INFLUENCE OF CONSTITUTION OF HYBRID FERROCENYL ALKANETHIOLS SELF-ASSEMBLED MONOLAYERS TO INTERFACIAL CHARACTERISTICS ON GOLD SURFACE

2010 ◽  
Vol 22 (01) ◽  
pp. 25-31
Author(s):  
Jhen-Gang Huang ◽  
Adam Shih-Yuan Lee ◽  
Shu-Fang Chu ◽  
Yun-Han Lin ◽  
Chii-Wann Lin
Keyword(s):  
Molar Fraction ◽  
Gold Surface ◽  
Self Assembled Monolayers ◽  
Low Power Consumption ◽  
Self Assembled Monolayer ◽  
Oxidation Potentials ◽  
Random Arrangement ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Interfacial Characteristics

The interfacial characteristics of self-assembled monolayer (SAM), that are applied in miniaturized sensor design, were strongly influenced by the SAM constitution. The electrochemical and interfacial characteristics of hybrid SAMs that constituted with ferrocenyl octanethiol ( FcC 8 SH ) and unsubstituted octanethiol ( C 8) or 2-mercaptopyrimidine (2-MPD) were investigated in this study. The peaks of anodic oxidation were observed at around 0.49 V (vs. Ag/AgCl ) in the FcC 8 SH/C 8 hybrid SAM. However, the oxidation potentials descended from 0.42–0.38 V as the molar fraction of FcC 8 SH was decreased from 0.8–0.2 in the FcC 8 SH /2-MPD hybrid SAM. On the other hand, the interfacial hydrophilicity of FcC 8 SH /2-MPD hybrid SAM was measured to be higher than the FcC 8 SH/C 8 hybrid SAM due to the random arrangement of SAM caused by the shape of 2-MPD. Then, the surface roughness of hybrid SAM and chain length of ferrocenyl alkanethiols were all considered to be the parameters of interfacial characteristics. In summary, doping of 2-MPD in SAMs might reduce the rigidity of ferrocenyl alkanethiol SAMs and increase the interfacial hydrophilicity. This result will be useful in the development of the low power consumption portable bioanalytical system. And a miniaturized bioanalytical system based on ferrocenyl SAMs would be developed in the future.

Spectral and cyclic voltammetric characterization of self-assembled monolayers on gold of pyrene end-labeled oligonucleotide duplexes

1999 ◽  
Vol 77 (5-6) ◽  
pp. 1077-1084 ◽  
Author(s):  
R Scott Reese ◽  
Marye Anne Fox
Keyword(s):  
Gold Surface ◽  
Self Assembled Monolayers ◽  
Self Assembled Monolayer ◽  
Surface Emission ◽  
Assembled Monolayers ◽  
Oligonucleotide Duplex ◽  
Self Assembled ◽  
Duplex Formation

Self-assembled monolayers of sulfur-terminated oligonucleotide duplexes were formed on flat gold surfaces, either by exposure of a self-assembled monolayer bearing one oligonucleotide strand to the complementary strand or by preformation of a oligonucleotide duplex that was then deposited on a fresh gold surface. Virtually identical spectral behavior was observed whether the duplex was produced before deposition or by in situ complementary association. With a duplex bearing an appropriate pyrene end-label, the resulting thin film was photoresponsive. Surface emission measurements show no evidence for pyrene aggregation on the modified surfaces. The polarity of the photocurrent, reflecting photoinduced electron transfer initiated by photoexcitation of pyrene, is opposite that expected from the oligonucleotide-mediated reduction of the appended pyrene excited state.Key words: oligonucleotide, self-assembled monolayer, duplex formation, photoelectrochemistry, surface emission.

Specific Immobilization of Streptavidin on Mixed Self-Assembled Monolayers as Mixing Ratio

2007 ◽  
Vol 121-123 ◽  
pp. 495-498 ◽  
Author(s):  
Jun Hyung Park ◽  
Buyng Su Park ◽  
Gu Huh ◽  
Seung Hyun Lee ◽  
Hyun Sook Lee ◽  
...  
Keyword(s):  
Colorimetric Detection ◽  
Gold Surface ◽  
Self Assembled Monolayers ◽  
Scanning Tunneling ◽  
Local Domain ◽  
Mixing Ratio ◽  
Tunneling Microscopy ◽  
Self Assembled Monolayer ◽  
Assembled Monolayers ◽  
Self Assembled

We report on the distribution of mixed self-assembled monolayers (SAMs) composed of biotinylated and diluent alkylthiolates for streptavidin immobilization. Two thiol derivatives, 11-mercapto-1-undecanol (MUOH) and 11-mercaptoundecanoic-(8-biotinylamido-3,6-dioxaoctyl) amide (MBDA), were employed for mixed SAM. These thiols formed self-assembled monolayer without local domain, and streptavidins were immobilized onto biotinylated gold surface without nonspecific binding. In order to find the optimized condition of immobilization of streptavidin, we controlled the mixing ratio of two kind thiols by colorimetric detection assay, and the immobilization was characterized by atomic force microscopy (AFM), scanning tunneling microscopy (STM), and ellipsometer.

scholarly journals Electron-Transfer Properties of Phenyleneethynylene Linkers Bound to Gold via a Self-Assembled Monolayer of Molecular Tripod

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2893 ◽  
Author(s):  
Toshikazu Kitagawa ◽  
Takashi Kawano ◽  
Takahiro Hase ◽  
Ikuma Hayakawa ◽  
Katsuyuki Hirai ◽  
...  
Keyword(s):  
Electron Transfer ◽  
High Surface ◽  
Gold Surface ◽  
Solid Surfaces ◽  
Self Assembled Monolayers ◽  
Self Assembled Monolayer ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Electron Transfer Properties ◽  
Transfer Properties

The three-point adsorption of tripod-shaped molecules enables the formation of robust self-assembled monolayers (SAMs) on solid surfaces, where the component molecules are fixed in a strictly upright orientation. In the present study, SAMs of a rigid molecular tripod consisting of an adamantane core and three CH2SH groups were employed to arrange ferrocene on a gold surface through oligo(p-phenyleneethynylene) linkers. Cyclic voltammetry of the monolayers demonstrated high surface coverage of ferrocene, yet the molecular interaction among adjacent ferrocene units was negligible. This was because of the extended intermolecular distance caused by the bulky tripod framework. The rates of electron transfer from the ferrocene to the gold surface through different linker lengths were determined by electrochemical measurements, from which the decay factor for oligo(p-phenyleneethynylene) wire was evaluated.

Self-Assembled Monolayers of Heme Derivatives on a Gold Surface

2000 ◽  
Vol 73 (9) ◽  
pp. 1993-2000 ◽  
Author(s):  
Kazutoshi Kobayashi ◽  
Shin'ichiro Imabayashi ◽  
Katsuhiko Fujita ◽  
Kazuhide Nonaka ◽  
Takashi Kakiuchi ◽  
...  
Keyword(s):  
Gold Surface ◽  
Self Assembled Monolayers ◽  
Assembled Monolayers ◽  
Self Assembled

Laser Polishing of Cold Work Steel AISI D2 for Dry Metal Forming Tools: Surface Homogenization, Refinement and Preparation for Self-Assembled Monolayers

2018 ◽  
Vol 767 ◽  
pp. 69-76 ◽  
Author(s):  
Ingo Ross ◽  
André Temmler ◽  
Moritz Küpper ◽  
Stephan Prünte ◽  
Marco Teller ◽  
...  
Keyword(s):  
Cold Extrusion ◽  
Self Assembled Monolayers ◽  
Homogeneous Distribution ◽  
Self Assembled Monolayer ◽  
Pulsed Laser Radiation ◽  
Laser Polishing ◽  
Assembled Monolayers ◽  
Aisi D2 ◽  
Self Assembled ◽  
Forming Tools

Liquid lubrication guarantees high precision and surface quality of workpieces in industrial forming processes. In the case of aluminum cold extrusion, wear and cold welding due to direct contact of tool and workpiece are usually prevented by the extensive use of lubricants. Since the use of lubricants is economically and ecologically unfavorable, surface treatments of tools by, e.g. laser polishing and/or coatings are in the focus of current investigations to substitute these lubricants and establish so called “dry metal forming” processes. The material AISI D2, a ledeburitic 12% chromium steel which is known to have a significant amount of chromium carbide precipitations, is widely used in cold extrusion for forming tools. The large fraction of chromium carbide precipitations, however, hinder the formation of a dense self-assembled monolayer (SAM) that is necessary to avoid direct contact of reactive aluminum with surface oxides of the tool. Therefore, a homogeneous distribution of the chemical elements with a smaller fraction or no chromium carbides in the steel matrix, particularly in the tool surface, is aimed for. Using laser polishing, the surface layer is molten by continuous or pulsed laser radiation. Within the melt pool, the elementary distribution is homogenized as a result of thermal convection and diffusion processes, as well as a smoothed surface and a grain refinement are achieved. Consequently, the effects of the surface treatment by laser polishing on the area coverage of self-assembled monolayers are investigated. Thus, a combined surface treatment by laser polishing and functionalization with a dense self-assembled monolayer shall reduce overall adhesive wear. For this investigation, several specimens of conventional manufactured and powder metallurgical molten AISI D2 are laser polished using continuous or pulsed laser radiation or a combination of both. The resulting surfaces are investigated by microscopy and spectroscopic techniques to analyze the surface topography and the elemental distribution near to the surface. These results are compared to those of conventionally hand-polished specimens. Furthermore, the influence of the element homogenization and grain refinement on the area coverage of self-assembled monolayers is explored. First results show that laser polishing of AISI D2 is suitable to achieve a reduction of grain size and a more homogeneous distribution of chromium carbides within the surface layer.

scholarly journals Density Functional Theory with Modified Dispersion Correction for Metals Applied to Self-Assembled Monolayers of Thiols on Au(111)

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
M. P. Andersson
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Dimethyl Disulfide ◽  
Gold Surface ◽  
Self Assembled Monolayers ◽  
Dispersion Correction ◽  
Dissociative Chemisorption ◽  
Functional Theory ◽  
Assembled Monolayers ◽  
Self Assembled

Using sound physical principles we modify the DFT-D2 atom pairwise semiempirical dispersion correction to density functional theory to work for metallic systems and in particular self-assembled monolayers of thiols on gold surfaces. We test our approximation for two functionals PBE-D and revPBE-D for lattice parameters and cohesive energies for Ni, Pd, Pt, Cu, Ag, and Au, adsorption energies of CO on (111) surfaces of Pd, Pt, Cu, Ag, and Au, and adsorption energy of benzene on Ag(111) and Au(111). Agreement with experimental data is substantially improved. We apply the method to self-assembled monolayers of alkanethiols on Au(111) and find reasonable agreement for PBE-D and revPBE-D for both physisorption of n-alkanethiols as well as dissociative chemisorption of dimethyl disulfide as an Au-adatom-dithiolate complex. By modifying the C6 coefficient for Au, we obtain quantitative agreement for physisorption and chemisorption for both PBE-D and revPBE-D using the same set of parameters. Our results confirm that inclusion of dispersion forces is crucial for any quantitative analysis of the thiol and thiolate bonds to the gold surface using quantum chemical calculations.

Self-Assembled Monolayers of Hexapeptides on Gold:  Surface Characterization and Orientation Distribution Analysis†

2004 ◽  
Vol 108 (45) ◽  
pp. 9673-9681 ◽  
Author(s):  
Xingu Wen ◽  
Richard W. Linton ◽  
Fernando Formaggio ◽  
Claudio Toniolo ◽  
Edward T. Samulski
Keyword(s):  
Surface Characterization ◽  
Gold Surface ◽  
Orientation Distribution ◽  
Self Assembled Monolayers ◽  
Distribution Analysis ◽  
Assembled Monolayers ◽  
Self Assembled

Self-Assembled Monolayers of 12-Mercaptododecylphosphonic Acid on Titania Particles; Application to the Extraction of Heavy Metals

2004 ◽  
Vol 847 ◽  
Author(s):  
Sébastien Anthérieu ◽  
Florence Brodard-Séverac ◽  
Gilles Guerrero ◽  
P. Hubert Mutin
Keyword(s):  
Heavy Metals ◽  
Chemical Analysis ◽  
Phosphonic Acid ◽  
Metal Extraction ◽  
Self Assembled Monolayers ◽  
Extraction Ability ◽  
Self Assembled Monolayer ◽  
Inorganic Hybrid ◽  
Assembled Monolayers ◽  
Self Assembled

ABSTRACTTitania particles (P25 DEGUSSA AG) were treated by a solution of 12-mercaptododecyl-phosphonic acid (MDPA) in toluene to obtain an organic-inorganic hybrid material with thiol functions at the surface. This material was characterized by chemical analysis, solid state 31P MAS NMR and FTIR spectroscopies, and XPS. Reaction of the phosphonic acid end of MDPA with the TiO2 surface led to the formation of a relatively dense and well-ordered self-assembled monolayer (SAM), with a density of about 3.9 SH functions per nm2. This material was tested for the extraction of mercury in water at pH 7, 9, and 11. Chemical analysis indicated no loss of SH functionality, even at pH 11. The best extraction results were obtained at pH 9 and 11, with a metal extraction ability between 85 and 90%.

Comparison of Proliferation and Growth of Human Keratinocytes on Plasma CO-Polymers of Acrylic acid/1,7- Octadiene and Self Assembled Monolayers

1998 ◽  
Vol 544 ◽  
Author(s):  
D. B. Haddow ◽  
R. M. France ◽  
R. D. Short ◽  
S. Macneil ◽  
R. A. Dawson
Keyword(s):  
Cell Proliferation ◽  
Tissue Culture ◽  
Carboxylic Acid ◽  
Cell Attachment ◽  
Human Keratinocytes ◽  
Collagen I ◽  
Self Assembled Monolayers ◽  
Self Assembled Monolayer ◽  
Assembled Monolayers ◽  
Self Assembled

AbstractHuman keratinocytes have been cultured on plasma co-polymers (PCPs), self assembled monolayers (SAMs), tissue culture poly(styrene) (TCPS) and collagen I. The degree of keratinocyte attachment was measured over 24 hours and cell proliferation and growth monitored over 7 days using optical microscopy and DNA concentrations. Cell attachment and proliferation and growth on the PCP surfaces were compared with 2 self assembled monolayer (SAM) systems. PCP surfaces containing carboxylic acid functionalities promoted keratinocyte attachment, with optimum attachment levels seen on surfaces containing less than 5% acid groups. The level of attachment on these surfaces was comparable to that seen on collagen I, a preferred substratum for the culturing of keratinocytes. After several days in culture the cells were well attached and proliferative. Keratinocytes attached well to acidterminated SAMs but attached poorly to methyl-terminated SAMs.

scholarly journals Adsorption and desorption of self-assembled L-cysteine monolayers on nanoporous gold monitored by in situ resistometry

2019 ◽  
Vol 10 ◽  
pp. 2275-2279
Author(s):  
Elisabeth Hengge ◽  
Eva-Maria Steyskal ◽  
Rupert Bachler ◽  
Alexander Dennig ◽  
Bernd Nidetzky ◽  
...  
Keyword(s):  
Gold Surface ◽  
Research Field ◽  
Nanoporous Gold ◽  
Self Assembled Monolayers ◽  
Initial Surface ◽  
Resistance Change ◽  
Adsorption And Desorption ◽  
Assembled Monolayers ◽  
Self Assembled

Surface modifications of nanoporous metals have become a highly attractive research field as they exhibit great potential for various applications, especially in biotechnology. Using self-assembled monolayers is one of the most promising approaches to modify a gold surface. However, only few techniques are capable of characterizing the formation of these monolayers on porous substrates. Here, we present a method to in situ monitor the adsorption and desorption of self-assembled monolayers on nanoporous gold by resistometry, using cysteine as example. During the adsorption an overall relative change in resistance of 18% is detected, which occurs in three distinct stages. First, the cysteine molecules are adsorbed on the outer surface. In the second stage, they are adsorbed on the internal surfaces and in the last stage the reordering accompanied by additional adsorption takes place. The successful binding of cysteine on the Au surface was confirmed by cyclic voltammetry, which showed a significant decrease of the double-layer capacitance. Also, the electrochemically controlled desorption of cysteine was monitored by concomitant in situ resistometry. From the desorption peak related to the (111) surface of the structure, which is associated with a resistance change of 4.8%, an initial surface coverage of 0.48 monolayers of cysteine could be estimated.

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