scholarly journals Effect of Processing Parameters on the Formation of Large Area Self-Assembled Monolayer of Polystyrene Beads by a Convective Self-Assembly Method

2015 ◽  
Vol 25 (12) ◽  
pp. 647-654
Author(s):  
Ahn-na Seo ◽  
Ji-Hwan Choi ◽  
Jae-chul Pyun ◽  
Won Mok Kim ◽  
Inho Kim ◽  
...  
Micromachines ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 195 ◽  
Author(s):  
Ngoc-Viet Nguyen ◽  
Chun-Ping Jen

This study established a microfluidic chip for the capture of A549 human lung circulating tumor cells via the aptamer-conjugated self-assembled monolayer (SAM) of gold nanoparticles (AuNPs) in the channel. AuNPs are among the most attractive nanomaterials for the signal enhancement of biosensors owing to their unique chemical, physical, and mechanical properties. The microchip was fabricated using soft photolithography and casting and molding techniques. A self-assembly method was designed to attach AuNPs, cell-specific aptamers, and target cells onto the desired area (i.e., SAM area). In this study, the gold microelectrode configuration was characterized by fluorescence microscopy and impedance measurements to confirm the important modification steps. Subsequently, several investigations with the proposed assay were conducted with different cell samples to determine the specific binding ability of the device for A549 adenocarcinoma cancer cells. This work has ensured a simple, convenient, selective, and sensitive approach for the development of biosensors for lung cancer detection during the early stages.


2011 ◽  
Vol 1335 ◽  
Author(s):  
Qiong Wu ◽  
Juanyuan Hao ◽  
Shoulei Shi ◽  
Weifeng Wang ◽  
Nan Lu

ABSTRACTWe report a low-cost and high-throughput method to fabricate large-area light emitting pattern via thermal evaporation of organic molecules on the patterned self-assembled monolayer of homogenous 3-aminopropyltrimethoxysilane. This method is based on the selective deposition of the organic light emitting molecules on the template of self-assembled monolayer (SAM), which is patterned with nanoimprinting lithography. The selectivity can be controlled by adjusting the design of the pattern, the storage duration and the substrate temperature. The deposition selectivity of the molecules may be caused by the different binding energy of the molecules with the SAM and the substrate surface.


2009 ◽  
Vol 1209 ◽  
Author(s):  
Eric L. Bruner

AbstractAculon, Inc. specializes in inventing and commercializing unique molecular-scale surface and interfacial coatings leveraging nanotechnology discoveries made at Princeton University. These coatings can be classified into three functional areas; non-stick, pro-stick/adhesion, and anti-corrosion. The company has formulated coating solutions and processes for numerous markets including optical, display, electronics, consumer products and industrial coatings. These specialized coatings outperform all known alternatives in characteristics such as adhesion, stain resistance, and scratch resistance. Fueling the company’s commercialization efforts are its proprietary Self-Assembled Monolayer of Phosphonates (SAMP) technology. The commercialization of SAMP treatments can be used for a variety of applications including imparting hydrophobicity, adhesion, or corrosion inhibition to numerous substrates. For surface treatments to be effective, they must be mechanically and chemically stable under conditions experienced in the intended area of use. Aculon’s proprietary Self-Assembled Monolayer of Phosphonates methodology can impart any of these properties as desired to metals, metal oxides and even some polymer surfaces by drawing on its library of structurally tailored phosphonic acids. The secret to the commercialization is covalent bonding, which creates a uniquely strong attachment between the SAMP and the substrate. Because the SAMP is one approximately 1.5 nm thick, it completely covers the material to which it is applied, and assures total surface coverage regardless of the type or texture of that material. The composition of the SAMP determines the properties that it imparts to its substrate. In 1998, Professor Jeffery Schwartz of Princeton University discovered that well-ordered monolayers of phosphonates could be formed by self-assembly on a wide variety of oxide and oxide-terminated surfaces. At that time Professor Schwartz and his team also discovered that a simple dip process enabled SAMP formation on substrates of complex structures and geometries, as well as traditionally “unreactive” surfaces. The research showed that SAMP adhesion to oxides was mechanically strong and resisted removal by hydrolysis and oxidation. It showed further that by using the dip method, SAMPs of a variety of molecular structures, including aliphatic, aromatic, and heteroaromatic, could be prepared. Commercialization of SAMPs proves that such surface-bound phosphonates can dictate control of the surface properties of myriad substrates and that they can be implemented using well-known industrial techniques and conditions. These processes can be scaled to meet the needs of large or small facilities, and can be applied to surfaces of nearly any size or shape without special needs. Based on the needs of the producer, surface modification can be completed during the time of manufacturing or can be performed as a post-production step.


Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2998 ◽  
Author(s):  
Shanshan Li ◽  
Qingying Luo ◽  
Zhiqing Zhang ◽  
Guanghui Shen ◽  
Hejun Wu ◽  
...  

We investigated the permselectivity and interfacial electron transfers of an amphiphilic branch-tailed fluorosurfactant self-assembled monolayer (FS-SAM) on a gold electrode by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The FS-SAM was prepared by a self-assembly technique and a “click” reaction. The barrier property and interfacial electron transfers of the FS-SAM were also evaluated using various probes with different features. The FS-SAM allowed a higher degree of permeation by small hydrophilic (Cl− and F−) electrolyte ions than large hydrophobic (ClO4− and PF6−) ones. Meanwhile, the redox reaction of the Fe(CN)63− couple was nearly completely blocked by the FS-SAM, whereas the electron transfer of Ru(NH3)63+ was easier than that of Fe(CN)63−, which may be due to the underlying tunneling mechanism. For hydrophobic dopamine, the hydrophobic bonding between the FS-SAM exterior fluoroalkyl moieties and the hydrophobic probes, as well as the hydration resistance from the interior hydration shell around the oligo (ethylene glycol) moieties, hindered the transport of hydrophobic probes into the FS-SAM. These results may have profound implications for understanding the permselectivity and electron transfers of amphiphilic surfaces consisting of molecules containing aromatic groups and branch-tailed fluorosurfactants in their structures.


2010 ◽  
Vol 14 (01) ◽  
pp. 101-107 ◽  
Author(s):  
Christoph S. Eberle ◽  
Ana S. Viana ◽  
Franz-Peter Montforts ◽  
Luisa Maria Abrantes

A novel Co(II) porphyrin lipoic acid derivative was synthesized starting from the commerically available red blood pigment hemin. The disulfide functionalities of the lipoic acid moieties allowed its immobilization on gold by a self-assembly method. The Co(II) porphyrin self-assembled monolayer (SAMs) on gold (111) surfaces were characterized electrochemically through monolayer reductive desorption and evaluation of the redox properties of the immobilized molecules in organic medium, and by scanning tunneling microscopy (STM). It was found that after assembly the Co(II) porphyrin is electroactive exhibiting the typical redox processes observed for its precursor without the appended lipoic acid in solution. A coverage of 2.7 × 10-10 mol.cm -2 has been estimated assuming that four electrons (one per each sulfur atom) are involved in the process. The porphyrin-modified gold electrodes exhibit catalytic acitivity demonstrated towards the reduction of molecular oxygen in acidic solution.


2003 ◽  
Vol 68 (8) ◽  
pp. 1395-1406 ◽  
Author(s):  
Massimo Marcaccio ◽  
Massimo Margotti ◽  
Marco Montalti ◽  
Francesco Paolucci ◽  
Luca Prodi ◽  
...  

Redox behaviour of an array of dodecanethiol-coated silver nanoparticles, self-assembled on the gold electrode surface by dithiol linkers, is dominated in aqueous electrolytes by a reversible faradaic process that has been attributed to the anodic oxidation of silver nanoparticles. The nanoparticle array may be switched between the oxidised and reduced states repeatedly without any significant loss of electroactive material, thus showing a remarkable stability under electrochemical conditions. The mainly capacitive high-frequency electrical response of the nanoparticle array/electrolyte interface is characterised by a low value of capacitance, typical of a self assembled monolayer (SAM) of long-chain alkanethiols on gold; it has been associated with the compact organic layer interposed between the nanoparticles and the gold substrate. At lower frequencies, the interface displays a poorer electrical behaviour with both capacitive and resistive elements, which was associated with the more disordered organic layer located on the outer side of the film.


RSC Advances ◽  
2015 ◽  
Vol 5 (120) ◽  
pp. 98814-98821 ◽  
Author(s):  
Tianhao Ouyang ◽  
Arash Akbari-Sharbaf ◽  
Jaewoo Park ◽  
Reg Bauld ◽  
Michael G. Cottam ◽  
...  

Self-assembly of copper nanoparticle (Cu-np) superlattices on graphene thin films is demonstrated. These superlattices show visible light evanescent waveguiding properties.


2002 ◽  
Vol 01 (05n06) ◽  
pp. 593-596 ◽  
Author(s):  
J. Y. OCK ◽  
H. K. SHIN ◽  
Y. S. KWON ◽  
S. H. SONG ◽  
S. M. CHANG ◽  
...  

The electrochemical behavior of viologen self-assembled monolayer has been investigated with QCM, which has been known as ng order mass detector. The self-assembly process of viologen was monitored using resonant frequency (ΔF) and resonant resistance (R). The QCM measurements indicated a mass adsorption for viologen assembling on the gold surface with a frequency change of about 300, 135 Hz and its surface coverage (Γ) was calculated to be 5.02 × 10-9 and 1.64 × 10-9 mol/cm2. A reversible redox process was also observed and analyzed with an ionic interaction at the viologen/solution interface using ΔF.


2009 ◽  
Vol 1202 ◽  
Author(s):  
Chi-Shun Chiu ◽  
Hong-Mao Lee ◽  
Shangjr Gwo

AbstractSurface biofunctionalization of group-III nitride semiconductors has recently attracted much interest due to their biocompatibility, nontoxicity, and long-term chemical stability under demanding physiochemical conditions for chemical and biological sensing. Among III-nitrides, aluminum nitride (AlN) and aluminum gallium nitride (AlGaN) are particularly important because they are often used as the sensing surfaces for sensors based on field-effect transistor or surface acoustic wave sensor structures. Patterned self-assembled monolayer (SAM) templates are composed of two types of organosilane molecules terminated with different functional groups (amino and methyl), which were fabricated on AlN/sapphire substrates by combining photolithography, lift-off process, and self-assembly technique. Clear imaging contrast of SAM micropatterns can be observed by field emission scanning electron microscopy (FE-SEM) operating at a low accelerating voltage in the range of 0.5–1.5 kV. In this work, the formation of green fluorescent protein (GFP) antibody microarrays was demonstrated by the specific protein binding of enhanced GFP (EGFP) labeling. The observed strong fluorescent signal from antibody functionalized regions on the SAM-patterned AlN surface indicates the retained biological activity of specific molecular recognition resulting from the antibody–EGFP interaction. The results reported here show that micropatterning of organosilane SAMs by the combination of photolithographic process and lift-off technique is a practical approach for the fabrication of reaction regions on AlN-based bioanalytical microdevices.


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