Novel Copper Superparticle-Based Bragg Scattering Coupling Luminescence Strategy for Detection of Ginseng Exosomal miRNA

Ginseng exosomes are a kind of promising extracellular vesicle containing unique bioactive components. However, the investigation on ginseng-derived exosomes is still in the initial stage. This study developed a photonic crystal-based Bragg scattering coupling electrochemiluminescence (BSC-ECL) biosensor for detection of miRNA396a-3p in exosome-like nanoparticles (GENs) and ginseng exosomes (Gexos). First, copper nanoclusters were engineered into Cu superparticles with π-π stacking of 2,6-dimethylbenzenethiol ligands via a ligand-mediated self-assembly strategy. The prepared Cu superparticles with significantly enhanced luminescence intensity and stability can be used as a nanoprobe. Furthermore, the Bragg scattering law was utilized to modulate the ECL intensity of the Cu superparticles. Due to the highly periodic structure of MIL-96-based photonic crystals, multiple scattering pathways in photonic crystals greatly increased the effective photon flux of Cu superparticles, thus creating a positive feedback loop between photon absorption and emission. Therefore, this cascade amplification mechanism ultimately led to significant BSC-ECL enhancement. The BSC-ECL provided a new quantitative analysis method for key miRNA detection in plant extracellular vesicles, which revealed distinct miRNA concentrations in GENs and Gexos. The method also demonstrated considerable potential in areas such as ginseng quality control, product development, and bioanalysis applications.