Since Faraday first described gold sol synthesis, synthetic routes to nanoparticles, as well as their applications, have experienced a huge growth. Variations in synthesis conditions such as pH, temperature, reduction, and the stabilizing agent used will determine the morphology, size, monodispersity, and stability of nanoparticles obtained, allowing for modulation of their physical and chemical properties. Although many studies have been made about the synthesis and characterization of individual nanosystems of interest, to our knowledge the common, general traits that all those synthesis share have not been previously compiled. In this review, we aim to offer a global vision of some of the most relevant synthetic procedures reported up to date, with a special focus on nonfunctionalized gold nanoparticle synthetic routes in aqueous media, and to display a broad overview of the influence that synthesis conditions have on the shape, stability, and reactivity of nanoparticle systems.

Electrogenerated chemiluminescence (ECL) from aqueous solutions of tris(2,2'-bipyridine)ruthenium(II), [Ru(bpy)(3)](2+), in the presence of PAMAM G1.5 and G4.5 dendrimers, was observed without the addition of coreactants. The ECL efficiency, Φ(ECL), was enhanced with the addition of increasing amounts of G1.5 dendrimer. Indeed, the ECL efficiency for the [Ru(bpy)(3)](2+)/G1.5 dendrimer became about 10 times higher than that for the [Ru(bpy)(3)](2+)/ oxalate anion system. However, the ECL efficiency in the presence of the G4.5 dendrimer was smaller than that for the G1.5 dendrimer at concentrations similar to those for G1.5 with identical medium conditions. Besides, the addition of NaCl at a given concentration of G1.5 dendrimer decreased the ECL efficiency. The results of Φ(ECL) were interpreted by taking into account the coreactant effect and the electrostatic (long-range and short-range) interactions between the ruthenium(II) complex and the electric field of the dendrimer surface. Standard formal potentials of the [Ru(bpy)(3)](3+/2+) couple in the presence of G1.5 and G4.5 dendrimers were also determined.

The extent of DNA decompaction induced by m-s-m gemini surfactants depend on the surfactant's tail length and on spacer's length.

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