Abstract

Plasmon-modulated nanostructure and composition of gold nanorods (GNRs) have been developed. Fine-tuning of the reaction conditions allows modulation of longitudinal plasmon wavelength (LPW) without the limit of that possessed by starting GNRs, in turn acting as indicator to tailor the nanorods with different nanostructure and composition. Importantly, a label-free multiplex plasmonic sensor has been developed to selectively determine different metal ions including Hg²⁺, Cu²⁺ and Ag⁺ ions based on single type of gold nanorod (GNR). Under proper conditions, these metal ions can react with GNRs, resulting in changes of nanostructure and composition. The determination of Hg²⁺, Cu²⁺ and Ag⁺ ions is therefore readily implemented due to changes of longitudinal plasmon wavelength (LPW) of nanorods. The special nanostructure and composition of the nanorods are induced by these metal ions, which allow this sensor to maintain high selectivity to determine these metal ions. This nanosensor abrogates the need for complicated chemosensors or sophisticated equipment, providing a simple and highly selective detection platform.

© 2013 Optical Society of America