Monolayer-protected gold nanoparticles for molecular sensing and catalysis

This chapter shows how monolayer-protected gold nanoparticles (AuNPs), which are nanometer-sized gold colloids coated with a monolayer of organic molecules, are rapidly emerging as a class of molecular systems with a true potential to behave as artificial proteins. It starts with a short discussion of the analytical techniques that are commonly used to study molecular recognition processes at the monolayer. The chapter then illustrates how the monolayer can be equipped with recognition elements for the selective interaction with guests, and shows how such systems can be applied for chemosensing applications. It also discusses catalytic AuNPs, which display enzyme-like reaction kinetics. These so-called nanozymes rely on the selective recognition of small molecules followed by a chemical conversion assisted by catalytic centers embedded in the monolayer. Finally, the chapter focuses on the introduction of regulatory elements that permit spatiotemporal control to be gained over the molecular recognition processes occurring at the monolayer by means of external triggers.