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Raßmann N, Weber M, Glaß REJ, Kreger K, Helfricht N, Schmidt HW, Papastavrou G. Electrogelation: Controlled Fast Formation of Micrometer-Thick Films from Low-Molecular Weight Hydrogelators. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:17190-17200. [PMID: 37976397 DOI: 10.1021/acs.langmuir.3c02270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
The controlled electrochemical deposition of hydrogels from low-molecular weight hydrogelators (LMWHGs) allows for the defined formation of thin films on electrodes. Here, the deposition of fibrillar networks consisting of N,N',N″-tris(4-carboxyphenylene)-1,3,5-benzenetricarboxamide (BTA) onto ultraflat gold electrodes has been studied. This process, also termed electrogelation, is based on a local change in the pH due to electrolysis of water at the electrode. The protonation of the BTA sodium salt leads to self-assembly into supramolecular fibrillar structures mainly via hydrogen bonding of the uncharged molecules. The resulting hydrogel film was characterized in terms of its thickness by atomic force microscopy (AFM). Two different AFM-based techniques have been used: ex situ imaging of dried films and in situ nanoindentation of the hydrated hydrogel films. The deposition process was studied as a function of gelator concentration, applied potential, and gelation time. These parameters allow control of the film thickness to a high degree of accuracy within a few tenths of nanometers. Film formation takes place in a few seconds at moderate applied potentials, which is beneficial for biomedical applications. The results obtained for the BTA presented here can be transferred to any type of pH-responsive LMWHG and many reversibly formed hydrogel films.
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Affiliation(s)
- Nadine Raßmann
- Department of Physical Chemistry II, University of Bayreuth, Universitaetsstrasse 30, 95447 Bayreuth, Germany
| | - Melina Weber
- Department of Macromolecular Chemistry I, University of Bayreuth, Universitaetsstrasse 30, 95447 Bayreuth, Germany
| | - Roman E J Glaß
- Department of Physical Chemistry II, University of Bayreuth, Universitaetsstrasse 30, 95447 Bayreuth, Germany
| | - Klaus Kreger
- Department of Macromolecular Chemistry I, University of Bayreuth, Universitaetsstrasse 30, 95447 Bayreuth, Germany
| | - Nicolas Helfricht
- Department of Physical Chemistry II, University of Bayreuth, Universitaetsstrasse 30, 95447 Bayreuth, Germany
| | - Hans-Werner Schmidt
- Department of Macromolecular Chemistry I, University of Bayreuth, Universitaetsstrasse 30, 95447 Bayreuth, Germany
- Bavarian Polymer Institute, University of Bayreuth, Universitaetsstrasse 30, 95447 Bayreuth, Germany
| | - Georg Papastavrou
- Department of Physical Chemistry II, University of Bayreuth, Universitaetsstrasse 30, 95447 Bayreuth, Germany
- Bavarian Polymer Institute, University of Bayreuth, Universitaetsstrasse 30, 95447 Bayreuth, Germany
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2
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Raczyński P, Górny K, Bełdowski P, Marciniak B, Pöschel T, Dendzik Z. Influence of silicon nanocone on cell membrane self-sealing capabilities for targeted drug delivery-Computer simulation study. Arch Biochem Biophys 2023; 749:109802. [PMID: 37913856 DOI: 10.1016/j.abb.2023.109802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 10/06/2023] [Accepted: 10/27/2023] [Indexed: 11/03/2023]
Abstract
Efficient and non-invasive techniques of cargo delivery to biological cells are the focus of biomedical research because of their great potential importance for targeted drug therapy. Therefore, much effort is being made to study the characteristics of using nano-based biocompatible materials as systems that can facilitate this task while ensuring appropriate self-sealing of the cell membrane. Here, we study the effects of indentation and withdrawal of nanocone on phospholipid membrane by applying steered molecular dynamics (SMD) technique. Our results show that the withdrawal process directly depends on the initial position of the nanocone. The average force and work are considerably more significant in case of the withdrawal starting from a larger depth. This result is attributed to stronger hydrophobic interactions between the nanocone and lipid tails of the membrane molecules. Furthermore, when the indenter was started from the lower initial depth, the number of lipids removed from the membrane was several times smaller than the deeper indentation. The choice of the least invasive method for nanostructure-assisted drug delivery is crucial for possible applications in medicine. Therefore, the results presented in this work might be helpful in efficient and safe drug delivery with nanomaterials.
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Affiliation(s)
- Przemysław Raczyński
- University of Silesia in Katowice, Faculty of Science and Technology, 75 Pułku Piechoty 1A, Chorzów, 41-500, Poland.
| | - Krzysztof Górny
- University of Silesia in Katowice, Faculty of Science and Technology, 75 Pułku Piechoty 1A, Chorzów, 41-500, Poland
| | - Piotr Bełdowski
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Chemistry, Surface and Corrosion Science, KTH Royal Institute of Technology, Drottning Kristinas Väg 51, Stockholm, SE-10044, Sweden; Institute of Mathematics and Physics, UTP University of Science and Technology, Bydgoszcz, 85-796, Poland
| | - Beata Marciniak
- Faculty of Telecommunications, Computer Science and Electrical Engineering, UTP University of Science and Technology, Bydgoszcz, 85-796, Poland
| | - Thorsten Pöschel
- Institute for Multiscale Simulation, Friedrich-Alexander-Universität Erlangen-Nürnber, IZNF Cauerstraße 3, Erlangen, 91058, Germany
| | - Zbigniew Dendzik
- University of Silesia in Katowice, Faculty of Science and Technology, 75 Pułku Piechoty 1A, Chorzów, 41-500, Poland
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Ishiguro R, Kameyama K. Solid-Supported Assembly Composed of n-Octyl-β-D-glucopyranoside and 1,2-Dioleoyl-sn-glycero-3-phosphocholine in Equilibrium with Its Ambient Aqueous Solution System Including Dispersed Assembly. J Oleo Sci 2022; 71:223-233. [PMID: 35110465 DOI: 10.5650/jos.ess21097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In the last few decades, the preparation of solid-supported lipid bilayers by immersing a solid substrate in an aqueous solution where the lipid is dissolved with the aid of a surfactant, followed by dilution of the solution, has been reported. In this study, we attempted to interpret the evolution of supported surfactant/lipid assemblies towards the supported lipid bilayer in terms of a phase equilibrium between the supported assembly phase and its ambient solution system consisting of the dispersed surfactant/lipid assembly phase and the bulk solution phase comprising monomeric surfactant and lipid. We characterized the supported assembly formed on hydrophilized Ge or mica substrates in equilibrium with aqueous solutions containing various concentrations of the nonionic surfactant, n-octyl-β-D-glucopyranoside (OG) and the amphoteric phospholipid, 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), using interaction-force-profile measurements by atomic force microscopy (AFM), and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). We also investigated the ambient solution system using equilibrium dialysis to obtain the partition equilibrium profile of OG between the bulk solution and dispersed assembly phases in the micellar or vesicular states. These studies indicate that the properties of the supported assembly depend on the composition of the dispersed assembly and concentration of monomerically dissolved OG. Further, a type of micellar-bilayer state transition occurs in the supported assembly, roughly synchronized with that in the dispersed assembly.
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Fonseka NM, Arce FT, Christie HS, Aspinwall CA, Saavedra SS. Nanomechanical Properties of Artificial Lipid Bilayers Composed of Fluid and Polymerizable Lipids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:100-111. [PMID: 34968052 DOI: 10.1021/acs.langmuir.1c02098] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Polymerization enhances the stability of a planar supported lipid bilayer (PSLB) but it also changes its chemical and mechanical properties, attenuates lipid diffusion, and may affect the activity of integral membrane proteins. Mixed bilayers composed of fluid lipids and poly(lipids) may provide an appropriate combination of polymeric stability coupled with the fluidity and elasticity needed to maintain the bioactivity of reconstituted receptors. Previously (Langmuir, 2019, 35, 12483-12491) we showed that binary mixtures of the polymerizable lipid bis-SorbPC and the fluid lipid DPhPC form phase-segregated PSLBs composed of nanoscale fluid and poly(lipid) domains. Here we used atomic force microscopy (AFM) to compare the nanoscale mechanical properties of these binary PSLBs with single-component PSLBs. The elastic (Young's) modulus, area compressibility modulus, and bending modulus of bis-SorbPC PSLBs increased upon polymerization. Before polymerization, breakthrough events at forces below 5 nN were observed, but after polymerization, the AFM tip could not penetrate the PSLB up to an applied force of 20 nN. These results are attributed to the polymeric network in poly(bis-SorbPC), which increases the bilayer stiffness and resists compression and bending. In binary DPhPC/poly(bis-SorbPC) PSLBs, the DPhPC domains are less stiff, more compressible, and are less resistant to rupture and bending compared to pure DPhPC bilayers. These differences are attributed to bis-SorbPC monomers and oligomers present in DPhPC domains that disrupt the packing of DPhPC molecules. In contrast, the poly(bis-SorbPC) domains are stiffer and less compressible relative to pure PSLBs; this difference is attributed to DPhPC filling the nm-scale pores in the polymerized domains that are created during bis-SorbPC polymerization. Thus, incomplete phase segregation increases the stability of poly(bis-SorbPC) but has the opposite, detrimental effect for DPhPC. Overall, these results provide guidance for the design of partially polymerized bilayers for technological uses.
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Affiliation(s)
- N Malithi Fonseka
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Fernando Teran Arce
- Department of Medicine, University of Arizona, Tucson, Arizona 85721, United States
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - Hamish S Christie
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Craig A Aspinwall
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
- BIO5 Institute and Department of Biomedical Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - S Scott Saavedra
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
- BIO5 Institute and Department of Biomedical Engineering, University of Arizona, Tucson, Arizona 85721, United States
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Vázquez RF, Ovalle-García E, Antillón A, Ortega-Blake I, Muñoz-Garay C, Maté SM. Formation and Nanoscale Characterization of Asymmetric Supported Lipid Bilayers Containing Raft-Like Domains. Methods Mol Biol 2022; 2402:243-256. [PMID: 34854049 DOI: 10.1007/978-1-0716-1843-1_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The development of new strategies for achieving stable asymmetric membrane models has turned interleaflet lipid asymmetry into a topic of major interest. Cyclodextrin-mediated lipid exchange constitutes a simple and versatile method for preparing asymmetric membrane models without the need for sophisticated equipment. Here we describe a protocol for preparing asymmetric supported lipid bilayers mimicking membrane rafts by cyclodextrin-mediated lipid exchange and the main guidelines for obtaining structural information and quantitative measures of their mechanical properties using Atomic force microscopy and Force spectroscopy; two powerful techniques that allow membrane characterization at the nanoscale.
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Affiliation(s)
- Romina F Vázquez
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT-La Plata, CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina.
- Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina.
| | - Erasmo Ovalle-García
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Armando Antillón
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Iván Ortega-Blake
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Carlos Muñoz-Garay
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Sabina M Maté
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT-La Plata, CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina.
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6
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Shamaeva DV, Okotrub KA, Surovtsev NV. Coexistence of lipid phases in multilayer phospholipid films probed by Raman mapping. Analyst 2022; 147:3748-3755. [DOI: 10.1039/d2an00490a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Raman spectroscopy of stacked phospholipid bilayers reveals the chemical and conformational composition of coexisting domains.
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Affiliation(s)
- Daria V. Shamaeva
- Institute of Automation and Electrometry, Russian Academy of Sciences, pr. Ak. Koptyuga 1, Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova 2, Novosibirsk, 630090, Russia
| | - Konstantin A. Okotrub
- Institute of Automation and Electrometry, Russian Academy of Sciences, pr. Ak. Koptyuga 1, Novosibirsk, 630090, Russia
| | - Nikolay V. Surovtsev
- Institute of Automation and Electrometry, Russian Academy of Sciences, pr. Ak. Koptyuga 1, Novosibirsk, 630090, Russia
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7
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Cosentino K, Hermann E, von Kügelgen N, Unsay JD, Ros U, García-Sáez AJ. Force Mapping Study of Actinoporin Effect in Membranes Presenting Phase Domains. Toxins (Basel) 2021; 13:toxins13090669. [PMID: 34564674 PMCID: PMC8473010 DOI: 10.3390/toxins13090669] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 09/08/2021] [Accepted: 09/14/2021] [Indexed: 11/16/2022] Open
Abstract
Equinatoxin II (EqtII) and Fragaceatoxin C (FraC) are pore-forming toxins (PFTs) from the actinoporin family that have enhanced membrane affinity in the presence of sphingomyelin (SM) and phase coexistence in the membrane. However, little is known about the effect of these proteins on the nanoscopic properties of membrane domains. Here, we used combined confocal microscopy and force mapping by atomic force microscopy to study the effect of EqtII and FraC on the organization of phase-separated phosphatidylcholine/SM/cholesterol membranes. To this aim, we developed a fast, high-throughput processing tool to correlate structural and nano-mechanical information from force mapping. We found that both proteins changed the lipid domain shape. Strikingly, they induced a reduction in the domain area and circularity, suggesting a decrease in the line tension due to a lipid phase height mismatch, which correlated with proteins binding to the domain interfaces. Moreover, force mapping suggested that the proteins affected the mechanical properties at the edge, but not in the bulk, of the domains. This effect could not be revealed by ensemble force spectroscopy measurements supporting the suitability of force mapping to study local membrane topographical and mechanical alterations by membranotropic proteins.
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8
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Domingues MM, Gomes B, Hollmann A, Santos NC. 25-Hydroxycholesterol Effect on Membrane Structure and Mechanical Properties. Int J Mol Sci 2021; 22:ijms22052574. [PMID: 33806504 PMCID: PMC7961727 DOI: 10.3390/ijms22052574] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 02/08/2021] [Accepted: 02/14/2021] [Indexed: 12/20/2022] Open
Abstract
Cholesterol is responsible for the plasticity of plasma membranes and is involved in physiological and pathophysiological responses. Cholesterol homeostasis is regulated by oxysterols, such as 25-hydroxycholesterol. The presence of 25-hydroxycholesterol at the membrane level has been shown to interfere with several viruses’ entry into their target cells. We used atomic force microscopy to assess the effect of 25-hydroxycholesterol on different properties of supported lipid bilayers with controlled lipid compositions. In particular, we showed that 25-hydroxycholesterol inhibits the lipid-condensing effects of cholesterol, rendering the bilayers less rigid. This study indicates that the inclusion of 25-hydroxycholesterol in plasma membranes or the conversion of part of their cholesterol content into 25-hydroxycholesterol leads to morphological alterations of the sphingomyelin (SM)-enriched domains and promotes lipid packing inhomogeneities. These changes culminate in membrane stiffness variations.
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Affiliation(s)
- Marco M. Domingues
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal;
- Correspondence: (M.M.D.); (N.C.S.)
| | - Bárbara Gomes
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal;
| | - Axel Hollmann
- Centro de Investigación en Biofísica Aplicada y Alimentos (CIBAAL), Universidad Nacional de Santiago Del Estero-CONICET, Santiago del Estero 4206, Argentina;
| | - Nuno C. Santos
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal;
- Correspondence: (M.M.D.); (N.C.S.)
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9
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Frankel D, Davies M, Bhushan B, Kulaberoglu Y, Urriola-Munoz P, Bertrand-Michel J, Pergande MR, Smith AA, Preet S, Park TJ, Vendruscolo M, Rankin KS, Cologna SM, Kumita JR, Cenac N, St John Smith E. Cholesterol-rich naked mole-rat brain lipid membranes are susceptible to amyloid beta-induced damage in vitro. Aging (Albany NY) 2020; 12:22266-22290. [PMID: 33147569 PMCID: PMC7695401 DOI: 10.18632/aging.202138] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/03/2020] [Indexed: 04/08/2023]
Abstract
Naked mole-rats are extraordinarily long-lived rodents that offer unique opportunities to study the molecular origins of age-related neurodegenerative diseases. Remarkably, they do not accumulate amyloid plaques, even though their brains contain high concentrations of amyloid beta (Aβ) peptide from a young age. Therefore, they represent a particularly favourable organism to study the mechanisms of resistance against Aβ neurotoxicity. Here we examine the composition, phase behaviour, and Aβ interactions of naked mole-rat brain lipids. Relative to mouse, naked mole-rat brain lipids are rich in cholesterol and contain sphingomyelin in lower amounts and of shorter chain lengths. Proteins associated with the metabolism of ceramides, sphingomyelins and sphingosine-1-phosphate receptor 1 were also found to be decreased in naked mole-rat brain lysates. Correspondingly, we find that naked mole-rat brain lipid membranes exhibit a high degree of phase separation, with the liquid ordered phase extending to 80% of the supported lipid bilayer. These observations are consistent with the 'membrane pacemaker' hypothesis of ageing, according to which long-living species have lipid membranes particularly resistant to oxidative damage. We also found that exposure to Aβ disrupts naked mole-rat brain lipid membranes significantly, breaking the membrane into pieces while mouse brain derived lipids remain largely intact upon Aβ exposure.
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Affiliation(s)
- Daniel Frankel
- School of Engineering, Newcastle University, Newcastle Upon Tyne NE1 7RU, UK
| | - Matthew Davies
- School of Engineering, Newcastle University, Newcastle Upon Tyne NE1 7RU, UK
| | - Bharat Bhushan
- School of Engineering, Newcastle University, Newcastle Upon Tyne NE1 7RU, UK
| | - Yavuz Kulaberoglu
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD, UK
| | | | | | - Melissa R. Pergande
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Andrew A. Smith
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Swapan Preet
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Thomas J. Park
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Kenneth S. Rankin
- Translational and Clinical Research Institute, Newcastle University, Paul O’Gorman Building, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Stephanie M. Cologna
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Janet R. Kumita
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD, UK
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Nicolas Cenac
- IRSD, INSERM, INRA, INP-ENVT, Toulouse University 3 Paul Sabatier, Toulouse, France
| | - Ewan St John Smith
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD, UK
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10
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Chiodini S, Ruiz-Rincón S, Garcia PD, Martin S, Kettelhoit K, Armenia I, Werz DB, Cea P. Bottom Effect in Atomic Force Microscopy Nanomechanics. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2000269. [PMID: 32761794 DOI: 10.1002/smll.202000269] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 06/04/2020] [Indexed: 05/27/2023]
Abstract
In this work, the influence of the rigid substrate on the determination of the sample Young's modulus, the so-called bottom-effect artifact, is demonstrated by an atomic force microscopy force-spectroscopy experiment. The nanomechanical properties of a one-component supported lipid membrane (SLM) exhibiting areas of two different thicknesses are studied: While a standard contact mechanics model (Sneddon) provides two different elastic moduli for these two morphologies, it is shown that Garcia's bottom-effect artifact correction yields a unique value, as expected for an intrinsic material property. Remarkably, it is demonstrated that the ratio between the contact radius (and not only the indentation) and the sample thickness is the key parameter addressing the relevance of the bottom-effect artifact. The experimental results are validated by finite element method simulations providing a solid support to Garcia's theory. The amphiphilic nature of the investigated material is representative of several kinds of lipids, suggesting that the results have far reaching implications for determining the correct Young's modulus of SLMs. The generality of Garcia's bottom-effect artifact correction allows its application to every kind of supported soft film.
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Affiliation(s)
- Stefano Chiodini
- Instituto de Nanociencia de Aragón (INA), Campus Rio Ebro, Universidad de Zaragoza, C/Mariano Esquillor s/n, Zaragoza, 50018, Spain
- Laboratorio de Microscopias Avanzadas (LMA), Campus Río Ebro, Universidad de Zaragoza, C/Mariano Esquillor s/n, Zaragoza, 50018, Spain
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, C/Pedro Cerbuna 12, Zaragoza, 50009, Spain
| | - Silvia Ruiz-Rincón
- Instituto de Nanociencia de Aragón (INA), Campus Rio Ebro, Universidad de Zaragoza, C/Mariano Esquillor s/n, Zaragoza, 50018, Spain
- Laboratorio de Microscopias Avanzadas (LMA), Campus Río Ebro, Universidad de Zaragoza, C/Mariano Esquillor s/n, Zaragoza, 50018, Spain
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, C/Pedro Cerbuna 12, Zaragoza, 50009, Spain
| | - Pablo D Garcia
- Instituto de Ciencia de Materiales, ICMM-CSIC, Campus de Cantoblanco, C/Sor Juana Inés de la Cruz, 3, Madrid, 28049, Spain
| | - Santiago Martin
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, C/Pedro Cerbuna 12, Zaragoza, 50009, Spain
- Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, C/Pedro Cerbuna 12, Zaragoza, 50009, Spain
| | - Katharina Kettelhoit
- Technische Universität Braunschweig, Institut für Organische Chemie, Hagenring 30, Braunschweig, 38106, Germany
| | - Ilaria Armenia
- Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, C/Pedro Cerbuna 12, Zaragoza, 50009, Spain
| | - Daniel B Werz
- Technische Universität Braunschweig, Institut für Organische Chemie, Hagenring 30, Braunschweig, 38106, Germany
| | - Pilar Cea
- Instituto de Nanociencia de Aragón (INA), Campus Rio Ebro, Universidad de Zaragoza, C/Mariano Esquillor s/n, Zaragoza, 50018, Spain
- Laboratorio de Microscopias Avanzadas (LMA), Campus Río Ebro, Universidad de Zaragoza, C/Mariano Esquillor s/n, Zaragoza, 50018, Spain
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, C/Pedro Cerbuna 12, Zaragoza, 50009, Spain
- Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, C/Pedro Cerbuna 12, Zaragoza, 50009, Spain
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11
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Vázquez RF, Ovalle-García E, Antillón A, Ortega-Blake I, Bakás LS, Muñoz-Garay C, Maté SM. Asymmetric bilayers mimicking membrane rafts prepared by lipid exchange: Nanoscale characterization using AFM-Force spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183467. [PMID: 32871116 DOI: 10.1016/j.bbamem.2020.183467] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/07/2020] [Accepted: 08/24/2020] [Indexed: 01/03/2023]
Abstract
Sphingolipids-enriched rafts domains are proposed to occur in plasma membranes and to mediate important cellular functions. Notwithstanding, the asymmetric transbilayer distribution of phospholipids that exists in the membrane confers the two leaflets different potentials to form lateral domains as next to no sphingolipids are present in the inner leaflet. How the physical properties of one leaflet can influence the properties of the other and its importance on signal transduction across the membrane are questions still unresolved. In this work, we combined AFM imaging and Force spectroscopy measurements to assess domain formation and to study the nanomechanical properties of asymmetric supported lipid bilayers (SLBs) mimicking membrane rafts. Asymmetric SLBs were formed by incorporating N-palmitoyl-sphingomyelin (16:0SM) into the outer leaflet of preformed 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC)/Cholesterol SLBs through methyl-β-cyclodextrin-mediated lipid exchange. Lipid domains were detected after incorporation of 16:0SM though their phase state varied from gel to liquid ordered (Lo) phase if the procedure was performed at 24 or 37 °C, respectively. When comparing symmetric and asymmetric Lo domains, differences in size and morphology were observed, with asymmetric domains being smaller and more interconnected. Both types of Lo domains showed similar mechanical stability in terms of rupture forces and Young's moduli. Notably, force curves in asymmetric domains presented two rupture events that could be attributed to the sequential rupture of a liquid disordered (Ld) and a Lo phase. Interleaflet coupling in asymmetric Lo domains could also be inferred from those measurements. The experimental approach outlined here would significantly enhance the applicability of membrane models.
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Affiliation(s)
- Romina F Vázquez
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT- La Plata, CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, 60 y 120, 1900 La Plata, Argentina; Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 47 y 115, 1900 La Plata, Argentina.
| | - Erasmo Ovalle-García
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, 62210 Cuernavaca, México
| | - Armando Antillón
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, 62210 Cuernavaca, México
| | - Iván Ortega-Blake
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, 62210 Cuernavaca, México
| | - Laura S Bakás
- Centro de Investigación en Proteínas Vegetales (CIProVe), Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 47 y 115, 1900 La Plata, Argentina
| | - Carlos Muñoz-Garay
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, 62210 Cuernavaca, México
| | - Sabina M Maté
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT- La Plata, CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, 60 y 120, 1900 La Plata, Argentina.
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12
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Morshed A, Karawdeniya BI, Bandara Y, Kim MJ, Dutta P. Mechanical characterization of vesicles and cells: A review. Electrophoresis 2020; 41:449-470. [PMID: 31967658 PMCID: PMC7567447 DOI: 10.1002/elps.201900362] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 12/05/2019] [Accepted: 12/08/2019] [Indexed: 12/30/2022]
Abstract
Vesicles perform many essential functions in all living organisms. They respond like a transducer to mechanical stress in converting the applied force into mechanical and biological responses. At the same time, both biochemical and biophysical signals influence the vesicular response in bearing mechanical loads. In recent years, liposomes, artificial lipid vesicles, have gained substantial attention from the pharmaceutical industry as a prospective drug carrier which can also serve as an artificial cell-mimetic system. The ability of these vesicles to enter through pores of even smaller size makes them ideal candidates for therapeutic agents to reach the infected sites effectively. Engineering of vesicles with desired mechanical properties that can encapsulate drugs and release as required is the prime challenge in this field. This requirement has led to the modifications of the composition of the bilayer membrane by adding cholesterol, sphingomyelin, etc. In this article, we review the manufacturing and characterization techniques of various artificial/synthetic vesicles. We particularly focus on the electric field-driven characterization techniques to determine different properties of vesicle and its membranes, such as bending rigidity, viscosity, capacitance, conductance, etc., which are indicators of their content and mobility. Similarities and differences between artificial vesicles, natural vesicles, and cells are highlighted throughout the manuscript since most of these artificial vesicles are intended for cell mimetic functions.
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Affiliation(s)
- Adnan Morshed
- School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920
| | - Buddini Iroshika Karawdeniya
- Department of Mechanical Engineering, Lyle School of Engineering, Southern Methodist University, Dallas, Texas, USA
| | - Y.M.NuwanD.Y. Bandara
- Department of Mechanical Engineering, Lyle School of Engineering, Southern Methodist University, Dallas, Texas, USA
| | - Min Jun Kim
- Department of Mechanical Engineering, Lyle School of Engineering, Southern Methodist University, Dallas, Texas, USA
| | - Prashanta Dutta
- School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920
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13
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Et-Thakafy O, Guyomarc'h F, Lopez C. Young modulus of supported lipid membranes containing milk sphingomyelin in the gel, fluid or liquid-ordered phase, determined using AFM force spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:1523-1532. [DOI: 10.1016/j.bbamem.2019.07.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 06/12/2019] [Accepted: 07/04/2019] [Indexed: 10/26/2022]
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14
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Gumí-Audenis B, Illa-Tuset S, Grimaldi N, Pasquina-Lemonche L, Ferrer-Tasies L, Sanz F, Veciana J, Ratera I, Faraudo J, Ventosa N, Giannotti MI. Insights into the structure and nanomechanics of a quatsome membrane by force spectroscopy measurements and molecular simulations. NANOSCALE 2018; 10:23001-23011. [PMID: 30500043 DOI: 10.1039/c8nr07110a] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Quatsomes (QS) are unilamellar nanovesicles constituted by quaternary ammonium surfactants and sterols in defined molar ratios. Unlike conventional liposomes, QS are stable upon long storage such as for several years, they show outstanding vesicle-to-vesicle homogeneity regarding size and lamellarity, and they have the structural and physicochemical requirements to be a potential platform for site-specific delivery of hydrophilic and lipophilic molecules. Knowing in detail the structure and mechanical properties of the QS membrane is of great importance for the design of deformable and flexible nanovesicle alternatives, highly pursued in nanomedicine applications such as the transdermal administration route. In this work, we report the first study on the detailed structure of the cholesterol : CTAB QS membrane at the nanoscale, using atomic force microscopy (AFM) and spectroscopy (AFM-FS) in a controlled liquid environment (ionic medium and temperature) to assess the topography of supported QS membranes (SQMs) and to evaluate the local membrane mechanics. We further perform molecular dynamics (MD) simulations to provide an atomistic interpretation of the obtained results. Our results are direct evidence of the bilayer nature of the QS membrane, with characteristics of a fluid-like membrane, compact and homogeneous in composition, and with structural and mechanical properties that depend on the surrounding environment. We show how ions alter the lateral packing, modifying the membrane mechanics. We observe that according to the ionic environment and temperature, different domains may coexist in the QS membranes, ascribed to variations in molecular tilt angles. Our results indicate that QS membrane properties may be easily tuned by altering the lateral interactions with either different environmental ions or counterions.
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Affiliation(s)
- Berta Gumí-Audenis
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.
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15
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Liu X. Interactions of Silver Nanoparticles Formed in Situ on AFM Tips with Supported Lipid Bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:10774-10781. [PMID: 30109936 DOI: 10.1021/acs.langmuir.8b01545] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A facile approach for functionalizing atomic force microscopy (AFM) tips with nanoparticles (NPs) will provide exciting opportunities in the field of tip-enhanced vibrational spectroscopy and in probing the interactions between NPs and biological systems. In this study, through successive exposure to polydopamine and AgNO3 solutions, the apex of AFM tips was functionalized with silver nanoparticles (AgNPs). The AgNP-modified AFM tips were used to measure the interaction forces between AgNPs and supported lipid bilayers (SLBs) formed on mica, as well as to probe the penetration of SLBs by AgNPs, with an emphasis on the effect of human serum albumin (HSA) proteins. AgNPs experienced predominantly repulsive forces when approaching SLBs. The presence of HSA resulted in an enhancement in the repulsive interactions between AgNPs and SLBs, likely through steric repulsion. Finally, the forces required for AgNPs to penetrate SLBs were higher in the presence of HSA probably due to the increase in the effective size of the nanoscale protuberances on the AFM tip stemming from the formation of protein coronas around the AgNPs.
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Affiliation(s)
- Xitong Liu
- Department of Environmental Health and Engineering , Johns Hopkins University , Baltimore , Maryland 21218-2686 , United States
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16
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Puiggalí-Jou A, Pawlowski J, del Valle LJ, Michaux C, Perpète EA, Sek S, Alemán C. Properties of Omp2a-Based Supported Lipid Bilayers: Comparison with Polymeric Bioinspired Membranes. ACS OMEGA 2018; 3:9003-9019. [PMID: 31459033 PMCID: PMC6645002 DOI: 10.1021/acsomega.8b00913] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Accepted: 07/19/2018] [Indexed: 05/31/2023]
Abstract
Omp2a β-barrel outer membrane protein has been reconstituted into supported lipid bilayers (SLBs) to compare the nanomechanical properties (elastic modulus, adhesion forces, and deformation) and functionality of the resulting bioinspired system with those of Omp2a-based polymeric nanomembranes (NMs). Protein reconstitution into lipid bilayers has been performed using different strategies, the most successful one consisting of a detergent-mediated process into preformed liposomes. The elastic modulus obtained for the lipid bilayer and Omp2a are ∼19 and 10.5 ± 1.7 MPa, respectively. Accordingly, the protein is softer than the lipid bilayer, whereas the latter exhibits less mechanical strength than polymeric NMs. Besides, the function of Omp2a in the SLB is similar to that observed for Omp2a-based polymeric NMs. Results open the door to hybrid bioinspired substrates based on the integration of Omp2a-proteoliposomes and nanoperforated polymeric freestanding NMs.
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Affiliation(s)
- Anna Puiggalí-Jou
- Departament
d’Enginyeria Química, EEBE, Universitat Politècnica de Catalunya, C/Eduard Maristany, 10-14, Ed. I2, 08019 Barcelona, Spain
- Barcelona
Research Center for Multiscale Science and Engineering, Universitat Politècnica de Catalunya, C/Eduard Maristany, 10-14, Ed. C, 08019 Barcelona, Spain
| | - Jan Pawlowski
- Biological
and Chemical Research Centre, Faculty of Chemistry, University of Warsaw, Zwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Luis J. del Valle
- Departament
d’Enginyeria Química, EEBE, Universitat Politècnica de Catalunya, C/Eduard Maristany, 10-14, Ed. I2, 08019 Barcelona, Spain
- Barcelona
Research Center for Multiscale Science and Engineering, Universitat Politècnica de Catalunya, C/Eduard Maristany, 10-14, Ed. C, 08019 Barcelona, Spain
| | - Catherine Michaux
- Laboratoire
de Chimie Physique des Biomolécules, University of Namur, Rue de Bruxelles, 61, 5000 Namur, Belgium
| | - Eric A. Perpète
- Laboratoire
de Chimie Physique des Biomolécules, University of Namur, Rue de Bruxelles, 61, 5000 Namur, Belgium
| | - Slawomir Sek
- Biological
and Chemical Research Centre, Faculty of Chemistry, University of Warsaw, Zwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Carlos Alemán
- Departament
d’Enginyeria Química, EEBE, Universitat Politècnica de Catalunya, C/Eduard Maristany, 10-14, Ed. I2, 08019 Barcelona, Spain
- Barcelona
Research Center for Multiscale Science and Engineering, Universitat Politècnica de Catalunya, C/Eduard Maristany, 10-14, Ed. C, 08019 Barcelona, Spain
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17
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Bi H, Wang X, Han X, Voïtchovsky K. Impact of Electric Fields on the Nanoscale Behavior of Lipid Monolayers at the Surface of Graphite in Solution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:9561-9571. [PMID: 30028144 DOI: 10.1021/acs.langmuir.8b01631] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The nanoscale organization and dynamics of lipid molecules in self-assembled membranes is central to the biological function of cells and in the technological development of synthetic lipid structures as well as in devices such as biosensors. Here, we explore the nanoscale molecular arrangement and dynamics of lipids assembled in monolayers at the surface of highly ordered pyrolytic graphite (HOPG), in different ionic solutions, and under electrical potentials. Using a combination of atomic force microscopy and fluorescence recovery after photobleaching, we show that HOPG is able to support fully formed and fluid lipid membranes, but mesoscale order and corrugations can be observed depending on the type of the lipid considered (1,2-dioleoyl- sn-glycero-3-phosphocholine, 1,2-dioleoyl- sn-glycero-3-phospho-l-serine (DOPS), and 1,2-dioleoyl-3-trimethylammoniumpropane) and the ion present (Na+, Ca2+, Cl-). Interfacial solvation forces and ion-specific effects dominate over the electrostatic changes induced by moderate electric fields (±1.0 V vs Ag/AgCl reference electrode) with particularly marked effects in the presence of calcium, and for DOPS. Our results provide insights into the interplay between the molecular, ionic, and electrostatic interactions and the formation of dynamical ordered structures in fluid lipid membranes.
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Affiliation(s)
- Hongmei Bi
- College of Science , Heilongjiang Bayi Agricultural University , Daqing 163319 , China
| | - Xuejing Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Chemistry and Chemical Engineering , Harbin Institute of Technology , Harbin 150001 , China
| | - Xiaojun Han
- State Key Laboratory of Urban Water Resource and Environment, School of Chemistry and Chemical Engineering , Harbin Institute of Technology , Harbin 150001 , China
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18
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Gumí-Audenis B, Costa L, Ferrer-Tasies L, Ratera I, Ventosa N, Sanz F, Giannotti MI. Pulling lipid tubes from supported bilayers unveils the underlying substrate contribution to the membrane mechanics. NANOSCALE 2018; 10:14763-14770. [PMID: 30043793 DOI: 10.1039/c8nr03249a] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Cell processes like endocytosis, membrane resealing, signaling and transcription involve conformational changes which depend on the chemical composition and the physicochemical properties of the lipid membrane. The better understanding of the mechanical role of lipids in cell membrane force-triggered and sensing mechanisms has recently become the focus of attention. Different membrane models and experimental methodologies are commonly explored. While general approaches involve controlled vesicle deformation using micropipettes or optical tweezers, due to the local and dynamic nature of the membrane, high spatial resolution atomic force microscopy (AFM) has been widely used to study the mechanical compression and indentation of supported lipid bilayers (SLBs). However, the substrate contribution remains unkown. Here, we demonstrate how pulling lipid tubes with an AFM out of model SLBs can be used to assess the nanomechanics of SLBs through the evaluation of the tube growing force (Ftube), allowing for very local evaluation with high spatial and force resolution of the lipid membrane tension. We first validate this approach to determine the contribution of different phospholipids, by varying the membrane composition, in both one-component and phase-segregated membranes. Finally, we successfully assess the contribution of the underlying substrate to the membrane mechanics, demonstrating that SLB models may represent an intermediate scenario between a free membrane (blebs) and a cytoskeleton supported membrane.
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Affiliation(s)
- Berta Gumí-Audenis
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 10-12, 08028 Barcelona, Spain.
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19
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Hamon JJ, Tabor RF, Striolo A, Grady BP. Atomic Force Microscopy Force Mapping Analysis of an Adsorbed Surfactant above and below the Critical Micelle Concentration. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:7223-7239. [PMID: 29807434 DOI: 10.1021/acs.langmuir.8b00574] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Force curves collected using an atomic force microscope (AFM) in the presence of adsorbed surfactants are often used to draw conclusions about adsorbed film packing, rigidity, and thickness. However, some noteworthy features of such force curve characteristics have yet to be thoroughly investigated and explained. In this work, we collected force curves from tetradecyltrimethylammonium bromide films adsorbed on highly oriented pyrolytic graphite (HOPG), silica, and silica that had been hydrophobized by functionalization with dichlorodimethyl silane. Breakthrough events in the force curves from several different trials were compared to show that the breakthrough distance, often reported as the adsorbed film thickness, increased with concentration below the critical micelle concentration (CMC) but was approximately 3.5 nm on all surfaces between 2× and 10× CMC; an unexpected result because of the different surface chemistries for the three surfaces. We employed an AFM probe with a different force constant ( k) value as well as a colloidal probe and the breakthrough distance remained approximately 3.5 nm in all cases. Gradient mapping, a variant of force mapping, was also implemented on the three surfaces and resulted in a new technique for visualizing adsorbed surfactant in situ. The resulting maps showed patches of adsorbed surfactant below the CMC and revealed that with increasing concentration, the size of the patches increased resulting in full coverage near and above the CMC. These results are, to our knowledge, the first time force mapping has been used to spatially track patches of adsorbed surfactant. Finally, layers of surfactants on an AFM tip were investigated by collecting a force map on a single AFM tip using the tip of a separate AFM probe. A breakthrough event was observed between the tips, indicating that a layer of surfactant was present on at least one, if not both tips.
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Affiliation(s)
- J J Hamon
- School of Chemical, Biological and Materials Engineering and Institute of Applied Surfactant Research , University of Oklahoma , Norman , Oklahoma 73019 , United States
| | - Rico F Tabor
- School of Chemistry , Monash University , Wellington Road , Clayton , Victoria 3800 , Australia
| | - Alberto Striolo
- Department of Chemical Engineering , University College London , London WC1E 7JE , U.K
| | - Brian P Grady
- School of Chemical, Biological and Materials Engineering and Institute of Applied Surfactant Research , University of Oklahoma , Norman , Oklahoma 73019 , United States
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20
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Dehnert M, Magerle R. 3D depth profiling of the interaction between an AFM tip and fluid polymer solutions. NANOSCALE 2018. [PMID: 29532845 DOI: 10.1039/c8nr00299a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
In the atomic force microscopy (AFM) investigation of soft polymers and liquids, the tip-sample interaction is dominated by long-range van der Waals forces, capillary forces and adhesion. Furthermore, the tip can indent several tens of nanometres into the surface, and it can pull off a polymer filament from the surface. Therefore, measuring the unperturbed shape of a polymeric fluid can be challenging. Here, we study the tip-sample interaction with polystyrene droplets swollen in chloroform vapour, where we can utilize the solvent vapour concentration to adjust the specimen's mechanical properties from a stiff solid to a fluid film. With the same AFM tip, we use two different AFM force spectroscopy methods to measure three-dimensional (3D) depth profiles of the tip-sample interaction: force-distance (FD) curves and amplitude-phase-distance (APD) curves. The 3D depth profiles reconstructed from FD and APD measurements provide detailed insight into the tip-sample interaction mechanism for a fluid polymer solution. The fluid's intrinsic relaxation time, which we measure with an AFM-based step-strain experiment, is essential for understanding the tip-sample interaction mechanism. Furthermore, measuring 3D depth profiles and using APD data to reconstruct the unperturbed surface comprise a versatile methodology for obtaining accurate dimensional measurements of fluid and gel-like objects on the nanometre scale.
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Affiliation(s)
- Martin Dehnert
- Fakultät für Naturwissenschaften, Technische Universität Chemnitz, D-09107 Chemnitz, Germany.
| | - Robert Magerle
- Fakultät für Naturwissenschaften, Technische Universität Chemnitz, D-09107 Chemnitz, Germany.
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21
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Bhojoo U, Chen M, Zou S. Temperature induced lipid membrane restructuring and changes in nanomechanics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:700-709. [DOI: 10.1016/j.bbamem.2017.12.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 11/17/2017] [Accepted: 12/08/2017] [Indexed: 11/26/2022]
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22
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Murthy AVR, Guyomarc'h F, Lopez C. Palmitoyl ceramide promotes milk sphingomyelin gel phase domains formation and affects the mechanical properties of the fluid phase in milk-SM/DOPC supported membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:635-644. [DOI: 10.1016/j.bbamem.2017.12.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 12/06/2017] [Accepted: 12/07/2017] [Indexed: 01/08/2023]
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23
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Hall AR, Geoghegan M. Polymers and biopolymers at interfaces. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:036601. [PMID: 29368695 DOI: 10.1088/1361-6633/aa9e9c] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
This review updates recent progress in the understanding of the behaviour of polymers at surfaces and interfaces, highlighting examples in the areas of wetting, dewetting, crystallization, and 'smart' materials. Recent developments in analysis tools have yielded a large increase in the study of biological systems, and some of these will also be discussed, focussing on areas where surfaces are important. These areas include molecular binding events and protein adsorption as well as the mapping of the surfaces of cells. Important techniques commonly used for the analysis of surfaces and interfaces are discussed separately to aid the understanding of their application.
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Affiliation(s)
- A R Hall
- Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield S3 7RH, United Kingdom. Fraunhofer Project Centre for Embedded Bioanalytical Systems, Dublin City University, Glasnevin, Dublin 9, Ireland
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24
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Cholesterol induced asymmetry in DOPC bilayers probed by AFM force spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:953-959. [PMID: 29408513 DOI: 10.1016/j.bbamem.2018.01.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 01/24/2018] [Accepted: 01/28/2018] [Indexed: 11/21/2022]
Abstract
Cholesterol induced mechanical effects on artificial lipid bilayers are well known and have been thoroughly investigated by AFM force spectroscopy. However, dynamics of cholesterol impingement into bilayers at various cholesterol concentrations and their effects have not been clearly understood. In this paper we present, the effect of cholesterol as a function of its concentration in a simple single component dioleoylphosphatidylcholine (DOPC) bilayer. The nature of measured breakthrough forces on a bilayer with the addition of cholesterol, suggested that it is not just responsible to increase the mechanical stability but also introduces irregularities across the leaflets of the bilayer. This cholesterol induced asymmetry across the (in the inner and outer leaflets) bilayer is related to the phenomena of interleaflet coupling and is a function of cholesterol concentration probed by AFM can provide an unprecedented direction on mechanical properties of lipid membrane as it can be directly correlated to biophysical properties of a cell membrane.
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25
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Liu HY, Grant H, Hsu HL, Sorkin R, Bošković F, Wuite G, Daniel S. Supported Planar Mammalian Membranes as Models of in Vivo Cell Surface Architectures. ACS APPLIED MATERIALS & INTERFACES 2017; 9:35526-35538. [PMID: 28930438 DOI: 10.1021/acsami.7b07500] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Emerging technologies use cell plasma membrane vesicles or "blebs" as an intermediate to form molecularly complete, planar cell surface mimetics that are compatible with a variety of characterization tools and microscopy methods. This approach enables direct incorporation of membrane proteins into supported lipid bilayers without using detergents and reconstitution and preserves native lipids and membrane species. Such a system can be advantageous as in vitro models of in vivo cell surfaces for study of the roles of membrane proteins as drug targets in drug delivery, host-pathogen interactions, tissue engineering, and many other bioanalytical and sensing applications. However, the impact of methods used to induce cell blebbing (vesiculation) on protein and membrane properties is still unknown. This study focuses on characterization of cell blebs created under various bleb-inducing conditions and the result on protein properties (orientation, mobility, activity, etc.) and lipid scrambling in this platform. The orientation of proteins in the cell blebs and planar bilayers is revealed using a protease cleavage assay. Lipid scrambling in both cell blebs and planar bilayers is indicated through an annexin V binding assay. To quantify protein confinement, immobility, etc., incorporation of GPI-linked yellow fluorescent protein (GPI-YFP) was used in conjunction with single-molecule tracking (SMT) microscopy. Finally, to investigate the impact of the bleb induction method on protein activity and expression level, cell blebs expressing human aminopeptidase N (hAPN) were analyzed by an enzyme activity assay and immunoblotting. This work enriches our understanding of cell plasma membrane bleb bilayers as a biomimetic platform, reveals conditions under which specific properties are met, and represents one of the few ways to make molecularly complete supported bilayers directly from cell plasma membranes.
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Affiliation(s)
- Han-Yuan Liu
- School of Chemical and Biomolecular Engineering, Cornell University , Ithaca, New York 14853, United States
| | - Hannah Grant
- School of Chemical and Biomolecular Engineering, Cornell University , Ithaca, New York 14853, United States
| | - Hung-Lun Hsu
- School of Chemical and Biomolecular Engineering, Cornell University , Ithaca, New York 14853, United States
| | - Raya Sorkin
- Department of Physics and Astronomy and Laser Lab, Vrije Universiteit Amsterdam , Amsterdam 1081 HV, The Netherlands
| | - Filip Bošković
- Department of Physics and Astronomy and Laser Lab, Vrije Universiteit Amsterdam , Amsterdam 1081 HV, The Netherlands
| | - Gijs Wuite
- Department of Physics and Astronomy and Laser Lab, Vrije Universiteit Amsterdam , Amsterdam 1081 HV, The Netherlands
| | - Susan Daniel
- School of Chemical and Biomolecular Engineering, Cornell University , Ithaca, New York 14853, United States
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26
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Micklavzina BL, Longo ML. Characterization of Repulsive Forces and Surface Deformation in Thin Micellar Films via AFM. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:10483-10491. [PMID: 28903007 DOI: 10.1021/acs.langmuir.7b02508] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Here we examine how the force on an atomic force microscope (AFM) tip varies as it approaches micellar surfactant films, and use this information to discern the film's surface structure and Young's modulus. Rows of wormlike hemimicelles were created at a graphite interface using 10 mM sodium dodecyl sulfate (SDS). We found that the repulsive force on a silicon nitride tip as it approached the surface was exponential, with a decay length of 2.0 ± 0.1 nm. The addition of Na2SO4 was found to cause a change in this behavior, with a clear split into two exponential regions at concentrations above 1 mM. We also observed that the range of these forces increased with added salt from ∼15 nm in pure SDS to ∼20 nm at a Na2SO4 concentration of 1.34 mM. These forces were inconsistent with electrostatic repulsion, and were determined to be steric in nature. We show that the behavior at higher salt concentrations is consistent with the theory of polyelectrolyte brushes in the osmotic regime. From this, we hypothesize the presence of micellar brushes at the surface that behave similarly to adsorbed polymer chains. In addition, the Young's modulus of the film was taken from data near the interface using Sneddon's model, and found to be 80 ± 40 MPa. Similar experiments were performed with 10 mM dodecylamine hydrochloride (DAH) solutions in the presence of added magnesium chloride. The decay length for the pure DAH solution was found to be 2.6 ± 0.3 nm, and the addition of 1.34 mM of MgCl2 caused this to increase to 3.7 ± 0.3 nm. No decay length splitting was observed for DAH. We conclude that the behavior at the surface resembles that of an uncharged polymer brush, as the ionic and surface charge densities are much lower for DAH than for SDS.
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Affiliation(s)
- Benjamin L Micklavzina
- Department of Materials Science and Engineering, University of California Davis , Davis, California 95616, United States
| | - Marjorie L Longo
- Department of Chemical Engineering, University of California Davis , Davis, California 95616, United States
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Et-Thakafy O, Delorme N, Gaillard C, Mériadec C, Artzner F, Lopez C, Guyomarc'h F. Mechanical Properties of Membranes Composed of Gel-Phase or Fluid-Phase Phospholipids Probed on Liposomes by Atomic Force Spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:5117-5126. [PMID: 28475345 DOI: 10.1021/acs.langmuir.7b00363] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
In many liposome applications, the nanomechanical properties of the membrane envelope are essential to ensure, e.g., physical stability, protection, or penetration into tissues. Of all factors, the lipid composition and its phase behavior are susceptible to tune the mechanical properties of membranes. To investigate this, small unilamellar vesicles (SUV; diameter < 200 nm), referred to as liposomes, were produced using either unsaturated 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) or saturated 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) in aqueous buffer at pH 6.7. The respective melting temperatures of these phospholipids were -20 and 41 °C. X-ray diffraction analysis confirmed that at 20 °C DOPC was in the fluid phase and DPPC was in the gel phase. After adsorption of the liposomes onto flat silicon substrates, atomic force microscopy (AFM) was used to image and probe the mechanical properties of the liposome membrane. The resulting force-distance curves were treated using an analytical model based on the shell theory to yield the Young's modulus (E) and the bending rigidity (kC) of the curved membranes. The mechanical investigation showed that DPPC membranes were much stiffer (E = 116 ± 45 MPa) than those of DOPC (E = 13 ± 9 MPa) at 20 °C. The study demonstrates that the employed methodology allows discrimination of the respective properties of gel- or fluid-phase membranes when in the shape of liposomes. It opens perspectives to map the mechanical properties of liposomes containing both fluid and gel phases or of biological systems.
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Affiliation(s)
| | - Nicolas Delorme
- UMR CNRS 6283 Institut des Molécules et Matériaux du Mans, Université du Maine, Université Bretagne-Loire, 72000 Le Mans, France
| | - Cédric Gaillard
- UR BIA 1268 Biopolymères Interactions Assemblages, INRA, 44316 Nantes, France
| | - Cristelle Mériadec
- Institut de Physique de Rennes, UMR 6251, CNRS, Université de Rennes 1, 263 Av. Général Leclerc, 35042 Rennes, France
| | - Franck Artzner
- Institut de Physique de Rennes, UMR 6251, CNRS, Université de Rennes 1, 263 Av. Général Leclerc, 35042 Rennes, France
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Gumí-Audenis B, Costa L, Carlá F, Comin F, Sanz F, Giannotti MI. Structure and Nanomechanics of Model Membranes by Atomic Force Microscopy and Spectroscopy: Insights into the Role of Cholesterol and Sphingolipids. MEMBRANES 2016; 6:E58. [PMID: 27999368 PMCID: PMC5192414 DOI: 10.3390/membranes6040058] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 12/12/2016] [Accepted: 12/14/2016] [Indexed: 11/17/2022]
Abstract
Biological membranes mediate several biological processes that are directly associated with their physical properties but sometimes difficult to evaluate. Supported lipid bilayers (SLBs) are model systems widely used to characterize the structure of biological membranes. Cholesterol (Chol) plays an essential role in the modulation of membrane physical properties. It directly influences the order and mechanical stability of the lipid bilayers, and it is known to laterally segregate in rafts in the outer leaflet of the membrane together with sphingolipids (SLs). Atomic force microscope (AFM) is a powerful tool as it is capable to sense and apply forces with high accuracy, with distance and force resolution at the nanoscale, and in a controlled environment. AFM-based force spectroscopy (AFM-FS) has become a crucial technique to study the nanomechanical stability of SLBs by controlling the liquid media and the temperature variations. In this contribution, we review recent AFM and AFM-FS studies on the effect of Chol on the morphology and mechanical properties of model SLBs, including complex bilayers containing SLs. We also introduce a promising combination of AFM and X-ray (XR) techniques that allows for in situ characterization of dynamic processes, providing structural, morphological, and nanomechanical information.
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Affiliation(s)
- Berta Gumí-Audenis
- Nanoprobes and Nanoswitches group, Institute for Bioengineering of Catalunya (IBEC), Barcelona 08028, Spain.
- Physical Chemistry Department, Universitat de Barcelona, Barcelona 08028, Spain.
- European Synchrotron Radiation Facility (ESRF), Grenoble 38043, France.
- Networking Biomedical Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid 28028, Spain.
| | - Luca Costa
- Structure and Dynamics of Nucleoproteic and Membrane Assemblies, Centre de Biochimie Structurale (CBS), Montpellier 34090, France.
| | - Francesco Carlá
- European Synchrotron Radiation Facility (ESRF), Grenoble 38043, France.
| | - Fabio Comin
- European Synchrotron Radiation Facility (ESRF), Grenoble 38043, France.
| | - Fausto Sanz
- Nanoprobes and Nanoswitches group, Institute for Bioengineering of Catalunya (IBEC), Barcelona 08028, Spain.
- Physical Chemistry Department, Universitat de Barcelona, Barcelona 08028, Spain.
- Networking Biomedical Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid 28028, Spain.
| | - Marina I Giannotti
- Nanoprobes and Nanoswitches group, Institute for Bioengineering of Catalunya (IBEC), Barcelona 08028, Spain.
- Physical Chemistry Department, Universitat de Barcelona, Barcelona 08028, Spain.
- Networking Biomedical Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid 28028, Spain.
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Kulkarni A, Pandey P, Rao P, Mahmoud A, Goldman A, Sabbisetti V, Parcha S, Natarajan SK, Chandrasekar V, Dinulescu D, Roy S, Sengupta S. Algorithm for Designing Nanoscale Supramolecular Therapeutics with Increased Anticancer Efficacy. ACS NANO 2016; 10:8154-68. [PMID: 27452234 DOI: 10.1021/acsnano.6b00241] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
In the chemical world, evolution is mirrored in the origin of nanoscale supramolecular structures from molecular subunits. The complexity of function acquired in a supramolecular system over a molecular subunit can be harnessed in the treatment of cancer. However, the design of supramolecular nanostructures is hindered by a limited atomistic level understanding of interactions between building blocks. Here, we report the development of a computational algorithm, which we term Volvox after the first multicellular organism, that sequentially integrates quantum mechanical energy-state- and force-field-based models with large-scale all-atomistic explicit water molecular dynamics simulations to design stable nanoscale lipidic supramolecular structures. In one example, we demonstrate that Volvox enables the design of a nanoscale taxane supramolecular therapeutic. In another example, we demonstrate that Volvox can be extended to optimizing the ratio of excipients to form a stable nanoscale supramolecular therapeutic. The nanoscale taxane supramolecular therapeutic exerts greater antitumor efficacy than a clinically used taxane in vivo. Volvox can emerge as a powerful tool in the design of nanoscale supramolecular therapeutics for effective treatment of cancer.
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Affiliation(s)
- Ashish Kulkarni
- Department of Medicine, Harvard Medical School , Boston, Massachusetts 02115, United States
- Harvard-MIT Division of Health Sciences and Technology , Cambridge, Massachusetts 02139, United States
| | - Prithvi Pandey
- India Innovation Research Center , Invictus Oncology, New Delhi 110092, India
| | | | | | - Aaron Goldman
- Department of Medicine, Harvard Medical School , Boston, Massachusetts 02115, United States
- Harvard-MIT Division of Health Sciences and Technology , Cambridge, Massachusetts 02139, United States
- Harvard Digestive Diseases Center , Boston, Massachusetts 02115, United States
| | - Venkata Sabbisetti
- Department of Medicine, Harvard Medical School , Boston, Massachusetts 02115, United States
| | | | | | | | | | - Sudip Roy
- India Innovation Research Center , Invictus Oncology, New Delhi 110092, India
| | - Shiladitya Sengupta
- Department of Medicine, Harvard Medical School , Boston, Massachusetts 02115, United States
- Harvard-MIT Division of Health Sciences and Technology , Cambridge, Massachusetts 02139, United States
- Dana Farber Cancer Institute , Boston, Massachusetts 02115, United States
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The temperature-dependent physical state of polar lipids and their miscibility impact the topography and mechanical properties of bilayer models of the milk fat globule membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2181-2190. [DOI: 10.1016/j.bbamem.2016.06.020] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 06/19/2016] [Accepted: 06/22/2016] [Indexed: 11/23/2022]
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Murthy AVR, Guyomarc'h F, Lopez C. Cholesterol Decreases the Size and the Mechanical Resistance to Rupture of Sphingomyelin Rich Domains, in Lipid Bilayers Studied as a Model of the Milk Fat Globule Membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:6757-6765. [PMID: 27300157 DOI: 10.1021/acs.langmuir.6b01040] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Sphingomyelin-rich microdomains have been observed in the biological membrane surrounding milk fat globules (MFGM). The role played by cholesterol in these domains and in the physical properties and functions of the MFGM remains poorly understood. The objective of this work was therefore to investigate the phase state, topography, and mechanical properties of MFGM polar lipid bilayers as a function of cholesterol concentration, by combining X-ray diffraction, atomic force microscopy imaging, and force spectroscopy. At room temperature, i.e. below the phase transition temperature of the MFGM polar lipids, the bilayers showed the formation of sphingomyelin-rich domains in the solid ordered (so) phase that protruded about 1 nm above the liquid disordered (ld) phase. These so phase domains have a higher mechanical resistance to rupture than the ld phase (30 nN versus 15 nN). Addition of cholesterol in the MFGM polar lipid bilayers (i) induced the formation of liquid ordered (lo) phase for up to 27 mol % in the bilayers, (ii) decreased the height difference between the thicker ordered domains and the surrounding ld phase, (iii) promoted the formation of small sized domains, and (iv) decreased the mechanical resistance to rupture of the sphingomyelin-rich domains down to ∼5 nN. The biological and functional relevance of the lo phase cholesterol/sphingomyelin-rich domains in the membrane surrounding fat globules in milk remains to be elucidated. This study brought new insight about the functional role of cholesterol in milk polar lipid ingredients, which can be used in the preparation of food emulsions, e.g. infant milk formulas.
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Lopez C, Cauty C, Guyomarc'h F. Organization of lipids in milks, infant milk formulas and various dairy products: role of technological processes and potential impacts. ACTA ACUST UNITED AC 2015; 95:863-893. [PMID: 26568788 PMCID: PMC4641158 DOI: 10.1007/s13594-015-0263-0] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 10/02/2015] [Accepted: 10/02/2015] [Indexed: 12/02/2022]
Abstract
The microstructure of milk fat in processed dairy products is poorly known despite its importance in their functional, sensorial and nutritional properties. However, for the last 10 years, several research groups including our laboratory have significantly contributed to increasing knowledge on the organization of lipids in situ in dairy products. This paper provides an overview of recent advances on the organization of lipids in the milk fat globule membrane using microscopy techniques (mainly confocal microscopy and atomic force microscopy). Also, this overview brings structural information about the organization of lipids in situ in commercialized milks, infant milk formulas and various dairy products (cream, butter, buttermilk, butter serum and cheeses). The main mechanical treatment used in the dairy industry, homogenization, decreases the size of milk fat globules, changes the architecture (composition and organization) of the fat/water interface and affects the interactions between lipid droplets and the protein network (concept of inert vs active fillers). The potential impacts of the organization of lipids and of the alteration of the milk fat globule membrane are discussed, and technological strategies are proposed, in priority to design biomimetic lipid droplets in infant milk formulas.
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Affiliation(s)
- Christelle Lopez
- INRA, UMR1253 STLO, 65 rue de Saint Brieuc, 35000 Rennes, France ; Agrocampus Ouest, UMR1253 STLO, 65 rue de Saint Brieuc, 35000 Rennes, France
| | - Chantal Cauty
- INRA, UMR1253 STLO, 65 rue de Saint Brieuc, 35000 Rennes, France ; Agrocampus Ouest, UMR1253 STLO, 65 rue de Saint Brieuc, 35000 Rennes, France
| | - Fanny Guyomarc'h
- INRA, UMR1253 STLO, 65 rue de Saint Brieuc, 35000 Rennes, France ; Agrocampus Ouest, UMR1253 STLO, 65 rue de Saint Brieuc, 35000 Rennes, France
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Diamanti E, Cuellar L, Gregurec D, Moya SE, Donath E. Role of Hydrogen Bonding and Polyanion Composition in the Formation of Lipid Bilayers on Top of Polyelectrolyte Multilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:8623-8632. [PMID: 26158307 DOI: 10.1021/acs.langmuir.5b01731] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The self-assembly of mixed vesicles of zwitterionic phosphatidylcholine (PC) and anionic phosphatidylserine (PS) phospholipids on top of polyelectrolyte multilayers (PEMs) of poly(allylamine hydrochloride) (PAH), as a polycation, and polystyrenesulfonate (PSS), as a polyanion, is investigated as a function of the vesicle composition by means of the quartz crystal microbalance with dissipation (QCM-D), cryo-transmission electron microscopy (Cryo-TEM), atomic force microscopy (AFM), and atomic force spectroscopy (AFS). Vesicles with molar percentages of PS between 50% and 70% result in the formation of lipid bilayers on top of the PEMs. Vesicles with over 50% of PC or over 80% of PS do not assembly into bilayers. AFS studies performed with a PAH-modified cantilever approaching and retracting from the lipid assemblies reveal that the main interaction between PAH and the lipids takes place through hydrogen bonding between the amine groups of PAH and the carboxylate and phosphate groups of PS and with the phosphate groups of PC. The interaction of PAH with PS is much stronger than with PC. AFS measurements on assemblies with 50% PC and 50% PS revealed similar adhesion forces to pure PS assemblies, but the PAH chains can reorganize much better on the lipids as a consequence of the presence of PC. QCM-D experiments show that vesicles with a lipid composition of 50% PC and 50% PS do not form bilayers if PSS is replaced by alginate (Alg) or poly(acrylic acid) (PAA).
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Affiliation(s)
- E Diamanti
- †Soft Matter Nanotechnology Group, CIC biomaGUNE, Paseo Marimón 182 C, 20009 San Sebastián, Guipúzcoa, Spain
| | - L Cuellar
- ‡Institute of Biophysics and Medical Physics, Faculty of Medicine, University of Leipzig, 04107 Leipzig, Germany
| | - D Gregurec
- †Soft Matter Nanotechnology Group, CIC biomaGUNE, Paseo Marimón 182 C, 20009 San Sebastián, Guipúzcoa, Spain
| | - S E Moya
- †Soft Matter Nanotechnology Group, CIC biomaGUNE, Paseo Marimón 182 C, 20009 San Sebastián, Guipúzcoa, Spain
| | - E Donath
- ‡Institute of Biophysics and Medical Physics, Faculty of Medicine, University of Leipzig, 04107 Leipzig, Germany
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Diao M, Nguyen TA, Taran E, Mahler SM, Nguyen AV. Effect of energy source, salt concentration and loading force on colloidal interactions between Acidithiobacillus ferrooxidans cells and mineral surfaces. Colloids Surf B Biointerfaces 2015; 132:271-80. [DOI: 10.1016/j.colsurfb.2015.05.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 05/11/2015] [Accepted: 05/14/2015] [Indexed: 11/28/2022]
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35
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Seghezza S, Dante S, Diaspro A, Canale C. High resolution nanomechanical characterization of multi-domain model membranes by fast Force Volume. J Mol Recognit 2015. [DOI: 10.1002/jmr.2490] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Silvia Seghezza
- Fondazione Istituto Italiano di Tecnologia; Nanophysics; Via Morego 30 Genova GE 16163 Italy
| | - Silvia Dante
- Fondazione Istituto Italiano di Tecnologia; Nanophysics; Via Morego 30 Genova GE 16163 Italy
| | - Alberto Diaspro
- Fondazione Istituto Italiano di Tecnologia; Nanophysics; Via Morego 30 Genova GE 16163 Italy
- University of Genova; Department of Physics; Genova GE Italy
| | - Claudio Canale
- Fondazione Istituto Italiano di Tecnologia; Nanophysics; Via Morego 30 Genova GE 16163 Italy
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Alessandrini A, Facci P. Phase transitions in supported lipid bilayers studied by AFM. SOFT MATTER 2014; 10:7145-7164. [PMID: 25090108 DOI: 10.1039/c4sm01104j] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We review the capabilities of Atomic Force Microscopy (AFM) in the study of phase transitions in Supported Lipid Bilayers (SLBs). AFM represents a powerful technique to cover the resolution range not available to fluorescence imaging techniques and where spectroscopic data suggest what the relevant lateral scale for domain formation might be. Phase transitions of lipid bilayers involve the formation of domains characterized by different heights with respect to the surrounding phase and are therefore easily identified by AFM in liquid solution once the bilayer is confined to a flat surface. Even if not endowed with high time resolution, AFM allows light to be shed on some aspects related to lipid phase transitions in the case of both a single lipid component and lipid mixtures containing sterols also. We discuss here the obtained results in light of the peculiarities of supported lipid bilayer model systems.
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Affiliation(s)
- Andrea Alessandrini
- Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Via Campi 213/A, 41125, Modena, Italy.
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37
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Lü J, Yang J, Dong M, Sahin O. Nanomechanical spectroscopy of synthetic and biological membranes. NANOSCALE 2014; 6:7604-8. [PMID: 24895687 DOI: 10.1039/c3nr02643d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We report that atomic force microscopy based high-speed nanomechanical analysis can identify components of complex heterogeneous synthetic and biological membranes from the measured spectrum of nanomechanical properties. We have investigated phase separated ternary lipid bilayers and purple membranes of Halobacterium salinarum. The nanomechanical spectra recorded on these samples identify all membrane components, some of which are difficult to resolve in conventional phase images. This non-destructive approach can aid the design of synthetic lipid bilayers and studies lateral organization of complex heterogeneous cellular membranes.
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Affiliation(s)
- Junhong Lü
- The Rowland Institute at Harvard, Harvard University, Cambridge, MA, USA
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Guyomarc'h F, Zou S, Chen M, Milhiet PE, Godefroy C, Vié V, Lopez C. Milk sphingomyelin domains in biomimetic membranes and the role of cholesterol: morphology and nanomechanical properties investigated using AFM and force spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:6516-6524. [PMID: 24835749 DOI: 10.1021/la501640y] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Milk sphingomyelin (MSM) and cholesterol segregate into domains in the outer bilayer membrane surrounding milk fat globules. To elucidate the morphology and mechanical properties of theses domains, supported lipid bilayers with controlled molar proportions of MSM, dioleoylphosphatidylcholine (DOPC) and cholesterol were produced in buffer mimicking conditions of the milk aqueous phase. Atomic force microscopy imaging showed that (i) for T < 35 °C MSM segregated in gel phase domains protruding above the fluid phase, (ii) the addition of 20 mol % cholesterol resulted in smaller and more elongated l(o) phase domains than in equimolar MSM/DOPC membranes, (iii) the MSM/cholesterol-enriched l(o) phase domains were less salient than the MSM gel phase domains. Force spectroscopy measurements furthermore showed that cholesterol reduced the resistance of MSM/DOPC membrane to perforation. The results are discussed with respect to the effect of cholesterol on the biophysical properties of lipid membranes. The combination of AFM imaging and force mapping provides unprecedented insight into the structural and mechanical properties of milk lipid membranes, and opens perspectives for investigation of the functional properties of MSM domains during milk fat processing or digestion.
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Pfreundschuh M, Martinez-Martin D, Mulvihill E, Wegmann S, Muller DJ. Multiparametric high-resolution imaging of native proteins by force-distance curve–based AFM. Nat Protoc 2014; 9:1113-30. [DOI: 10.1038/nprot.2014.070] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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40
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Lima LMC, Giannotti MI, Redondo-Morata L, Vale MLC, Marques EF, Sanz F. Morphological and nanomechanical behavior of supported lipid bilayers on addition of cationic surfactants. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:9352-61. [PMID: 23782267 DOI: 10.1021/la400067n] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The addition of surfactants to lipid bilayers is important for the modulation of lipid bilayer properties (e.g., in protein reconstitution and development of nonviral gene delivery vehicles) and to provide insight on the properties of natural biomembranes. In this work, the thermal behavior, organization, and nanomechanical stability of model cationic lipid-surfactant bilayers have been investigated. Two different cationic surfactants, hexadecyltrimethylammonium bromide (CTAB) and a novel derivative of the amino acid serine (Ser16TFAc), have been added (up to 50 mol %) to both liposomes and supported lipid bilayers (SLBs) composed by the zwitterionic phospholipid DPPC. The thermal phase behavior of mixed liposomes has been probed by differential scanning calorimetry (DSC), and the morphology and nanomechanical properties of mixed SLBs by atomic force microscopy-based force spectroscopy (AFM-FS). Although DSC thermograms show different results for the two mixed liposomes, when both are deposited on mica substrates similar trends on the morphology and the mechanical response of the lipid-surfactant bilayers are observed. DSC thermograms indicate microdomain formation in both systems, but while CTAB decreases the degree of organization on the liposome bilayer, Ser16TFAc ultimately induces the opposite effect. Regarding the AFM-FS studies, they show that microphase segregation occurs for these systems and that the effect is dependent on the surfactant content. In both SLB systems, different microdomains characterized by their height and breakthrough force Fb are formed. The molecular organization and composition is critically discussed in the light of our experimental results and literature data on similar lipid-surfactant systems.
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Affiliation(s)
- Lia M C Lima
- Centro de Investigação em Química, Department of Chemistry and Biochemistry, University of Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
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Üzüm C, Hellwig J, Madaboosi N, Volodkin D, von Klitzing R. Growth behaviour and mechanical properties of PLL/HA multilayer films studied by AFM. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2012; 3:778-88. [PMID: 23213641 PMCID: PMC3512127 DOI: 10.3762/bjnano.3.87] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 10/21/2012] [Indexed: 05/19/2023]
Abstract
Scanning- and colloidal-probe atomic force microscopy were used to study the mechanical properties of poly(L-lysine)/hyaluronan (PLL/HA)(n) films as a function of indentation velocity and the number of polymer deposition steps n. The film thickness was determined by two independent AFM-based methods: scratch-and-scan and newly developed full-indentation. The advantages and disadvantages of both methods are highlighted, and error minimization techniques in elasticity measurements are addressed. It was found that the film thickness increases linearly with the bilayer number n, ranging between 400 and 7500 nm for n = 12 and 96, respectively. The apparent Young's modulus E ranges between 15 and 40 kPa and does not depend on the indenter size or the film bilayer number n. Stress relaxation measurements show that PLL/HA films have a viscoelastic behaviour, regardless of their thickness. If indentation is performed several times at the same lateral position on the film, a viscous/plastic deformation takes place.
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Affiliation(s)
- Cagri Üzüm
- Stranski-Laboratorium, Department of Chemistry, TU Berlin, Strasse des 17. Juni 124, D-10623 Berlin, Germany
| | - Johannes Hellwig
- Stranski-Laboratorium, Department of Chemistry, TU Berlin, Strasse des 17. Juni 124, D-10623 Berlin, Germany
| | - Narayanan Madaboosi
- Fraunhofer Institute for Biomedical Engineering, Am Mühlenberg 13, 14476 Potsdam-Golm, Germany
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Dmitry Volodkin
- Stranski-Laboratorium, Department of Chemistry, TU Berlin, Strasse des 17. Juni 124, D-10623 Berlin, Germany
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Regine von Klitzing
- Stranski-Laboratorium, Department of Chemistry, TU Berlin, Strasse des 17. Juni 124, D-10623 Berlin, Germany
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Abstract
Lipid bilayers are natural barriers of biological cells and cellular compartments. Membrane proteins integrated in biological membranes enable vital cell functions such as signal transduction and the transport of ions or small molecules. In order to determine the activity of a protein of interest at defined conditions, the membrane protein has to be integrated into artificial lipid bilayers immobilized on a surface. For the fabrication of such biosensors expertise is required in material science, surface and analytical chemistry, molecular biology and biotechnology. Specifically, techniques are needed for structuring surfaces in the micro- and nanometer scale, chemical modification and analysis, lipid bilayer formation, protein expression, purification and solubilization, and most importantly, protein integration into engineered lipid bilayers. Electrochemical and optical methods are suitable to detect membrane activity-related signals. The importance of structural knowledge to understand membrane protein function is obvious. Presently only a few structures of membrane proteins are solved at atomic resolution. Functional assays together with known structures of individual membrane proteins will contribute to a better understanding of vital biological processes occurring at biological membranes. Such assays will be utilized in the discovery of drugs, since membrane proteins are major drug targets.
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Shamitko-Klingensmith N, Molchanoff KM, Burke KA, Magnone GJ, Legleiter J. Mapping the mechanical properties of cholesterol-containing supported lipid bilayers with nanoscale spatial resolution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:13411-13422. [PMID: 22924735 DOI: 10.1021/la302705f] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
It has been demonstrated that many biological processes are influenced by mechanical changes in membranes comprised of a variety of lipid components. As a result, the ability to map physicomechanical properties of surfaces with high temporal and spatial resolution is desirable. Tapping mode atomic force microscopy (AFM) has proven to be a useful technique for imaging biological surfaces due to its ability to operate in solution; however, access to information concerning the mechanical properties of these surfaces can also be obtained by reconstructing the time-resolved tip/sample force interactions during the imaging process. An advantage of such an approach is the direct correlation of topographical features with mechanical properties. Reconstruction of the tip/sample force is achievable by a technique called scanning probe acceleration microscopy (SPAM), which treats the cantilever as an accelerometer. The acceleration, which is directly related to the tip/sample force, of the cantilever is obtained by taking the second derivative of the cantilever deflection signal during a tapping mode AFM experiment in solution with standard cantilevers. Herein, we describe the applicability of SPAM to study mechanical properties of supported lipid bilayers with nanoscale spatial resolution via numerical simulations and experiment. The maximum and minimum tapping forces respond to changes in specific surface mechanical properties. Furthermore, we demonstrate how these changes can be used to map relative changes in the Young's modulus and adhesive properties of supported total brain lipid extract bilayers containing exogenous cholesterol. Finally, the ability of SPAM to distinguish nanoscale lipid raft domains based on changes in local mechanical properties is demonstrated.
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Redondo-Morata L, Giannotti MI, Sanz F. Influence of cholesterol on the phase transition of lipid bilayers: a temperature-controlled force spectroscopy study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:12851-12860. [PMID: 22873775 DOI: 10.1021/la302620t] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Cholesterol (Chol) plays the essential function of regulating the physical properties of the cell membrane by controlling the lipid organization and phase behavior and, thus, managing the membrane fluidity and its mechanical strength. Here, we explore the model system DPPC:Chol by means of temperature-controlled atomic force microscopy (AFM) imaging and AFM-based force spectroscopy (AFM-FS) to assess the influence of Chol on the membrane ordering and stability. We analyze the system in a representative range of compositions up to 50 mol % Chol studying the phase evolution upon temperature increase (from room temperature to temperatures high above the T(m) of the DPPC bilayer) and the corresponding (nano)mechanical stability. By this means, we correlate the mechanical behavior and composition with the lateral order of each phase present in the bilayers. We prove that low Chol contents lead to a phase-segregated system, whereas high contents of Chol can give a homogeneous bilayer. In both cases, Chol enhances the mechanical stability of the membrane, and an extraordinarily stable system is observed for equimolar fractions (50 mol % Chol). In addition, even when no thermal transition is detected by the traditional bulk analysis techniques for liposomes with high Chol content (40 and 50 mol %), we demonstrate that temperature-controlled AFM-FS is capable of identifying a thermal transition for the supported lipid bilayers. Finally, our results validate the AFM-FS technique as an ideal platform to differentiate phase coexistence and transitions in lipid bilayers and bridge the gap between the results obtained by traditional methods for bulk analysis, the theoretical predictions, and the behavior of these systems at the nanoscale.
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Affiliation(s)
- Lorena Redondo-Morata
- Institute for Bioengineering of Catalonia (IBEC), Baldiri i Reixac 15-21, 08028, Barcelona, Spain
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Zhong J, He D. Recent Progress in the Application of Atomic Force Microscopy for Supported Lipid Bilayers. Chemistry 2012; 18:4148-55. [DOI: 10.1002/chem.201102831] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Strulson MK, Maurer JA. Microcontact printing for creation of patterned lipid bilayers on tetraethylene glycol self-assembled monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:12052-12057. [PMID: 21866896 PMCID: PMC3188422 DOI: 10.1021/la201839w] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Supported lipid bilayers (SLBs) formed on many different substrates have been widely used in the study of lipid bilayers. However, most SLBs suffer from inhomogeneities due to interactions between the lipid bilayer and the substrate. In order to avoid this problem, we have used microcontact printing to create patterned SLBs on top of ethylene-glycol-terminated self-assembled monolayers (SAMs). Glycol-terminated SAMs have previously been shown to resist absorbance of biomolecules including lipid vesicles. In our system, patterned lipid bilayer regions are separated by lipid monolayers, which form over the patterned hexadecanethiol portions of the surface. Furthermore, we demonstrate that α-hemolysin, a large transmembrane protein, inserts preferentially into the lipid bilayer regions of the substrate.
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