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

In this work, plasmon-enhanced electrochemiluminescence (ECL) nanosensor based on magnetic-plasmonic Fe3O4 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-C3N4 QDs) have low toxicity, and stable chemical properties. However, the low ECL intensity of g-C3N4 QDs limits its sensing application. Herein, a sandwich-typed sensor with a combination of M@Au and g-C3N4 QDs is constructed. In yolk-shell M@Au, the internal Fe3O4 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 Fe3O4 NP and Au shell. Therefore, the yolk-shell M@Au shows strong surface SPC effect, which amplifies the ECL signal of g-C3N4 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.