Poly -gold nanoparticle

Elghanian, R., Storhoff, J.J., Mucic, R. C., Letsinger, R.L. and Mirkin, C.A. (1997) Selective colorimetric detection of poly-nucleotides based on the distance-dependent optical properties of gold nanoparticles. Science, 277, 1078-1081. 

H. Otsuka, Y. Akiyama, Y. Nagasaki, and K. Kataoka, Quantitative and reversible lectin-induced association of gold nanoparticles modified with a-lactosyl-co-mercapto-poly(ethyleneglycol), J. Am. Chem. Soc., 123 (2001) 8226-8230. 

Ishii T, Otsuka H, Kataoka K, Nagasaki Y (2004) Preparation of functionally Pegylated gold nanoparticles with narrow distribution through autoreduction of auric cation by alpha-biotinyl-PEG-block-[poly (2-(N, N-dimethylamino) ethyl methacrylate)]. Langmuir 20 561-564... 

A different example of gold-nanoparticle-modified electrodes for N O detection was shovm by Caruso and coworkers [66]. In this work, the layer-by-layer technique was utilized as a means to immobilize oppositely charged layers of gold-nanoparticle-loaded poly(sodium 4-styrene-sulfonate) (PSS) and poly(allylamine hydrochloride)... 

Fig. 9.33 SPM micrograph of gold nanoparticles decorated with grafted chains of poly(n-...

Fig. 38 (Upper panel) Scanning force microscopy images of gold nanoparticles (diameter 17 nm) adsorbed along a surface-anchored poly(acryl amide) brush with a molecular weight gradient (Edge of each image = 1 p.m). (Lower panel) Dry thickness of poly(acryl amide) on the substrate before particle attachment (right, ) and particle number density profile (left, ). (Reproduced with permission from [140])...

Sakai T, Alexandridis P (2005) Spontaneous Formation of Gold Nanoparticles in Poly(ethylene oxide)-Poly(propylene oxide) Solutions Solvent Quality and Polymer Structure Effects. Langmuir 21 8019-8025... 

For example, Mandal et al. have reported the synthesis of Au core-shell NPs containing a gold core and poly(methyl methacrylate) (PMMA) shells by surface-confined living radical polymerization on gold nanoparticles. The synthesis of Au NPs has been carried out in the presence of 11-mercaptoundecanol (MUD) and subsequent esterification with 2-bromoisobutyryl bromide (BIB). Atom transfer... 

Spherical gold nanoparticles coated with poly(N-isopropylacrylamide) (PNIPAM) grafts have been synthesized by controlled radical polymerization. The polymerization of N-isopropylacrylamide was initiated from the surface of the nanoparticles modified with 4-cyanopentanoic acid dithiobenzoate for reversible addition-fragmentation chain-transfer polymerization. The mean diameter of the Au core was 3.2 nm, as observed by means of high-resolution transmission electron microscopy [90]. 

In a recent report, new nanocomposites of Au NPs and poly(4-vinylpyridine) were obtained through surface-initiated atom-transfer radical polymerization (SI-ATRP). The citrate-stabilized gold nanoparticles were first modified by the disulfide initiator [BrC(CH3)2COO(CH2)iiS]2 for ATRP initiation, and the subsequent polymerization of 4-vinylpyridine occurred on the surface of the gold particles. The assembled Au PVP nanocomposites are pH-responsive because of the pyridyl groups, which are facially protonated and positively charged. The micrographs show Au N Ps of around 15 nm size [92] (Scheme 3.14). 

Gold nanoparticles coated by short thiol end functional polystyrene homopolymers (PS-SH) can be incorporated into a poly(styrene-fo-2-vinylpyridine) diblock copolymer template (PS-NP2VP). It has been found that the surface density of PS chains on the gold particles is critical in controlling their location in block copolymer templates [95]. 

Template core-shell particles with cores comprised mainly of poly(glycidyl methacrylate) (GMA) and shells consisting mainly of PNIPAM and amino or thiol-functionalized have been used for the synthesis of Au NPs. The obtained hybrid particles exhibited a reversible color change from red to purple, which originated from the surface plasmon resonance of gold nanoparticles and was temperature-dependent in the range 25-40 °C [96] (Scheme 3.15). 

Gold nanoparticles can also be stabilized using polymers that do not have specific functional groups through physisorption. Among the possible stabilizers, the polymers used most often to stabilize Au NPs are the water soluble polymers poly(N-vinylpyrrolidone) (PVP), polyethylene glycol) (PEG), poly(vinyl pyridine), poly(vinyl alcohol) (PVA), poly(vinyl methyl ether) (PVME), and polyelectrolytes such as PAA, chitosan, polyethyleneimine (PEI) or poly(diallyl dimethylammonium) chloride (PDDA) [99]. 

Chitosan-stabilized Au NPs can be selectively synthesized on surfaces like poly (dimethylsiloxane) (PDMS) films using HAuC14 as precursor. The computation of surface plasmon bands (SPBs) based on Mie theory and experimental results indicates that the particles are partially coated by chitosan. The proposed mechanism implies that chitosan acts as a reducing/stabilizing agent. Furthermore, PDMS films patterned with chitosan could induce localized synthesis of gold nanoparticles in regions capped with chitosan only [110]. 

Polyethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) (Pluronic) block copolymer is a very efficient reducing agent and nanoparticle stabilizer. Au NPs of about 10 nm can be stabilized with PEO-PPO-PEO block copolymer solutions in water and at room temperature and using HAuC14 as precursor. The formation of gold nanoparticles is controlled by the overall molecular weight and relative block length of the block copolymer [118]. 

A.-J. Wang, J.-J. Xu, Q. Zhang and H.-Y. Chen, The use of poly(dime-thylsiloxane) surface modification with gold nanoparticles for the microchip electrophoresis, Talanta, 69 (2006) 210-215. 

Polyalkylarylsilanes, solid-state studies, 3, 605 Poly[(alkyl)(aryl)silylene]s, preferential screw sense, 3, 616 Polyamides, aromatic, 7t-complexed, 12, 362 Polyamidoferrocenylalkylthiolate—gold nanoparticles, synthesis, 6, 195—196... 

The LBL self-assembly onto the CD functionalized surface requires at least two complementary substrates in order that multiple layers can be built up upon repeated alternating applications of the substrates, until a desired thickness has been achieved. Reinhoudt and coworkers chose the self-assembled interaction between CD-modified gold nanoparticles and either adamantyl- or ferrocene-functionalized dendrimers, which in turn were composed either of poly(propyleni-mine) (PPI) or poly(amidoamine) (PAMAM) [118, 122]. 

Otsuka H, Akiyama Y, Nagasaki Y, Kataoka K. Quantitative and reversible lecitin-induced association of gold nanoparticles modified with oc-lactosyl-co-mercapto-poly(ethylene glycol). J Am Chem Soc 2001 123 8226-30. 

F. Karadas, G. Ertas, E. Ozkaraoglu, and S. Suzer, X-Ray-Induced Production of Gold Nanoparticles on a Si02/Si System and in a Poly(Methyl Methacrylate) Matrix, Langmuir 21, 437-442 (2005). 

Recently, gold has emerged as one of the most active catalysts for alcohol oxidation and is especially selective for poly alcohols. In 2005, Corma [184] and Tsu-kuda [185], independently demonstrated the potential of gold nanoparticles for the oxidation of aliphatic alcohols. For example, in the case of gold nanoparticles deposited on nanocrystalline cerium oxide [184], a TOF of 12 500 h 1 was obtained for the conversion of 1-phenylethanol into acetophenone at 160 °C (Fig. 4.67). Moreover this catalyst is fully recyclable. Another example of a gold catalyst with exceptional activity is a 2.5% Au-2.5% Pd/Ti02 as catalyst [186]. In this case for 1-octanol a TOF of 2000 h-1 was observed at 160 °C (reaction without solvent, Fig. 4.67). 

Wang Y, Wei G, Wen F, Zhang X, Zhang W, Shi L (2008) Synthesis of gold nanoparticles stabilized with poly((V-isopropylacrylamide)-co-poly(4-vinyl pyridine) colloid and their application in responsive catalysis. J Mol Catal A Chem 280 1-6... 

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