ABSTRACT
Nanoscience and nanotechnology generally refer to materials with at least one structural dimension ranging from 1 to 100 nanometres. Various nanomaterials such as liposomes (Kisak et al. 2004), polymers (Xu et al. 2007), dentrimers (Paleos et al. 2004), and carbon nanotubes (Wu et al. 2005) have been used for various delivery applications. Among nanomaterials, inorganic nanomaterials play important roles in numerous applications in various fields, such as optical, electronics, catalysis, environmental and biomedical particularly biomedicine, due to their unique chemical, electrical magnetic and physical properties (De et al. 2008, Shipway et al. 2000, Guo and Wang 2011). The unique properties of metal and metal oxide nanomaterials can be finely tuned through the engineering of their compositions and dimensions such as diameter, length, ratio and shape (e.g., spherical, rods, triangles, cubes, plates, wires) (Lu et al. 2007, Xia et al. 2013, Polavarapu et al. 2015). In general, there are two approaches in the preparation of metal and metal oxide nanomaterials, either from “top to bottom” or “bottom to top” (Fig. 4.1). In the top to bottom approach, suitable bulk materials are split into fine particles by thermal/laser ablation, milling, grinding, sputtering and other techniques. In the bottom to top approach, nanomaterials can be synthesized using chemical reduction and biological methods via self-assembly of atoms to new nuclei that grow into a nanoscale particle (Niu and Xu 2011).
