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Altunbaş Şahin E. The use of avocado seed self‐assembly monolayer films for the catalysis of methanol electrooxidation reaction. J CHIN CHEM SOC-TAIP 2022. [DOI: 10.1002/jccs.202200106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Ece Altunbaş Şahin
- Property Protection and Security Department Bingol University, Genç Vocational School, Civil Defense and Firefighting Program Bingol Turkey
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2
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Zaborowska M, Dziubak D, Fontaine P, Matyszewska D. Influence of lipophilicity of anthracyclines on the interactions with cholesterol in the model cell membranes - Langmuir monolayer and SEIRAS studies. Colloids Surf B Biointerfaces 2021; 211:112297. [PMID: 34953365 DOI: 10.1016/j.colsurfb.2021.112297] [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: 10/13/2021] [Revised: 12/11/2021] [Accepted: 12/15/2021] [Indexed: 10/19/2022]
Abstract
The interactions of anthracyclines with biological membranes strongly depend on the drug lipophilicity, which might also determine the specific affinity to cholesterol molecules. Therefore, in this work we show the studies concerning the effect of two selected anthracyclines, daunorubicin (DNR) and idarubicin (IDA) on simple models of healthy (DMPC:Chol 7:3) and cancer cells membranes with increased level of cholesterol (DMPC:Chol 3:7) as well as pure cholesterol monolayers prepared at the air-water interface and supported on gold surface. It has been shown that more lipophilic IDA is able to penetrate cholesterol monolayers more effectively than DNR due to the formation of IDA-cholesterol arrangements at the interface, as proved by the thermodynamic analysis of compression-expansion cycles. The increased interactions of IDA were also confirmed by the time measurements of pre-compressed monolayers exposed to drug solutions as well as grazing incidence X-ray diffraction studies demonstrating differences in the 2D organization of cholesterol monolayers. Langmuir studies of mixed DMPC:Chol membranes revealed the reorganization of molecules in the cancer cell models at the air-water interface at higher surface pressures due to the removal of DNR, while increased affinity of IDA towards cholesterol allowed this drug to penetrate the layer more efficiently without its removal. The SEIRAS spectra obtained for supported DMPC:Chol bilayers proved that IDA locates both in the ester group and in the acyl chain region of the bilayer, while DNR does not penetrate the membranes as deeply as IDA. The increased penetration of the mixed phospholipid layers by idarubicin might be attributed to the higher lipophilicity caused by the lack of methoxy group and resulting in a specific affinity towards cholesterol.
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Affiliation(s)
| | - Damian Dziubak
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02089 Warsaw, Poland
| | - Philippe Fontaine
- Synchrotron Soleil, L'Orme des Merisiers, Saint Aubin, BP 48, 91192 Gif-sur-Yvette Cedex, France
| | - Dorota Matyszewska
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02089 Warsaw, Poland
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3
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Majewska M, Zamlynny V, Pieta IS, Nowakowski R, Pieta P. Interaction of LL-37 human cathelicidin peptide with a model microbial-like lipid membrane. Bioelectrochemistry 2021; 141:107842. [PMID: 34049238 DOI: 10.1016/j.bioelechem.2021.107842] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 05/07/2021] [Accepted: 05/09/2021] [Indexed: 10/21/2022]
Abstract
The only representative of cathelicidin peptides in humans is LL-37, a multifunctional antimicrobial peptide (AMP) that is a part of the innate immune response. Details of the LL-37 direct activity against pathogens are not well understood at the molecular level. Here, we present research on the mechanism of interaction between LL-37 and a model multicomponent bilayer lipid membrane (BLM), mimicking microbial cell membrane. Electrochemical impedance spectroscopy (EIS), high-resolution atomic force microscopy (AFM) imaging, and polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS) were applied to study the peptide influence on a model microbial-like membrane. We show that LL-37 causes changes in the phospholipid molecules conformation and orientation, leading to membrane disintegration, significantly affecting the membrane electrical parameters, such as capacitance and resistance. High-resolution AFM imaging shows topographical and mechanical effects of such disintegration, while PM-IRRAS data indicates that introduction of LL-37 causes changes in the phospholipid acyl chains from all-trans to gauche conformations. Moreover, the presence of LL-37 significantly alters the value of the phospholipid tilt angle. Altogether, our results suggest a "carpet" membrane dissolution followed by a detergent-like membrane disruption mechanism upon LL-37 activity. This research gives a novel insight into the understanding of LL-37 influence on multicomponent model membranes and a promising contribution to the development of LL-37-derived therapeutic agents against drug-resistant bacteria.
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Affiliation(s)
- Marta Majewska
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Vlad Zamlynny
- Chemistry Department, Acadia University, 6 University Avenue, Wolfville, NS B4P 2R6, Canada
| | - Izabela S Pieta
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Robert Nowakowski
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Piotr Pieta
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
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4
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Su Z, Goodall B, Leitch JJ, Lipkowski J. Ion transport mechanism in gramicidin A channels formed in floating bilayer lipid membranes supported on gold electrodes. Electrochim Acta 2021. [DOI: 10.1016/j.electacta.2021.137892] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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5
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Electrochemical Properties of Lipid Membranes Self-Assembled from Bicelles. MEMBRANES 2020; 11:membranes11010011. [PMID: 33374818 PMCID: PMC7824464 DOI: 10.3390/membranes11010011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 12/18/2020] [Accepted: 12/21/2020] [Indexed: 12/16/2022]
Abstract
Supported lipid membranes are widely used platforms which serve as simplified models of cell membranes. Among numerous methods used for preparation of planar lipid films, self-assembly of bicelles appears to be promising strategy. Therefore, in this paper we have examined the mechanism of formation and the electrochemical properties of lipid films deposited onto thioglucose-modified gold electrodes from bicellar mixtures. It was found that adsorption of the bicelles occurs by replacement of interfacial water and it leads to formation of a double bilayer structure on the electrode surface. The resulting lipid assembly contains numerous defects and pinholes which affect the permeability of the membrane for ions and water. Significant improvement in morphology and electrochemical characteristics is achieved upon freeze–thaw treatment of the deposited membrane. The lipid assembly is rearranged to single bilayer configuration with locally occurring patches of the second bilayer, and the number of pinholes is substantially decreased. Electrochemical characterization of the lipid membrane after freeze–thaw treatment demonstrated that its permeability for ions and water is significantly reduced, which was manifested by the relatively high value of the membrane resistance.
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7
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Su Z, Juhaniewicz-Debinska J, Sek S, Lipkowski J. Water Structure in the Submembrane Region of a Floating Lipid Bilayer: The Effect of an Ion Channel Formation and the Channel Blocker. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:409-418. [PMID: 31815479 DOI: 10.1021/acs.langmuir.9b03271] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The structure of water in the submembrane region of the bilayer of DPhPC floating (fBLM) on a monolayer of 1-thio-β-d-glucose (β-Tg)-modified gold nanoparticle film was studied by the surface-enhanced infrared absorption spectroscopy (SEIRAS). SEIRAS employs surface enhancement of the mean square electric field of the photon, which is acting on a few molecular layers above the film of gold nanoparticles. Therefore, it is uniquely suited to probe water molecules in the submembrane region and provides unique information concerning the structure of the hydrogen bond network of water surrounding the lipid bilayer. The IR spectra indicated that water with a strong hydrogen network is separating the membrane from the gold surface. This water is more ordered than the water in the bulk. When alamethicin, a peptide forming ion channels, is inserted into the membrane, the network is only slightly loosened. The addition of amiloride, an ion channel blocker, results in a significant decrease in the amount of water in the submembrane region. The remaining water has a significantly distorted hydrogen bond network. This study provides unique information about the effect of the ion channel on water transport across the bilayer. The electrode potential has a relatively small effect on water structure in the submembrane region. However, the IR studies demonstrated that water is less ordered at positive transmembrane potentials. The present results provide significant insight into the nature of hydration of a floating lipid bilayer on the gold electrode surface.
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Affiliation(s)
- ZhangFei Su
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | - Joanna Juhaniewicz-Debinska
- Faculty of Chemistry, Biological and Chemical Research Centre , University of Warsaw , Żwirki i Wigury 101 , 02-089 Warsaw , Poland
| | - Slawomir Sek
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
- Faculty of Chemistry, Biological and Chemical Research Centre , University of Warsaw , Żwirki i Wigury 101 , 02-089 Warsaw , Poland
| | - Jacek Lipkowski
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
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8
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Juhaniewicz-Dębińska J, Konarzewska D, Sęk S. Effect of Interfacial Water on the Nanomechanical Properties of Negatively Charged Floating Bilayers Supported on Gold Electrodes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:9422-9429. [PMID: 31241963 DOI: 10.1021/acs.langmuir.9b01311] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Floating lipid bilayers composed of phosphatidylglycerols and cardiolipin were deposited on gold electrodes premodified with 1-thio-β-d-glucose monolayer by spreading of small unilamellar vesicles. The resulting lipid membrane was homogeneous, and its thickness was ∼5.0 nm. Electrochemical characterization combined with surface-enhanced infrared absorption spectroscopy revealed that negative polarization of the electrode leads to accumulation of water molecules in the interfacial region between lipid membrane and the thioglucose film. Moreover, the buildup of water layer was demonstrated to affect the nanomechanical properties of the membrane. The latter was manifested by well-pronounced decrease of Young's modulus of the lipid bilayer correlating with increasing hydration. This effect was ascribed to the decoupling of the membrane from supporting thioglucose film due to the accumulation of interfacial water. As a result, the effective stiffness of the supporting layer is lower and it alters the nanomechanical behavior of lipid membrane. Our results provide strong experimental proof for the correlation between elastic properties of floating lipid membrane and the amount of water accumulated in the submembrane region.
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Affiliation(s)
- Joanna Juhaniewicz-Dębińska
- Faculty of Chemistry, Biological and Chemical Research Centre , University of Warsaw , Żwirki i Wigury 101 , 02-089 Warsaw , Poland
| | - Dorota Konarzewska
- Faculty of Chemistry, Biological and Chemical Research Centre , University of Warsaw , Żwirki i Wigury 101 , 02-089 Warsaw , Poland
| | - Sławomir Sęk
- Faculty of Chemistry, Biological and Chemical Research Centre , University of Warsaw , Żwirki i Wigury 101 , 02-089 Warsaw , Poland
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9
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Abbasi F, Leitch JJ, Su Z, Szymanski G, Lipkowski J. Direct visualization of alamethicin ion pores formed in a floating phospholipid membrane supported on a gold electrode surface. Electrochim Acta 2018. [DOI: 10.1016/j.electacta.2018.02.057] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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10
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Juhaniewicz-Dębińska J, Tymecka D, Sęk S. Lipopeptide-induced changes in permeability of solid supported bilayers composed of bacterial membrane lipids. J Electroanal Chem (Lausanne) 2018. [DOI: 10.1016/j.jelechem.2017.12.065] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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11
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Fudickar W, Pavashe P, Linker T. Thiocarbohydrates on Gold Nanoparticles: Strong Influence of Stereocenters on Binding Affinity and Interparticle Forces. Chemistry 2017; 23:8685-8693. [DOI: 10.1002/chem.201700846] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Indexed: 12/22/2022]
Affiliation(s)
- Werner Fudickar
- Department of Chemistry; University of Potsdam; Karl-Liebknecht-Str. 24-25 14476 Potsdam Germany
| | - Prashant Pavashe
- Department of Chemistry; University of Potsdam; Karl-Liebknecht-Str. 24-25 14476 Potsdam Germany
| | - Torsten Linker
- Department of Chemistry; University of Potsdam; Karl-Liebknecht-Str. 24-25 14476 Potsdam Germany
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12
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Matyszewska D, Bilewicz R, Su Z, Abbasi F, Leitch JJ, Lipkowski J. PM-IRRAS Studies of DMPC Bilayers Supported on Au(111) Electrodes Modified with Hydrophilic Monolayers of Thioglucose. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:1791-1798. [PMID: 26829620 DOI: 10.1021/acs.langmuir.5b04052] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A phospholipid bilayer composed of 1,2-dimyristoyl-d54-sn-glycero-3-phosphocholine (d54-DMPC) was deposited onto the Au(111) electrode modified with a self-assembled monolayer of 1-thio-β-d-glucose (β-Tg) via the Langmuir-Blodgett and Langmuir-Schaefer (LB-LS) techniques. Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) measurements were used to characterize structural and orientational changes in this model biological membrane on a hydrophilic surface modified gold electrode. The results of the spectroscopic measurements showed that the tilt angle of acyl chains obtained for deuterated DMPC bilayers supported on the β-Tg-modified gold is significantly lower than that reported previously for DMPC bilayers deposited directly on Au(111) electrodes. Moreover, tilt angles of ∼18° were obtained for d54-DMPC bilayers on β-Tg self-assembled monolayers (SAMs) at positive potentials, which are similar to the values calculated for h-DMPC deposited on bare gold in the desorbed state and to those observed for a stack of hydrated DMPC bilayers. This data confirms that the β-thioglucose SAM promotes the formation of a water cushion that separates the phospholipid bilayer from the metal surface. As a result, the DMPC polar heads are not in direct contact with the electrode and can adopt a zigzag configuration, which strengthens the chain-chain interactions and allows for an overall decrease in the tilt of the acyl chains. These novel supported model membranes may be especially useful in studies pertaining to the incorporation of peptides and proteins into phospholipid bilayers.
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Affiliation(s)
- Dorota Matyszewska
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw , Żwirki i Wigury 101, 02089 Warsaw, Poland
| | - Renata Bilewicz
- Faculty of Chemistry, University of Warsaw , ul. Pasteura 1, 02093 Warsaw, Poland
| | - ZhangFei Su
- Department of Chemistry, University of Guelph , Guelph, Ontario N1G 2W1, Canada
| | - Fatemah Abbasi
- Department of Chemistry, University of Guelph , Guelph, Ontario N1G 2W1, Canada
| | - J Jay Leitch
- Department of Chemistry, University of Guelph , Guelph, Ontario N1G 2W1, Canada
| | - Jacek Lipkowski
- Department of Chemistry, University of Guelph , Guelph, Ontario N1G 2W1, Canada
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13
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Smith SR, Seenath R, Kulak MR, Lipkowski J. Characterization of a Self-Assembled Monolayer of 1-Thio-β-D-Glucose with Electrochemical Surface Enhanced Raman Spectroscopy Using a Nanoparticle Modified Gold Electrode. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:10076-10086. [PMID: 26313341 DOI: 10.1021/acs.langmuir.5b02767] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Preparation of a nanoparticle modified gold substrate designed for characterization of hydrophilic self-assembled monolayers (SAMs) of 1-thio-β-D-glucose (TG) with electrochemical surface-enhanced Raman spectroscopy (EC-SERS) is presented. Citrate stabilized gold nanoparticles were deposited on a polycrystalline gold electrode and subjected to an electrochemical desorption procedure to completely remove all traces of adsorbed citrate. Complete desorption of citrate was confirmed by recording cyclic voltammetry curves and SERS spectra. The citrate-free nanoparticle modified gold electrode was then incubated in a 1 mg mL(-1) aqueous solution of TG for 16 h prior to being characterized by EC-SERS. The SERS spectra confirmed that at potentials more negative than -0.10 V vs SCE thioglucose forms a monolayer in which the majority of the molecules preserve their lactol ring structure and only a small fraction of molecules appear to be oxidized. At potentials more positive than -0.10 V, the oxidation of TG molecules becomes prominent, and at potentials more positive than 0.20 V vs SCE, the monolayer of TG consists chiefly of oxidized product. The SERS spectra collected in the double layer region suggest the SAM of TG is well hydrated and hence can be used for hydrophilic modifications of a gold surface.
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Affiliation(s)
- Scott R Smith
- Department of Chemistry, University of Guelph , Guelph ON, Canada N1G 2W1
| | - Ryan Seenath
- Department of Chemistry, University of Guelph , Guelph ON, Canada N1G 2W1
| | - Monika R Kulak
- Department of Chemistry, University of Guelph , Guelph ON, Canada N1G 2W1
| | - Jacek Lipkowski
- Department of Chemistry, University of Guelph , Guelph ON, Canada N1G 2W1
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14
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Singh S, Su Z, Grossutti M, Auzanneau FI. Attempts to prepare tethered bilayer lipid membranes using synthetic thioglycolipid anchors: synthesis of 6″-thiotrisaccharide glycolipid analogues and applications. Carbohydr Res 2014; 390:50-8. [PMID: 24704433 DOI: 10.1016/j.carres.2014.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 03/07/2014] [Accepted: 03/08/2014] [Indexed: 11/29/2022]
Abstract
The synthesis of the three 6″-deoxy-6″-thio glycolipid analogues β-d-Gal-(1→6)-β-d-Gal-(1→4)-β-d-Glu-(1→OCH2)-[1,2,3]-triazole-1-dodecane, β-d-Gal-(1→4)-β-d-Glu-(1→4)-β-d-Glu-(1→OCH2)-[1,2,3]-triazole-1-dodecane and β-d-Gal-(1→4)-β-d-Glu-(1→4)-β-d-Glu-(1→OCH2)-[1,2,3]-triazole-1-octadecane is presented. Glycosylation at position O-4' of a propargyl cellobioside glycosyl acceptor and position O-6' of a propargyl lactoside glycosyl acceptor with a 6-deoxy-6-thio galactosyl donor gave rise to two unique trisaccharides that in turn underwent copper-catalyzed azide-alkyne cycloadditions with either 1-azidododecane or 1-azidooctadecane. The potential for each of these analogues to function as tethers of lipid bilayers to Au(111) surface was assessed by differential capacitance experiments. A monolayer of the previously described monosaccharide 1-octadecane-4-(6-thio-β-d-galacto-pyranosyloxymethyl)-[1,2,3]-triazole either self-assembled or prepared by Langmuir-Blodgett (LB) transfer was found to support an outer leaflet monolayer (DMPC/cholesterol, 70:30) deposited by Langmuir-Schaefer (LS) touch. The bilayers obtained with this monosaccharide analogue had minimum differential capacitances of 1.0 and 0.9μF/cm(2) when the inner monolayer was prepared by self-assembly and LS touch, respectively. Attempts to produce bilayers using the trisaccharides synthesized here were unsuccessful; we are attributing these unsuccessful results mostly to the high water solubility of trisaccharides combined with the relatively short length of the hydrocarbon chains used in this study.
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Affiliation(s)
- Serena Singh
- Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Zhangfei Su
- Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Michael Grossutti
- Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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15
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Raegen AN, Reiter K, Dion A, Clarke AJ, Lipkowski J, Dutcher JR. Advances in Surface Plasmon Resonance Imaging Enable Quantitative Tracking of Nanoscale Changes in Thickness and Roughness. Anal Chem 2014; 86:3346-54. [DOI: 10.1021/ac4034664] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Adam N. Raegen
- Department of Physics, ‡Department of Molecular
and Cellular Biology, and §Department of
Chemistry, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Kyle Reiter
- Department of Physics, ‡Department of Molecular
and Cellular Biology, and §Department of
Chemistry, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Alexander Dion
- Department of Physics, ‡Department of Molecular
and Cellular Biology, and §Department of
Chemistry, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Anthony J. Clarke
- Department of Physics, ‡Department of Molecular
and Cellular Biology, and §Department of
Chemistry, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Jacek Lipkowski
- Department of Physics, ‡Department of Molecular
and Cellular Biology, and §Department of
Chemistry, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - John R. Dutcher
- Department of Physics, ‡Department of Molecular
and Cellular Biology, and §Department of
Chemistry, University of Guelph, Guelph, ON, Canada N1G 2W1
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16
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Tsuji T, Kuwamura N, Yoshinari N, Konno T. Synthesis and Coordination Behavior of a Bipyridine Platinum(II) Complex with Thioglucose. Inorg Chem 2013; 52:5350-8. [DOI: 10.1021/ic400287g] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Takaaki Tsuji
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
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17
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Su Z, Jiang Y, Velázquez-Manzanares M, Jay Leitch J, Kycia A, Lipkowski J. Electrochemical and PM-IRRAS studies of floating lipid bilayers assembled at the Au(111) electrode pre-modified with a hydrophilic monolayer. J Electroanal Chem (Lausanne) 2013. [DOI: 10.1016/j.jelechem.2012.09.044] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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18
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Fischer JA, Zoldan VC, Benitez G, Rubert AA, Ramirez EA, Carro P, Salvarezza RC, Pasa AA, Vela ME. Sulfidization of Au(111) from thioacetic acid: an experimental and theoretical study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:15278-15285. [PMID: 23002810 DOI: 10.1021/la303059u] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We have studied the adsorption of thioacetic acid (TAAH) on Au(111) from solution deposition. The close proximity of the SH groups to CO groups makes this molecule very attractive for exploring the effect of the functional group on the stability of the S-C and S-Au bonds. Although thioacetic acid was supposed to decompose slowly in water by hydrolysis supplying hydrogen sulfide, this behavior is not expected in nonpolar solvents such as toluene or hexane. Therefore, we have used these solvents for TAAH self-assembly on the Au(111) surface. The characterization of the adsorbates has been done by electrochemical techniques, X-ray photoelectron spectroscopy (XPS), and scanning tunneling microscopy (STM). We have found that even in nonpolar solvents thioacetic acid decomposes to S. The results have been discussed on the basis that the adsorbed species suffer a cleavage on the Au surface, leaving the S attached to it. The dissociation is a spontaneous process that reaches the final state very fast once it is energetically favorable, as can be interpreted from DFT calculations. The thioacetic acid adsorption reveals the strong effect that produces a functional group and the key role of the S-H bond cleavage in the self-assembly process.
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Affiliation(s)
- Jeison A Fischer
- Laboratório de Filmes Finos e Superfícies, Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
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Su Z, Leitch J, Lipkowski J. Measurements of the Potentials of Zero Free Charge and Zero Total Charge for 1-thio- ± bβ-D-glucose and DPTL Modified Au(111) Surface in Different Electrolyte Solutions. ACTA ACUST UNITED AC 2012. [DOI: 10.1524/zpch.2012.0280] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Abstract
The immersion method was used to measure the potential of zero free charge (E
pzfc) of a bare Au(111) electrode and the electrode modified by self-assembled monolayers (SAMs) of 1-thio-β-D-glucose (β-Tg) and 2,3-di-O-phytanyl-sn-glycerol-1-tetraethylene glycol-D,L-α-lipoic acid ester (DPTL). The measurements were performed in three electrolyte solutions: 0.1 M NaH2PO4, 0.1 MKClO4 and 0.1 M NaF. The E
pzc of the Au(111) electrode has different values in these electrolyte solutions due to the specific adsorption of phosphate and fluoride anions on the Au(111) surface. In contrast, when the gold surface is covered by a SAM of β-Tg, the adsorption of anions is suppressed and similar values of E
pzfc were measured in the three electrolytes. Additional chronocoulometric experiments were performed to determine the potentials of the zero total charge (E
pztc) for the thiol covered electrode. Significant differences between numerical values of potentials of the zero free charge E
pzfc and potentials of the zero total charge E
pztc were observed.
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Ramírez EA, Cortés E, Rubert AA, Carro P, Benítez G, Vela ME, Salvarezza RC. Complex surface chemistry of 4-mercaptopyridine self-assembled monolayers on Au(111). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:6839-6847. [PMID: 22497438 DOI: 10.1021/la204951u] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The adsorption of 4-mercaptopyridine on Au(111) from aqueous or ethanolic solutions is studied by different surface characterization techniques and density functional theory calculations (DFT) including van der Waals interactions. X-ray photoelectron spectroscopy and electrochemical data indicate that self-assembly from 4-mercaptopyridine-containing aqueous 0.1 M NaOH solutions for short immersion times (few minutes) results in a 4-mercaptopyridine (PyS) self-assembled monolayer (SAM) with surface coverage 0.2. Scanning tunneling microscopy images show an island-covered Au surface. The increase in the immersion time from minutes to hours results in a complete SAM degradation yielding adsorbed sulfur and a heavily pitted Au surface. Adsorbed sulfur is also the main product when the self-assembly process is made in ethanolic solutions irrespective of the immersion time. We demonstrate for the first time that a surface reaction is involved in PyS SAM decomposition in ethanol, a surface process not favored in water. DFT calculations suggest that the surface reaction takes place via disulfide formation driven by the higher stability of the S-Au(111) system. Other reactions that contribute to sulfidization are also detected and discussed.
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Affiliation(s)
- E A Ramírez
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata-CONICET, La Plata, Argentina
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