Nanoparticles monolayers

Y. D. Jin, Y. Shen, and S. J. Dong, Electrochemical design of ultrathin platinum-coated gold nanoparticle monolayer films as a novel nanostructured electrocatalyst for oxygen reduction, J. Phys. Chem. B 108, 8142-8147 (2004). 

Synthesis and characterization of CdS nanoparticles embedded in a polymethylmethacrylate matrix was presented [165]. The assembly of CdS semiconductor nanoparticle monolayer on Au electrode was obtained, and its structural properties and photoelectrochemical applications were studied [166]. 

Andres and coworkers demonstrated the iCP of densely packed alkanethiolate-functionalized Au nanoparticle arrays in monolayer and multilayer structures.81,82 Dense and hexagonally packed monolayers of nanoparticles were first assembled on a water surface. By using the Langmuir-Schafer technique, the Au nanoparticle monolayer was transferred to a PDMS stamp, and printed onto a substrate. Multilayers were prepared by repeating the printing process in an LbL scheme, in which subsequent particle layers may be made up of the same or different types of particles. Similarly, the assembly of irregular, densely packed monolayers of polystyrene nanoparticles on iCP substrates via carbodiimide coupling was reported.83 The conformal contact of the carbodiimide-functionalized polystyrene particles resulted in the covalent attachment of the nanoparticles at a carboxylate-functionalized surface. 

To arrange AuNPs into a monolayer, Simon and coworkers [74] reported a simple protocol via the oligonucleotides complementary immobiUzation. 5 -Amino-modified oligonucleotide was immobilized on the substrate surface first, and then, 15 nm gold particles modified with thiolated DNA oligomers were coupled to the surface through DNA base pairing. The resulted nanoparticle monolayers were demonstrated to have a thermally activated conductivity. A similar approach has been used to insert a liposome into a DNA chip [75] (Fig. lib). 

Abstract. Surface pressure/area isotherms of monolayers of micro- and nanoparticles at fluid/liquid interfaces can be used to obtain information about particle properties (dimensions, interfacial contact angles), the structure of interfacial particle layers, interparticle interactions as well as relaxation processes within layers. Such information is important for understanding the stabilisation/destabilisation effects of particles for emulsions and foams. For a correct description of II-A isotherms of nanoparticle monolayers, the significant differences in particle size and solvent molecule size should be taken into account. The corresponding equations are derived by using the thermodynamic model of a two-dimensional solution. The equations not only provide satisfactory agreement with experimental data for the surface pressure of monolayers in a wide range of particle sizes from 75 pm to 7.5 nm, but also predict the areas per particle and per solvent molecule close to the experimental values. Similar equations can also be applied to protein molecule monolayers at liquid interfaces. 

Granot, E., F. Patolsky and I. Willner (2004). Electrochemical assembly of a CdS semiconductor nanoparticle monolayer on surfaces Structural properties and photoelectrochemical applications. Journal of Physical Chemistry B, 108(19), 5875-5881. 

Pugnaloni, L.A., Ettelaie, R., and Dickinson, E. Computer simulation of the microstructure of a nanoparticle monolayer formed under interfacial compression, Langmuir, 20, 6096, 2004b. 

To study particle correlation effects in the plasmon resonance absorption in the visible we have firstly compared the spectral characteristics of silver nanoparticles monolayers at the various particle surface concentrations o (Fig- ) The monolayer overlap parameter j = ngn d l4 was equal to 0.4 for the particle diameter of... 

The separating layer optical thicknesses were fixed (Fig. 3) about or AqU, where corresponds to the plasmon absorption maximum of a metallic nanoparticle monolayer in the KCl environment. These multilayer structures were fabricated by the thermal evaporation technique followed by deposition of metal and dielectric materials without breaking the vacuum between the evaporation steps. The structures grown by this technique are realized as a sequence of Ag island films separated by KCl intermediate layers of a subwavelength thickness. These data... 

Figure 3. Transmission spectra for a stack of Ag nanoparticle monolayers (layer number N=l, rf=3.5 nm, rj=0A) separated by KCl films at their different thickness / (a) experimental data (b) calculated data.

Figure 5.58 (a) TEM image of a nanoparticle monolayer printed onto a silicon nitride membrane window (b) TEM image of a bilayer printed onto a silicon nitride membrane ... 

The preparation of a gold nanoparticle monolayer on the surface of a polymer inclusion membrane using EDTA as the reducing agent Journal of Membrane Science 379 322-329. 

Nanoparticle monolayers and multilayers can also be prepared directly by electrochemistry without performation of the nanoparticles. For example, Ag nanoparticles monolayer can be formed by Ag grafted on 4-aminophenyl monolayer on highly oriented pyrolytic graphite followed by pulse electroreduction, and then the uniformly dispersed Ag nanoparticles as ordered monolayers are prepared. By a similar design Pd and Pt ordered monolayers can also be fabricated. For Pt (or Pd) nanoparticle ordered multilayers, they can be assembled with PtCl (or PdCl4 ) and CoTMPyP alternatively followed by electroreduction. The Pt or Pd nanoparticle ordered multilayers formed on the electrode surface demonstrate high catalytic activity to O2 and H2O2 reduction. 

Another approach to prepare nanoparticle ordered multilayers by preceding the formation of the nanoparticle monolayer can be achieved by a bottom-up... 

Using underpotential deposition with the redox replacement technique a novel electrochemical approach for nanoparticle-based catalyst has been designed. Here, the as-prepared Pt-coated Au nanoparticle monolayer at atomic level on the electrode surface can reduce O2 predominately by 4e to H2O, which was confirmed by rotating ring disk electrode technique (Figure 8). 

Kim CK, Ghosh P, Pagliuca C, Zhu ZJ, Menichetti S, Rotello VM (2009) Entrapment of hydrophobic drugs in nanoparticle monolayers with efficient release into cancer cells. J Am Chem Soc 131 1360-1361... 

Yang, G.-J., Huang, J.-L., Meng, W.-J., Shen, M., and Jiao, X.-A. (2009) A reusable capacitive immunosensor for detection of Salmonella spp. based on grafted ethylene diamine and self-assembled gold nanoparticle monolayers. Anal Chim. Acta, 647, 159-166. 

Figure 15.2 Examples of 2D layers fabricated by convective assembly, [a] Examples of a crystal monolayer obtained from 1.1 jam PS latex particles. The crystalline order leadingto bright diffraction is revealed when illuminated with a white light from behind. [b) SEM images of a 100 nm gold nanoparticles monolayer assembled on a silicon surface (unpublished results], a monolayer (c], and a bilayer (d] obtained with 500 nm PS particles. The structures were first assembled on a flat PDMS substrate and then transferred onto a silicon wafer by printing. Abbreviations SEM, scanning electron microscopy PDMS, polydimethylsiloxane PS, polystyrene.

FIGURE 3.1 Variation of nanoparticle monolayer conductivity (o) with interparticle edge-to-edge separation (/) at different temperatures for three Au-PET particles of different core diameters (A) 1.39 + 0.73 nm, (B) 1.64 + 0.79 nm, and (C) 2.97 + 0.62 nm. Error bars reflect statistical average of at least three measurements. Insets show the representative I-V profiles of the corresponding nanoparticles at / = 0.90 nm with the temperature increased as indicated by the arrow. Potential scan rate 20 mV/s. (Pradhan, S., D. Ghosh, L. P. Xu, and S. W. Chen, 2007, J Am Chem Soc 129 10622-10623. Used with permission.)... 

Figure 9. A) Change in extinction spectram of 12 nm diameter gold nanoparticle monolayer with layer-by-layer deposition of polyelctrolytes. B) Plot of peak extinction as a function of the number of deposited polyelectrolyte layers for immobilized 12 nm and 39 nm diameter gold nanoparticles on amine-functionalized glass.

Figure 11 Binding of streptavidin and anti-biotin mAb to a biotin-functionalized gold nanoparticle monolayer studied by surface plasmon absorbance of gold nanoparticles at 550 nm. (A) Baseline extinction in PBS-Tween as a function of time. (B) Incubation of the biotin-functionalized surface with streptavidin (10 ig/ml) or antibiotin mAb (50 pg/ml) results in an increase in the absorbance due to protein-ligand binding. No increase in extinction was observed on incubation of biotin-functionalized surface with BSA(10 pg/ml) (a), human IgG (50 pg/ml) (b) or streptavidin (30 g/ml) pre-incubated with 1.0 mM biotin (c). (C) Incubation of the protein-ligand complex on the surface with I mM biotin in solution causes decrease in signal due to dissociation of biotin-mAb complex. No dissociation was observed for biotin-streptavidin complex due to its slow off-rate constant.

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