Sonochemical Preparation of Inorganic Nanoparticles and Nanocomposites for Drug Release-A Review

Inorganic nanoparticles (NPs) and nanocomposites (NCs) generally possess versatile properties, that is, good specific surface area (SSA), magnetism, easy functionalization with ligands, etc.; thus, such nanomaterials have rapidly been appearing in drug release and diagnosis. This review presents the sonochemical synthesis of nano-SiO2, magnetic Fe3O4, graphene oxide, metal-organic frameworks, ZnO, Ca3(PO4)2, and ZrP2O7, and their NCs. The cavitation effects, such as extremely high temperature and pressure, radical reactions, high-speed microjets, shock waves, deagglomeration, and strong hydrodynamic shear-forces at collapsing cavities assist the preparation of inorganic NPs and NCs. As compared to conventional hydrothermal synthesis, the ultrasound (US)-assisted method can shorten preparation time and reduce particle size. Moreover, the prepared NPs are much more uniform in size distribution and form. Most US-assisted prepared NPs and NCs were proven to be appropriate as drug nanocarriers. Also, the drug release mechanisms are briefly presented and discussed. Furthermore, the effects of ultrasonic equipment, power, sonication time, substrate concentration, pH value, and surfactants on the characteristics and morphology of NPs and NCs are summarized.