Magnetic-plasmonic yolk-shell nanostructure-based plasmon-enhanced electrochemiluminescence sensor

摘要

In this work, plasmon-enhanced electrochemiluminescence (ECL) nanosensor based on magnetic-plasmonic Fe_3O_4 yolk/Au shell (M@Au) is designed for Kirsten rat sarcoma (K-RAS) gene detection. K-RAS is a mouse sarcoma virus oncogene, which mutation occurs in the initial phase of malignant tumor transformation. Thus, the detection of K-AS is meaningful for the diagnosis of early cancer. Graphite phase carbon nitride quantum dots (g-C_3N_4 QDs) have low toxicity, and stable chemical properties. However, the low ECL intensity of g-C_3N_4 QDs limits its sensing application. Herein, a sandwich-typed sensor with a combination of M@Au and g-C_3N_4 QDs is constructed. In yolk-shell M@Au, the internal Fe_3O_4 nanoparticle (NP) has good magnetic property. The outer Au shell has better surface plasmon coupling (SPC) effect than conventional Au NPs. Furthermore, the middle cavity in the yolk-shell nanostructure solves the problem of electron transfer between Fe_3O_4 NP and Au shell. Therefore, the yolk-shell M@Au shows strong surface SPC effect, which amplifies the ECL signal of g-C_3N_4 QDs 2.8-fold. Based on the plasmon-enhanced ECL mode, this sensor performs well with a wide range (1 fM - 1 nM) for nucleic acid detection. It also shows the high stability and selectivity of the sensing system in human serum test.