ABSTRACT

In this chapter, we attempt to present the development and applications of metal nanoparticle-based colorimetric assays. The sensing strategies are based on analyte-induced nanoparticle (NP) aggregation and dispersion. We begin with the preparation, stabilization, and surface functionalization of Au and Ag NPs. A general introduction of the optical properties of Au and Ag NPs brieϐly follows. After providing a general background, we concentrate on their applications of sensing analytes, including DNA, proteins, and small solutes, through interparticle crosslinking and noncrosslinking aggregation events.