1
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Nepal B, Stine KJ. Atomic force microscopy study of the complexation of sterols and the glycoalkaloid α-tomatine in Langmuir-Blodgett monolayers. Chem Phys Lipids 2023; 252:105293. [PMID: 36931584 DOI: 10.1016/j.chemphyslip.2023.105293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 03/04/2023] [Accepted: 03/14/2023] [Indexed: 03/17/2023]
Abstract
Glycoalkaloids are secondary metabolites produced by plants that aid in their protection from pathogens and pests. They are known to form 1:1 complexes with 3β-hydroxysterols such as cholesterol causing membrane disruption. So far, the visual evidence showcasing the complexes formed between glycoalkaloids and sterols in monolayers has been mainly restricted to some earlier studies using Brewster angle microscopy which were of low resolution showing the formation of floating aggregates of these complexes. This study is aimed at using atomic force microscopy (AFM) for topographic and morphological analysis of the aggregates of these sterol-glycoalkaloid complexes. Langmuir-Blodgett (LB) transfer of mixed monolayers of the glycoalkaloid α-tomatine, sterols, and lipids in varying molar ratios onto mica followed by AFM examination was performed. The AFM method allowed visualization of the aggregation of sterol-glycoalkaloid complexes at nanometer resolution. While aggregation was observed in mixed monolayers of α-tomatine with cholesterol and in mixed monolayers with coprostanol, no sign of complexation was observed for the mixed monolayers of epicholesterol and α-tomatine, confirming their lack of interaction found in prior monolayer studies. Aggregates were observed in transferred monolayers of ternary mixtures of α-tomatine with cholesterol and the phospholipids 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) or egg sphingomyelin (egg SM). The formation of aggregates was found to be less prevalent for mixed monolayers of DMPC and cholesterol containing α-tomatine than it was for mixed monolayers containing egg SM and cholesterol with α-tomatine. The observed aggregates were generally elongated structures, of a width ranging from about 40-70 nm.
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Affiliation(s)
- Bishal Nepal
- Department of Chemistry and Biochemistry, University of Missouri-Saint Louis, Saint Louis, MO 63121, USA
| | - Keith J Stine
- Department of Chemistry and Biochemistry, University of Missouri-Saint Louis, Saint Louis, MO 63121, USA.
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2
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Dotor L, García-Pinilla JM, Martín S, Cea P. Langmuir and Langmuir-Blodgett technologies as nanoarchitectonic tools for the incorporation of curcumin in membrane systems. NANOSCALE 2023; 15:2891-2903. [PMID: 36691853 DOI: 10.1039/d2nr06631a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Curcumin (CCM) is a molecule of particular interest in health applications due to its wide spectrum of benefits for humans. However, its water-insoluble character and low bioavailability have so far prevented its extended use as a therapeutic agent. Incorporation of CCM in drug delivery vehicles (liposomes, vesicles, exosomes, etc.) is expected to contribute to increasing its bioavailability. Studies of the affinity of CCM with the components of the membrane systems of such vehicles and determination of factors that may enhance curcumin entrapment in biological membranes are of fundamental importance. To that end, here we take advantage of the nanoarchitectonic capabilities of the Langmuir technique for the construction of model cell membranes and determination of thermodynamic properties in mixed films. The obtained results may serve to: (i) provide some light on the miscibility of CCM with the components in the cell membrane and (ii) determine the optimal conditions for the fabrication of membrane systems incorporating CCM. For that, binary and ternary mixed Langmuir films of CCM, DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) and CHOL (cholesterol) have been prepared. Whilst binary mixtures of DPPC and CCM exhibit poor miscibility and even phase segregation, CHOL has shown itself as a key element to promote the incorporation of CCM in the phospholipidic membrane containing DPPC. Both the thermodynamic studies of the ternary Langmuir films and the Atomic Force Microscopy (AFM) images of Langmuir-Blodgett films have shown that ternary mixed films with a molar fraction composition of xDPPC/xCHOL/xCCM = 0.4/0.4/0.2 exhibit good miscibility, stability, and result in monolayers with a very homogeneous topography.
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Affiliation(s)
- Laura Dotor
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain.
- Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, 50018, Zaragoza, Spain
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - José Miguel García-Pinilla
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain.
- Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, 50018, Zaragoza, Spain
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Santiago Martín
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain.
- Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, 50018, Zaragoza, Spain
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Pilar Cea
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain.
- Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, 50018, Zaragoza, Spain
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza, Spain
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3
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Oliveira ON, Caseli L, Ariga K. The Past and the Future of Langmuir and Langmuir-Blodgett Films. Chem Rev 2022; 122:6459-6513. [PMID: 35113523 DOI: 10.1021/acs.chemrev.1c00754] [Citation(s) in RCA: 122] [Impact Index Per Article: 61.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The Langmuir-Blodgett (LB) technique, through which monolayers are transferred from the air/water interface onto a solid substrate, was the first method to allow for the controlled assembly of organic molecules. With its almost 100 year history, it has been the inspiration for most methods to functionalize surfaces and produce nanocoatings, in addition to serving to explore concepts in molecular electronics and nanoarchitectonics. This paper provides an overview of the history of Langmuir monolayers and LB films, including the potential use in devices and a discussion on why LB films are seldom considered for practical applications today. Emphasis is then given to two areas where these films offer unique opportunities, namely, in mimicking cell membrane models and exploiting nanoarchitectonics concepts to produce sensors, investigate molecular recognitions, and assemble molecular machines. The most promising topics for the short- and long-term prospects of the LB technique are also highlighted.
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Affiliation(s)
- Osvaldo N Oliveira
- São Carlos Institute of Physics, University of Sao Paulo, CP 369, 13560-970 Sao Carlos, SP, Brazil
| | - Luciano Caseli
- Department of Chemistry, Federal University of São Paulo, 09913-030 Diadema, SP, Brazil
| | - Katsuhiko Ariga
- World Premier International (WPI) Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 305-0044 Tsukuba, Japan.,Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-0827, Japan
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4
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Jurak M, Szafran K, Cea P, Martín S. Analysis of Molecular Interactions between Components in Phospholipid-Immunosuppressant-Antioxidant Mixed Langmuir Films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:5601-5616. [PMID: 33915045 PMCID: PMC8280729 DOI: 10.1021/acs.langmuir.1c00434] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The study of Langmuir monolayers incorporating biomimetic and bioactive substances plays an important role today in assessing the properties and quality of the molecular films for potential biomedical applications. Here, miscibility of binary and ternary monolayers of phospholipid (dioleoyl phosphatidylcholine, DOPC), immunosuppressant (cyclosporine A, CsA), and antioxidant (lauryl gallate, LG) of varying molar fractions was analyzed by means of the Langmuir technique coupled with a surface potential (ΔV) module at the air-water interface. The surface pressure-area per molecule (π-A) isotherms provided information on the physical state of the films at a given surface pressure, the monolayer packing and ordering, and the type and strength of intermolecular interactions. Surface potential-area (ΔV-A) isotherms revealed the molecular orientation changes at the interface upon compression. In addition, the apparent dipole moment of the monolayer-forming molecules was determined from the surface potential isotherms. The obtained results indicated that the film compression provoked subsequent changes of CsA conformation and/or orientation, conferring better affinity for the hydrocarbon environment. The mutual interactions between the components were analyzed here in terms of the excess and total Gibbs energy of mixing, whose values depended on the stoichiometry of the mixed films. The strongest attraction, thus the highest thermodynamic stability, was found for a DOPC-CsA-LG mixture with a 1:1:2 molar ratio. Based on these results, a molecular model for the organization of the molecules within the Langmuir film was proposed. Through this model, we elucidated the significant role of LG in improving the miscibility of CsA in the model DOPC membrane and thus in increasing the stability of self-assembled monolayers by noncovalent interactions, such as H-bonds and Lifshitz-van der Waals forces. The above 1:1:2 combination of three components is revealed as the most promising film composition for the modification of implant device surfaces to improve their biocompatibility. Further insight into mechanisms concerning drug-membrane interactions at the molecular level is provided, which results in great importance for biocoating design and development as well as for drug release at target sites.
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Affiliation(s)
- Małgorzata Jurak
- Department
of Interfacial Phenomena, Institute of Chemical Sciences, Faculty
of Chemistry, Maria Curie-Skłodowska
University, 20031 Lublin, Poland
- . Phone: +48815375547. Fax: +48815375656
| | - Klaudia Szafran
- Department
of Interfacial Phenomena, Institute of Chemical Sciences, Faculty
of Chemistry, Maria Curie-Skłodowska
University, 20031 Lublin, Poland
| | - Pilar Cea
- Instituto
de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
- Departamento
de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Santiago Martín
- Instituto
de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
- Departamento
de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza, Spain
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5
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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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6
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Ruiz-Rincón S, González-Orive A, Grazú V, Fratila RM, Fuente JMDL, Cea P. Altering model cell membranes by means of localized magnetic heating. Colloids Surf B Biointerfaces 2020; 196:111315. [PMID: 32818926 DOI: 10.1016/j.colsurfb.2020.111315] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 08/04/2020] [Accepted: 08/07/2020] [Indexed: 10/23/2022]
Abstract
Isolated iron oxide magnetic nanoparticles (MNPs), 12 nm in diameter, coated with oleic acid molecules as capping agents have been deposited by the Langmuir-Blodgett (LB) method onto a model cell membrane incorporating 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and Cholesterol (Chol) in the 1:1 ratio, which was also fabricated by the LB technique. Atomic Force Microscopy (AFM) experiments showed that the application of an alternating magnetic field results in the embedding of the MNPs through the phospholipidic layer. These experimental results reveal that the heating of individual MNPs may induce a local increase in the fluidity of the film with a large control of the spatial and temporal specificity.
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Affiliation(s)
- Silvia Ruiz-Rincón
- Instituto de Nanociencia de Aragón (INA), Campus Rio Ebro, Universidad de Zaragoza, C/Mariano Esquillor, s/n, 50018 Zaragoza, Spain; Laboratorio de Microscopias Avanzadas (LMA),Campus Río Ebro, Universidad de Zaragoza, C/Mariano Esquillor, s/n, 50018 Zaragoza, Spain; Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, C/Pedro Cerbuna 12, 50009 Zaragoza, Spain
| | - Alejandro González-Orive
- Technical and Macromolecular Chemistry, University of Paderborn, Warburger Strasse 100, 33098 Paderborn, Germany
| | - Valeria Grazú
- Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, C/Pedro Cerbuna 12, 50009 Zaragoza, Spain; Networking Biomedical Research Centre of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Spain
| | - Raluca M Fratila
- Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, C/Pedro Cerbuna 12, 50009 Zaragoza, Spain; Networking Biomedical Research Centre of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Spain
| | - Jesús M de la Fuente
- Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, C/Pedro Cerbuna 12, 50009 Zaragoza, Spain; Networking Biomedical Research Centre of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Spain
| | - Pilar Cea
- Instituto de Nanociencia de Aragón (INA), Campus Rio Ebro, Universidad de Zaragoza, C/Mariano Esquillor, s/n, 50018 Zaragoza, Spain; Laboratorio de Microscopias Avanzadas (LMA),Campus Río Ebro, Universidad de Zaragoza, C/Mariano Esquillor, s/n, 50018 Zaragoza, Spain; Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, C/Pedro Cerbuna 12, 50009 Zaragoza, Spain; Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009, Zaragoza, Spain.
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7
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Ruiz-Rincón S, González-Orive A, de la Fuente JM, Cea P. Reversible Monolayer-Bilayer Transition in Supported Phospholipid LB Films under the Presence of Water: Morphological and Nanomechanical Behavior. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:7538-7547. [PMID: 28691823 DOI: 10.1021/acs.langmuir.7b01268] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Mixed monolayer Langmuir-Blodgett (LB) films of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and cholesterol (Chol) in the 1:1 ratio have been prepared onto solid mica substrates. Upon immersion in water or in an aqueous HEPES solution (pH 7.4) the monolayer LB films were spontaneously converted into well-organized bilayers leaving free mica areas. The process has been demonstrated to be reversible upon removal of the aqueous solution, resulting in remarkably free of defects monolayers that are homogeneously distributed onto the mica. In addition, the nanomechanical properties exhibited by the as-formed bilayers have been determined by means of AFM breakthrough force studies. The bilayers formed by immersion of the monolayer in an aqueous media exhibit nanomechanical properties and stability under compression analogous to those of DPPC:Chol supported bilayers obtained by other methods previously described in the literature. Consequently, the hydration of a monolayer LB film has been revealed as an easy method to produce well-ordered bilayers that mimic the cell membrane and that could be used as model cell membranes.
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Affiliation(s)
| | | | - Jesús M de la Fuente
- Instituto de Ciencia de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC , 50009 Zaragoza, Spain
- Networking Biomedical Research Center of Bioengineering, Biomaterials, and Nanomedicine (CIBER-BBN), Zaragoza, Spain
| | - Pilar Cea
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza , 50009, Zaragoza, Spain
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8
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Jayamurugan G, Gowri V, Hernández D, Martin S, González-Orive A, Dengiz C, Dumele O, Pérez-Murano F, Gisselbrecht JP, Boudon C, Schweizer WB, Breiten B, Finke AD, Jeschke G, Bernet B, Ruhlmann L, Cea P, Diederich F. Design and Synthesis of Aviram-Ratner-Type Dyads and Rectification Studies in Langmuir-Blodgett (LB) Films. Chemistry 2016; 22:10539-47. [DOI: 10.1002/chem.201505216] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 04/30/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Govindasamy Jayamurugan
- Laboratorium für Organische Chemie; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland), Fax: (+41) 44-632-1109
- Institute of Nano Science and Technology, Habitat Centre, Sector-64, Phase-X; Mohali India
| | - Vijayendran Gowri
- Laboratorium für Organische Chemie; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland), Fax: (+41) 44-632-1109
| | - David Hernández
- Departamento de Química Física; Facultad de Ciencias; Universidad de Zaragoza; 50009 Zaragoza Spain), Fax: (+34) 976-761-202
| | - Santiago Martin
- Departamento de Química Física; Facultad de Ciencias; Universidad de Zaragoza; 50009 Zaragoza Spain), Fax: (+34) 976-761-202
- Instituto de Ciencia de Materiales de Aragón (ICMA); Universidad de Zaragoza-CSIC; 50009 Zaragoza Spain
| | - Alejandro González-Orive
- Instituto de Nanociencia de Aragón (INA) and Laboratorio de Microscopias Avanzadas (LMA), Edificio i+d. Campus Rio Ebro; Universidad de Zaragoza, C/Mariano Esquillor, s/n; 50017 Zaragoza Spain
| | - Cagatay Dengiz
- Laboratorium für Organische Chemie; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland), Fax: (+41) 44-632-1109
| | - Oliver Dumele
- Laboratorium für Organische Chemie; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland), Fax: (+41) 44-632-1109
| | - Francesc Pérez-Murano
- Instituto de Microelectrónica de Barcelona (IMB-CNM, CSIC), Campus UAB; 08193 Bellaterra Spain
| | - Jean-Paul Gisselbrecht
- Laboratoire d'Electrochimie et de Chimie Physique du Corps Solide; Institut de Chimie-UMR 7177, C.N.R.S.; Université de Strasbourg; 4 rue Blaise Pascal, CS 90032 67081 Strasbourg Cedex France
| | - Corinne Boudon
- Laboratoire d'Electrochimie et de Chimie Physique du Corps Solide; Institut de Chimie-UMR 7177, C.N.R.S.; Université de Strasbourg; 4 rue Blaise Pascal, CS 90032 67081 Strasbourg Cedex France
| | - W. Bernd Schweizer
- Laboratorium für Organische Chemie; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland), Fax: (+41) 44-632-1109
| | - Benjamin Breiten
- Laboratorium für Organische Chemie; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland), Fax: (+41) 44-632-1109
| | - Aaron D. Finke
- Laboratorium für Organische Chemie; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland), Fax: (+41) 44-632-1109
| | - Gunnar Jeschke
- Laboratory of Physical Chemistry; ETH Zurich; Vladimir-Prelog-Weg 2 8093 Zurich Switzerland
| | - Bruno Bernet
- Laboratorium für Organische Chemie; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland), Fax: (+41) 44-632-1109
| | - Laurent Ruhlmann
- Laboratoire d'Electrochimie et de Chimie Physique du Corps Solide; Institut de Chimie-UMR 7177, C.N.R.S.; Université de Strasbourg; 4 rue Blaise Pascal, CS 90032 67081 Strasbourg Cedex France
| | - Pilar Cea
- Departamento de Química Física; Facultad de Ciencias; Universidad de Zaragoza; 50009 Zaragoza Spain), Fax: (+34) 976-761-202
- Instituto de Nanociencia de Aragón (INA) and Laboratorio de Microscopias Avanzadas (LMA), Edificio i+d. Campus Rio Ebro; Universidad de Zaragoza, C/Mariano Esquillor, s/n; 50017 Zaragoza Spain
| | - François Diederich
- Laboratorium für Organische Chemie; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland), Fax: (+41) 44-632-1109
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9
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Solís-Calero C, Ortega-Castro J, Frau J, Muñoz F. Nonenzymatic Reactions above Phospholipid Surfaces of Biological Membranes: Reactivity of Phospholipids and Their Oxidation Derivatives. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:319505. [PMID: 25977746 PMCID: PMC4419266 DOI: 10.1155/2015/319505] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 03/24/2015] [Accepted: 03/25/2015] [Indexed: 01/03/2023]
Abstract
Phospholipids play multiple and essential roles in cells, as components of biological membranes. Although phospholipid bilayers provide the supporting matrix and surface for many enzymatic reactions, their inherent reactivity and possible catalytic role have not been highlighted. As other biomolecules, phospholipids are frequent targets of nonenzymatic modifications by reactive substances including oxidants and glycating agents which conduct to the formation of advanced lipoxidation end products (ALEs) and advanced glycation end products (AGEs). There are some theoretical studies about the mechanisms of reactions related to these processes on phosphatidylethanolamine surfaces, which hypothesize that cell membrane phospholipids surface environment could enhance some reactions through a catalyst effect. On the other hand, the phospholipid bilayers are susceptible to oxidative damage by oxidant agents as reactive oxygen species (ROS). Molecular dynamics simulations performed on phospholipid bilayers models, which include modified phospholipids by these reactions and subsequent reactions that conduct to formation of ALEs and AGEs, have revealed changes in the molecular interactions and biophysical properties of these bilayers as consequence of these reactions. Then, more studies are desirable which could correlate the biophysics of modified phospholipids with metabolism in processes such as aging and diseases such as diabetes, atherosclerosis, and Alzheimer's disease.
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Affiliation(s)
- Christian Solís-Calero
- Institut d'Investigació en Ciències de la Salut (IUNICS), Departament de Química, Universitat de les Illes Balears, 07122 Palma de Mallorca, Spain
- Instituto de Investigación Sanitaria de Palma, 07010 Palma, Spain
| | - Joaquín Ortega-Castro
- Institut d'Investigació en Ciències de la Salut (IUNICS), Departament de Química, Universitat de les Illes Balears, 07122 Palma de Mallorca, Spain
- Instituto de Investigación Sanitaria de Palma, 07010 Palma, Spain
| | - Juan Frau
- Institut d'Investigació en Ciències de la Salut (IUNICS), Departament de Química, Universitat de les Illes Balears, 07122 Palma de Mallorca, Spain
- Instituto de Investigación Sanitaria de Palma, 07010 Palma, Spain
| | - Francisco Muñoz
- Institut d'Investigació en Ciències de la Salut (IUNICS), Departament de Química, Universitat de les Illes Balears, 07122 Palma de Mallorca, Spain
- Instituto de Investigación Sanitaria de Palma, 07010 Palma, Spain
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10
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Mao G, VanWyck D, Xiao X, Mack Correa MC, Gunn E, Flach CR, Mendelsohn R, Walters RM. Oleic acid disorders stratum corneum lipids in Langmuir monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:4857-4865. [PMID: 23517601 DOI: 10.1021/la4002384] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Oleic acid (OA) is well-known to affect the function of the skin barrier. In this study, the molecular interactions between OA and model stratum corneum (SC) lipids consisting of ceramide, cholesterol, and palmitic acid (PA) were investigated with Langmuir monolayer and associated techniques. Mixtures with different OA/SC lipid compositions were spread at the air/water interface, and the phase behavior was tracked with surface pressure-molecular area (π-A) isotherms. With increasing OA levels in the monolayer, the films became more fluid and more compressible. The thermodynamic parameters derived from π-A isotherms indicated that there are preferential interactions between OA and SC lipids and that films of their mixtures were thermodynamically stable. The domain structure and lipid conformational order of the monolayers were studied through Brewster angle microscopy (BAM) and infrared reflection absorption spectroscopy (IRRAS), respectively. Results indicate that lower concentrations of OA preferentially mix with and disorder the ceramide-enriched domains, followed by perturbation of the PA-enriched domains and disruption of SC lipid domain separation at higher OA levels.
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Affiliation(s)
- Guangru Mao
- Johnson and Johnson Consumer Companies, Incorporated , 199 Grandview Road, Skillman, New Jersey 08558, United States.
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11
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Li R, Hu P, Ren X, Worley S, Huang T. Antimicrobial N-halamine modified chitosan films. Carbohydr Polym 2013; 92:534-9. [DOI: 10.1016/j.carbpol.2012.08.115] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2012] [Revised: 08/30/2012] [Accepted: 08/31/2012] [Indexed: 10/27/2022]
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12
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Torrent-Burgués J. Phase separation in mixed monolayers of arachidic acid and a phthalocyanine of zinc. Colloids Surf A Physicochem Eng Asp 2012. [DOI: 10.1016/j.colsurfa.2011.12.057] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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13
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Scheibe P, Schoenhentz J, Platen T, Hoffmann-Röder A, Zentel R. Langmuir-Blodgett films of fluorinated glycolipids and polymerizable lipids and their phase separating behavior. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:18246-18255. [PMID: 21058675 DOI: 10.1021/la1029917] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This paper describes the phase separating behavior of Langmuir monolayers from mixtures of different lipids that (i) either carry already a glycopeptide recognition site or can be easily modified to carry one and (ii) polymerizable lipids. To ensure demixing during compression, we used fluorinated lipids for the biological headgroups and hydrocarbon based lipids as polymerizable lipids. As a representative for a lipid monomer, which can be polymerized in the hydrophilic headgroup, a methacrylic monomer was used. As a monomer, which can be polymerized in the hydrophobic tail, a lipid with a diacetylene unit was used (pentacosadiynoic acid, PDA). The fluorinated lipids were on the one hand a perfluorinated lipid with three chains and on the other hand a partially fluorinated lipid with a T(N)-antigen headgroup. The macroscopic phase separation was observed by Brewster angle microscopy, whereas the phase separation on the nanoscale level was observed by atomic force microscopy. It turned out that all lipid mixtures showed (at least) a partial miscibility of the hydrocarbon compounds in the fluorinated compounds. This is positive for pattern formation, as it allows the formation of small demixed 2D patterned structures during crystallization from the homogeneous phase. For miscibility especially a liquid analogue phase proved to be advantageous. As lipid 3 with three fluorinated lipid chains (very stable monolayer) is miscible with the polymerizable lipids 1 and 2, it was mostly used for further investigations. For all three lipid mixtures, a phase separation on both the micrometer and the nanometer level was observed. The size of the crystalline domains could be controlled not only by varying the surface pressure but also by varying the molar composition of the mixtures. Furthermore, we showed that the binary mixture can be stabilized via UV polymerization. After polymerization and subsequent expansion of the barriers, the locked-in polymerized structures are stable even at low surface pressures (10 mN/m), where the unpolymerized mixture did not show any segregation.
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Affiliation(s)
- Patrick Scheibe
- Institute of Organic Chemistry, Johannes Gutenberg-University Mainz, Duesbergweg 10-14, 55099 Mainz, Germany
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14
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Pera G, Martín S, Ballesteros LM, Hope AJ, Low PJ, Nichols RJ, Cea P. Metal-Molecule-Metal Junctions in Langmuir-Blodgett Films Using a New Linker: Trimethylsilane. Chemistry 2010; 16:13398-405. [DOI: 10.1002/chem.201001181] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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15
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Preparation and characterization of Langmuir and Langmuir–Blodgett films from a pyridine-terminated stilbene. Colloids Surf A Physicochem Eng Asp 2010. [DOI: 10.1016/j.colsurfa.2010.06.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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16
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Li R, Chen Q, Liu H, Hu Y. Influence of spacer of gemini on the interactions between cationic gemini surfactant and stearic acid in mixed monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:9342-9350. [PMID: 20394381 DOI: 10.1021/la1003287] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Mixed Langmuir-Blodgett (LB) films composed of a cationic gemini surfactant, [C(18)H(37)(CH(3))(2)N(+)-(CH(2))(s)-N(+)(CH(3))(2)C(18)H(37)],2Br(-) (18-s-18 with s = 3, 6, 8, 10 and 12), and a fatty acid of stearic acid (SA) were studied by the pi-A isotherm measurement, as well as by AFM and FT-IR. The analysis of the mean molecular area, the excess area and the excess Gibbs free energy from pi-A isotherms suggests the existence of attractive interactions between 18-s-18 and SA molecules in the mixed monolayers. The spacer group of 18-s-18 plays a very important role in the surface properties of 18-s-18/SA mixed monolayers. When s < or = 8, 18-s-18 and SA are completely miscible, while partially miscible mixed monolayers are presented when s > 8. Especially, in the latter case, when s = 12, phase separation appears in two composition regions of X(SA) = 0.4-0.75 and X(SA) = 0.75-0.85, respectively. This miscible phenomenon is confirmed by AFM observation. The result of FT-IR indicates that when X(SA) < or = 0.67, SA could ionize completely and form a "cationic-anionic surfactant" with 18-s-18 owing to the electrostatic interaction between the head groups, while when X(SA) > 0.67, SA only partially ionizes, -COO(-) and -COOH coexist in mixed monolayers.
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Affiliation(s)
- Rong Li
- Laboratory for Advanced Materials and Department of Chemistry, East China University of Science and Technology, Shanghai 200237, China
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17
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Villares A, Pera G, Lydon DP, López MC, Low PJ, Cea P. Mixing behaviour of a conjugated molecular wire candidate and an insulating fatty acid within Langmuir–Blodgett films. Colloids Surf A Physicochem Eng Asp 2009. [DOI: 10.1016/j.colsurfa.2009.06.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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18
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Fernández-Botello A, Comelles F, Alsina MA, Cea P, Reig F. A monolayer study on interactions of docetaxel with model lipid membranes. J Phys Chem B 2008; 112:13834-41. [PMID: 18844394 DOI: 10.1021/jp806423k] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Docetaxel (DCT) is an antineoplastic drug for the treatment of a wide spectrum of cancers. DCT surface properties as well as miscibility studies with l-alpha-dipalmitoyl phosphatidylcholine (DPPC), which constitutes the main component of biological membranes, are comprehensively described in this contribution. Penetration studies have revealed that when DCT is injected under DPPC monolayers compressed to different surface pressures, it penetrates into the lipid monolayer promoting an increase in the surface pressure. DCT is a surface active molecule able to decrease the surface tension of water and to form insoluble films when spread on aqueous subphases. The maximum surface pressure reached after compression of a DCT Langmuir film was 13 mN/m. Miscibility of DPPC and DCT in Langmuir films has been studied by means of thermodynamic properties as well as by Brewster angle microscopy (BAM) analysis of the mixed films at the air-water interface, concluding that DPPC and DCT are miscible and they form non-ideally mixed monolayers at the air-water interface. Helmholtz energies of mixing revealed that no phase separation occurs. In addition, Helmholtz energies of mixing become more negative with decreasing areas per molecule, which suggests that the stability of the mixed monolayers increases as the monolayers become more condensed. Compressibility values together with BAM images indicate that DCT has a fluidizing effect on DPPC monolayers.
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Affiliation(s)
- Alfonso Fernández-Botello
- Peptides Department and Surfactant Department, Institute for Chemical and Environmental Research (IIQAB-CSIC), Jordi Girona 18-26, 08034 Barcelona, Spain.
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19
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Mazaleyrat JP, Wright K. Binaphthyl substituted 1,8-bis(dimethylamino)naphthalenes, the first chiral, atropisomeric, proton sponges. Tetrahedron Lett 2008. [DOI: 10.1016/j.tetlet.2008.05.042] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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20
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Villares A, Martín S, Giner I, Díaz J, Lydon DP, Low PJ, Cea P. The use of scanning polarization force microscopy to study the miscibility of a molecular wire candidate and an insulating fatty acid in mixed films. SOFT MATTER 2008; 4:1508-1514. [PMID: 32907118 DOI: 10.1039/b716798a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Mixed films containing a conjugated "molecular wire" candidate and an "insulating" fatty acid have been prepared by the Langmuir-Blodgett technique. Specifically, this paper reports the fabrication of mixed films as well as miscibility studies of 4-[4-(4-hexyloxyphenylethynyl)phenylethynyl]benzoic acid (HBPEB) and docosanoic (or behenic) acid (BA). Surface pressure vs. area per molecule isotherms were recorded, with excess area and excess Gibbs energy of mixing calculated. Surface potential-area per molecule isotherms were also recorded for mixtures over the whole range of mole fractions, with negative deviations from the additivity rule revealing orientational changes induced in the HBPEB molecules. The Langmuir films were transferred onto solid supports and characterized by SPM techniques, with atomic force microscopy (AFM) revealing that well-ordered, defect-free films are obtained. The use of scanning polarization force microscopy (SPFM), which provides non-contact imaging based on differences in surface charge distribution, i.e., surface potential, provides complimentary information regarding distribution of the components within the mixed films. From the comprehensive miscibility study performed, which includes thermodynamic and imaging methods, it can be concluded that the wire-like molecule and the fatty acid are miscible over the 0-0.1 and 0.8-1 ranges of HBPEB mole fraction while phase separation occurs for HBPEB mole fractions over the 0.1-0.8 range.
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Affiliation(s)
- Ana Villares
- Department of Organic and Physical Chemistry, University of Zaragoza, 50009 Zaragoza, Spain.
| | - Santiago Martín
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, UKL69 7ZD
| | - Ignacio Giner
- Department of Organic and Physical Chemistry, University of Zaragoza, 50009 Zaragoza, Spain.
| | - Jordi Díaz
- Laboratory of Electrochemistry and Materials (LCTEM), Department of Physical Chemistry, University of Barcelona, Martí I Franquès 1 and Scientific-technical Services (Nanometric Techniques) of the University of Barcelona, Solé I Sabaris, 1, 08028 Barcelona, Spain
| | - Donocadh P Lydon
- Department of Chemistry, University of Durham, Durham, UKDH1 3LE
| | - Paul J Low
- Department of Chemistry, University of Durham, Durham, UKDH1 3LE
| | - Pilar Cea
- Department of Organic and Physical Chemistry, University of Zaragoza, 50009 Zaragoza, Spain. and Institute of Nanoscience of Aragón (INA), 50009 Zaragoza, Spain
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21
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Torrent-Burgués J, Oncins G, Sanz F. Study of mixed Langmuir and Langmuir–Blodgett films of dissimilar components by AFM and force spectroscopy. Colloids Surf A Physicochem Eng Asp 2008. [DOI: 10.1016/j.colsurfa.2007.12.051] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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22
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Haro M, Gascón I, Aroca R, López MC, Royo FM. Structural characterization and properties of an azopolymer arranged in Langmuir and Langmuir-Blodgett films. J Colloid Interface Sci 2007; 319:277-86. [PMID: 17991483 DOI: 10.1016/j.jcis.2007.10.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2007] [Revised: 10/01/2007] [Accepted: 10/02/2007] [Indexed: 11/29/2022]
Abstract
The fabrication of Langmuir and Langmuir-Blodgett (LB) films of an acid-azopolymer (PAzCOOH) is reported. Several techniques were used in their characterization: surface pressure (pi) and surface potential (DeltaV) isotherms, UV-vis reflection spectroscopy, and Brewster angle microscopy (BAM) for the Langmuir films and contact angle measurements, UV-vis, fluorescence, IR and Raman spectroscopy and scanning electronic microscopy (SEM) for the LB films. Our study reveals that lateral chains of the polymer situate preferentially onto the water surface with the acid group in contact with the water, where aggregates are scarcely formed. Therefore, the lateral chains of PAzCOOH can be treated as individual monomers to determine structural properties of the fabricated Langmuir and LB films. Monomeric treatment has been used to interpret UV-vis reflection spectroscopy, and a monomer model has been performed to represent lateral chains using density functional theory at B3LYP 6-31G(d,p) level of theory to assign the observed vibrational spectra.
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Affiliation(s)
- Marta Haro
- Departamento de Química Orgánica-Química Física, Facultad de Ciencias, Universidad de Zaragoza, Plaza de San Francisco s/n, 50009 Zaragoza, Spain
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23
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Martín S, Cea P, Pera G, Haro M, López MC. Pure and mixed films of a nitrostilbene derivative at the air–water interface, Langmuir–Blodgett multilayer fabrication, and optical characterization. J Colloid Interface Sci 2007; 308:239-48. [PMID: 17257610 DOI: 10.1016/j.jcis.2006.12.080] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Revised: 12/04/2006] [Accepted: 12/16/2006] [Indexed: 11/29/2022]
Abstract
This paper reports the preparation and characterization of pure Langmuir and Langmuir-Blodgett (LB) films of a stilbene derivative containing two alkyl chains, namely 4-dioctadecylamino-4'-nitrostilbene. Mixed films incorporating docosanoic acid and the stilbene derivative are also studied. Brewster angle microscopy (BAM) analysis has revealed the existence of randomly oriented three-dimensional (3D) aggregates, spontaneously formed immediately after the spreading process of the stilbene derivative onto the water surface. These 3D aggregates coexist with a Langmuir film that shows the typical gas, liquid, and solid-like phases in the surface pressure and surface potential vs area per molecule isotherms, indicative of an average preferential orientation of the stilbene compound at the air-water interface, and a gradual molecular arrangement into a defined structure upon compression. A blue shift of 55 nm of the reflection spectrum of the Langmuir film with respect to the spectrum of a chloroform solution of the nitrostilbene indicates that two-dimensional (2D) H-aggregates are formed at the air-water interface. The monolayers are transferred undisturbed onto solid substrates with atomic force microscopy (AFM) revealing that the one layer LB films are constituted by a monolayer of the stilbene derivative together with some 3D aggregates. When the nitrostilbene compound is blended with docosanoic acid, the 3D aggregation is avoided in the Langmuir and Langmuir-Blodgett films, but does not limit the formation of 2D H-aggregates, desirable for second-order nonlinear optical response in the blue domain. The AFM images of the mixed LB films show that they are formed by a docosanoic acid monolayer and, on the top of it, a bilayer of the stilbene derivative.
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Affiliation(s)
- Santiago Martín
- Departamento de Química Orgánica-Química Física, Facultad de Ciencias, Plaza San Francisco, Ciudad Universitaria, 50009 Zaragoza, Spain
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24
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Haro M, Cea P, Gascón I, Royo FM, López MC. Mixed Langmuir and Langmuir−Blodgett Films of a Proton Sponge and a Fatty Acid: Influence of the Subphase Nature on the Interactions between the Two Components. J Phys Chem B 2007; 111:2845-55. [PMID: 17319711 DOI: 10.1021/jp065954b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The H+ acceptor activity of a proton sponge, namely, diphenyl bis(octadecylamino)phosphonium bromide, has been studied at the air-liquid interface using several subphases. Mixed Langmuir and Langmuir-Blodgett (LB) films containing the proton sponge and a fatty acid (behenic acid) in the whole composition range have been prepared. Surface pressure versus area per molecule isotherms were recorded and excess Gibbs energies of mixing calculated. The existence of strong interactions between the proton sponge and the fatty acid is observed when the subphase is either pure water or a NaOH aqueous solution. A stoichiometric 1:1 reaction between both molecules takes place at the air-water interface. This reaction has an efficiency close to 100% at high surface pressures, provided the majority anion present in the subphase is OH-. However, when the majority anion is another one, this complex is hardly formed. From the experimental results, we conclude that the acid-base reaction is highly dependent on the protonation state of the proton sponge at the air-liquid interface that is a function of the present counterion in the subphase. The floating films were also transferred onto solid substrates and characterized by means of IR spectroscopy, atomic force microscopy (AFM), and X-ray diffraction to investigate in more detail the complex formation. The interactions between the complex (when formed) and the excess component have been studied in terms of the subphase nature. It was found that the complex is immiscible with the proton sponge, yielding films made of different domains. Nevertheless, the complex is miscible with the fatty acid when the subphase used is an alkaline solution, presumably due to electrostatic interactions between the carboxylate group of the acid and the complex.
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Affiliation(s)
- Marta Haro
- Departamento de Química OrgAnica-Química Física, Facultad de Ciencias, Plaza de San Francisco, Ciudad Universitaria, 50009 Zaragoza, Spain
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25
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Rajdev P, Chatterji D. Thermodynamic and spectroscopic studies on the nickel arachidate-RNA polymerase Langmuir-Blodgett monolayer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:2037-41. [PMID: 17279692 DOI: 10.1021/la062486o] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The Langmuir-Blodgett (LB) monolayers offer a unique system to study molecular interaction at the air-water interface with reduced dimensionality. In order to develop this further to follow macromolecular interactions at equilibrium, we first characterized the Ni (II)-arachidate (NiA) monolayer at varying conditions. Subsequently, the interaction between NiA and histidine-tagged RNA polymerase (HisRNAP) were also studied. LB films of arachidic acid-NiA and NiA-RNAP with different mole fractions were fabricated systematically. Surface pressure versus area per molecule (P-A) isotherms were registered, and the excess Gibbs energy of mixing was calculated. The LB films were then deposited on solid supports for Fourier transform infrared (FTIR) spectroscopic measurements. The FTIR spectra revealed the change in the amount of incorporated Ni (II) ions into the arachidic acid monolayer with the change in pH and the increasing mole fraction of RNAP in the NiA monolayer with its increasing concentration in the subphase. The system developed here seems to be robust and can be utilized to follow macromolecular interactions.
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Affiliation(s)
- Priya Rajdev
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore-560012, India
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Mulkidjanian AY, Heberle J, Cherepanov DA. Protons @ interfaces: implications for biological energy conversion. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2006; 1757:913-30. [PMID: 16624250 DOI: 10.1016/j.bbabio.2006.02.015] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2005] [Revised: 02/09/2006] [Accepted: 02/16/2006] [Indexed: 12/01/2022]
Abstract
The review focuses on the anisotropy of proton transfer at the surface of biological membranes. We consider (i) the data from "pulsed" experiments, where light-triggered enzymes capture or eject protons at the membrane surface, (ii) the electrostatic properties of water at charged interfaces, and (iii) the specific structural attributes of proton-translocating enzymes. The pulsed experiments revealed that proton exchange between the membrane surface and the bulk aqueous phase takes as much as about 1 ms, but could be accelerated by added mobile pH-buffers. Since the accelerating capacity of the latter decreased with the increase in their electric charge, it was concluded that the membrane surface is separated from the bulk aqueous phase by a barrier of electrostatic nature. The barrier could arise owing to the water polarization at the negatively charged membrane surface. The barrier height depends linearly on the charge of penetrating ions; for protons, it has been estimated as about 0.12 eV. While the proton exchange between the surface and the bulk aqueous phase is retarded by the interfacial barrier, the proton diffusion along the membrane, between neighboring enzymes, takes only microseconds. The proton spreading over the membrane is facilitated by the hydrogen-bonded networks at the surface. The membrane-buried layers of these networks can eventually serve as a storage/buffer for protons (proton sponges). As the proton equilibration between the surface and the bulk aqueous phase is slower than the lateral proton diffusion between the "sources" and "sinks", the proton activity at the membrane surface, as sensed by the energy transducing enzymes at steady state, might deviate from that measured in the adjoining water phase. This trait should increase the driving force for ATP synthesis, especially in the case of alkaliphilic bacteria.
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Affiliation(s)
- Armen Y Mulkidjanian
- AN Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia.
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