DNA stabilized Ag–Au alloy nanoclusters and their application as sensing probes for mercury ions

Abstract

Metal nanoclusters (NCs) have attracted plenty of attention because of their unique properties and great application potentials. In this work, DNA scaffold Ag–Au alloy nanoclusters (Ag–Au ANCs) were fabricated by a one pot wet-chemical strategy and characterized by various techniques, including TEM, XPS and mass spectrometery (MS). The results indicate that owing to the strong interaction between DNA and Ag⁺, the silver NCs were formed first, then bundled with Au shells. In the Ag–Au ANCs, some of the Au is in an oxidized state as Au(I), which can largely modify the optical properties of the silver NCs. The Ag–Au ANCs demonstrate tunable emissions from green to red with highly improved stability. The fluorescence of Ag–Au ANCs was explored to detect Hg²⁺ in contrast to Ag NCs. The detection using Ag–Au ANCs demonstrated highly improved and excellent linearity and selectivity, which could effectively avoid the disturbance of Cu²⁺ and was promising for applications.