Physical and Chemical Consequences of Size-Reduction of Gold: Bioresponse and Biodistribution

The article is dealing with the dependency of physical and chemical properties on size and coating of gold nanoparticles (Au NPs) and their potential in medicine. Full-shell clusters of the type Au₅₅(PR₃)₁₂Cl₆ are in the focal point due to their special properties. They act as quantum dots at room temperature and their stability is based on the perfect cuboctahedral structure. The bioresponse of the 1.4 nm Au₅₅ clusters is, compared with smaller and larger Au NPs, very special, indicated by high cytotoxicity. It is caused by oxidative stress in cells accompanied by direct interactions with DNA. Biodistribution in Wistar–Kyoto rats differs also characteristically from larger Au NPs. Larger Au NPs, intravenously injected, assemble almost quantitatively in the liver, whereas Au₅₅ clusters distribute over numerous other organs. All comparisons have been carried out by Au species with identical ligand molecules in order to have the same conditions concerning surface behaviour.