DNA-Mediated Au-Au Dimer-Based Surface Plasmon Coupling Electrochemiluminescence Sensor for BRCA1 Gene Detection.

Herein, we constructed a DNA-mediated Au-Au dimer-based surface plasmon coupling electrochemiluminescence (SPC-ECL) sensor. In the SPC-ECL sensing system, graphite phase carbon nitride quantum dots (GCN QDs) worked as an ECL emitter. A DNA rigid chain structure was employed to connect two Au NPs in an equilateral triangle configuration to form the Au-Au dimers. Due to the hot spot effect, the designed Au-Au dimers had a strong electromagnetic field intensity, which can greatly enhance the ECL signal of GCN QDs than a single Au nanoparticle. The gap distance of dimers can be effectively regulated by the DNA length, which resulted in different electromagnetic field intensities. Therefore, the different SPC-ECL amplification effects on the GCN QD signal by Au-Au dimers have been revealed. The maximum ECL signal of GCN QDs can be enhanced fourfold based on the Au-Au dimers with a gap distance of 2 nm. Furthermore, the biosensor showed good analytical performance for the detection of breast cancer susceptibility gene 1 (BRCA1 genes) (1 fM-1 nM) with a detection limit of 0.83 fM. This work provided an effective and precise SPC-ECL sensing mode for the diagnosis and prognosis of breast cancer.