151
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Fernandez A, Bautista M, Stanciauskas R, Chung T, Pinaud F. Cell-Shaping Micropatterns for Quantitative Super-Resolution Microscopy Imaging of Membrane Mechanosensing Proteins. ACS Appl Mater Interfaces 2017; 9:27575-27586. [PMID: 28766344 DOI: 10.1021/acsami.7b09743] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Patterning cells on microcontact-printed substrates is a powerful approach to control cell morphology and introduce specific mechanical cues on a cell's molecular organization. Although global changes in cellular architectures caused by micropatterns can easily be probed with diffraction-limited optical microscopy, studying molecular reorganizations at the nanoscale demands micropatterned substrates that accommodate the optical requirements of single molecule microscopy techniques. Here, we developed a simple micropatterning strategy that provides control of cellular architectures and is optimized for nanometer accuracy single molecule tracking and three-dimensional super-resolution imaging of plasma and nuclear membrane proteins in cells. This approach, based on fibronectin microcontact printing on hydrophobic organosilane monolayers, allows evanescent wave and light-sheet microscopy of cells whilst fulfilling the stringent optical demands of point reconstruction optical microscopy. By imposing steady-state mechanical cues on cells grown in these micropatterns, we reveal nanoscale remodeling in the dynamics and the structural organizations of the nuclear envelope mechanotransducing protein emerin and of the plasma membrane mechanosensing protein caveolin-1 using single particle tracking photoactivated localization microscopy and direct stochastic optical reconstruction microscopy imaging. In addition to allowing quantitative biophysical studies of mechanoresponsive membrane proteins, this approach provides an easy means to probe mechanical regulations in cellular membranes with high optical resolution and nanometer precision.
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Affiliation(s)
- Anthony Fernandez
- Department of Biological Sciences, ‡Department of Chemistry, and §Department of Physics and Astronomy, University of Southern California , Los Angeles, California 90089, United States
| | - Markville Bautista
- Department of Biological Sciences, ‡Department of Chemistry, and §Department of Physics and Astronomy, University of Southern California , Los Angeles, California 90089, United States
| | - Ramunas Stanciauskas
- Department of Biological Sciences, ‡Department of Chemistry, and §Department of Physics and Astronomy, University of Southern California , Los Angeles, California 90089, United States
| | - Taerin Chung
- Department of Biological Sciences, ‡Department of Chemistry, and §Department of Physics and Astronomy, University of Southern California , Los Angeles, California 90089, United States
| | - Fabien Pinaud
- Department of Biological Sciences, ‡Department of Chemistry, and §Department of Physics and Astronomy, University of Southern California , Los Angeles, California 90089, United States
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152
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Xie Z, Gordiichuk P, Lin QY, Meckes B, Chen PC, Sun L, Du JS, Zhu J, Liu Y, Dravid VP, Mirkin CA. Solution-Phase Photochemical Nanopatterning Enabled by High-Refractive-Index Beam Pen Arrays. ACS Nano 2017; 11:8231-8241. [PMID: 28617585 DOI: 10.1021/acsnano.7b03282] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A high-throughput, solution-based, scanning-probe photochemical nanopatterning approach, which does not require the use of probes with subwavelength apertures, is reported. Specifically, pyramid arrays made from high-refractive-index polymeric materials were constructed and studied as patterning tools in a conventional liquid-phase beam pen lithography experiment. Two versions of the arrays were explored with either metal-coated or metal-free tips. Importantly, light can be channeled through both types of tips and the appropriate solution phase (e.g., H2O or CH3OH) and focused on subwavelength regions of a substrate to effect a photoreaction in solution that results in localized patterning of a self-assembled monolayer (SAM)-coated Au thin film substrate. Arrays with as many as 4500 pyramid-shaped probes were used to simultaneously initiate thousands of localized free-radical photoreactions (decomposition of a lithium acylphosphinate photoinitiator in an aqueous solution) that result in oxidative removal of the SAM. The technique is attractive since it allows one to rapidly generate features less than 200 nm in diameter, and the metal-free tips afford more than 10-fold higher intensity than the tips with nanoapertures over a micrometer propagation length. In principle, this mask-free method can be utilized as a versatile tool for performing a wide variety of photochemistries across multiple scales that may be important in high-throughput combinatorial screening applications related to chemistry, biology, and materials science.
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Affiliation(s)
| | | | - Qing-Yuan Lin
- Department of Materials Science and Engineering, Northwestern University , 2220 Campus Drive, Evanston, Illinois 60208, United States
| | | | - Peng-Cheng Chen
- Department of Materials Science and Engineering, Northwestern University , 2220 Campus Drive, Evanston, Illinois 60208, United States
| | - Lin Sun
- Department of Materials Science and Engineering, Northwestern University , 2220 Campus Drive, Evanston, Illinois 60208, United States
| | - Jingshan S Du
- Department of Materials Science and Engineering, Northwestern University , 2220 Campus Drive, Evanston, Illinois 60208, United States
| | - Jinghan Zhu
- Department of Materials Science and Engineering, Northwestern University , 2220 Campus Drive, Evanston, Illinois 60208, United States
| | | | - Vinayak P Dravid
- Department of Materials Science and Engineering, Northwestern University , 2220 Campus Drive, Evanston, Illinois 60208, United States
| | - Chad A Mirkin
- Department of Materials Science and Engineering, Northwestern University , 2220 Campus Drive, Evanston, Illinois 60208, United States
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153
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Di Martino G, Turek VA, Lombardi A, Szabó I, de Nijs B, Kuhn A, Rosta E, Baumberg JJ. Tracking Nanoelectrochemistry Using Individual Plasmonic Nanocavities. Nano Lett 2017; 17:4840-4845. [PMID: 28686457 DOI: 10.1021/acs.nanolett.7b01676] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We study in real time the optical response of individual plasmonic nanoparticles on a mirror, utilized as electrodes in an electrochemical cell when a voltage is applied. In this geometry, Au nanoparticles are separated from a bulk Au film by an ultrathin molecular spacer. The nanoscale plasmonic hotspot underneath the nanoparticles locally reveals the modified charge on the Au surface and changes in the polarizability of the molecular spacer. Dark-field and Raman spectroscopy performed on the same nanoparticle show our ability to exploit isolated plasmonic junctions to track the dynamics of nanoelectrochemistry. Enhancements in Raman emission and blue-shifts at a negative potential show the ability to shift electrons within the gap molecules.
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Affiliation(s)
- G Di Martino
- NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge CB3 0HE, U.K
| | - V A Turek
- NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge CB3 0HE, U.K
| | - A Lombardi
- NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge CB3 0HE, U.K
| | - I Szabó
- Department of Chemistry, King's College London , London SE1 1DB, U.K
| | - B de Nijs
- NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge CB3 0HE, U.K
| | - A Kuhn
- Univ. Bordeaux , CNRS UMR 5255, Bordeaux INP, Site ENSCBP, 33607, Pessac, France
| | - E Rosta
- Department of Chemistry, King's College London , London SE1 1DB, U.K
| | - J J Baumberg
- NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge CB3 0HE, U.K
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154
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Nolte KA, Schwarze J, Rosenhahn A. Microfluidic accumulation assay probes attachment of biofilm forming diatom cells. Biofouling 2017; 33:531-543. [PMID: 28675050 DOI: 10.1080/08927014.2017.1328058] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 05/02/2017] [Indexed: 06/07/2023]
Abstract
Testing of fouling release (FR) technologies is of great relevance for discovery of the next generation of protective marine coatings. In this paper, an accumulation assay to test diatom interaction under laminar flow with the model organism Navicula perminuta is introduced. Using time lapse microscopy with large area sampling allows determination of the accumulation kinetics of the diatom on three model surfaces with different surface properties at different wall shear stresses. The hydrodynamic conditions within the flow cell are described and a suitable shear stress range to perform accumulation experiments is identified at which statistically significant discrimination of surfaces is possible. The observed trends compare well to published adhesion preferences of N. perminuta. Also, previously determined trends of critical wall shear stresses required for cell removal from the same set of functionalized interfaces shows consistent trends. Initial attachment mediated by extracellular polymeric substances (EPS) present outside the diatoms leads to the conclusion that the FR potential of the tested coating candidates can be deducted from dynamic accumulation experiments under well-defined hydrodynamic conditions. As well as testing new coating candidates for their FR properties, monitoring of the adhesion process under flow provides additional information on the mechanism and geometry of attachment and the population kinetics.
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Affiliation(s)
- Kim A Nolte
- a Analytical Chemistry - Biointerfaces , Ruhr- Universität Bochum , Bochum , Germany
| | - Jana Schwarze
- a Analytical Chemistry - Biointerfaces , Ruhr- Universität Bochum , Bochum , Germany
| | - Axel Rosenhahn
- a Analytical Chemistry - Biointerfaces , Ruhr- Universität Bochum , Bochum , Germany
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155
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Cheng X, McVey BFP, Robinson AB, Longatte G, O'Mara PB, Tan VTG, Thordarson P, Tilley RD, Gaus K, Justin Gooding J. Protease sensing using nontoxic silicon quantum dots. J Biomed Opt 2017; 22:1-7. [PMID: 28836415 DOI: 10.1117/1.jbo.22.8.087002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 07/31/2017] [Indexed: 06/07/2023]
Abstract
Herein is presented a proof-of-concept study of protease sensing that combines nontoxic silicon quantum dots (SiQDs) with Förster resonance energy transfer (FRET). The SiQDs serve as the donor and an organic dye as the acceptor. The dye is covalently attached to the SiQDs using a peptide linker. Enzymatic cleavage of the peptide leads to changes in FRET efficiency. The combination of interfacial design and optical imaging presented in this work opens opportunities for use of nontoxic SiQDs relevant to intracellular sensing and imaging.
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Affiliation(s)
- Xiaoyu Cheng
- University of New South Wales, School of Chemistry, Australian Centre for NanoMedicine, ARC Centre o, Australia
- University of New South Wales, EMBL Australia Node in Single Molecule Science, School of Medical Sci, Australia
| | - Benjamin F P McVey
- University of New South Wales, School of Chemistry, Australian Centre for NanoMedicine, ARC Centre o, Australia
| | - Andrew B Robinson
- University of New South Wales, School of Chemistry, Australian Centre for NanoMedicine, ARC Centre o, Australia
| | - Guillaume Longatte
- University of New South Wales, School of Chemistry, Australian Centre for NanoMedicine, ARC Centre o, Australia
| | - Peter B O'Mara
- University of New South Wales, School of Chemistry, Australian Centre for NanoMedicine, ARC Centre o, Australia
| | - Vincent T G Tan
- University of New South Wales, School of Chemistry, Australian Centre for NanoMedicine, ARC Centre o, Australia
| | - Pall Thordarson
- University of New South Wales, School of Chemistry, Australian Centre for NanoMedicine, ARC Centre o, Australia
| | - Richard D Tilley
- University of New South Wales, School of Chemistry, Australian Centre for NanoMedicine, ARC Centre o, Australia
| | - Katharina Gaus
- University of New South Wales, EMBL Australia Node in Single Molecule Science, School of Medical Sci, Australia
| | - John Justin Gooding
- University of New South Wales, School of Chemistry, Australian Centre for NanoMedicine, ARC Centre o, Australia
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156
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Abstract
An ultimate goal of molecular electronics, which seeks to incorporate molecular components into electronic circuit units, is to generate functional molecular electronic devices using individual or ensemble molecules to fulfill the increasing technical demands of the miniaturization of traditional silicon-based electronics. This review article presents a summary of recent efforts to pursue this ultimate aim, covering the development of reliable device platforms for high-yield ensemble molecular junctions and their utilization in functional molecular electronic devices, in which distinctive electronic functionalities are observed due to the functional molecules. In addition, other aspects pertaining to the practical application of molecular devices such as manufacturing compatibility with existing complementary metal-oxide-semiconductor technology, their integration, and flexible device applications are also discussed. These advances may contribute to a deeper understanding of charge transport characteristics through functional molecular junctions and provide a desirable roadmap for future practical molecular electronics applications.
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Affiliation(s)
- Hyunhak Jeong
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University , Seoul 08826, Korea
| | - Dongku Kim
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University , Seoul 08826, Korea
| | - Dong Xiang
- Key Laboratory of Optical Information Science and Technology, Institute of Modern Optics, College of Electronic Information and Optical Engineering, Nankai University , Tianjin 300071, China
| | - Takhee Lee
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University , Seoul 08826, Korea
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157
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Meena SK, Goldmann C, Nassoko D, Seydou M, Marchandier T, Moldovan S, Ersen O, Ribot F, Chanéac C, Sanchez C, Portehault D, Tielens F, Sulpizi M. Nanophase Segregation of Self-Assembled Monolayers on Gold Nanoparticles. ACS Nano 2017; 11:7371-7381. [PMID: 28613838 DOI: 10.1021/acsnano.7b03616] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Nanophase segregation of a bicomponent thiol self-assembled monolayer is predicted using atomistic molecular dynamics simulations and experimentally confirmed. The simulations suggest the formation of domains rich in acid-terminated chains, on one hand, and of domains rich in amide-functionalized ethylene glycol oligomers, on the other hand. In particular, within the amide-ethylene glycol oligomers region, a key role is played by the formation of interchain hydrogen bonds. The predicted phase segregation is experimentally confirmed by the synthesis of 35 and 15 nm gold nanoparticles functionalized with several binary mixtures of ligands. An extensive study by transmission electron microscopy and electron tomography, using silica selective heterogeneous nucleation on acid-rich domains to provide electron contrast, supports simulations and highlights patchy nanoparticles with a trend toward Janus nano-objects depending on the nature of the ligands and the particle size. These results validate our computational platform as an effective tool to predict nanophase separation in organic mixtures on a surface and drive further exploration of advanced nanoparticle functionalization.
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Affiliation(s)
- Santosh Kumar Meena
- Institute of Physics, Johannes Gutenberg University Mainz , Staudingerweg 7, 55099 Mainz, Germany
| | - Claire Goldmann
- Sorbonne Universités UPMC Univ Paris 06, CNRS, Collège de France, Laboratoire de Chimie de la Matière Condensée de Paris, Sorbonne Universités , 11 place Marcelin Berthelot, 75005 Paris, France
| | - Douga Nassoko
- Sorbonne Universités UPMC Univ Paris 06, CNRS, Collège de France, Laboratoire de Chimie de la Matière Condensée de Paris, Sorbonne Universités , 11 place Marcelin Berthelot, 75005 Paris, France
- Ecole Normale Supérieure , Rue du 22 Octobre, Quartier du Fleuve, BP 241 Bamako, Mali
| | - Mahamadou Seydou
- Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS , 15 rue J.-A. de Baïf, 75205 CEDEX 13 Paris, France
| | - Thomas Marchandier
- Sorbonne Universités UPMC Univ Paris 06, CNRS, Collège de France, Laboratoire de Chimie de la Matière Condensée de Paris, Sorbonne Universités , 11 place Marcelin Berthelot, 75005 Paris, France
| | - Simona Moldovan
- Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 du CNRS , 23 rue du Loess, 67087 Strasbourg, France
| | - Ovidiu Ersen
- Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 du CNRS , 23 rue du Loess, 67087 Strasbourg, France
| | - François Ribot
- Sorbonne Universités UPMC Univ Paris 06, CNRS, Collège de France, Laboratoire de Chimie de la Matière Condensée de Paris, Sorbonne Universités , 11 place Marcelin Berthelot, 75005 Paris, France
| | - Corinne Chanéac
- Sorbonne Universités UPMC Univ Paris 06, CNRS, Collège de France, Laboratoire de Chimie de la Matière Condensée de Paris, Sorbonne Universités , 11 place Marcelin Berthelot, 75005 Paris, France
| | - Clément Sanchez
- Sorbonne Universités UPMC Univ Paris 06, CNRS, Collège de France, Laboratoire de Chimie de la Matière Condensée de Paris, Sorbonne Universités , 11 place Marcelin Berthelot, 75005 Paris, France
| | - David Portehault
- Sorbonne Universités UPMC Univ Paris 06, CNRS, Collège de France, Laboratoire de Chimie de la Matière Condensée de Paris, Sorbonne Universités , 11 place Marcelin Berthelot, 75005 Paris, France
| | - Frederik Tielens
- Sorbonne Universités UPMC Univ Paris 06, CNRS, Collège de France, Laboratoire de Chimie de la Matière Condensée de Paris, Sorbonne Universités , 11 place Marcelin Berthelot, 75005 Paris, France
| | - Marialore Sulpizi
- Institute of Physics, Johannes Gutenberg University Mainz , Staudingerweg 7, 55099 Mainz, Germany
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158
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Ryu T, Lansac Y, Jang YH. Shuttlecock-Shaped Molecular Rectifier: Asymmetric Electron Transport Coupled with Controlled Molecular Motion. Nano Lett 2017; 17:4061-4066. [PMID: 28541693 DOI: 10.1021/acs.nanolett.7b00596] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A fullerene derivative with five hydroxyphenyl groups attached around a pentagon, (4-HOC6H4)5HC60 (1), has shown an asymmetric current-voltage (I-V) curve in a conducting atomic force microscopy experiment on gold. Such molecular rectification has been ascribed to the asymmetric distribution of frontier molecular orbitals over its shuttlecock-shaped structure. Our nonequilibrium Green's function (NEGF) calculations based on density functional theory (DFT) indeed exhibit an asymmetric I-V curve for 1 standing up between two Au(111) electrodes, but the resulting rectification ratio (RR ∼ 3) is insufficient to explain the wide range of RR observed in experiments performed under a high bias voltage. Therefore, we formulate a hypothesis that high RR (>10) may come from molecular orientation switching induced by a strong electric field applied between two electrodes. Indeed, molecular dynamics simulations of a self-assembled monolayer of 1 on Au(111) show that the orientation of 1 can be switched between standing-up and lying-on-the-side configurations in a manner to align its molecular dipole moment with the direction of the applied electric field. The DFT-NEGF calculations taking into account such field-induced reorientation between up and side configurations indeed yield RR of ∼13, which agrees well with the experimental value obtained under a high bias voltage.
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Affiliation(s)
- Taekhee Ryu
- Department of Energy Systems Engineering, DGIST , Daegu 42988, Korea
| | - Yves Lansac
- GREMAN, UMR 7347, CNRS, Université François Rabelais , 37200 Tours, France
- Laboratoire de Physique des Solides, CNRS, Université Paris-Sud , 91405 Orsay, France
| | - Yun Hee Jang
- Department of Energy Systems Engineering, DGIST , Daegu 42988, Korea
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159
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Abstract
A programmable electrochemical rectifier based on thin-layer electrochemistry is described here. Both the rectification ratio and the response time of the device are programmable by controlling the gap distance of the thin-layer electrochemical cell, which is easily controlled using commercially available beads. One of the electrodes was modified using a ferrocene-terminated self-assembled monolayer to offer unidirectional charge transfers via soluble redox species. The thin-layer configuration provided enhanced mass transport, which was determined by the gap thickness. The device with the smallest gap thickness (∼4 μm) showed an unprecedented, high rectification ratio (up to 160) with a fast response time in a two-terminal configuration using conventional electronics.
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Affiliation(s)
- Seungjin Park
- Department of Chemistry, Korea Advanced Institute of Science and Technology , Daejeon 34141, Korea
| | - Jun Hui Park
- Department of Chemistry Education and Institute of Fusion Science, Chonbuk National University , Jeonju 54896, Korea
| | - Seongpil Hwang
- Department of Advanced Materials Chemistry, Korea University , Sejong 30019, Korea
| | - Juhyoun Kwak
- Department of Chemistry, Korea Advanced Institute of Science and Technology , Daejeon 34141, Korea
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160
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Choong SW, Russell SR, Bang JJ, Patterson JK, Claridge SA. Sitting Phase Monolayers of Polymerizable Phospholipids Create Dimensional, Molecular-Scale Wetting Control for Scalable Solution-Based Patterning of Layered Materials. ACS Appl Mater Interfaces 2017; 9:19326-19334. [PMID: 28535061 DOI: 10.1021/acsami.7b03279] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The use of dimensionally ordered ligands on layered materials to direct local electronic structure and interactions with the environment promises to streamline integration into nanostructured electronic, optoelectronic, sensing, and nanofluidic interfaces. Substantial progress has been made in using ligands to control substrate electronic structure. Conversely, using the exposed face of the ligand layer to structure wetting and binding interactions, particularly with scalable solution- or spray-processed materials, remains a significant challenge. However, nature routinely utilizes wetting control at scales from nanometer to micrometer to build interfaces of striking geometric precision and functional complexity, suggesting the possibility of leveraging similar control in synthetic materials. Here, we assemble striped "sitting" phases of polymerizable phospholipids on highly oriented pyrolytic graphite, producing a surface consisting of 1 nm wide hydrophilic stripes alternating with 5 nm wide hydrophobic stripes. Protruding, strongly wetting headgroup chemistries in these monolayers enable formation of rodlike wetted patterns with widths as little as ∼6 nm and lengths up to 100 nm from high-surface-tension liquids (aqueous solutions of glycerol) commonly utilized to assess interfacial wetting properties at larger length scales. In contrast, commonly used lying-down phases of diynoic acids with in-plane headgroups do not promote droplet sticking or directional spreading. These results point to a broadly applicable strategy for achieving high-resolution solution-based patterning on layered materials, utilizing nanometer-wide patterns of protruding, charged functional groups in a noncovalent monolayer to define pattern edges.
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Affiliation(s)
- Shi Wah Choong
- Department of Chemistry, and ‡Weldon School of Biomedical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| | - Shane R Russell
- Department of Chemistry, and ‡Weldon School of Biomedical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| | - Jae Jin Bang
- Department of Chemistry, and ‡Weldon School of Biomedical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| | - Justin K Patterson
- Department of Chemistry, and ‡Weldon School of Biomedical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| | - Shelley A Claridge
- Department of Chemistry, and ‡Weldon School of Biomedical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
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161
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Kim YH, Lee EY, Lee HH, Seo TS. Characteristics of Reduced Graphene Oxide Quantum Dots for a Flexible Memory Thin Film Transistor. ACS Appl Mater Interfaces 2017; 9:16375-16380. [PMID: 28445035 DOI: 10.1021/acsami.7b00714] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Reduced graphene oxide quantum dot (rGOQD) devices in formats of capacitor and thin film transistor (TFT) were demonstrated and examined as the first trial to achieve nonambipolar channel property. In addition, through a gold nanoparticle (Au NP) layer embedded between the rGOQD active channel and dielectric layer, memory capacitor and TFT performances were realized by capacitance-voltage (C-V) hysteresis and gate program, erase, and reprogram biases. First, capacitor structure of the rGOQD memory device was constructed to examine memory charging effect featured in hysteretic C-V behavior with a 30 nm dielectric layer of cross-linked poly(vinyl alcohol). For the intervening Au NP charging layer, self-assembled monolayer (SAM) formation of the Au NP was executed to utilize electrostatic interaction by a dip-coating process under ambient environments with a conformal fabrication uniformity. Second, the rGOQD memory TFT device was also constructed in the same format of the Au NPs SAMs on a flexible substrate. Characteristics of the rGOQD TFT output showed novel saturation curves unlike typical graphene-based TFTs. However, The rGOQD TFT device reveals relatively low on/off ratio of 101 and mobility of 5.005 cm2/V·s. For the memory capacitor, the flat-band voltage shift (ΔVFB) was measured as 3.74 V for ±10 V sweep, and for the memory TFT, the threshold voltage shift (ΔVth) by the Au NP charging was detected as 7.84 V. In summary, it was concluded that the rGOQD memory device could accomplish an ideal graphene-based memory performance, which could have provided a wide memory window and saturated output characteristics.
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Affiliation(s)
- Yo-Han Kim
- Department of Chemical Engineering, Myongji University , 116 Myongji-ro, Cheoin-gu, Yongin-si, Gyeonggi-do 17058, Republic of Korea
| | - Eun Yeol Lee
- Department of Chemical Engineering, College of Engineering, Kyung Hee University , 1 Seochon-dong, Giheung-gu, Yongin-si, Gyeonggi-do 17104, Republic of Korea
| | - Hyun Ho Lee
- Department of Chemical Engineering, Myongji University , 116 Myongji-ro, Cheoin-gu, Yongin-si, Gyeonggi-do 17058, Republic of Korea
| | - Tae Seok Seo
- Department of Chemical Engineering, College of Engineering, Kyung Hee University , 1 Seochon-dong, Giheung-gu, Yongin-si, Gyeonggi-do 17104, Republic of Korea
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162
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Shibuta M, Hirata N, Eguchi T, Nakajima A. Photoexcited State Confinement in Two-Dimensional Crystalline Anthracene Monolayer at Room Temperature. ACS Nano 2017; 11:4307-4314. [PMID: 28399361 DOI: 10.1021/acsnano.7b01506] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Organic thin film electronics place a high demand on bottom-up technology to form a two-dimensionally (2D) functional unit consisting of a single molecular crystalline layer bound to a layered structure. As the strong interaction between a substrate and molecules makes it difficult to evaluate the electronic properties of organic films, the nature of electronic excited states has not been elucidated. Here, we study a 2D crystalline anthracene monolayer electronically decoupled by alkanethiolates on a gold substrate using scanning tunneling microscopy and time-resolved two-photon photoemission spectroscopy and unravel the geometric/electronic structures and excited electron dynamics. Our data reveal that dispersive 2D excited electrons on the surface can be highly coupled with an annihilation of nondispersive excitons that facilitate electron emission with vibronic interaction. Our results provide a fundamental framework for understanding photoexcited anthracene monolayer and show how the coupling between dispersive and nondispersive excited states may assist charge separation in crystalline molecular layers.
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Affiliation(s)
- Masahiro Shibuta
- Keio Institute of Pure and Applied Science (KiPAS), Keio University , 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - Naoyuki Hirata
- Nakajima Designer Nanocluster Assembly Project, ERATO, Japan Science and Technology Agency (JST) , 3-2-1 Sakado, Takatsu-ku, Kawasaki 213-0012, Japan
- Department of Chemistry, Faculty of Science and Technology, Keio University , 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - Toyoaki Eguchi
- Nakajima Designer Nanocluster Assembly Project, ERATO, Japan Science and Technology Agency (JST) , 3-2-1 Sakado, Takatsu-ku, Kawasaki 213-0012, Japan
- Department of Chemistry, Faculty of Science and Technology, Keio University , 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - Atsushi Nakajima
- Keio Institute of Pure and Applied Science (KiPAS), Keio University , 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
- Nakajima Designer Nanocluster Assembly Project, ERATO, Japan Science and Technology Agency (JST) , 3-2-1 Sakado, Takatsu-ku, Kawasaki 213-0012, Japan
- Department of Chemistry, Faculty of Science and Technology, Keio University , 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
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163
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Muhammad P, Tu X, Liu J, Wang Y, Liu Z. Molecularly Imprinted Plasmonic Substrates for Specific and Ultrasensitive Immunoassay of Trace Glycoproteins in Biological Samples. ACS Appl Mater Interfaces 2017; 9:12082-12091. [PMID: 28290193 DOI: 10.1021/acsami.7b00628] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Assays of glycoproteins hold significant biological importance and clinical values, for which immunoassay has been the workhorse tool. As immunoassays are associated with disadvantages such as poor availability of high-specificity antibodies, limited stability of biological reagents, and tedious procedure, innovative alternatives that can overcome these drawbacks are highly desirable. Plasmonic immunosandwich assay (PISA) has emerged as an appealing alternative to immunoassay for fast and sensitive determination of trace glycoproteins in biosamples. Plasmonic substrates play key roles in PISA, not only in determining the specificity but also in greatly influencing the detection sensitivity. Herein, we report a new type of molecularly imprinted plasmonic substrates for rapid and ultrasensitive PISA assay of trace glycoproteins in complex real samples. The substrates were fabricated from glass slides, first coated with self-assembled monolayer (SAM) of gold nanoparticles (AuNPs) and then molecularly imprinted with organo-siloxane polymer in the presence of template glycoproteins. The prepared molecularly imprinted substrates exhibited not only a significant plasmonic effect but also excellent binding properties, ensuring the sensitivity as well as the specificity of the assay. Alkaline phosphatase (ALP) and α-fetoprotein (AFP), glycoproteins that are routinely used as disease markers in clinical diagnosis, were used as representative targets. The limit of detection (LOD) was 3.1 × 10-12 M for ALP and 1.5 × 10-14 M for AFP, which is the best among the PISA approaches reported. The sample volume required was only 5 μL, and the total time required was within 30 min for each assay. Specific and ultrasensitive determination of ALP and AFP in human serum was demonstrated. Because many disease biomarkers are glycoproteins, the developed PISA approach holds great promise in disease diagnostics.
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Affiliation(s)
- Pir Muhammad
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210023, China
| | - Xueying Tu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210023, China
| | - Jia Liu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210023, China
| | - Yijia Wang
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210023, China
| | - Zhen Liu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210023, China
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164
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Stock P, Monroe JI, Utzig T, Smith DJ, Shell MS, Valtiner M. Unraveling Hydrophobic Interactions at the Molecular Scale Using Force Spectroscopy and Molecular Dynamics Simulations. ACS Nano 2017; 11:2586-2597. [PMID: 28267918 DOI: 10.1021/acsnano.6b06360] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Interactions between hydrophobic moieties steer ubiquitous processes in aqueous media, including the self-organization of biologic matter. Recent decades have seen tremendous progress in understanding these for macroscopic hydrophobic interfaces. Yet, it is still a challenge to experimentally measure hydrophobic interactions (HIs) at the single-molecule scale and thus to compare with theory. Here, we present a combined experimental-simulation approach to directly measure and quantify the sequence dependence and additivity of HIs in peptide systems at the single-molecule scale. We combine dynamic single-molecule force spectroscopy on model peptides with fully atomistic, both equilibrium and nonequilibrium, molecular dynamics (MD) simulations of the same systems. Specifically, we mutate a flexible (GS)5 peptide scaffold with increasing numbers of hydrophobic leucine monomers and measure the peptides' desorption from hydrophobic self-assembled monolayer surfaces. Based on the analysis of nonequilibrium work-trajectories, we measure an interaction free energy that scales linearly with 3.0-3.4 kBT per leucine. In good agreement, simulations indicate a similar trend with 2.1 kBT per leucine, while also providing a detailed molecular view into HIs. This approach potentially provides a roadmap for directly extracting qualitative and quantitative single-molecule interactions at solid/liquid interfaces in a wide range of fields, including interactions at biointerfaces and adhesive interactions in industrial applications.
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Affiliation(s)
- Philipp Stock
- Department for Interface Chemistry and Surface Engineering, Max-Planck-Institut für Eisenforschung GmbH , D-40237 Düsseldorf, Germany
| | - Jacob I Monroe
- Department of Chemical Engineering, University of California Santa Barbara , Santa Barbara, California 93106-5080, United States
| | - Thomas Utzig
- Department for Interface Chemistry and Surface Engineering, Max-Planck-Institut für Eisenforschung GmbH , D-40237 Düsseldorf, Germany
| | - David J Smith
- Department of Chemical Engineering, University of California Santa Barbara , Santa Barbara, California 93106-5080, United States
| | - M Scott Shell
- Department of Chemical Engineering, University of California Santa Barbara , Santa Barbara, California 93106-5080, United States
| | - Markus Valtiner
- Department for Interface Chemistry and Surface Engineering, Max-Planck-Institut für Eisenforschung GmbH , D-40237 Düsseldorf, Germany
- Department for Physical Chemistry, Technische Universität Bergakademie Freiberg , D-09599 Freiberg, Germany
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165
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Tu Q, Kim HS, Oweida TJ, Parlak Z, Yingling YG, Zauscher S. Interfacial Mechanical Properties of Graphene on Self-Assembled Monolayers: Experiments and Simulations. ACS Appl Mater Interfaces 2017; 9:10203-10213. [PMID: 28230343 DOI: 10.1021/acsami.6b16593] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Self-assembled monolayers (SAMs) have been widely used to engineer the electronic properties of substrate-supported graphene devices. However, little is known about how the surface chemistry of SAMs affects the interfacial mechanical properties of graphene supported on SAMs. Fluctuations and changes in these properties affect the stress transfer between substrate and the supported graphene and thus the performance of graphene-based devices. The changes in interfacial mechanical properties can be characterized by measuring the out-of-plane elastic properties. Combining contact resonance atomic force microcopy experiments with molecular dynamics simulations, we show that the head group chemistry of a SAM, which affects the interfacial interactions, can have a significant effect on the out-of-plane elastic modulus of the graphene-SAM heterostructure. Graphene supported on hydrophobic SAMs leads to heterostructures stiffer than those of graphene supported on hydrophilic SAMs, which is largely due to fewer water molecules present at the graphene-SAM interface. Our results provide an important, and often overlooked, insight into the mechanical properties of substrate-supported graphene electronics.
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Affiliation(s)
- Qing Tu
- Department of Mechanical Engineering and Materials Science, Duke University , Durham, North Carolina 27708, United States
- NSF Research Triangle, Materials Research Science and Engineering Center , Durham, North Carolina 27708, United States
| | - Ho Shin Kim
- NSF Research Triangle, Materials Research Science and Engineering Center , Durham, North Carolina 27708, United States
- Department of Materials Science and Engineering, North Carolina State University , Raleigh, North Carolina 27695, United States
| | - Thomas J Oweida
- Department of Materials Science and Engineering, North Carolina State University , Raleigh, North Carolina 27695, United States
| | - Zehra Parlak
- Department of Mechanical Engineering and Materials Science, Duke University , Durham, North Carolina 27708, United States
| | - Yaroslava G Yingling
- NSF Research Triangle, Materials Research Science and Engineering Center , Durham, North Carolina 27708, United States
- Department of Materials Science and Engineering, North Carolina State University , Raleigh, North Carolina 27695, United States
| | - Stefan Zauscher
- Department of Mechanical Engineering and Materials Science, Duke University , Durham, North Carolina 27708, United States
- NSF Research Triangle, Materials Research Science and Engineering Center , Durham, North Carolina 27708, United States
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166
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Zhang J, Ma W, He XP, Tian H. Taking Orders from Light: Photo-Switchable Working/Inactive Smart Surfaces for Protein and Cell Adhesion. ACS Appl Mater Interfaces 2017; 9:8498-8507. [PMID: 28221015 DOI: 10.1021/acsami.6b15599] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Photoresponsive smart surfaces are promising candidates for a variety of applications in optoelectronics and sensing devices. The use of light as an order signal provides advantages of remote and noninvasive control with high temporal and spatial resolutions. Modification of the photoswitches with target biomacromolecules, such as peptides, DNA, and small molecules including folic acid derivatives and sugars, has recently become a popular strategy to empower the smart surfaces with an improved detection efficiency and specificity. Herein, we report the construction of photoswitchable self-assembled monolayers (SAMs) based on sugar (galactose/mannose)-decorated azobenzene derivatives and determine their photoswitchable, selective protein/cell adhesion performances via electrochemistry. Under alternate UV/vis irradiation, interconvertible high/low recognition and binding affinity toward selective lectins (proteins that recognize sugars) and cells that highly express sugar receptors are achieved. Furthermore, the cis-SAMs with a low binding affinity toward selective proteins and cells also exhibit minimal response toward unselective protein and cell samples, which offers the possibility in avoiding unwanted contamination and consumption of probes prior to functioning for practical applications. Besides, the electrochemical technique used facilitates the development of portable devices based on the smart surfaces for on-demand disease diagnosis.
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Affiliation(s)
- Junji Zhang
- Key Laboratory for Advanced Materials & Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology , 130 Meilong Road, Shanghai 200237, P. R. China
| | - Wenjing Ma
- Key Laboratory for Advanced Materials & Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology , 130 Meilong Road, Shanghai 200237, P. R. China
| | - Xiao-Peng He
- Key Laboratory for Advanced Materials & Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology , 130 Meilong Road, Shanghai 200237, P. R. China
| | - He Tian
- Key Laboratory for Advanced Materials & Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology , 130 Meilong Road, Shanghai 200237, P. R. China
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167
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Abstract
The interfacial electrochemistry of self-assembled monolayers (SAMs) of ferrocenyldodecanethiolate on gold (FcC12SAu) electrodes is applied to detect the micellization of some common anionic surfactants, sodium n-alkyl sulfates, sodium n-alkyl sulfonates, sodium diamyl sulfosuccinate, and sodium dodecanoate, in aqueous solution by cyclic voltammetry. The apparent formal redox potential (E°'SAM) of the FcC12SAu SAM is used to track changes in the concentration of the unaggregated surfactant anions and determine the critical micelle concentration (cmc). The effect of added salt (NaF) on the sodium alkyl sulfate concentration dependence of E°'SAM is also investigated. Weakly hydrated anions, such as ClO4-, pair with the electrogenerated SAM-bound ferroceniums to neutralize the excess positive charge created at the SAM/electrolyte solution interface and stabilize the oxidized cations. E°'SAM exhibits a Nernstian-type dependence on the anion activity in solution. Aggregation of the surfactant anions into micelles above the cmc causes the free surfactant anion activity to deviate from the molar concentration of added surfactant, resulting in a break in the plot of E°'SAM versus the logarithm of the concentration of anionic surfactant. The concentration at which this deviation occurs is in good agreement with literature or experimentally determined values of the cmc. The effects of Ohmic potential drop, liquid junction potential, and surfactant adsorption behavior on E°'SAM are addressed. Ultimately, the E°'SAM response as a function of the anionic surfactant concentration exhibits the same features reported using potentiometry and surfactant ion-selective electrodes, which provide a direct measure of the free surfactant anion activity, thus making FcC12SAu SAM electrodes useful for the detection of surfactant aggregation and micelle formation.
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Affiliation(s)
- Eric R Dionne
- Département de chimie, FRQNT Centre for Self-Assembled Chemical Structures, and Regroupement québécois sur les matériaux de pointe, Université de Montréal , C.P. 6128 succursale Centre-ville, Montréal, Quebec H3C 3J7, Canada
| | - Antonella Badia
- Département de chimie, FRQNT Centre for Self-Assembled Chemical Structures, and Regroupement québécois sur les matériaux de pointe, Université de Montréal , C.P. 6128 succursale Centre-ville, Montréal, Quebec H3C 3J7, Canada
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168
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Lee J, Lee JY, Yeo JS. Optimally Functionalized Adhesion for Contact Transfer Printing of Plasmonic Nanostructures on Flexible Substrate. ACS Appl Mater Interfaces 2017; 9:3251-3259. [PMID: 28085243 DOI: 10.1021/acsami.6b12739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This paper demonstrates a facile method to achieve high yield and uniform fabrication for the transfer printing of nanoplasmonic structures on a flexible substrate by providing novel understanding on adhesion layers. The mercapto alkyl carboxylic acids and the alkyl dithiols are used as functionalized adhesion layers and further optimized by controlling the terminal group as well as the length and composition of the functionalization on flat and nanostructured gold surfaces. Our approach of optimized adhesion has been successfully implemented to the transfer printing of functionalized gold nanostructure arrays, thus producing much higher yield of 97.6% and uniform fabrication of nanostructures on a flexible substrate and enabling applications such as flexible nanoplasmonic devices and biosensing platforms.
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Affiliation(s)
- Jihye Lee
- School of Integrated Technology and ‡Yonsei Institute of Convergence Technology, Yonsei University , Incheon, 406-840, Republic of Korea
| | - Jun-Young Lee
- School of Integrated Technology and ‡Yonsei Institute of Convergence Technology, Yonsei University , Incheon, 406-840, Republic of Korea
| | - Jong-Souk Yeo
- School of Integrated Technology and ‡Yonsei Institute of Convergence Technology, Yonsei University , Incheon, 406-840, Republic of Korea
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169
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Tseng YT, Lu HY, Li JR, Tung WJ, Chen WH, Chau LK. Facile Functionalization of Polymer Surfaces in Aqueous and Polar Organic Solvents via 3-Mercaptopropylsilatrane. ACS Appl Mater Interfaces 2016; 8:34159-34169. [PMID: 27960363 DOI: 10.1021/acsami.6b13926] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Surface modification of a polymer substrate with a mercapto functionality is crucial in many applications such as flexible circuitry and point-of-care biosensors. We present here a novel bifunctional molecular adhesive, 3-mercaptopropylsilatrane (MPS), as an interface between polymer and metal surfaces. Under ambient conditions, surface modification of polymer surfaces with a mercapto functionality can be achieved with low concentration (0.46 mM) of MPS in aqueous solvent (50% ethanol) in a short time (<30 min). Three popular polymers for optical sensors, polycarbonate, polyethylene terephthalate, and poly(methyl methacrylate), were employed as substrates, and MPS films formed on these substrates were examined and compared with that on a glass substrate. The films were characterized by UV-vis spectroscopy, water contact angle, X-ray photoelectron spectroscopy, and atomic force microscopy. MPS was also used as a bifunctional linker for the construction of a gold nanoparticle (AuNP) sub-monolayer on these polymer surfaces. Under optimized preparation conditions, the absorbance and full width at half-maximum of the plasmon band are comparable to those of a AuNP-modified glass substrate. Hence, MPS may have a potential to be a key component in polymer substrate-based localized surface plasmon resonance sensors. A self-catalytic surface reaction mechanism is also proposed to account for the results. As compared to a glass surface with a high number of silanol groups, the successful formation of an MPS film on polymer surfaces with relatively few reactive sites is probably due to the lateral polymerization of MPS starting from a condensed MPS molecule on a reactive site of a polymer surface.
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Affiliation(s)
| | - Hsin-Yu Lu
- Department of Chemistry, National Cheng-Kung University , Tainan City 70101, Taiwan
| | - Jie-Ren Li
- Department of Chemistry, National Cheng-Kung University , Tainan City 70101, Taiwan
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170
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Minamiki T, Minami T, Sasaki Y, Wakida SI, Kurita R, Niwa O, Tokito S. Label-Free Detection of Human Glycoprotein (CgA) Using an Extended-Gated Organic Transistor-Based Immunosensor. Sensors (Basel) 2016; 16:s16122033. [PMID: 27916899 PMCID: PMC5191014 DOI: 10.3390/s16122033] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/26/2016] [Accepted: 11/28/2016] [Indexed: 11/16/2022]
Abstract
Herein, we report on the fabrication of an extended-gated organic field-effect transistor (OFET)-based immunosensor and its application in the detection of human chromogranin A (hCgA). The fabricated OFET device possesses an extended-gate electrode immobilized with an anti-CgA antibody. The titration results of hCgA showed that the electrical changes in the OFET characteristics corresponded to the glycoprotein recognition ability of the monoclonal antibody (anti-CgA). The observed sensitivity (detection limit: 0.11 µg/mL) and selectivity indicate that the OFET-based immunosensor can be potentially applied to the rapid detection of the glycoprotein concentration without any labeling.
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Affiliation(s)
- Tsukuru Minamiki
- Research Center for Organic Electronics, Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan.
- Japan Society for the Promotion of Science (JSPS), Ichibancho, Chiyoda-ku, Tokyo 102-8471, Japan.
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.
| | - Tsuyoshi Minami
- Research Center for Organic Electronics, Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan.
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.
| | - Yui Sasaki
- Research Center for Organic Electronics, Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan.
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.
| | - Shin-Ichi Wakida
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan.
| | - Ryoji Kurita
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan.
| | - Osamu Niwa
- Advanced Science Research Laboratory, Saitama Institute of Technology, Fukaya, Saitama 369-0293, Japan.
| | - Shizuo Tokito
- Research Center for Organic Electronics, Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan.
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171
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Abstract
Large-area graphene needs to be directly synthesized on the desired substrates without using a transfer process so that it can easily be used in industrial applications. However, the development of a direct method for graphene growth on an arbitrary substrate remains challenging. Here, we demonstrate a bottom-up and transfer-free growth method for preparing multilayer graphene using a self-assembled monolayer (trimethoxy phenylsilane) as the carbon source. Graphene was directly grown on various substrates such as SiO2/Si, quartz, GaN, and textured Si by a simple thermal annealing process employing catalytic metal encapsulation. To determine the optimal growth conditions, experimental parameters such as the choice of catalytic metal, growth temperatures, and gas flow rate were investigated. The optical transmittance at 550 nm and the sheet resistance of the prepared transfer-free graphene are 84.3% and 3500 Ω/□, respectively. The synthesized graphene samples were fabricated into chemical sensors. High and fast responses to both NO2 and NH3 gas molecules were observed. The transfer-free graphene growth method proposed in this study is highly compatible with previously established fabrication systems, thereby opening up new possibilities for using graphene in versatile applications.
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Affiliation(s)
- Gwangseok Yang
- Department of Chemical and Biological Engineering, Korea University , Seoul 02841, South Korea
| | - Hong-Yeol Kim
- Department of Chemical and Biological Engineering, Korea University , Seoul 02841, South Korea
| | - Soohwan Jang
- Department of Chemical Engineering, Dankook University , Yongin 16890, South Korea
| | - Jihyun Kim
- Department of Chemical and Biological Engineering, Korea University , Seoul 02841, South Korea
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172
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Guo C, Yu X, Refaely-Abramson S, Sepunaru L, Bendikov T, Pecht I, Kronik L, Vilan A, Sheves M, Cahen D. Tuning electronic transport via hepta-alanine peptides junction by tryptophan doping. Proc Natl Acad Sci U S A 2016; 113:10785-90. [PMID: 27621456 DOI: 10.1073/pnas.1606779113] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Charge migration for electron transfer via the polypeptide matrix of proteins is a key process in biological energy conversion and signaling systems. It is sensitive to the sequence of amino acids composing the protein and, therefore, offers a tool for chemical control of charge transport across biomaterial-based devices. We designed a series of linear oligoalanine peptides with a single tryptophan substitution that acts as a "dopant," introducing an energy level closer to the electrodes' Fermi level than that of the alanine homopeptide. We investigated the solid-state electron transport (ETp) across a self-assembled monolayer of these peptides between gold contacts. The single tryptophan "doping" markedly increased the conductance of the peptide chain, especially when its location in the sequence is close to the electrodes. Combining inelastic tunneling spectroscopy, UV photoelectron spectroscopy, electronic structure calculations by advanced density-functional theory, and dc current-voltage analysis, the role of tryptophan in ETp is rationalized by charge tunneling across a heterogeneous energy barrier, via electronic states of alanine and tryptophan, and by relatively efficient direct coupling of tryptophan to a Au electrode. These results reveal a controlled way of modulating the electrical properties of molecular junctions by tailor-made "building block" peptides.
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173
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Epstein J, Ong WL, Bettinger CJ, Malen JA. Temperature Dependent Thermal Conductivity and Thermal Interface Resistance of Pentacene Thin Films with Varying Morphology. ACS Appl Mater Interfaces 2016; 8:19168-19174. [PMID: 27391107 DOI: 10.1021/acsami.6b06338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Temperature dependent thermal conductivities and thermal interface resistances of pentacene (Pn) thin films deposited on silicon substrates and self-assembled monolayer-modified [octadecyltrichlorosilane (OTS) and (3-aminopropyl)triethoxysilane (APTES)] silicon substrates were measured using frequency domain thermoreflectance. Atomic force microscopy images were used to derive an effective film thickness for thermal transport that accounts for surface roughness. Data taken over a temperature range of 77-300 K for various morphologies and film thicknesses show that the thermal conductivity increases with increasing Pn grain size. The sum of the substrate-Pn and Pn-gold thermal interface resistances was isolated from the intrinsic thermal resistance of the Pn films and found to be independent of surface chemistry. Corresponding Kapitza lengths of approximately 150 nm are larger than the physical thicknesses of typical Pn thin films and indicate that the interfaces play a dominant role in the total thermal resistance. This study has implications for increasing the performance and effective thermal management of small molecule electronic and energy conversion devices.
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Affiliation(s)
- Jillian Epstein
- Department of Materials Science and Engineering, Carnegie Mellon University , 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Wee-Liat Ong
- Department of Mechanical Engineering, Carnegie Mellon University , 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Christopher J Bettinger
- Department of Materials Science and Engineering, Carnegie Mellon University , 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Jonathan A Malen
- Department of Materials Science and Engineering, Carnegie Mellon University , 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
- Department of Mechanical Engineering, Carnegie Mellon University , 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
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174
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Imaizumi Y, Goda T, Toya Y, Matsumoto A, Miyahara Y. Oleyl group-functionalized insulating gate transistors for measuring extracellular pH of floating cells. Sci Technol Adv Mater 2016; 17:337-345. [PMID: 27877886 PMCID: PMC5101916 DOI: 10.1080/14686996.2016.1198217] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/20/2016] [Accepted: 06/02/2016] [Indexed: 05/23/2023]
Abstract
The extracellular ionic microenvironment has a close relationship to biological activities such as by cellular respiration, cancer development, and immune response. A system composed of ion-sensitive field-effect transistors (ISFET), cells, and program-controlled fluidics has enabled the acquisition of real-time information about the integrity of the cell membrane via pH measurement. Here we aimed to extend this system toward floating cells such as T lymphocytes for investigating complement activation and pharmacokinetics through alternations in the plasma membrane integrity. We functionalized the surface of tantalum oxide gate insulator of ISFET with oleyl-tethered phosphonic acid for interacting with the plasma membranes of floating cells without affecting the cell signaling. The surface modification was characterized by X-ray photoelectron spectroscopy and water contact angle measurements. The Nernst response of -37.8 mV/pH was obtained for the surface-modified ISFET at 37 °C. The oleyl group-functionalized gate insulator successfully captured Jurkat T cells in a fluidic condition without acute cytotoxicity. The system was able to record the time course of pH changes at the cells/ISFET interface during the process of instant addition and withdrawal of ammonium chloride. Further, the plasma membrane injury of floating cells after exposure by detergent Triton™ X-100 was successfully determined using the modified ISFET with enhanced sensitivity as compared with conventional hemolysis assays.
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Affiliation(s)
- Yuki Imaizumi
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Tatsuro Goda
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Yutaro Toya
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Akira Matsumoto
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Yuji Miyahara
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
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175
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Byun KE, Cho Y, Seol M, Kim S, Kim SW, Shin HJ, Park S, Hwang S. Control of Triboelectrification by Engineering Surface Dipole and Surface Electronic State. ACS Appl Mater Interfaces 2016; 8:18519-25. [PMID: 27337938 DOI: 10.1021/acsami.6b02802] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Although triboelectrification is a well-known phenomenon, fundamental understanding of its principle on a material surface has not been studied systematically. Here, we demonstrated that the surface potential, especially the surface dipoles and surface electronic states, governed the triboelectrification by controlling the surface with various electron-donating and -withdrawing functional groups. The functional groups critically affected the surface dipoles and surface electronic states followed by controlling the amount of and even the polarity of triboelectric charges. As a result, only one monolayer with a thickness of less than 1 nm significantly changed the conventional triboelectric series. First-principles simulations confirmed the atomistic origins of triboelectric charges and helped elucidate the triboelectrification mechanism. The simulation also revealed for the first time where charges are retained after triboelectrification. This study provides new insights to understand triboelectrification.
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Affiliation(s)
- Kyung-Eun Byun
- Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea
| | - Yeonchoo Cho
- Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea
| | - Minsu Seol
- Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea
| | - Seongsu Kim
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU) , Suwon 440-746, Republic of Korea
| | - Sang-Woo Kim
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU) , Suwon 440-746, Republic of Korea
| | - Hyeon-Jin Shin
- Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea
| | - Seongjun Park
- Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea
| | - Sungwoo Hwang
- Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea
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176
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Markov A, Greben K, Mayer D, Offenhäusser A, Wördenweber R. In Situ Analysis of the Growth and Dielectric Properties of Organic Self-Assembled Monolayers: A Way To Tailor Organic Layers for Electronic Applications. ACS Appl Mater Interfaces 2016; 8:16451-16456. [PMID: 27268402 DOI: 10.1021/acsami.6b04021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Organic nanoscale science and technology relies on the control of phenomena occurring at the molecular level. This is of particular importance for the self-assembly of molecular monolayers (SAM) that can be used in various applications ranging from organic electronics to bioelectronic applications. However, the understanding of the elementary nanoscopic processes in molecular film growth is still in its infancy. Here, we developed a novel in situ and extremely sensitive detection method for the analysis of the electronic properties of molecular layer during molecular layer deposition. This low-frequency sensor (1 kHz) is employed to analyze the standard vapor deposition process of SAMs of molecules and, subsequently, it is used to optimize the growth process itself. By combining this method with an ex situ determination of the effective thickness of the resulting layers via ellipsometry, we observe a large difference of the permittivity (1 kHz) of the examined aminosilanes in the liquid state (εliquid = 5.5-8.8) and in SAMs (εSAM = 22-52, electric field in the plane of the layer). We ascribe this difference to either the different orientation and order of the molecules, the different density of molecules, or a combination of both effects. Our novel in situ analyses not only allows monitoring and optimizing the deposition of organic layers but also demonstrates the high potential of organic SAMs as organic high-k layers in electronic devices.
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Affiliation(s)
- Aleksandr Markov
- Peter Grünberg Institute (PGI-8), Forschungszentrum Jülich , Jülich 52425, Germany
| | - Kyrylo Greben
- Peter Grünberg Institute (PGI-8), Forschungszentrum Jülich , Jülich 52425, Germany
| | - Dirk Mayer
- Peter Grünberg Institute (PGI-8), Forschungszentrum Jülich , Jülich 52425, Germany
| | - Andreas Offenhäusser
- Peter Grünberg Institute (PGI-8), Forschungszentrum Jülich , Jülich 52425, Germany
| | - Roger Wördenweber
- Peter Grünberg Institute (PGI-8), Forschungszentrum Jülich , Jülich 52425, Germany
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177
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Ostapenko A, Klöffel T, Eußner J, Harms K, Dehnen S, Meyer B, Witte G. Etching of Crystalline ZnO Surfaces upon Phosphonic Acid Adsorption: Guidelines for the Realization of Well-Engineered Functional Self-Assembled Monolayers. ACS Appl Mater Interfaces 2016; 8:13472-13483. [PMID: 27159837 DOI: 10.1021/acsami.6b02190] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Functionalization of metal oxides by means of covalently bound self-assembled monolayers (SAMs) offers a tailoring of surface electronic properties such as their work function and, in combination with its large charge carrier mobility, renders ZnO a promising conductive oxide for use as transparent electrode material in optoelectronic devices. In this study, we show that the formation of phosphonic acid-anchored SAMs on ZnO competes with an unwanted chemical side reaction, leading to the formation of surface precipitates and severe surface damage at prolonged immersion times of several days. Combining atomic force microscopy (AFM), X-ray diffraction (XRD), and thermal desorption spectroscopy (TDS), the stability and structure of the aggregates formed upon immersion of ZnO single crystal surfaces of different orientations [(0001̅), (0001), and (101̅0)] in phenylphosphonic acid (PPA) solution were studied. By intentionally increasing the immersion time to more than 1 week, large crystalline precipitates are formed, which are identified as zinc phosphonate. Moreover, the energetics and the reaction pathway of this transformation have been evaluated using density functional theory (DFT), showing that zinc phosphonate is thermodynamically more favorable than phosphonic acid SAMs on ZnO. Precipitation is also found for phosphonic acids with fluorinated aromatic backbones, while less precipitation occurs upon formation of SAMs with phenylphosphinic anchoring units. By contrast, no precipitates are formed when PPA monolayer films are prepared by sublimation under vacuum conditions, yielding smooth surfaces without noticeable etching.
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Affiliation(s)
- Alexandra Ostapenko
- Fachbereich Physik, Molekulare Festkörperphysik and Wissenschaftliches Zentrum für Materialwissenschaften (WZMW), Philipps-Universität Marburg , Renthof 7, 35032 Marburg, Germany
| | - Tobias Klöffel
- Interdisciplinary Center for Molecular Materials (ICMM) and Computer-Chemistry-Center (CCC), Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg , Nägelsbachstrasse 25, 91052 Erlangen, Germany
| | - Jens Eußner
- Fachbereich Chemie and Wissenschaftliches Zentrum für Materialwissenschaften (WZMW), Philipps-Universität Marburg , Hans-Meerwein-Strasse 4, 35043 Marburg, Germany
| | - Klaus Harms
- Fachbereich Chemie and Wissenschaftliches Zentrum für Materialwissenschaften (WZMW), Philipps-Universität Marburg , Hans-Meerwein-Strasse 4, 35043 Marburg, Germany
| | - Stefanie Dehnen
- Fachbereich Chemie and Wissenschaftliches Zentrum für Materialwissenschaften (WZMW), Philipps-Universität Marburg , Hans-Meerwein-Strasse 4, 35043 Marburg, Germany
| | - Bernd Meyer
- Interdisciplinary Center for Molecular Materials (ICMM) and Computer-Chemistry-Center (CCC), Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg , Nägelsbachstrasse 25, 91052 Erlangen, Germany
| | - Gregor Witte
- Fachbereich Physik, Molekulare Festkörperphysik and Wissenschaftliches Zentrum für Materialwissenschaften (WZMW), Philipps-Universität Marburg , Renthof 7, 35032 Marburg, Germany
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178
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Narita A, Fujii K, Baba Y, Shimoyama I. Use of a DNA film on a self-assembled monolayer for investigating the physical process of DNA damage induced by core electron ionization. Int J Radiat Biol 2016; 92:733-738. [PMID: 27192925 DOI: 10.1080/09553002.2016.1179812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
PURPOSE A novel two-layer sample composed of a deoxyribonucleic acid (DNA) film and self-assembled monolayer (SAM) was prepared on an inorganic surface to mimic the processes in which DNA is damaged by soft X-ray irradiation. MATERIALS AND METHODS A mercaptopropyltrimethoxysilane (MPTS) SAM was formed on a sapphire surface, then oligonucleotide (OGN) molecules were adsorbed on the MPTS-SAM. The thicknesses and chemical states of the layers were determined by X-ray photoelectron spectroscopy (XPS) and near-edge X-ray fine structure (NEXAFS) around the phosphorus (P) and sulfur (S) K-edges. To induce the damage to the OGN molecules, the sample was irradiated with synchrotron soft X-rays. The chemical state of the OGN molecules before and after irradiation was examined by NEXAFS around the nitrogen (N) K-edge region. RESULTS The thickness of the MPTS-OGN layer was approximately 7.7 nm. The S atom of the OGN molecules was located at the bottom of the OGN layer. The peak shape of the N K-edge NEXAFS spectra of the MPTS-OGN layers clearly changed following irradiation. CONCLUSIONS The MPTS-OGN layer formed on the sapphire surface. The chemical states and the structure of the interface were elucidated using synchrotron soft X-rays. The OGN molecules adsorbed on the MPTS films decomposed upon exposure to soft X-ray irradiation.
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Affiliation(s)
- Ayumi Narita
- a Japan Atomic Energy Agency , Shirakata, Tokai , Naka , Ibaraki , Japan
| | - Kentaro Fujii
- a Japan Atomic Energy Agency , Shirakata, Tokai , Naka , Ibaraki , Japan
| | - Yuji Baba
- a Japan Atomic Energy Agency , Shirakata, Tokai , Naka , Ibaraki , Japan
| | - Iwao Shimoyama
- a Japan Atomic Energy Agency , Shirakata, Tokai , Naka , Ibaraki , Japan
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179
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Abraham F, Ford WE, Scholz F, Nelles G, Sandford G, von Wrochem F. Surface Energy and Work Function Control of AlOx/Al Surfaces by Fluorinated Benzylphosphonic Acids. ACS Appl Mater Interfaces 2016; 8:11857-11867. [PMID: 27093557 DOI: 10.1021/acsami.6b02012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The performance of organic electronic devices can be significantly improved by modifying metal electrodes with organic monolayers, which alter the physical and chemical nature of the interface between conductor and semiconductor. In this paper we examine a series of 12 phosphonic acid compounds deposited on the native oxide layer of aluminum (AlOx/Al), an electrode material with widespread applications in organic electronics. This series includes dodecylphosphonic acid as a reference and 11 benzylphosphonic acids, seven of which are fluorinated, including five newly synthesized derivatives. The monolayers are experimentally characterized by contact angle goniometry and by X-ray photoemission spectroscopy (XPS), and work function data obtained by low-intensity XPS are correlated with molecular dipoles obtained from DFT calculations. We find that monolayers are formed with molecular areas ranging from 17.7 to 42.9 Å(2)/molecule, and, by the choice of appropriate terminal groups, the surface energy can be tuned from 23.5 mJ/m(2) to 70.5 mJ/m(2). Depending on the number and position of fluorine substituents on the aromatic rings, a variation in the work function of AlOx/Al substrates over a range of 0.91 eV is achieved, and a renormalization procedure based on molecular density yields a surprising agreement of work function changes with interface dipoles as expected from Helmholtz' equation. The ability to adjust energetics and adhesion at organic semiconductor/AlOx interfaces has immediate applications in devices such as OLEDs, OTFTs, organic solar cells, and printed organic circuits.
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Affiliation(s)
- Ffion Abraham
- Department of Chemistry, Durham University , South Road, Durham DH1 3LE, U.K
| | - William E Ford
- Materials Science Laboratory, Sony Deutschland GmbH , Hedelfinger Strasse 61, 70327 Stuttgart, Germany
| | - Frank Scholz
- Materials Science Laboratory, Sony Deutschland GmbH , Hedelfinger Strasse 61, 70327 Stuttgart, Germany
| | - Gabriele Nelles
- Materials Science Laboratory, Sony Deutschland GmbH , Hedelfinger Strasse 61, 70327 Stuttgart, Germany
| | - Graham Sandford
- Department of Chemistry, Durham University , South Road, Durham DH1 3LE, U.K
| | - Florian von Wrochem
- Materials Science Laboratory, Sony Deutschland GmbH , Hedelfinger Strasse 61, 70327 Stuttgart, Germany
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180
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Corra S, Lewandowska U, Benetti EM, Wennemers H. Size-Controlled Formation of Noble-Metal Nanoparticles in Aqueous Solution with a Thiol-Free Tripeptide. Angew Chem Int Ed Engl 2016; 55:8542-5. [PMID: 27098442 DOI: 10.1002/anie.201510337] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 03/23/2016] [Indexed: 11/09/2022]
Abstract
A combinatorial screening revealed the peptide H-His-d-Leu-d-Asp-NH2 (1) as an additive for the generation of monodisperse, water-soluble palladium nanoparticles with average diameters of 3 nm and stabilities of over 9 months. The tripeptide proved to be also applicable for the size-controlled formation of other noble-metal nanoparticles (Pt and Au). Studies with close analogues of peptide 1 revealed a specific role of each of the three amino acids for the formation and stabilization of the nanoparticles. These data combined with microscopic and spectroscopic analyses provided insight into the structure of the self-assembled peptidic monolayer around the metal core. The results open interesting prospects for the development of functionalized metal nanoparticles.
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Affiliation(s)
- Stefano Corra
- Laboratory of Organic Chemistry, D-CHAB, ETH Zürich, Vladimir-Prelog-Weg 3, 8093, Zürich, Switzerland
| | - Urszula Lewandowska
- Laboratory of Organic Chemistry, D-CHAB, ETH Zürich, Vladimir-Prelog-Weg 3, 8093, Zürich, Switzerland
| | - Edmondo M Benetti
- Laboratory for Surface Science and Technology, D-MATL, ETH Zürich, Vladimir-Prelog-Weg 5, 8093, Zürich, Switzerland
| | - Helma Wennemers
- Laboratory of Organic Chemistry, D-CHAB, ETH Zürich, Vladimir-Prelog-Weg 3, 8093, Zürich, Switzerland.
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181
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Yan C, Yuan R, Pfalzgraff WC, Nishida J, Wang L, Markland TE, Fayer MD. Unraveling the dynamics and structure of functionalized self-assembled monolayers on gold using 2D IR spectroscopy and MD simulations. Proc Natl Acad Sci U S A 2016; 113:4929-34. [PMID: 27044113 DOI: 10.1073/pnas.1603080113] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Functionalized self-assembled monolayers (SAMs) are the focus of ongoing investigations because they can be chemically tuned to control their structure and dynamics for a wide variety of applications, including electrochemistry, catalysis, and as models of biological interfaces. Here we combine reflection 2D infrared vibrational echo spectroscopy (R-2D IR) and molecular dynamics simulations to determine the relationship between the structures of functionalized alkanethiol SAMs on gold surfaces and their underlying molecular motions on timescales of tens to hundreds of picoseconds. We find that at higher head group density, the monolayers have more disorder in the alkyl chain packing and faster dynamics. The dynamics of alkanethiol SAMs on gold are much slower than the dynamics of alkylsiloxane SAMs on silica. Using the simulations, we assess how the different molecular motions of the alkyl chain monolayers give rise to the dynamics observed in the experiments.
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182
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Peng L, Yarman A, Jetzschmann KJ, Jeoung JH, Schad D, Dobbek H, Wollenberger U, Scheller FW. Molecularly Imprinted Electropolymer for a Hexameric Heme Protein with Direct Electron Transfer and Peroxide Electrocatalysis. Sensors (Basel) 2016; 16:272. [PMID: 26907299 DOI: 10.3390/s16030272] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 02/12/2016] [Accepted: 02/18/2016] [Indexed: 12/20/2022]
Abstract
For the first time a molecularly imprinted polymer (MIP) with direct electron transfer (DET) and bioelectrocatalytic activity of the target protein is presented. Thin films of MIPs for the recognition of a hexameric tyrosine-coordinated heme protein (HTHP) have been prepared by electropolymerization of scopoletin after oriented assembly of HTHP on a self-assembled monolayer (SAM) of mercaptoundecanoic acid (MUA) on gold electrodes. Cavities which should resemble the shape and size of HTHP were formed by template removal. Rebinding of the target protein sums up the recognition by non-covalent interactions between the protein and the MIP with the electrostatic attraction of the protein by the SAM. HTHP bound to the MIP exhibits quasi-reversible DET which is reflected by a pair of well pronounced redox peaks in the cyclic voltammograms (CVs) with a formal potential of -184.4 ± 13.7 mV vs. Ag/AgCl (1 M KCl) at pH 8.0 and it was able to catalyze the cathodic reduction of peroxide. At saturation the MIP films show a 12-fold higher electroactive surface concentration of HTHP than the non-imprinted polymer (NIP).
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183
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Widmer-Cooper A, Geissler PL. Ligand-Mediated Interactions between Nanoscale Surfaces Depend Sensitively and Nonlinearly on Temperature, Facet Dimensions, and Ligand Coverage. ACS Nano 2016; 10:1877-87. [PMID: 26756464 DOI: 10.1021/acsnano.5b05569] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Nanoparticles are often covered in ligand monolayers, which can undergo a temperature-dependent order-disorder transition that switches the particle-particle interaction from repulsive to attractive in solution. In this work, we examine how changes in the ligand surface coverage and facet dimensions affect the ordering of ligands, the arrangement of nearby solvent molecules, and the interaction between ligand monolayers on different particles. In particular, we consider the case of strongly bound octadecyl ligands on the (100) facet of CdS in the presence of an explicit n-hexane solvent. Depending on the facet dimensions and surface coverage, we observe three distinct ordered states that differ in how the ligands are packed together, and which affect the thickness of the ligand shell and the structure of the ligand-solvent interface. The temperature dependence of the order-disorder transition also broadens and shifts to lower temperature in a nonlinear manner as the nanoscale is approached from above. We find that ligands on nanoscale facets can behave very similarly to those on macroscopic surfaces in solution, and that some facet dimensions affect the ligand alignment more strongly than others. As the ligands order, the interaction between opposing monolayers becomes attractive, even well below full surface coverage. The strength of attraction per unit surface area is strongly affected by ligand coverage, but only weakly by facet width. Conversely, we find that bringing two monolayers together just above the order-disorder transition temperature can induce ordering and attraction.
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Affiliation(s)
- Asaph Widmer-Cooper
- School of Chemistry, University of Sydney , Sydney, New South Wales 2006, Australia
| | - Phillip L Geissler
- Department of Chemistry, University of California Berkeley , Berkeley, California 94720, United States
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184
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Chen H, Cheng N, Ma W, Li M, Hu S, Gu L, Meng S, Guo X. Design of a Photoactive Hybrid Bilayer Dielectric for Flexible Nonvolatile Organic Memory Transistors. ACS Nano 2016; 10:436-45. [PMID: 26673624 DOI: 10.1021/acsnano.5b05313] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Organic field-effect transistors (OFETs) featuring a photoactive hybrid bilayer dielectric (PHBD) that comprises a self-assembled monolayer (SAM) of photochromic diarylethenes (DAEs) and an ultrathin solution-processed hafnium oxide layer are described here. We photoengineer the energy levels of DAE SAMs to facilitate the charging and discharging of the interface of the two dielectrics, thus yielding an OFET that functions as a nonvolatile memory device. The transistors use light signals for programming and electrical signals for erasing (≤3 V) to produce a large, reversible threshold-voltage shift with long retention times and good nondestructive signal processing ability. The memory effect can be exercised by more than 10(4) memory cycles. Furthermore, these memory cells have demonstrated the capacity to be arrayed into a photosensor matrix on flexible plastic substrates to detect the spatial distribution of a confined light and then store the analog sensor input as a two-dimensional image with high precision over a long period of time.
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Affiliation(s)
- Hongliang Chen
- Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, People's Republic of China
| | - Nongyi Cheng
- Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, People's Republic of China
| | - Wei Ma
- Institute of Physics, Chinese Academy of Sciences , Beijing 100190, People's Republic of China
| | - Mingliang Li
- Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, People's Republic of China
| | - Shuxin Hu
- Institute of Physics, Chinese Academy of Sciences , Beijing 100190, People's Republic of China
| | - Lin Gu
- Institute of Physics, Chinese Academy of Sciences , Beijing 100190, People's Republic of China
| | - Sheng Meng
- Institute of Physics, Chinese Academy of Sciences , Beijing 100190, People's Republic of China
| | - Xuefeng Guo
- Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, People's Republic of China
- Department of Materials Science and Engineering, College of Engineering, Peking University , Beijing 100871, People's Republic of China
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185
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Wang B, Huang M, Tao L, Lee SH, Jang AR, Li BW, Shin HS, Akinwande D, Ruoff RS. Support-Free Transfer of Ultrasmooth Graphene Films Facilitated by Self-Assembled Monolayers for Electronic Devices and Patterns. ACS Nano 2016; 10:1404-10. [PMID: 26701198 DOI: 10.1021/acsnano.5b06842] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We explored a support-free method for transferring large area graphene films grown by chemical vapor deposition to various fluoric self-assembled monolayer (F-SAM) modified substrates including SiO2/Si wafers, polyethylene terephthalate films, and glass. This method yields clean, ultrasmooth, and high-quality graphene films for promising applications such as transparent, conductive, and flexible films due to the absence of residues and limited structural defects such as cracks. The F-SAM introduced in the transfer process can also lead to graphene transistors with enhanced field-effect mobility (up to 10,663 cm(2)/Vs) and resistance modulation (up to 12×) on a standard silicon dioxide dielectric. Clean graphene patterns can be realized by transfer of graphene onto only the F-SAM modified surfaces.
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Affiliation(s)
- Bin Wang
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS) , Ulsan 689-798, Republic of Korea
| | - Ming Huang
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS) , Ulsan 689-798, Republic of Korea
| | - Li Tao
- Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas , Austin, Texas 78758, United States
| | - Sun Hwa Lee
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS) , Ulsan 689-798, Republic of Korea
| | | | - Bao-Wen Li
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS) , Ulsan 689-798, Republic of Korea
| | | | - Deji Akinwande
- Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas , Austin, Texas 78758, United States
| | - Rodney S Ruoff
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS) , Ulsan 689-798, Republic of Korea
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186
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Kyaw HH, Al-Harthi SH, Sellai A, Dutta J. Self-organization of gold nanoparticles on silanated surfaces. Beilstein J Nanotechnol 2015; 6:2345-53. [PMID: 26734526 PMCID: PMC4685859 DOI: 10.3762/bjnano.6.242] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 11/24/2015] [Indexed: 05/28/2023]
Abstract
The self-organization of monolayer gold nanoparticles (AuNPs) on 3-aminopropyltriethoxysilane (APTES)-functionalized glass substrate is reported. The orientation of APTES molecules on glass substrates plays an important role in the interaction between AuNPs and APTES molecules on the glass substrates. Different orientations of APTES affect the self-organization of AuNps on APTES-functionalized glass substrates. The as grown monolayers and films annealed in ultrahigh vacuum and air (600 °C) were studied by water contact angle measurements, atomic force microscopy, X-ray photoelectron spectroscopy, UV-visible spectroscopy and ultraviolet photoelectron spectroscopy. Results of this study are fundamentally important and also can be applied for designing and modelling of surface plasmon resonance based sensor applications.
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Affiliation(s)
- Htet H Kyaw
- Physics Department, College of Science, Sultan Qaboos University, P.O. Box 36, Al-Khoudh, Muscat 123, Sultanate of Oman
| | - Salim H Al-Harthi
- Physics Department, College of Science, Sultan Qaboos University, P.O. Box 36, Al-Khoudh, Muscat 123, Sultanate of Oman
| | - Azzouz Sellai
- Physics Department, College of Science, Sultan Qaboos University, P.O. Box 36, Al-Khoudh, Muscat 123, Sultanate of Oman
| | - Joydeep Dutta
- Chair in Nanotechnology, Water Research Center, Sultan Qaboos University, PO Box 17, Al-Khoudh, Muscat 123, Sultanate of Oman
- Functional Materials Division, School of Information and Communication Technology, KTH Royal Institute of Technology, Isafjordsgatan 22, SE-164 40 Kista Stockholm, Sweden
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187
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Palazon F, Léonard D, Le Mogne T, Zuttion F, Chevalier C, Phaner-Goutorbe M, Souteyrand É, Chevolot Y, Cloarec JP. Orthogonal chemical functionalization of patterned gold on silica surfaces. Beilstein J Nanotechnol 2015; 6:2272-2277. [PMID: 26734519 PMCID: PMC4685923 DOI: 10.3762/bjnano.6.233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 11/11/2015] [Indexed: 06/05/2023]
Abstract
Single-step orthogonal chemical functionalization procedures have been developed with patterned gold on silica surfaces. Different combinations of a silane and a thiol were simultaneously deposited on a gold/silica heterogeneous substrate. The orthogonality of the functionalization (i.e., selective grafting of the thiol on the gold areas and the silane on the silica) was demonstrated by X-ray photoelectron spectroscopy (XPS) as well as time-of-flight secondary ion mass spectrometry (ToF-SIMS) mapping. The orthogonal functionalization was used to immobilize proteins onto gold nanostructures on a silica substrate, as demonstrated by atomic force microscopy (AFM). These results are especially promising in the development of future biosensors where the selective anchoring of target molecules onto nanostructured transducers (e.g., nanoplasmonic biosensors) is a major challenge.
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Affiliation(s)
- Francisco Palazon
- Université de Lyon, Institut des Nanotechnologies de Lyon, site École Centrale de Lyon, CNRS UMR 5270, 36 Avenue Guy de Collongue, 69134 Écully, France
| | - Didier Léonard
- Université de Lyon, Institut des Sciences Analytiques, Université Claude Bernard Lyon 1 / CNRS / ENS de Lyon, CNRS UMR 5280, 5 rue de la Doua, 69100 Villeurbanne, France
| | - Thierry Le Mogne
- Université de Lyon, École Centrale de Lyon, Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR 5513, 36 Avenue Guy de Collongue, 69134 Écully, France
| | - Francesca Zuttion
- Université de Lyon, Institut des Nanotechnologies de Lyon, site École Centrale de Lyon, CNRS UMR 5270, 36 Avenue Guy de Collongue, 69134 Écully, France
| | - Céline Chevalier
- Laboratoire Nanotechnologies & Nanosystèmes (UMI-LN2 3463), Université de Sherbrooke - CNRS - INSA de Lyon - ECL - UJF-CPE Lyon, Université de Sherbrooke, 3000 Boulevard de l’Université, Sherbrooke, Québec J1K 0A5, Canada
- LTM/CNRS/RENATECH, 17 rue des martyrs, 38054 Grenoble, France
| | - Magali Phaner-Goutorbe
- Université de Lyon, Institut des Nanotechnologies de Lyon, site École Centrale de Lyon, CNRS UMR 5270, 36 Avenue Guy de Collongue, 69134 Écully, France
| | - Éliane Souteyrand
- Université de Lyon, Institut des Nanotechnologies de Lyon, site École Centrale de Lyon, CNRS UMR 5270, 36 Avenue Guy de Collongue, 69134 Écully, France
| | - Yann Chevolot
- Université de Lyon, Institut des Nanotechnologies de Lyon, site École Centrale de Lyon, CNRS UMR 5270, 36 Avenue Guy de Collongue, 69134 Écully, France
| | - Jean-Pierre Cloarec
- Université de Lyon, Institut des Nanotechnologies de Lyon, site École Centrale de Lyon, CNRS UMR 5270, 36 Avenue Guy de Collongue, 69134 Écully, France
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188
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Kang T, Oh DX, Heo J, Lee HK, Choy S, Hawker CJ, Hwang DS. Formation, Removal, and Reformation of Surface Coatings on Various Metal Oxide Surfaces Inspired by Mussel Adhesives. ACS Appl Mater Interfaces 2015; 7:24656-24662. [PMID: 26492561 DOI: 10.1021/acsami.5b06910] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Mussels survive by strongly attaching to a variety of different surfaces, primarily subsurface rocks composed of metal oxides, through the formation of coordinative interactions driven by protein-based catechol repeating units contained within their adhesive secretions. From a chemistry perspective, catechols are known to form strong and reversible complexes with metal ions or metal oxides, with the binding affinity being dependent on the nature of the metal ion. As a result, catechol binding with metal oxides is reversible and can be broken in the presence of a free metal ion with a higher stability constant. It is proposed to exploit this competitive exchange in the design of a new strategy for the formation, removal, and reformation of surface coatings and self-assembled monolayers (SAM) based on catechols as the adhesive unit. In this study, catechol-functionalized tri(ethylene oxide) (TEO) was synthesized as a removable and recoverable self-assembled monolayer (SAM) for use on oxides surfaces. Attachment and detachment of these catechol derivatives on a variety of surfaces was shown to be reversible and controllable by exploiting the high stability constant of catechol to soluble metal ions, such as Fe(III). This tunable assembly based on catechol binding to metal oxides represents a new concept for reformable coatings with applications in fields ranging from friction/wettability control to biomolecular sensing and antifouling.
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Affiliation(s)
- Taegon Kang
- Chemical Research Institute, Samsung Cheil Industries, Inc. , Uiwang-si, Gyeonggi-do, 437-711, Republic of Korea
| | | | | | - Han-Koo Lee
- Pohang Accelerator Laboratory , Pohang, Gyeongbuk 790-784, Republic of Korea
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189
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Yamamoto H, Demura T, Sekine K, Kono S, Niwano M, Hirano-Iwata A, Tanii T. Photopatterning Proteins and Cells in Aqueous Environment Using TiO2 Photocatalysis. J Vis Exp 2015:e53045. [PMID: 26554338 PMCID: PMC4692672 DOI: 10.3791/53045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Organic contaminants adsorbed on the surface of titanium dioxide (TiO2) can be decomposed by photocatalysis under ultraviolet (UV) light. Here we describe a novel protocol employing the TiO2 photocatalysis to locally alter cell affinity of the substrate surface. For this experiment, a thin TiO2 film was sputter-coated on a glass coverslip, and the TiO2 surface was subsequently modified with an organosilane monolayer derived from octadecyltrichlorosilane (OTS), which inhibits cell adhesion. The sample was immersed in a cell culture medium, and focused UV light was irradiated to an octagonal region. When a neuronal cell line PC12 cells were plated on the sample, cells adhered only on the UV-irradiated area. We further show that this surface modification can also be performed in situ, i.e., even when cells are growing on the substrate. Proper modification of the surface required an extracellular matrix protein collagen to be present in the medium at the time of UV irradiation. The technique presented here can potentially be employed in patterning multiple cell types for constructing coculture systems or to arbitrarily manipulate cells under culture.
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Affiliation(s)
- Hideaki Yamamoto
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University; CREST, Japan Science and Technology Agency;
| | - Takanori Demura
- School of Fundamental Science and Engineering, Waseda University
| | - Kohei Sekine
- School of Fundamental Science and Engineering, Waseda University
| | - Sho Kono
- School of Fundamental Science and Engineering, Waseda University
| | - Michio Niwano
- CREST, Japan Science and Technology Agency; Research Institute of Electrical Communication, Tohoku University
| | - Ayumi Hirano-Iwata
- CREST, Japan Science and Technology Agency; Graduate School of Biomedical Engineering, Tohoku University
| | - Takashi Tanii
- Faculty of Science and Engineering, Waseda University
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190
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Kim J, Park CJ, Yi G, Choi MS, Park SK. Low-Temperature Solution-Processed Gate Dielectrics for High-Performance Organic Thin Film Transistors. Materials (Basel) 2015; 8:6926-6934. [PMID: 28793608 PMCID: PMC5455382 DOI: 10.3390/ma8105352] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 09/23/2015] [Accepted: 10/08/2015] [Indexed: 11/16/2022]
Abstract
A low-temperature solution-processed high-k gate dielectric layer for use in a high-performance solution-processed semiconducting polymer organic thin-film transistor (OTFT) was demonstrated. Photochemical activation of sol-gel-derived AlOx films under 150 °C permitted the formation of a dense film with low leakage and relatively high dielectric-permittivity characteristics, which are almost comparable to the results yielded by the conventionally used vacuum deposition and high temperature annealing method. Octadecylphosphonic acid (ODPA) self-assembled monolayer (SAM) treatment of the AlOx was employed in order to realize high-performance (>0.4 cm2/Vs saturation mobility) and low-operation-voltage (<5 V) diketopyrrolopyrrole (DPP)-based OTFTs on an ultra-thin polyimide film (3-μm thick). Thus, low-temperature photochemically-annealed solution-processed AlOx film with SAM layer is an attractive candidate as a dielectric-layer for use in high-performance organic TFTs operated at low voltages.
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Affiliation(s)
- Jaekyun Kim
- Department of Applied Materials Engineering, Hanbat National University, Daejeon 305-719, Korea.
| | - Chang Jun Park
- School of Electrical and Electronics Engineering, Chung-Ang University, Seoul 156-756, Korea.
| | - Gyeongmin Yi
- School of Electrical and Electronics Engineering, Chung-Ang University, Seoul 156-756, Korea.
| | - Myung-Seok Choi
- Department of Materials Chemistry and Engineering, Konkuk University, Seoul 143-701, Korea.
| | - Sung Kyu Park
- School of Electrical and Electronics Engineering, Chung-Ang University, Seoul 156-756, Korea.
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191
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Shen J, Qi Y, Jin B, Wang X, Hu Y, Jiang Q. Control of hydroxyapatite coating by self-assembled monolayers on titanium and improvement of osteoblast adhesion. J Biomed Mater Res B Appl Biomater 2015; 105:124-135. [PMID: 26426988 DOI: 10.1002/jbm.b.33539] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 08/24/2015] [Accepted: 09/12/2015] [Indexed: 11/11/2022]
Abstract
Self-assembly technique was applied to introduce functional groups and form hydroxyl-, amine-, and carboxyl-terminal self-assembled monolayers (SAMs). The SAMs were grafted onto titanium substrates to obtain a molecularly smooth functional surface. Subsequent hydrothermal crystal growth formed homogeneous and crack-free crystalline hydroxyapatite (HA) coatings on these substrates. AFM and XPS were used to characterize the SAM surfaces, and XRD, SEM, and TEM were used to characterize the HA coatings. Results show that highly crystalline, dense, and oriented HA coatings can be formed on the OH-, NH2 -, and COOH-SAM surfaces. The SAM surface with -COOH exhibited stronger nucleating ability than that with -OH and -NH2 . The nucleation and growth processes of HA coatings were effectively controlled by varying reaction time, pH, and temperature. By using this method, highly crystalline, dense, and adherent HA coatings were obtained. In addition, in vitro cell evaluation demonstrated that HA coatings improved cell adhesion as compared with pristine titanium substrate. The proposed method is considerably effective in introducing the HA coatings on titanium surfaces for various biomedical applications and further usage in other industries. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 124-135, 2017.
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Affiliation(s)
- Juan Shen
- Department of Chemistry, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang, 621010, China.,Department of Chemistry, State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Yongcheng Qi
- Department of Chemistry, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Bo Jin
- Department of Chemistry, State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Xiaoyan Wang
- Department of Chemistry, Research Center for Nano-Biomaterials, Analytical and Testing Center, Sichuan University, Chengdu, 610064, China
| | - Yamin Hu
- Department of Chemistry, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Qiying Jiang
- Department of Chemistry, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang, 621010, China
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192
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Abstract
The design, development, and application of high-speed scanning electrochemical probe microscopy is reported. The approach allows the acquisition of a series of high-resolution images (typically 1000 pixels μm(-2)) at rates approaching 4 seconds per frame, while collecting up to 8000 image pixels per second, about 1000 times faster than typical imaging speeds used up to now. The focus is on scanning electrochemical cell microscopy (SECCM), but the principles and practicalities are applicable to many electrochemical imaging methods. The versatility of the high-speed scan concept is demonstrated at a variety of substrates, including imaging the electroactivity of a patterned self-assembled monolayer on gold, visualization of chemical reactions occurring at single wall carbon nanotubes, and probing nanoscale electrocatalysts for water splitting. These studies provide movies of spatial variations of electrochemical fluxes as a function of potential and a platform for the further development of high speed scanning with other electrochemical imaging techniques.
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Affiliation(s)
- Dmitry Momotenko
- Department of Chemistry, University of Warwick , Coventry CV4 7AL, United Kingdom
| | - Joshua C Byers
- Department of Chemistry, University of Warwick , Coventry CV4 7AL, United Kingdom
| | - Kim McKelvey
- Department of Chemistry, University of Warwick , Coventry CV4 7AL, United Kingdom
| | - Minkyung Kang
- Department of Chemistry, University of Warwick , Coventry CV4 7AL, United Kingdom
| | - Patrick R Unwin
- Department of Chemistry, University of Warwick , Coventry CV4 7AL, United Kingdom
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193
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Hayashi H, Higashino T, Kinjo Y, Fujimori Y, Kurotobi K, Chabera P, Sundström V, Isoda S, Imahori H. Effects of Immersion Solvent on Photovoltaic and Photophysical Properties of Porphyrin-Sensitized Solar Cells. ACS Appl Mater Interfaces 2015; 7:18689-18696. [PMID: 26266818 DOI: 10.1021/acsami.5b05163] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Memory effects in self-assembled monolayers (SAMs) of zinc porphyrin carboxylic acid on TiO2 electrodes have been demonstrated for the first time by evaluating the photovoltaic and electron transfer properties of porphyrin-sensitized solar cells prepared by using different immersion solvents sequentially. The structure of the SAM of the porphyrin on the TiO2 was maintained even after treating the porphyrin monolayer with different neat immersion solvents (memory effect), whereas it was altered by treatment with solutions containing different porphyrins (inverse memory effect). Infrared spectroscopy shows that the porphyrins in the SAM on the TiO2 could be exchanged with the same or analogous porphyrin, leading to a change in the structure of the porphyrin SAM. The memory and inverse memory effects are well correlated with a change in porphyrin geometry, mainly the tilt angle of the porphyrin along the long molecular axis from the surface normal on the TiO2, as well as with kinetics of electron transfer between the porphyrin and TiO2. Such a new structure-function relationship for DSSCs will be very useful for the rational design and optimization of photoelectrochemical and photovoltaic properties of molecular assemblies on semiconductor surfaces.
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Affiliation(s)
| | | | | | | | | | - Pavel Chabera
- Department of Chemical Physics, Lund University , Box 124, 22100 Lund, Sweden
| | - Villy Sundström
- Department of Chemical Physics, Lund University , Box 124, 22100 Lund, Sweden
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194
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Niroui F, Wang AI, Sletten EM, Song Y, Kong J, Yablonovitch E, Swager TM, Lang JH, Bulović V. Tunneling Nanoelectromechanical Switches Based on Compressible Molecular Thin Films. ACS Nano 2015; 9:7886-94. [PMID: 26244821 DOI: 10.1021/acsnano.5b02476] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Abrupt switching behavior and near-zero leakage current of nanoelectromechanical (NEM) switches are advantageous properties through which NEMs can outperform conventional semiconductor electrical switches. To date, however, typical NEMs structures require high actuation voltages and can prematurely fail through permanent adhesion (defined as stiction) of device components. To overcome these challenges, in the present work we propose a NEM switch, termed a "squitch," which is designed to electromechanically modulate the tunneling current through a nanometer-scale gap defined by an organic molecular film sandwiched between two electrodes. When voltage is applied across the electrodes, the generated electrostatic force compresses the sandwiched molecular layer, thereby reducing the tunneling gap and causing an exponential increase in the current through the device. The presence of the molecular layer avoids direct contact of the electrodes during the switching process. Furthermore, as the layer is compressed, the increasing surface adhesion forces are balanced by the elastic restoring force of the deformed molecules which can promote zero net stiction and recoverable switching. Through numerical analysis, we demonstrate the potential of optimizing squitch design to enable large on-off ratios beyond 6 orders of magnitude with operation in the sub-1 V regime and with nanoseconds switching times. Our preliminary experimental results based on metal-molecule-graphene devices suggest the feasibility of the proposed tunneling switching mechanism. With optimization of device design and material engineering, squitches can give rise to a broad range of low-power electronic applications.
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Affiliation(s)
| | | | | | | | | | - Eli Yablonovitch
- Department of Electrical Engineering and Computer Science, University of California , Berkeley, California 94720, United States
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195
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Valotteau C, Calers C, Casale S, Berton J, Stevens CV, Babonneau F, Pradier CM, Humblot V, Baccile N. Biocidal Properties of a Glycosylated Surface: Sophorolipids on Au(111). ACS Appl Mater Interfaces 2015; 7:18086-18095. [PMID: 26247605 DOI: 10.1021/acsami.5b05090] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Classical antibacterial surfaces usually involve antiadhesive and/or biocidal strategies. Glycosylated surfaces are usually used to prevent biofilm formation via antiadhesive mechanisms. We report here the first example of a glycosylated surface with biocidal properties created by the covalent grafting of sophorolipids (a sophorose unit linked by a glycosidic bond to an oleic acid) through a self-assembled monolayer (SAM) of short aminothiols on gold (111) surfaces. The biocidal effect of such surfaces on Gram+ bacteria was assessed by a wide combination of techniques including microscopy observations, fluorescent staining, and bacterial growth tests. About 50% of the bacteria are killed via alteration of the cell envelope. In addition, the roles of the sophorose unit and aliphatic chain configuration are highlighted by the lack of activity of substrates modified, respectively, with sophorose-free oleic acid and sophorolipid-derivative having a saturated aliphatic chain. This system demonstrates thus the direct implication of a carbohydrate in the destabilization and disruption of the bacterial cell envelope.
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Affiliation(s)
- Claire Valotteau
- †Sorbonne Universités, UPMC Univ Paris 06, CNRS, Collège de France, Laboratoire de Chimie de la Matière Condensée de Paris, UMR 7574, 11 Place Marcelin Berthelot, 75005 Paris, France
- ‡Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Réactivité de Surface, UMR 7197, 4 Place Jussieu, 75005 Paris, France
| | - Christophe Calers
- ‡Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Réactivité de Surface, UMR 7197, 4 Place Jussieu, 75005 Paris, France
| | - Sandra Casale
- ‡Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Réactivité de Surface, UMR 7197, 4 Place Jussieu, 75005 Paris, France
| | - Jan Berton
- §SynBioC Research Group, Departement of Sustainable Organic Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Gent, Belgium
| | - Christian V Stevens
- §SynBioC Research Group, Departement of Sustainable Organic Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Gent, Belgium
| | - Florence Babonneau
- †Sorbonne Universités, UPMC Univ Paris 06, CNRS, Collège de France, Laboratoire de Chimie de la Matière Condensée de Paris, UMR 7574, 11 Place Marcelin Berthelot, 75005 Paris, France
| | - Claire-Marie Pradier
- ‡Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Réactivité de Surface, UMR 7197, 4 Place Jussieu, 75005 Paris, France
| | - Vincent Humblot
- ‡Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Réactivité de Surface, UMR 7197, 4 Place Jussieu, 75005 Paris, France
| | - Niki Baccile
- †Sorbonne Universités, UPMC Univ Paris 06, CNRS, Collège de France, Laboratoire de Chimie de la Matière Condensée de Paris, UMR 7574, 11 Place Marcelin Berthelot, 75005 Paris, France
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196
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Deng H, Wang S, Wang X, Du C, Shen X, Wang Y, Cui F. Two competitive nucleation mechanisms of calcium carbonate biomineralization in response to surface functionality in low calcium ion concentration solution. Regen Biomater 2015; 2:187-95. [PMID: 26814639 PMCID: PMC4669016 DOI: 10.1093/rb/rbv010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 04/23/2015] [Accepted: 06/23/2015] [Indexed: 11/14/2022] Open
Abstract
Four self-assembled monolayer surfaces terminated with –COOH, –OH, –NH2 and –CH3 functional groups are used to direct the biomineralization processes of calcium carbonate (CaCO3) in low Ca2+ concentration, and the mechanism of nucleation and initial crystallization within 12 h was further explored. On −COOH surface, nucleation occurs mainly via ion aggregation mechanism while prenucleation ions clusters may be also involved. On −OH and −NH2 surfaces, however, nucleation forms via calcium carbonate clusters, which aggregate in solution and then are adsorbed onto surfaces following with nucleation of amorphous calcium carbonate (ACC). Furthermore, strongly negative-charged −COOH surface facilitates the direct formation of calcites, and the −OH and −NH2 surfaces determine the formation of vaterites with preferred crystalline orientations. Neither ACC nor crystalline CaCO3 is observed on −CH3 surface. Our findings present a valuable model to understand the CaCO3 biomineralization pathway in natural system where functional groups composition plays a determining role during calcium carbonate crystallization.
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Affiliation(s)
- Hua Deng
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China;; Department of Chemistry and Biochemistry, Jackson State University, Jackson, MS 39203, USA
| | - Shuo Wang
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Xiumei Wang
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Chang Du
- School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China and
| | - Xingcan Shen
- Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Chemical Engineering, Guangxi Normal University, Guilin 541004, China
| | - Yingjun Wang
- School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China and
| | - Fuzhai Cui
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
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197
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Nouchi R, Tanimoto T. Substituent-Controlled Reversible Switching of Charge Injection Barrier Heights at Metal/Organic Semiconductor Contacts Modified with Disordered Molecular Monolayers. ACS Nano 2015; 9:7429-7439. [PMID: 26161447 DOI: 10.1021/acsnano.5b02473] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Electrically stimulated switching of a charge injection barrier at the interface between an organic semiconductor and an electrode modified with a disordered monolayer (DM) is studied by using various benzenethiol derivatives as DM molecules. The switching behavior is induced by a structural change in the DM molecules and is manifested as a reversible inversion of the polarity of DM-modified Au electrode/rubrene/DM-modified Au electrode diodes. The switching direction is found to be dominantly determined by the push-back effect of the thiol bonding group, while the terminal group modulates the switching strength. A device with 1,2-benzenedithiol DMs exhibited the highest switching ratios of 20, 10(2), and 10(3) for the switching voltages of 3, 5, and 7 V, respectively. A variation in the tilt angle of benzenethiol DMs due to the application of 7 V is estimated to be smaller than 23.6° by model calculations. This study offers an understanding for obtaining highly stable operations of organic electronic devices, especially with molecular modification layers.
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Affiliation(s)
- Ryo Nouchi
- Nanoscience and Nanotechnology Research Center, Osaka Prefecture University, Sakai 599-8570, Japan
| | - Takaaki Tanimoto
- Nanoscience and Nanotechnology Research Center, Osaka Prefecture University, Sakai 599-8570, Japan
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198
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Jang H, Kim DE, Min DH. Self-assembled Monolayer Mediated Surface Environment Modification of Poly(vinylpyrrolidone)-Coated Hollow Au-Ag Nanoshells for Enhanced Loading of Hydrophobic Drug and Efficient Multimodal Therapy. ACS Appl Mater Interfaces 2015; 7:12789-12796. [PMID: 25996449 DOI: 10.1021/acsami.5b01903] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Hollow Au-Ag bimetallic nanoshell possessing hydrophobic interior space and hydrophilic exterior surface was prepared and its application as a chemo-thermo-gene therapeutic agent based on its high payload of multiple drugs having different water solubility was demonstrated. The multifunctional drug delivery system is based on the hydrophobic interior created by the self-assembled monolayer (SAM) of hexanethiol onto the inner surface of the hollow metallic nanoshells whereas the outer surface was mostly coated by hydrophilic biocompatible polymer. The nanoshells having surface environment modified by hexanethiol SAMs provided high capacity both for hydrophilic DNAzyme (Dz) to induce gene silencing and for hydrophobic SN38 (7-ethyl-10-hydroxycamptothecin), anticancer drug. The release of the loaded Dz and SN38 was independently triggered by an acidic environment and by photothermal temperature elevation upon irradiation, respectively. The chemo-thermo-gene multitherapy based on the present nanoshells having modified surface environment showed high efficacy in quantitative cell-based assays using Huh7 human liver cell containing hepatitis C viral NS3 gene replicon RNA.
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Affiliation(s)
- Hongje Jang
- †Department of Chemistry, Center for RNA Research, Institute for Basic Sciences (IBS), Seoul National University, Seoul 151-747, Republic of Korea
| | - Dong-Eun Kim
- ‡Department of Bioscience and Biotechnology, Konkuk University, Seoul 143-701, Republic of Korea
| | - Dal-Hee Min
- †Department of Chemistry, Center for RNA Research, Institute for Basic Sciences (IBS), Seoul National University, Seoul 151-747, Republic of Korea
- §Lemonex Inc., Seoul 151-742, Republic of Korea
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199
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Timpel M, Nardi MV, Ligorio G, Wegner B, Pätzel M, Kobin B, Hecht S, Koch N. Energy-Level Engineering at ZnO/Oligophenylene Interfaces with Phosphonate-Based Self-Assembled Monolayers. ACS Appl Mater Interfaces 2015; 7:11900-11907. [PMID: 25986080 DOI: 10.1021/acsami.5b01669] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We used aromatic phosphonates with substituted phenyl rings with different molecular dipole moments to form self-assembled monolayers (SAMs) on the Zn-terminated ZnO(0001) surface in order to engineer the energy-level alignment at hybrid inorganic/organic semiconductor interfaces, with an oligophenylene as organic component. The work function of ZnO was tuned over a wide range of more than 1.7 eV by different SAMs. The difference in the morphology and polarity of the SAM-modified ZnO surfaces led to different oligophenylene orientation, which resulted in an orientation-dependent ionization energy that varied by 0.7 eV. The interplay of SAM-induced work function modification and oligophenylene orientation changes allowed tuning of the offsets between the molecular frontier energy levels and the semiconductor band edges over a wide range. Our results demonstrate the versatile use of appropriate SAMs to tune the energy levels of ZnO-based hybrid semiconductor heterojunctions, which is important to optimize its function, e.g., targeting either interfacial energy- or charge-transfer.
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Affiliation(s)
| | | | | | | | - Michael Pätzel
- ∥Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Björn Kobin
- ∥Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Stefan Hecht
- ∥Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Norbert Koch
- ‡Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 16, 12489 Berlin, Germany
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200
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Nishitani N, Hirose T, Matsuda K. Investigation on the Surface-Confined Self-Assembly Stabilized by Hydrogen Bonds of Urea and Amide Groups: Quantitative Analysis of Concentration Dependence of Surface Coverage. Chem Asian J 2015; 10:1926-31. [PMID: 26033832 DOI: 10.1002/asia.201500453] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Indexed: 11/08/2022]
Abstract
Formation of a hydrogen-bond network via an amide group is a key driving force for the nucleation-elongation-type self-assembly that is often seen in biomolecules and artificial supramolecular assemblies. In this work, rod-coil-like aromatic compounds bearing an amide (1 a-3 a) or urea group (1 u-3 u) were synthesized, and their self-assemblies on a 2-D surface were investigated by scanning tunneling microscopy (STM). According to the quantitative analysis of the concentration dependence of the surface coverage, it was revealed that the strength of the hydrogen bond (i.e., amide or urea) and the number of non-hydrogen atoms in a molecular component (i.e., size of core and length of alkyl side chain) play a primary role in determining the stabilization energy during nucleation and elongation processes of molecular ordering on the HOPG surface.
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Affiliation(s)
- Nobuhiko Nishitani
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan
| | - Takashi Hirose
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan
| | - Kenji Matsuda
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan.
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