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/25/2020] [Indexed: 06/11/2023]
Abstract
Like many soft materials, lipids undergo a melting transition associated with a significant increase in their dynamics. At temperatures below the main melting transition (Tm ), all molecular and collective dynamics are suppressed, while above Tm the alkyl tail motions, lipid diffusivity, and collective membrane undulations are at least an order of magnitude faster. Here we study the collective dynamics of dimyristoylphosphatidylglycerol (DMPG, di 14:0 PG) using neutron spin echo spectroscopy throughout its anomalous phase transition that occurs over a 12 °C-20° C wide temperature window. Our results reveal that the membranes are softer and more dynamic during the phase transition than at higher temperatures corresponding to the fluid phase and provide direct experimental evidence for the predicted increase in membrane fluctuations during lipid melting. These results provide new insights into the nanoscale lipid membrane dynamics during the melting transition and demonstrate how these dynamics are coupled to changes in the membrane structure.
Collapse
Affiliation(s)
- Elizabeth G. Kelley
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20889, USA
| | | | | | - Lionel Porcar
- Institut Laue-Langevin (ILL), Grenoble F-38042, France
| | - Bela Farago
- Institut Laue-Langevin (ILL), Grenoble F-38042, France
| |
Collapse
|
11
|
Karal MAS, Ahmed M, Levadny V, Belaya M, Ahamed MK, Rahman M, Shakil MM. Electrostatic interaction effects on the size distribution of self-assembled giant unilamellar vesicles. Phys Rev E 2020; 101:012404. [PMID: 32069606 DOI: 10.1103/physreve.101.012404] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Indexed: 12/26/2022]
Abstract
The influence of electrostatic conditions (salt concentration of the solution and vesicle surface charge density) on the size distribution of self-assembled giant unilamellar vesicles (GUVs) is considered. The membranes of GUVs are synthesized by a mixture of dioleoylphosphatidylglycerol and dioleoylphosphatidylcholine in a physiological buffer using the natural swelling method. The experimental results are presented in the form of a set of histograms. The log-normal distribution is used for statistical treatment of results. It is obtained that the decrease of salt concentration and the increase of vesicle surface charge density of the membranes increase the average size of the GUV population. To explain the experimental results, a theory using the Helmholtz free energy of the system describing the GUV vesiculation is developed. The size distribution histograms and average size of GUVs under various conditions are fitted with the proposed theory. It is shown that the variation of the bending modulus due to changing of electrostatic parameters of the system is the main factor causing a change in the average size of GUVs.
Collapse
Affiliation(s)
- Mohammad Abu Sayem Karal
- Department of Physics, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh
| | - Marzuk Ahmed
- Department of Physics, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh
| | - Victor Levadny
- Theoretical Problem Center of Physico-Chemical Pharmacology, Russian Academy of Sciences, Moscow 117977, Russia
| | - Marina Belaya
- Department of Mathematics of Russian State University for the Humanities, Moscow GSP-3 125993, Russia
| | - Md Kabir Ahamed
- Department of Physics, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh
| | - Mostafizur Rahman
- Department of Physics, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh
| | - Md Mostofa Shakil
- Department of Physics, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh
| |
Collapse
|
12
|
Usuda H, Hishida M, Kelley EG, Yamamura Y, Nagao M, Saito K. Interleaflet coupling of n-alkane incorporated bilayers. Phys Chem Chem Phys 2020; 22:5418-5426. [PMID: 31904060 DOI: 10.1039/c9cp06059f] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The relationship between the membrane bending modulus (κ) and compressibility modulus (KA) depends on the extent of coupling between the two monolayers (leaflets). Using neutron spin echo (NSE) spectroscopy, we investigate the effects of n-alkanes on the interleaflet coupling of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers. Structural studies with small-angle X-ray and neutron scattering (SAXS and SANS) showed that the bilayer thickness increased with increasing n-alkane length, while NSE suggested that the bilayers became softer. Additional measurements of the membrane thickness fluctuations with NSE suggested that the changes in elastic moduli were due to a decrease in coupling between the leaflets upon addition of the longer n-alkanes. The decreased coupling with elongating n-alkane length was explained based on the n-alkane distribution within the bilayers characterized by SANS measurement of bilayers composed of protiated DPPC and deuterated n-alkanes. A higher fraction of the incorporated long n-alkanes were concentrated at the central plane of the bilayers and decreased the physical interaction between the leaflets. Using NSE and SANS, we successfully correlated changes in the mesoscopic collective dynamics and microscopic membrane structure upon incorporation of n-alkanes.
Collapse
Affiliation(s)
- Hatsuho Usuda
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
| | | | | | | | | | | |
Collapse
|
13
|
|
14
|
Faizi HA, Frey SL, Steinkühler J, Dimova R, Vlahovska PM. Bending rigidity of charged lipid bilayer membranes. SOFT MATTER 2019; 15:6006-6013. [PMID: 31298256 DOI: 10.1039/c9sm00772e] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We experimentally investigate the effect of lipid charge on the stiffness of bilayer membranes. The bending rigidity of membranes with composition 0-100 mol% of charged lipids, in the absence and presence of salt at different concentrations, is measured with the flicker spectroscopy method, using the shape fluctuations of giant unilamellar vesicles. The analysis considers both the mean squared amplitudes and the time autocorrelations of the shape modes. Our results show that membrane charge increases the bending rigidity relative to the charge-free membrane. The effect is diminished by the addition of monovalent salt to the suspending solutions. The trend shown by the membrane bending rigidity correlates with zeta potential measurements, confirming charge screening at different salt concentrations. The experimental results in the presence of salt are in good agreement with existing theories of membrane stiffening by surface charge.
Collapse
Affiliation(s)
- Hammad A Faizi
- Department of Mechanical Engineering, McCormick School of Engineering and Applied Science, Northwestern University, Evanston, Illinois 60208, USA
| | | | | | | | | |
Collapse
|
15
|
Cristofolini L, Orsi D, Isa L. Characterization of the dynamics of interfaces and of interface-dominated systems via spectroscopy and microscopy techniques. Curr Opin Colloid Interface Sci 2018. [DOI: 10.1016/j.cocis.2018.06.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
16
|
Duncan AL, Reddy T, Koldsø H, Hélie J, Fowler PW, Chavent M, Sansom MSP. Protein crowding and lipid complexity influence the nanoscale dynamic organization of ion channels in cell membranes. Sci Rep 2017; 7:16647. [PMID: 29192147 PMCID: PMC5709381 DOI: 10.1038/s41598-017-16865-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 11/15/2017] [Indexed: 01/07/2023] Open
Abstract
Cell membranes are crowded and complex environments. To investigate the effect of protein-lipid interactions on dynamic organization in mammalian cell membranes, we have performed coarse-grained molecular dynamics simulations containing >100 copies of an inwardly rectifying potassium (Kir) channel which forms specific interactions with the regulatory lipid phosphatidylinositol 4,5-bisphosphate (PIP2). The tendency of protein molecules to cluster has the effect of organizing the membrane into dynamic compartments. At the same time, the diversity of lipids present has a marked effect on the clustering behavior of ion channels. Sub-diffusion of proteins and lipids is observed. Protein crowding alters the sub-diffusive behavior of proteins and lipids such as PIP2 which interact tightly with Kir channels. Protein crowding also affects bilayer properties, such as membrane undulations and bending rigidity, in a PIP2-dependent manner. This interplay between the diffusion and the dynamic organization of Kir channels may have important implications for channel function.
Collapse
Affiliation(s)
- Anna L Duncan
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Tyler Reddy
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- T-6, MS K710, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Heidi Koldsø
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- D. E. Shaw Research, 120 W 45th St., New York, NY, 10036, USA
| | - Jean Hélie
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- Semmle, Blue Boar Court, 9 Alfred St, Oxford, OX1 4EH, UK
| | - Philip W Fowler
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- Nuffield Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK
| | - Matthieu Chavent
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- IPBS-CNRS, Toulouse, Midi-Pyrénées, France
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK.
| |
Collapse
|
17
|
Nagao M, Kelley EG, Ashkar R, Bradbury R, Butler PD. Probing Elastic and Viscous Properties of Phospholipid Bilayers Using Neutron Spin Echo Spectroscopy. J Phys Chem Lett 2017; 8:4679-4684. [PMID: 28892394 DOI: 10.1021/acs.jpclett.7b01830] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The elastic and viscous properties of self-assembled amphiphilic membranes dictate the intricate hierarchy of their structure and dynamics ranging from the diffusion of individual molecules to the large-scale deformation of the membrane. We previously demonstrated that neutron spin echo spectroscopy measurements of model amphiphilic membranes can access the naturally occurring submicrosecond membrane motions, such as bending and thickness fluctuations. Here we show how the experimentally measured fluctuation parameters can be used to determine the inherent membrane properties and demonstrate how membrane viscosity and compressibility modulus are influenced by lipid composition in a series of simple phosphatidylcholine bilayers with different tail lengths as a function of temperature. This approach highlights the interdependence of the bilayer elastic and viscous properties and the collective membrane dynamics and opens new avenues to investigating the mechanical properties of more complex and biologically inspired systems.
Collapse
Affiliation(s)
- Michihiro Nagao
- NIST Center for Neutron Research, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
- Center for Exploration of Energy and Matter, Department of Physics, Indiana University , Bloomington, Indiana 47408, United States
| | - Elizabeth G Kelley
- NIST Center for Neutron Research, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Rana Ashkar
- Biology and Soft Matter Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Robert Bradbury
- NIST Center for Neutron Research, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
- Center for Exploration of Energy and Matter, Department of Physics, Indiana University , Bloomington, Indiana 47408, United States
| | - Paul D Butler
- NIST Center for Neutron Research, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
- Department of Chemical & Biomolecular Engineering, University of Delaware , Newark, Delaware 19716, United States
| |
Collapse
|
18
|
Kawabata Y, Bradbury R, Kugizaki S, Weigandt K, Melnichenko YB, Sadakane K, Yamada NL, Endo H, Nagao M, Seto H. Effect of interlamellar interactions on shear induced multilamellar vesicle formation. J Chem Phys 2017; 147:034905. [PMID: 28734290 DOI: 10.1063/1.4994563] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Shear-induced multilamellar vesicle (MLV) formation has been studied by coupling the small-angle neutron scattering (SANS) technique with neutron spin echo (NSE) spectroscopy. A 10% mass fraction of the nonionic surfactant pentaethylene glycol dodecyl ether (C12E5) in water was selected as a model system for studying weak inter-lamellar interactions. These interactions are controlled either by adding an anionic surfactant, sodium dodecyl sulfate, or an antagonistic salt, rubidium tetraphenylborate. Increasing the charge density in the bilayer induces an enhanced ordering of the lamellar structure. The charge density dependence of the membrane bending modulus was determined by NSE and showed an increasing trend with charge. This behavior is well explained by a classical theoretical model. By considering the Caillé parameters calculated from the SANS data, the layer compressibility modulus B¯ is estimated and the nature of the dominant inter-lamellar interaction is determined. Shear flow induces MLV formation around a shear rate of 10 s-1, when a small amount of charge is included in the membrane. The flow-induced layer undulations are in-phase between neighboring layers when the inter-lamellar interaction is sufficiently strong. Under these conditions, MLV formation can occur without significantly changing the inter-lamellar spacing. On the other hand, in the case of weak inter-lamellar interactions, the flow-induced undulations are not in-phase, and greater steric repulsion leads to an increase in the inter-lamellar spacing with shear rate. In this case, MLV formation occurs as the amplitude of the undulations gets larger and the steric interaction leads to in-phase undulations between neighboring membranes.
Collapse
Affiliation(s)
- Y Kawabata
- Department of Chemistry, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
| | - R Bradbury
- Center for Exploration of Energy and Matter, Department of Physics, Indiana University, Bloomington, Indiana 47408, USA
| | - S Kugizaki
- Department of Chemistry, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
| | - K Weigandt
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6102, USA
| | - Y B Melnichenko
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393, USA
| | - K Sadakane
- Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto 610-0321, Japan
| | - N L Yamada
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tokai 319-1106, Japan
| | - H Endo
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tokai 319-1106, Japan
| | - M Nagao
- Center for Exploration of Energy and Matter, Department of Physics, Indiana University, Bloomington, Indiana 47408, USA
| | - H Seto
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tokai 319-1106, Japan
| |
Collapse
|
19
|
Gizynski K, Gorecki J. Chemical memory with states coded in light controlled oscillations of interacting Belousov–Zhabotinsky droplets. Phys Chem Chem Phys 2017; 19:6519-6531. [DOI: 10.1039/c6cp07492h] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The information storing potential of droplets, in which an oscillatory, photosensitive Belousov–Zhabotinsky (BZ) reaction proceeds, is investigated experimentally.
Collapse
Affiliation(s)
- Konrad Gizynski
- Institute of Physical Chemistry
- Polish Academy of Sciences
- 01-224 Warsaw
- Poland
| | - Jerzy Gorecki
- Institute of Physical Chemistry
- Polish Academy of Sciences
- 01-224 Warsaw
- Poland
| |
Collapse
|