Gold nanospheres

The topic of gold nanospheres attracted the interest of several famous nineteenth century scientists such as Michael Faraday, Richard Zsigmondy, and Gustov Mie [43]. Interest diminished in the mid-twentieth century although some excellent contributions were made by Turkevich [42, 44], Frens [45], and Brust [46] in that period regarding the controlled preparation of nearly monodisperse colloidal suspensions. 

There are very many papers in the literature that address some aspect of gold nanospheres. In particular, their plasmon response (see Section 7.3.1.1) has been well studied, as has their agglomeration [50-52] and the manner in which they can be assembled into highly ordered colloidal crystals [50, 53, 54]. The latter are interesting and will be further discussed in Section 7.3.8.2. Conjugation of gold nanospheres with proteins and antibodies, for use as a stain in microscopy [55] or possibly, in medical applications [23], is another rich field. 

Pissuwan, D., Cortie, C.H., Valenzuela, S. and Cortie, M.B. (2007) Gold nanosphere-antibody conjugates for therapeutic applications. Gold Bulletin, 40,... 

Harris, N., Ford, M.J. and Cortie, M.B. (2006) Optimization of plasmonic heating by gold nanospheres and nanoshells. The Journal of Physical Chemistry B, 110, 10701-10707. 

Figure 3.2 Extinction spectra of colloidal water solutions of gold nanospheres and nanorods. Dotted curve nanospheres (diameter 15-25 nm). Solid curve nanorods, low aspect ratio. Dashed curve nanorods, high aspect ratio. Extinction is normalized at about 520 nm. (Reproduced with permission from Royal Society of Chemistry [10]).

Figure 3.9 Near-field two-photon excitation images of gold nanosphere dimers, (a) Topography. Scale bar 500 nm. (b) and (c) Two-photon excitation images. The excitation wavelength is 780 nm. Incident polarization directions are indicated by arrows. The approximate positions ofthe particles are indicated by circles. (Reproduced with permission from The Japan Society of Applied Physics [12]).

Hamamoto K, Micheletto R, Oyama M et al (2006) An original planar multireflection system for sensing using the local surface plasmon resonance of gold nanospheres J Opt Pure Appl Opt 8 268-271... 

Figure 8.8 Electric-field enhancements in the vicinity of a gold nanosphere with radius a = 10 nm as a function of the distance from the surface of the nanosphere at wavelength of 516 nm.

Figure 8.9 Scattering of evanescent waves by a gold nanosphere wdth radius r. The refractive indices of the core of a step-index multimode fiber ( )...

Figure 8.13 Absorption efficiency of a gold nanosphere with diameter of 20 nm in the water as a function of the illuminating wavelength.

Figure 20.12 (A) Fluorescence spectra of NADH in the presence of different concentrations of gold nanospheres (OD = 1.0). (See text for full caption.)...

Abe S. and Kajikawa K., (2006) Linear and nonlinear optical properties of gold nanospheres immobilized on a metallic surface Phy, Rev. B 74 035416. 

Figure 20.12 (A) Fluorescence spectra of NADH in the presence of different concentrations of gold nanospheres (OD=1.0). Inset the fluorescence decay of NADH at 460 nm in the presence of different concentrations of gold nanospheres ( exci = 335 nm) (B) Absorption spectra of NADH (O.OSmM) in the presence of different concentrations of gold nanospheres (OD=1.0) Inset absorption spectra of NADH after subtraction of absorptions from gold nanospheres (C) Fluorescence spectra of NADH in the presence of different concentrations of gold nanorods (OD=1.0). X,exci = 325 nm Inset the fluorescence decay of NADH at 460 nm in the presence of different concentrations of gold nanorods ( exci = 335 nm) (D)Absorption spectra of NADH (O.OSmM) in the presence of different concentrations of gold nanorods (OD=1.0). Cited from reference 52.

The nanoparticles can be incorporated into cells by incubation the nanoparticies suspended in DMEM medium with the cells for 12 to 48 hours. From dark field light scattering imaging [54], it has been established that gold nanoparticies are taken intracellulariy into these cell lines. The nanoparticies are accumulated inside cytoplasm of live cells by receptor-mediated endocytosis processes. Figure 20.16 shows that for most of samples gold nanospheres quench the protein fluorescoice at 12 h incubation time. However, in some samples fluorescence enhancement is observed. 

Figure 20.15 . Fluorescence spectra of whole cells with and without gold nanospheres. Each cell type demonstrates characteristic decrease in fluorescence for all samples tested.X,exci = 280 nm. RFU relative fluorescence unites. NP nanoparticles. Cited from reference 52.

Figure 20.16 Fluorescence spectra of HSC 3 cells incubated with nanosphere solution. = 280 nm. Overall, gold nanospheres decrease the fluorescence of cells however, in some samples an increase in fluorescence is observed. The data is similar for all three cell lines (HaCat, HOC 313, and HSC 3) when the nanopaiticles were incubated with cells. Cited from reference 52.

Chon H, Lee S, Son SW, Oh CH, Choo J (2009) Highly sensitive immunoassay of lung cancer marker carcinoembryonic antigen using surface-enhanced Raman scattering of hollow gold nanospheres. Anal Chem 81 3029... 

We also examined the dissolution reaction of gold nanospheres, spheroids, and nanorods (aspect ratios 1, 2-5, and 18 respectively) with persulfate, which is thermodynamically a favorable reaction [62] ... 

The interparticle distance Ad is a key parameter that determines the electrodynamic conpling of metal [10] or dielectric [69] monomers. It has been shown [20] that for clnsters bnilt from silver or gold nanospheres, the... 

The transient absorption spectrum of gold nanospheres can be modeled relating the changes in the differential transmittance AT/T to the laser-induced changes in the real and imaginary parts of the dielectric function Asi and As2- T is defined as the ratio of the transmitted to the incident light [A = — log(r)]. 

Figure 11.2 Micrographs of PPy hollow nanocontainers after etching of the PS core in THF, obtained by (a) SEM and (b) TEM. (Reprinted with permission from Langmuir, Latex and Hollow Particles of Reactive Polypyrrole Preparation, Properties, and Decoration by Gold Nanospheres by Claire Mangeney et al., 22, 24, 10163-10169. Copyright (2006) American Chemical Society)...

C. Mangeney, S. Bousalem, C. Connan, M.-J. Vaulay, S. Bernard, and M.M. Chehimi, Latex and hollow particles of reactive pol3fpyrrole Preparation, properties, and decoration by gold nanospheres, Langmuir, 22(24), 10163-10169 (2006). 

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