Noble metal nanoparticles: Synthesis, and biomedical implementations

For centuries noble metal nanoparticles, especially of gold and silver, have been rigorously utilized in artwork based on their expressing vivacious colors through interaction with visible light. Further studies of the particular optoelectronic properties of gold and silver nanoparticles have shown strong correlations with their size, shape, surface chemistry, aggregation behavior, and environment. In addition, gold and silver nanoparticles have attracted intense scientific and technical interest due to retaining the unusual optical, electronic, and thermal properties; the facile synthesis and surface bioconjugation; and feasibility in clinical diagnostics and therapeutics. With the exception of applications ranging over conductors and catalysis, this chapter aims at depicting the main properties of particular noble metal nanoparticles, namely gold and silver nanoparticles, together with their corresponding synthetic methods and biomedical applications. We introduce the major types of noble metal nanoparticles, including size- and shape-dependent gold and silver nanosystems; the associated physicochemical, electronic, optical or thermal properties; and the relevant fabrication, modification, functionalization, and bioconjugation. A variety of biomedical implements, including hyperthermia therapy, therapeutic agency, drug delivery, imaging probes, and diagnostic and antibacterial applications, are discussed as well. Due to relatively limited biomedical applications and studies in palladium and platinum nanoparticles compared with those in gold and silver nanoparticles, palladium and platinum nanoparticles are excluded from the content of this chapter.