Self-Assembled Monolayers Formed on Electroless Gold Deposited on Silica Gel:  A Potential Stationary Phase for Biological Assays

Dubrovsky, T.; Hou, Zhizhong; Stroeve, Pieter; Abbott, Nicholas L.

doi:10.1021/ac9804745

Cited by 41 publications

(45 citation statements)

References 29 publications

(49 reference statements)

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“…The activation of nonconducting or noncatalytic surfaces is a well-known procedure used in ED. 17,63,64 To study the localized gold electroless deposition on an insulator, oxide-coated Si wafers were employed. These oxidized nonconducting surfaces were activated by a two-step procedure ͑described in the Experimental section͒ using acidic SnCl 2 solution as a sensitizer followed by Pd seeding.…”

Section: D464mentioning

confidence: 99%

Localized Electroless Deposition of Gold Nanoparticles Using Scanning Electrochemical Microscopy

Malel¹,

Mandler²

2008

J. Electrochem. Soc.

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The aim of this study is to locally deposit nanoparticles on an unbiased surface by electroless deposition ͑ED͒ using scanning electrochemical microscopy ͑SECM͒. We have developed an ED process that is based on the reduction of gold ions by hydroquinone ͑H 2 Q͒ and catalyzed by a metallic surface, such as palladium. One of the advantages of this system is the ability to drive the ED at pH 1-7. The metal ions were electrogenerated in a solution consisting of H 2 Q and KCl by anodic dissolution of a gold microelectrode. AuCl 4 − reacted with H 2 Q at the electrolyte/metallic interface to form benzoquinone and gold deposit. The ED has been studied initially in bulk solution containing KCl, H 2 Q, and HAuCl 4 , and then by SECM. We found that the pH had a significant effect on the nature of the deposited gold and could be correlated with the kinetics of gold ions reduction by H 2 Q. Hence, either nanoparticles or much larger crystals could be formed, depending on the pH of the deposition solution. Time of deposition and H 2 Q concentration also affected the shape and density of the deposition.Since the introduction of electroless deposition ͑ED͒ as a plating method for semiconductors and circuit boards by Bell Laboratories, 1 ED has been widely used in the microelectronics industry. 2,3 In this surface catalyzed process, metal ions are reduced by a reducing agent and deposited onto a catalytic substrate without applying an external electric current. A kinetic barrier, which prevents the reduction of the metal ions in the solution, is an essential feature of ED. Over the past 40 years, ED has been used for the deposition of various metals, such as Cu, 4-6 Ag, 7,8 Pt, 9 and Au, 10,11 on unbiased metals and on insulators. Gold plating is relevant in a number of fields because of its high conductivity and chemical stability. Gold ED offers several advantages, including simplicity, processability at low temperature, and coating uniformity. Several studies focusing on Au ED have been reported using different deposition baths. The first autocatalytic gold ED bath consisted of KAu͑CN͒ 2 as the source of gold and KBH 4 or dimethylammine borane ͑DMAB͒, 10 as the reducing agent in a basic solution. 12 Additional baths have been developed based on other reducing agents. For example, Iacovangelo 13 reported a bath for gold plating on nickel using DMAB and hydrazine as reducing agents. Hypophosphite, thiourea, and ascorbic acid have also been employed. 14 All these baths involve basic solutions that are required to increase the thermodynamic driving force of the reducing agents as well as to avoid the evolution of hydrogen cyanide. Therefore, alternative systems using different gold salts ͑e.g., ͓Au͑S 2 O 3 ͒ 2 ͔ 3− ͒ have been developed. 10,11,15,16 Interestingly and in spite of the large number of patents and studies on gold ED, there are only a few reports on the localized ED of gold. Martin and Menon 17 for example produced arrays of gold nanoelectrodes by ED techniques. In their work, a polycarbonate filter membrane ͑10-30 nm...

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Section: D464mentioning

confidence: 99%

Localized Electroless Deposition of Gold Nanoparticles Using Scanning Electrochemical Microscopy

Malel¹,

Mandler²

2008

J. Electrochem. Soc.

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“…16 Many studies have been undertaken into the self-assembly of Au NPs onto surfaces presenting SH and NH 2 groups because various potential applications are envisioned for such systems in the fields of optoelectronics, 17 microelectronics, 18 and bioscience. 19,20 For example, layers of alkanethiols self-assembled on Au behave as model surfaces for studying the interactions of proteins with surfaces. 19,20 In addition to the self-assembly of monolayers onto NP surfaces, layer-by-layer (LBL) assembly, a simple preparation technique, can be utilized for the structural organization of a large variety of NPs into multilayer films.…”

Section: Introductionmentioning

confidence: 99%

“…19,20 For example, layers of alkanethiols self-assembled on Au behave as model surfaces for studying the interactions of proteins with surfaces. 19,20 In addition to the self-assembly of monolayers onto NP surfaces, layer-by-layer (LBL) assembly, a simple preparation technique, can be utilized for the structural organization of a large variety of NPs into multilayer films. 21 In medical science and in biotechnology, multilayer films of proteins attached to solid surfaces are used widely in the areas of diagnostics, isolation, and localization.…”

Section: Introductionmentioning

confidence: 99%

“…For example, multilayer architectures of spatially organized proteins present a high density of biomolecules and, hence, exhibit enhanced sensitivity toward the detection of biomolecular species. 22 Although the application of such self-assembled films in the biosciences and chromatographic sciences has received a great deal of attention, 19,20,23,24 to the best of our knowledge the LBL deposition strategy has never been employed for the preparation of materials for SPE. In this paper, we describe the preparation of nonpolar SPE sorbents through the self-assembly of alkanethiols onto Au NP-coated silica gel.…”

Section: Introductionmentioning

confidence: 99%

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Solid Phase Extraction of Neutral Analytes through Silica Gel Coated with Layers of Au Nanoparticles Self‐Assembled with Alkanethiols

Liu

2008

J Chinese Chemical Soc

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In this study, we used Au nanoparticle (NP)-coated silica gel as a solid phase extraction sorbent for the preconcentration of neutral analytes (steroid drugs). The sorbent was fabricated using two alkanethiol self-assembly processes: one to deposit the Au NPs onto a 3-aminopropyltrimethoxysilane-modified silica gel and the other to functionalize the surfaces of the Au NPs. A large volume of the steroid solution was passed through the silica gel to facilitate adsorption mediated by hydrophobic interactions between the steroids and the hydrophobic moieties on the silica gel surface. Extraction of the steroids was accomplished by flushing the silica gel with a low-polarity solvent. In this preliminary study, we found that the particle size of the silica gel and the number of layers of Au NPs coated on the silica gel both affected the preconcentration performance for the steroids. When using six layers of Au NPs coated on 5-20-mm silica gel, the detection limits for steroids were below 80 ng L -1 ; the preconcentration efficiency was over 170-fold higher than that of the original steroid solution. Our findings provide further evidence that nanotechnology has much to benefit analytical science.

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“…Therefore, it can be handled in ambient conditions. However, the alkanethiols based self-assembly method has a drawback for the application to bioelectronics, because it can function as an insulator [15].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of functional biomolecular layer using recombinant technique for the bioelectronic device

Kim

Yea

et al. 2008

Korean J. Chem. Eng.

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A novel immobilization method of blue copper protein azurin on a gold surface was developed without a chemical linker using recombinant technique. Azurin was recombined with a cysteine anchors by site-directed mutagenesis (SDM) and used to effect the mutations, changing the codon for Leu39Cys (L39C) from CTG to TGC. The immobilization of the functionalized protein is confirmed by surface plasmon resonance (SPR) and its surface morphology is analyzed by scanning tunneling microscopy (STM). The immobilization efficiency has been increased about 76.3%, as compared to that of wild type azurin. The electrochemical property of the fabricated thin film was investigated by cyclic voltammetry (CV). As a result, cysteine-modified azurin can be used for making high quality protein film, and applied to the fabrication of nano-scale bioelectronics.

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Self-Assembled Monolayers Formed on Electroless Gold Deposited on Silica Gel: A Potential Stationary Phase for Biological Assays

Cited by 41 publications

References 29 publications

Localized Electroless Deposition of Gold Nanoparticles Using Scanning Electrochemical Microscopy

Localized Electroless Deposition of Gold Nanoparticles Using Scanning Electrochemical Microscopy

Solid Phase Extraction of Neutral Analytes through Silica Gel Coated with Layers of Au Nanoparticles Self‐Assembled with Alkanethiols

Fabrication of functional biomolecular layer using recombinant technique for the bioelectronic device

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