Dendritic DNA/quantum dot nanostructure-based electrochemiluminescence biosensor for sensitive assay of Hg²

A novel dendritic DNA-quantum dot (QD) electrochemiluminescence (ECL) probe was developed and an ECL biosensor constructed for sensitive detection of Hg²⁺ in water samples by combining with enzyme-assisted multiple cycle amplification strategy. Firstly, the Y-shaped structure was formed based on the Hg²⁺-induced enzymatic cycle amplification technique, which improved the cutting efficiency and realized the double-amplified DNA product. Moreover, a unique dendritic DNA nanostructure loading numerous QDs was constructed, which can greatly amplify the ECL signal. After the dendritic DNA signal probe was connected to the CNT/gold nanocomposites/electrode by DNA products, the ECL biosensor was constructed for sensitive detection of Hg²⁺. The proposed dendritic DNA probe opens new ECL application of quantum dots. The smart design of Y-structure coupled with multiple amplification strategy greatly improves detection accuracy and sensitivity; thus, the biosensor not only can detect Hg²⁺ in water samples, but also has a good application prospect for other targets in environmental analysis.