Chapter 38 Gold nanoparticles in DNA and protein analysis

Abstract

This chapter discusses the application of gold nanoparticles (NPs) (AuNPs) in electrochemical genosensors and immunosensors and some of the trends in their use for environmental and biomedical diagnostics among other application fields. Electrochemical methods used for AuNPs label detection are promising taking into account their high sensitivity, low detection limit, selectivity, simplicity, low cost and availability of portable instruments. The sensitivity of AuNPs detection is usually improved by the silver enhancement method. In this procedure, silver ions are reduced to silver metal by a reducing agent, at the surface of a gold NP, causing it to grow and so facilitating the detection. Many strategies based on DNA hybridization assays using AuNPs have been developed. Most of them rely on capturing the NP to the hybridised target in a three-component ‘sandwich’ format. technologies such as DNA sensors and immunosensors based on AuNPs might be exploited to fill specific niche applications in the environmental monitoring area. The analysis of trace substances in environmental science, pharmaceutical and food industries is a challenge because many of these applications demand a continuous monitoring mode. The use of immunosensors based on AuNPs in these applications should also be appropriate.