Title: Nanoparticles of silver and of silver-gold alloys: Synthesis, ultrastructure, and the mechanism of their biological action

Abstract

Metallic nanoparticles represent versatile tools to influence biological systems. Gold nanoparticles are well-known for their easy synthesis and chemical stability, silver nanoparticles can exert an antibacterial effect due to the release of silver ions. General to prepare and characterize metallic nanoparticles are presented and their biological effects are discussed. Special emphasis is placed on ultrasmall nanoparticles with a size of 1-2 nm, i.e. smaller than most proteins. Such particles consist of only a few hundred metal atoms. After suitable surface functionalization, they can be used to target the surface of proteins and also to bring molecular cargo into cells, across the blood-brain barrier, and even into the cell nucleus. Potential applications are outlined, together with an in-depth characterization of their chemical and crystallographic nature.