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

Abstract

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.

Electrochemiluminescence with semiconductor (nano)materials

“…Another smart DNA-mediated strategy based on Au–Au NPs dimer was developed recently. 213 The hybridization of a target DNA by the complementary capture DNA triggers the immobilization of the Au dimer and subsequent surface plasmon coupling with carbon nitride QDs. Cathodic ECL with persulfate co-reactant was chosen as signal readout affording a wide dynamic range for sequence-specific DNA sensing.…”

Strategies for Enhancing the Sensitivity of Electrochemiluminescence Biosensors

“…The detection range of EGFR ranged from 0.05 to 1 nmol/L, and the detection limit was 0.0043 nmol/L. Apart from Au monomers, Au–Au dimers can be applied in the construction of biosensors to further improve the signal intensity and the sensitivity due to the surface plasmon coupling between two Au monomers, resulting in high electromagnetic field enhancement [ 100 ]. It is worth noting that the metallic substrates used in most surface-enhanced strategies are limited to Au nanomaterials.…”

Polarization-Resolved Electrochemiluminescence Sensor Based on the Surface Plasmon Coupling Effect of a Au Nanotriangle-Patterned Structure

“…Recently, the surface coupling effect with “hot spots” in luminescence enhancement has attracted the attention of researchers. The anisotropy metallic nanostructures with large specific surface areas and sharp tip positions can provide a significantly stronger electromagnetic intensity, which is called the “hot spot” regions. , Metal nanoparticles composed of different elements and the gap coupling distance between Au nanoparticle dimers have further been explored for the research of surface plasmon coupling ECL . More importantly, the anisotropic geometry of the noble metal nanostructure allowed for the excitation of hot spots to effectively modulate the polarization properties of the emitted light .…”