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Yeung SY, Sergeeva Y, Pan G, Mittler S, Ederth T, Dam T, Jönsson P, El-Schich Z, Wingren AG, Tillo A, Hsiung Mattisson S, Holmqvist B, Stollenwerk MM, Sellergren B. Reversible Self-Assembled Monolayers with Tunable Surface Dynamics for Controlling Cell Adhesion Behavior. ACS APPLIED MATERIALS & INTERFACES 2022; 14:41790-41799. [PMID: 36074978 PMCID: PMC9501787 DOI: 10.1021/acsami.2c12029] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/29/2022] [Indexed: 05/26/2023]
Abstract
Cells adhering onto surfaces sense and respond to chemical and physical surface features. The control over cell adhesion behavior influences cell migration, proliferation, and differentiation, which are important considerations in biomaterial design for cell culture, tissue engineering, and regenerative medicine. Here, we report on a supramolecular-based approach to prepare reversible self-assembled monolayers (rSAMs) with tunable lateral mobility and dynamic control over surface composition to regulate cell adhesion behavior. These layers were prepared by incubating oxoacid-terminated thiol SAMs on gold in a pH 8 HEPES buffer solution containing different mole fractions of ω-(ethylene glycol)2-4- and ω-(GRGDS)-, α-benzamidino bolaamphiphiles. Cell shape and morphology were influenced by the strength of the interactions between the amidine-functionalized amphiphiles and the oxoacid of the underlying SAMs. Dynamic control over surface composition, achieved by the addition of inert filler amphiphiles to the RGD-functionalized rSAMs, reversed the cell adhesion process. In summary, rSAMs featuring mobile bioactive ligands offer unique capabilities to influence and control cell adhesion behavior, suggesting a broad use in biomaterial design, tissue engineering, and regenerative medicine.
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Affiliation(s)
- Sing Yee Yeung
- Department
of Biomedical Sciences and Biofilms-Research Center for Biointerfaces
(BRCB), Faculty of Health and Society, Malmö
University, 205 06 Malmö, Sweden
| | - Yulia Sergeeva
- Department
of Biomedical Sciences and Biofilms-Research Center for Biointerfaces
(BRCB), Faculty of Health and Society, Malmö
University, 205 06 Malmö, Sweden
| | - Guoqing Pan
- Department
of Biomedical Sciences and Biofilms-Research Center for Biointerfaces
(BRCB), Faculty of Health and Society, Malmö
University, 205 06 Malmö, Sweden
- Institute
for Advanced Materials, School of Materials Science and Engineering, Jiangsu University, Zhenjiang, Jiangsu 212
013, China
| | - Silvia Mittler
- Department
of Physics and Astronomy, University of
Western Ontario, 1151 Richmond Street, London, Ontario, Canada N6A 3K7
| | - Thomas Ederth
- Division
of Biophysics and Bioengineering, Department of Physics, Chemistry
and Biology (IFM), Linköping University, 581 83 Linköping, Sweden
| | - Tommy Dam
- Division
of Physical Chemistry, Department of Chemistry, Lund University, 221 00 Lund, Sweden
| | - Peter Jönsson
- Division
of Physical Chemistry, Department of Chemistry, Lund University, 221 00 Lund, Sweden
| | - Zahra El-Schich
- Department
of Biomedical Sciences and Biofilms-Research Center for Biointerfaces
(BRCB), Faculty of Health and Society, Malmö
University, 205 06 Malmö, Sweden
| | - Anette Gjörloff Wingren
- Department
of Biomedical Sciences and Biofilms-Research Center for Biointerfaces
(BRCB), Faculty of Health and Society, Malmö
University, 205 06 Malmö, Sweden
| | - Adam Tillo
- Department
of Biomedical Sciences and Biofilms-Research Center for Biointerfaces
(BRCB), Faculty of Health and Society, Malmö
University, 205 06 Malmö, Sweden
| | | | - Bo Holmqvist
- ImaGene-iT
AB, Medicon Village,
Scheelevägen 2, 223 81 Lund, Sweden
| | - Maria M. Stollenwerk
- Department
of Biomedical Sciences and Biofilms-Research Center for Biointerfaces
(BRCB), Faculty of Health and Society, Malmö
University, 205 06 Malmö, Sweden
| | - Börje Sellergren
- Department
of Biomedical Sciences and Biofilms-Research Center for Biointerfaces
(BRCB), Faculty of Health and Society, Malmö
University, 205 06 Malmö, Sweden
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Yeung SY, Sergeeva Y, Dam T, Jönsson P, Pan G, Chaturvedi V, Sellergren B. Lipid Bilayer-like Mixed Self-Assembled Monolayers with Strong Mobility and Clustering-Dependent Lectin Affinity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:8174-8181. [PMID: 31117738 DOI: 10.1021/acs.langmuir.9b01452] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Glycans at the surface of cellular membranes modulate biological activity via multivalent association with extracellular messengers. The lack of tuneable simplified models mimicking this dynamic environment complicates basic studies of these phenomena. We here present a series of mixed reversible self-assembled monolayers (rSAMs) that addresses this deficiency. Mixed rSAMs were prepared in water by simple immersion of a negatively charged surface in a mixture of sialic acid- and hydroxy-terminated benzamidine amphiphiles. Surface compositions derived from infrared reflection-absorption spectroscopy (IRAS) and film thickness information (atomic force microscopy, ellipsometry) suggest the latter to be statistically incorporated in the monolayer. These surfaces' affinity for the lectin hemagglutinin revealed a strong dependence of the affinity on the presentation, density, and mobility of the sialic acid ligands. Hence, a spacer length of 4 ethylene glycol and a surface density of 15% resulted in a dissociation constant Kd,multi of 1.3 × 10-13 M, on par with the best di- or tri-saccharide-based binders reported to date, whereas a density of 20% demonstrated complete resistance to hemagglutinin binding. These results correlated with ligand mobility measured by fluorescence recovery after photobleaching which showed a dramatic drop in the same interval. The results have a direct bearing on biological cell surface multivalent recognition involving lipid bilayers and may guide the design of model surfaces and sensors for both fundamental and applied studies.
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Affiliation(s)
- Sing Yee Yeung
- Department of Biomedical Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Faculty of Health and Society , Malmö University , 205 06 Malmö , Sweden
| | - Yulia Sergeeva
- Department of Biomedical Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Faculty of Health and Society , Malmö University , 205 06 Malmö , Sweden
| | - Tommy Dam
- Division of Physical Chemistry , Lund University , Box 124, 22100 Lund , Sweden
| | - Peter Jönsson
- Division of Physical Chemistry , Lund University , Box 124, 22100 Lund , Sweden
| | - Guoqing Pan
- Department of Biomedical Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Faculty of Health and Society , Malmö University , 205 06 Malmö , Sweden
| | - Vivek Chaturvedi
- Department of Biomedical Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Faculty of Health and Society , Malmö University , 205 06 Malmö , Sweden
| | - Börje Sellergren
- Department of Biomedical Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Faculty of Health and Society , Malmö University , 205 06 Malmö , Sweden
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3
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Yeung SY, Ederth T, Pan G, Cicėnaitė J, Cárdenas M, Arnebrant T, Sellergren B. Reversible Self-Assembled Monolayers (rSAMs) as Robust and Fluidic Lipid Bilayer Mimics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:4107-4115. [PMID: 29553755 DOI: 10.1021/acs.langmuir.8b00226] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Lipid bilayers, forming the outer barrier of cells, display a wide array of proteins and carbohydrates for modulating interfacial biological interactions. Formed by the spontaneous self-assembly of lipid molecules, these bilayers feature liquid crystalline order, while retaining a high degree of lateral mobility. Studies of these dynamic phenomena have been hampered by the fragility and instability of corresponding biomimetic cell membrane models. Here, we present the construct of a series of oligoethylene glycol-terminated reversible self-assembled monolayers (rSAMs) featuring lipid-bilayer-like fluidity, while retaining air and protein stability and resistance. These robust and ordered layers were prepared by simply immersing a carboxylic acid-terminated self-assembled monolayer into 5-50 μM aqueous ω-(4-ethylene glycol-phenoxy)-α-(4-amidinophenoxy)decane solutions. It is anticipated that this new class of robust and fluidic two-dimensional biomimetic surfaces will impact the design of rugged cell surface mimics and high-performance biosensors.
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Affiliation(s)
- Sing Yee Yeung
- Department of Biomedical Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Faculty of Health and Society , Malmö University , 205 06 Malmö , Sweden
| | - Thomas Ederth
- Division of Molecular Physics, Department of Physics, Chemistry and Biology (IFM) , Linköping University , 581 83 Linköping , Sweden
| | - Guoqing Pan
- Department of Biomedical Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Faculty of Health and Society , Malmö University , 205 06 Malmö , Sweden
| | - Judita Cicėnaitė
- Department of Biomedical Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Faculty of Health and Society , Malmö University , 205 06 Malmö , Sweden
| | - Marité Cárdenas
- Department of Biomedical Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Faculty of Health and Society , Malmö University , 205 06 Malmö , Sweden
| | - Thomas Arnebrant
- Department of Biomedical Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Faculty of Health and Society , Malmö University , 205 06 Malmö , Sweden
| | - Börje Sellergren
- Department of Biomedical Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Faculty of Health and Society , Malmö University , 205 06 Malmö , Sweden
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4
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Yeung SY, Mucha A, Deshmukh R, Boutrus M, Arnebrant T, Sellergren B. Reversible Self-Assembled Monolayers (rSAMs): Adaptable Surfaces for Enhanced Multivalent Interactions and Ultrasensitive Virus Detection. ACS CENTRAL SCIENCE 2017; 3:1198-1207. [PMID: 29202022 PMCID: PMC5704293 DOI: 10.1021/acscentsci.7b00412] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Indexed: 05/06/2023]
Abstract
We report on the design of pH-switchable monolayers allowing a reversible and ordered introduction of affinity reagents on sensor surfaces. The principal layer building blocks consist of α-(4-amidinophenoxy)alkanes decorated at the ω-position with affinity ligands. These spontaneously self-assemble on top of carboxylic acid terminated SAMs to form reversible homo or mixed monolayers (rSAMs) that are tunable with respect to the nature of the head group, layer order and stability while featuring pH responsiveness and the dynamic nature of noncovalent build assemblies. We show that this results in a range of unique biosensor features. As a first example a sialic acid rSAM featuring strong lectin affinity is here used to sense hemagglutinin and influenza virus (H5N1) at the pM and fM level by in situ ellipsometry in a fully reversible fashion. We believe that the rSAM concept will find widespread use in surface chemistry and overall for boosting sensitivity in affinity biosensors.
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Affiliation(s)
- Sing Yee Yeung
- Department of Biomedical
Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Faculty of Health and Society, Malmö University, 20506 Malmö, Sweden
| | - Annabell Mucha
- Faculty
of Chemistry, Technical University of Dortmund, Dortmund, 44227 Germany
| | - Ravindra Deshmukh
- Faculty
of Chemistry, Technical University of Dortmund, Dortmund, 44227 Germany
| | - Malak Boutrus
- Faculty
of Chemistry, Technical University of Dortmund, Dortmund, 44227 Germany
| | - Thomas Arnebrant
- Department of Biomedical
Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Faculty of Health and Society, Malmö University, 20506 Malmö, Sweden
| | - Börje Sellergren
- Department of Biomedical
Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Faculty of Health and Society, Malmö University, 20506 Malmö, Sweden
- Faculty
of Chemistry, Technical University of Dortmund, Dortmund, 44227 Germany
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5
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Martin S, Brown PS, Bhushan B. Fabrication techniques for bioinspired, mechanically-durable, superliquiphobic surfaces for water, oil, and surfactant repellency. Adv Colloid Interface Sci 2017; 241:1-23. [PMID: 28143675 DOI: 10.1016/j.cis.2017.01.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 12/07/2016] [Accepted: 01/18/2017] [Indexed: 11/16/2022]
Abstract
Nature provides inspiration for liquid-repellant and low-adhesive surfaces, such as the lotus leaf and pitcher plant. While water-repellency is frequently found in nature, oil-repellency and surfactant-repellency are uncommon to nonexistent. To obtain oil- and surfactant-repellency, hierarchical, re-entrant, bioinspired surface structures along with low surface energy materials are needed. This overview presents wetting literature, common liquids and their composition, and fabrication techniques for superliquiphobic surfaces with repellency toward water, oil, and surfactant-containing liquids. Four techniques for creating such surfaces are explained in detail: nanoparticle/binder, layer-by-layer, nanoparticle-encapsulation, and liquid-impregnation. Static contact and tilt angles with water and hexadecane liquids, morphology, wear, transparency, self-cleaning, anti-smudge, and oil-water separation data are examined to compare the techniques. Data for these techniques are presented showing evidence of re-entrant geometry and the ability for these surfaces to repel surfactant-containing liquids such as shampoo and laundry detergent. The data will provide guidance in implementing superliquiphobic surfaces for self-cleaning, anti-smudge, antifouling, and low-adhesion properties for various applications including plastic packaging and biomedical devices.
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Affiliation(s)
- Samuel Martin
- Nanoprobe Laboratory for Bio & Nanotechnology and Biomimetics (NLBB), The Ohio State University, 201 W. 19th Avenue, Columbus, OH 43210-1142, USA
| | - Philip S Brown
- Nanoprobe Laboratory for Bio & Nanotechnology and Biomimetics (NLBB), The Ohio State University, 201 W. 19th Avenue, Columbus, OH 43210-1142, USA
| | - Bharat Bhushan
- Nanoprobe Laboratory for Bio & Nanotechnology and Biomimetics (NLBB), The Ohio State University, 201 W. 19th Avenue, Columbus, OH 43210-1142, USA.
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6
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Brown PS, Bhushan B. Mechanically durable, superoleophobic coatings prepared by layer-by-layer technique for anti-smudge and oil-water separation. Sci Rep 2015; 5:8701. [PMID: 25731716 PMCID: PMC4346800 DOI: 10.1038/srep08701] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/30/2015] [Indexed: 12/22/2022] Open
Abstract
Superoleophobic surfaces are of interest for anti-fouling, self-cleaning, anti-smudge, low-drag, anti-fog, and oil-water separation applications. Current bioinspired surfaces are of limited use due to a lack of mechanical durability. A so-called layer-by-layer approach, involving charged species with electrostatic interactions between layers, can provide the flexibility needed to improve adhesion to the substrate while providing a low surface tension coating at the air interface. In this work, a polyelectrolyte binder, SiO2 nanoparticles, and a fluorosurfactant are spray deposited separately to create a durable, superoleophobic coating. Polydiallyldimethylammonium chloride (PDDA) polyelectrolyte was complexed with a fluorosurfactant layer (FL), which provides oil repellency while being hydrophilic. This oleophobic/superhydrophilic behavior was enhanced through the use of roughening with SiO2 particles resulting in a superoleophobic coating with hexadecane contact angles exceeding 155° and tilt angles of less than 4°. The coating is also superhydrophilic, which is desirable for oil-water separation applications. The durability of these coatings was examined through the use of micro- and macrowear experiments. These coatings currently display characteristics of transparency. Fabrication of these coatings via the layer-by-layer technique results in superoleophobic surfaces displaying improved durability compared to existing work where either the durability or the oil-repellency is compromised.
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Affiliation(s)
- Philip S Brown
- Nanoprobe Laboratory for Bio- &Nanotechnology and Biomimetics (NLBB), The Ohio State University, 201 W. 19th Avenue, Columbus, OH 43210-1142, USA
| | - Bharat Bhushan
- Nanoprobe Laboratory for Bio- &Nanotechnology and Biomimetics (NLBB), The Ohio State University, 201 W. 19th Avenue, Columbus, OH 43210-1142, USA
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7
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Turyan I, Mandler D. Characterization and Electroanalytical Application of ω-Mercaptoalkanesulfonic Acid Monolayers on Gold. Isr J Chem 2013. [DOI: 10.1002/ijch.199700026] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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8
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Choi I, Yeo WS. Self-Assembled Monolayers with Dynamicity Stemming from (Bio)Chemical Conversions: From Construction to Application. Chemphyschem 2012; 14:55-69. [DOI: 10.1002/cphc.201200293] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Indexed: 11/11/2022]
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9
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Self-Assembled Monolayers as Dynamic Model Substrates for Cell Biology. BIOACTIVE SURFACES 2010. [DOI: 10.1007/12_2010_87] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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10
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Abstract
The development of surfaces that have switchable properties, also known as smart surfaces, have been actively pursued in the past few years. The recent surge of interest in these switchable systems stems from the widespread number of applications to many areas in science and technology ranging from environmental cleanup to data storage, micro- and nanofluidic devices. Moreover, the ability to modulate biomolecule activity, protein immobilisation, and cell adhesion at the liquid-solid interface is important in a variety of biological and medical applications, including biofouling, chromatography, cell culture, regenerative medicine and tissue engineering. Different materials have been exploited to induce such changes in surface biological properties that are mostly based on self-assembled monolayers or polymer films. This critical review focuses on the recent progress in the preparation of these switchable surfaces, and highlights their applications in biological environments. The review is organized according to the external stimuli used to manipulate the properties of the substrate-chemical/biochemical, thermal, electric and optical stimuli. Current and future challenges in the field of smart biological surfaces are addressed (189 references).
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Affiliation(s)
- Paula M Mendes
- Department of Chemical Engineering, University of Birmingham, Birmingham, UK.
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11
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Dong TY, Huang C, Chen CP, Lin MC. Molecular self-assembled monolayers of ruthenium(II)-terpyridine dithiol complex on gold electrode and nanoparticles. J Organomet Chem 2007. [DOI: 10.1016/j.jorganchem.2007.07.055] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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12
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Abstract
The macroscopic properties of a surface can be intelligently controlled by alternating the states of the modified molecules, such as polymers, metallic oxide, or self-assembled monolayers (SAMs). This article reviews various approaches to create a switchable surface and different types of external stimuli used to switch the surface properties. This area is of potential benefit for biomaterials, biosensors, information storage, microfluidic systems, adhesive materials, nanolithography, and so on.
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Affiliation(s)
- Ying Liu
- Department of Chemistry, Fudan University, Shanghai 200433, China
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14
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Hong JD, Jung BD, Kim CH, Kim K. Effects of Spacer Chain Lengths on Layered Nanostructures Assembled with Main-Chain Azobenzene Ionenes and Polyelectrolytes. Macromolecules 2000. [DOI: 10.1021/ma000293g] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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15
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Fukuo T, Monjushiro H, Hong H, Haga M, Arakawa R. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of self-assembled monolayers of ruthenium complexes on gold. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2000; 14:1301-1306. [PMID: 10918384 DOI: 10.1002/1097-0231(20000730)14:14<1301::aid-rcm29>3.0.co;2-p] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Self-assembled monolayers (SAMs) of three ruthenium complexes, [Ru(L)(2)](PF(6))(2), [Ru(L)(tpyPO(3))](PF(6))(2), and [Ru(L18)(tpyPO(3))](PF(6))(2), were prepared on evaporated gold films on glass or stainless steel plates; where L = 2, 6-bis(benzimidazoyl)pyridine, tpyPO(3) = 2,6-bis(2,2':6', 2"-terpyridyl)pyridine phosphanate, and L18 = 2, 6-bis(N-octadecylbenzimidazoyl)pyridine. Structures of these SAM complexes were studied by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). The SAMs were either prepared by direct binding of Ru-complexes to Au films by alkanethiol or by the multilayer method. In the multilayer method 1,4-thiobutylphosphate was used to form a base layer on an Au film, and the base layer was then chemically bridged to the Ru-complexes by zirconium phosphate. MALDI-TOFMS of SAM1, that had been prepared by direct binding of [Ru(L)(2)](PF(6))(2) to the Au film by an octanethiol group, showed cleavage at the S-Au linkages and elimination of the counter anion to yield a molecular ion and its dimeric ion. On the other hand, SAM2 and SAM3, which had been prepared by bridging Ru-complexes [Ru(L)(tpyPO(3))](PF(6))(2) or [Ru(L18)(tpyPO(3))](PF(6))(2) to the base layers with zirconium phosphate, showed dissociation from the base layers and elimination of the counter anion to give ions of the Ru complex molecules and their fragmentation ions. No molecular ion containing the base layer resulting from the S-Au bond cleavage was observed. Copyright 2000 John Wiley & Sons, Ltd.
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Affiliation(s)
- T Fukuo
- Department of Applied Chemistry, Kansai University, Suita, Osaka 564-8680, Japan
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16
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Brunner H, Vallant T, Mayer U, Hoffmann H. Formation of Ultrathin Films at the Solid-Liquid Interface Studied by In Situ Ellipsometry. J Colloid Interface Sci 1999; 212:545-552. [PMID: 10092386 DOI: 10.1006/jcis.1998.6062] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ellipsometric investigations of self-assembled monolayers (SAMs) of alkylsiloxanes on native silicon substrates and of organothiols on gold substrates were performed under in situ conditions with the substrate in direct contact with the adsorbate solution. Specially designed liquid cells matched for different incidence angles were used to carry out measurements in a range of organic solvents with different refractive indices as the ambient medium. The observed shifts in the ellipsometric phase angles Delta upon monolayer formation were found to depend very sensitively on the incidence angle and the refractive indices of the adsorbate film and the ambient solvent, from which a rather simple method for determining the refractive index of the adsorbate film, based on a variation of the ambient refractive index, was derived. Time-resolved in situ measurements of SAM formation in different solvents and onto different substrates yielded accurate kinetic information on the monolayer growth process and revealed hitherto unknown strong solvent effects on the growth rate. Copyright 1999 Academic Press.
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Affiliation(s)
- H Brunner
- Department of Inorganic Chemistry, Vienna University of Technology, Getreidemark 9, Wien, A-1060, Austria
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17
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Yang Z, Engquist I, Liedberg B, Kauffmann JM. Electrochemical characterisation of mixed monolayer assemblies of thiol analogues of cholesterol and fatty acids on gold. J Electroanal Chem (Lausanne) 1997. [DOI: 10.1016/s0022-0728(97)00161-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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18
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Ariga K, Lvov Y, Kunitake T. Assembling Alternate Dye−Polyion Molecular Films by Electrostatic Layer-by-Layer Adsorption. J Am Chem Soc 1997. [DOI: 10.1021/ja963442c] [Citation(s) in RCA: 441] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Katsuhiko Ariga
- Contribution from the Supermolecules Project, JST (former JRDC), Kurume Research Center, 2432 Aikawa, Kurume 839, Japan
| | - Yuri Lvov
- Contribution from the Supermolecules Project, JST (former JRDC), Kurume Research Center, 2432 Aikawa, Kurume 839, Japan
| | - Toyoki Kunitake
- Contribution from the Supermolecules Project, JST (former JRDC), Kurume Research Center, 2432 Aikawa, Kurume 839, Japan
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