Nanorods aggregation

Ma, Z., Tian, L., Wang, T., Wang, C., 2010. Optical DNA detection based on gold nanorods aggregation. Anal. Chim. Acta 673 (2), 179—184. 

An initial study of the toxicity of carbon nanotubes and fuUerene implied that fiber-shaped nanomaterials were more toxic than spherical nanomaterials [25]. In the case of the carbon nanotube, its shape appeared to hamper the processes of endo-cytosis and phagocytosis, such that chronic pulmonary toxicity occurred. However, a recent in vitro toxicity study using different sizes of sihca nanomaterials showed spherical nanomaterials be more toxic than rods [68]. The suggested reason for this was that the sihca nanorod aggregated much more easily than the spherical sihca nanomaterials consequently, the large aggregates not only reduced the surface area-to-volume ratio of the nanomaterials but also slowed their rate of cehular uptake. It was also shown to be more difficult for ehiphcal nanomaterials to penetrate the skin layer than spherical ones [98]. Overall, however, the results of these studies indicated that the shape of nanomaterials could indeed affect their toxicity. 

Nikoobakht, B. and El-Sayed, M.A. (2003) Surface-enhanced Raman scattering studies on aggregated gold nanorods. Journal of Physical Chemistry A, 107,... 

The resulting GNRs are coated with a CTAB bilayer that prevents aggregation and facilitates the formation of relatively stable nanorod suspensions in aqueous solution. Smith et al. recently showed that very small amounts of iodide present as an impurity in CTAB samples purchased from different chemical suppliers have a dramatic influence on nanorod growth. In some cases, nanorods did not... 

Numerous nanostructures such as nanorods, nanotubes, or nanorings have been obtained by this approach. In particular, the use of organoge-lators as directors to control the morphologies of the aggregates has been explored recently. Cholesterol- and phospholipid-thethered trans-styl-benes are able to gelate different organic solvents in which the steroid and the lipid units serve as templates to form one-dimensional stacks. 

Micali N, Villari V, Castriciano M et al (2006) From fractal to nanorod porphyrin J-aggre-gates. Concentration-induced tuning of the aggregate size. J Phys Chem B 110 8289-8295... 

The comb-shaped supramolecules discussed at length in this review allow a novel and general concept to prepare crew-cut aggregates as well as more complex shaped disklike objects. The procedure to prepare crew-cut nanoobjects is illustrated in Fig. 27 for the case of nanorods. The starting material is again poly(4-vinyl pyridinej-foZocfc-polystyrene. The corresponding comb-coil... 

Fig. 11.5 Rationally fabricated SERS substrates. From (a) to (I), triangular nanoparticle array [30], silver nanowire bundles [32], Ag nanoparticle-assembled silica nanoparticle (SERS dots) [33], metal nanoparticle aggregates (COINs) [34], gold nanocrescent [49], gold nanoparticles with thin oxide shells [50], hollow-type gold nanoparticles [35-37], gold nanorods [38 10], nanocubes [41,42], flower-like gold nanoparticles [43], nanodisks [46], and gold nanorods immobilized on silica nanoparticles [48]...

Another example of self-assembly of porphyrin-containing polymer was illustrated by Li et al.73 Polyacetylene functionalized with fullerene and zinc porphyrin pendant groups were synthesized by polymerizing the corresponding fullerene/porphyrin substituted alkyne monomers with rhodium(I) norbomadiene catalyst (Scheme 5.5).74 Polymers with different ratio of C60 and porphyrin were synthesized. The polymers showed photocurrent response when the thin films were irradiated with white light, which was due to the electron transfer from the photo-excited porphyrin to the C60 units. In addition, the copolymers aggregated into ellipse-shaped nanorod structures with a diameter of approximately 100 nm and a length of... 

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