Tunable plasmon-assisted electrochemiluminescence strategy for determination of the rapidly accelerated fibrosarcoma B-type (BRAF) gene using concave gold nanocubes

A novel fluorescence-electrochemiluminescence dual-mode sensing platform for high-precision BRAF gene detection

In this study, we innovatively synthesized bipyridine ruthenium cluster nanosheets (RuMOFNCs), a novel metal-organic framework material that exhibits both fluorescence and electrochemiluminescence. Gold nanoparticles (AuNPs) were anchored onto RuMOFNCs via bipyridine chelation, enhancing optical signals and creating sites for attaching biologically functional probes. We employed tetraferrocene-modified DNA probes, linked via gold-sulfur (Au-S) bonds, to construct a dual-mode fluorescence-electrochemiluminescence biosensor. This sensor, exploiting exonuclease III (Exo III)-mediated cyclic amplification, inhibits the electron transfer from RuMOFNC to tetraferrocene, resulting in amplified fluorescence and electrochemiluminescence signals. The sensor demonstrates exceptional sensitivity for detecting the BRAF gene, with fluorescence and electrochemiluminescence detection limits of 10.3 aM (range: 0.1 fM to 1 nM) and 3.1 aM (range: 1 aM to 10 pM), respectively. These capabilities are attributed to RuMOFNCs' luminescence properties, tetraferrocene's quenching effect, and the specificity of base pairing. This study's findings hold substantial promise for biomedical research and clinical diagnostics, particularly in precision medicine and early disease detection.

Sulfur dots/Au@Ag nanorods array-based polarized ECL sensor for the detection of thyroid cancer biomarker

The combination of highly sensitive electrochemiluminescence (ECL) techniques with localized surface plasmon resonance (LSPR) effect can achieve the highly sensitive and specific detection in the analytical and biosensing applications. However, how to effectively improve the electromagnetic field intensity is an unresolved issue. Herein, we have developed an ECL biosensor based on sulfur dots and Au@Ag nanorod array architecture. Firstly, the high luminescent sulfur dots with ionic liquid capping (S dots (IL) have been prepared as the new ECL emitter. The ionic liquid greatly improved the conductivity of sulfur dots in the sensing process. Furthermore, Au@Ag nanorods array structure was constructed on the electrode surface by the evaporation induced self-assembly. On the one hand, the LSPR of Au@Ag nanorods was more significant than that of good nanomaterial due to the plasma hybridization and the competition between free electrons and oscillating electrons. On the other hand, nanorods array structure had strong electromagnetic field intensity as hot spots due to the surface plasmon coupling ECL effect (SPC-ECL) effect. Therefore, the Au @Ag nanorods array architecture not only greatly enhanced the ECL intensity of sulfur dots, but also changed the ECL signals into polarized emission. Finally, the constructed polarized ECL sensing system was used to detect the mutated BRAF DNA in the eluent of thyroid tumor tissue. The biosensor showed the linear range from 100 fM to 10 nM with a detection limit of 20 fM. The satisfactory results demonstrated that the developed sensing strategy had great potential in the clinical diagnosis of BRAF DNA mutation in thyroid cancer.