Quantum dots bilayers/Au@Ag-based electrochemiluminescence resonance energy transfer for detection of thrombin by autocatalytic multiple amplification strategy

摘要

A novel CdSe quantum dots (QDs) bilayers/Au@Ag electrochemiluminescence (ECL) resonance energy transfer (ERET) system was designed for sensitive determination of thrombin by autocatalytic multiple amplification strategy. In this protocol, the graded-gapquantum dots (QDs) bilayers were fabricated by layer-by layer assembly of differently sized CdSe-NH_2 and CdSe-COOH QDs on a Au-graphite oxide (Au-GO) nanocomposite modified electrode. A surprising ECL enhancement effect in the QDs bilayers was observed, ECL signal from the QDs bilayers was enhanced 3-foldcompared to that of the monolayer CdSe-NH_2 QDs. Furthermore, a new Au@Ag core-shell nanopartide (NP) was synthesized, the ECL signal from the bilayers QDs was efficiently quenched by the Au@Ag NPs. Based on the ECL energy transfer between the bilayers QDs and the Au@AgNPs, we designed a new ECL biosensor for thrombin detection by using multiple nuclease-assisted autocatalytic amplification strategy. Importanly, the layered QDs with highly intense ECL could provide a promising candidate for the development of a sensitive ECL biosensor, and it is for the first time that layered QDs were used as ECL probe and combined with recycling amplification for highly sensitive detection of biomolecules. The proposed scheme may open a new QDs-based ERET system for highly sensitive detection of versatile target biomolecules, and has a good prospect for clinical diagnosis in the future.