Nanoparticle assembly

While nanostructure size, shape, and medium can be employed as handles to tune the LSPR, the most effective approach to customize the near- and far-field field response is via the arrangement of nanoparticles into complex groupings. 

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Enhanced Optical Fields in Spherical Nanoparticle Assemblies and Surface Enhanced Raman Scattering... 

To summarize, we have shown here that enhanced electric-field distribution in metal nanoparticle assemblies can be visualized on the nanoscale by a near-field two-photon excitation imaging method. By combining this method and near-field Raman imaging, we have clearly demonstrated that hot spots in noble metal nanoparticle assemblies make a major contribution to surface enhanced Raman scattering. 

Imura, K., Okamoto, H., Hossain, M. K. and Kitaj ima, M. (2006) Visualization of localized intense optical fields in single gold-nanoparticle assemblies and ultrasensitive Raman active sites. Nano Lett., 6, 2173-2176. 

Fig. 57. DNA-nanoparticle assembly based on biotin-streptavidin binding. Discrete, A and B, and extended, C, networks have been constructed. Adapted from Ref. 186).

Daniel M-C, Astruc D (2004) Gold nanoparticles assembly, supramolecularchemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology. Chem Rev 104 293-346... 

Generalized fabrication of multifunctional nanoparticle assemblies on silica spheres. Angewandte Chemie International Edition, 45 (29), 4789—4793. 

Fig. 5.2 SEM micrograph of a silica nanoparticles assembly resulting from the interaction between silicates and gelatine.

In fact, such biomimetic molecules demonstrate the ability to tailor the growth of silica nanoparticles in a way that is very similar to diatom-extracted species. However, they demonstrate the same limitations in terms of morphological control of nanoparticle assembly. This is because the diatom shell architecture results not only from interactions of silica precursors with templating molecules but also benefits from a cell-driven molding of the vesicular compartment where silicification occurs [29]. Thus, it is very likely that diatom-like synthetic silica will only be achieved when such confinement/molding effects are taken into account in the design of biomimetic experiments [30]. 

Synthesis of DNA-Au hybrid nanocomposites holds promise for applications in nanotechnology. Following the pioneering work of Mirkin et al., these modified Au nanopartides can act as useful building blocks to form spatially well-defined superstructures, including nanocrystals [108], binary and multilayered nanoparticle assemblies [109,110] and also well-ordered 3D nanoclusters [111]. 

Shenhar, R., Norsten, T.B. and Rotello, V.M. (2005) Polymer-mediated nanoparticle assembly structural control and applications. Advanced Materials, 17, 657-669. 

Single-step fabrication of drug-encapsulated inorganic microspheres with complex form by sonication-induced nanoparticle assembly Chemical Communications,... 

Figure 6.8 Illustration of colloid-templated nanoparticle assemblies. The process involves the layer-by-layer adsorption of charged polymers and oppositely charged nanoparticles onto the surfaces of the colloidal template. The colloidal core particles may then be removed to generate a hollow sphere of nanoparticles, held together by electrostatic interactions with the linear polymer glue ...

Govoroch AO, Bryant GW, Zhang W, Skeini T, Lee J, Kotov NA, Slocik JM, Naik RR (2006) Exciton-plasmon interaction and hybrid excitons in semiconductor-metal nanoparticle assemblies. Nano Lett 6 984—994... 

Fig. 40 Gold-to-carbon ratio as a function of the XPS take-off angle measured on gold nanoparticle assemblies on PAAm for nanoparticles having a diameter of 3.5 nm (a) and 16 nm (b). The dry thickness of bare PAAm is given in the legend. The lines are meant to guide the eye. (Reproduced with permission from [140])...

A well-controlled pol5mierization method in terms of pol5mer length, polydispersity, and spatial distribution of functional groups is cmcial for effective nanoparticle assembly (Chiefari et al. 1998 Bielawski and Gmbbs 2000 Coessens et al. 2001 ... 

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