Study on the Enhancement of Electrochemical and Electrochemiluminescence Behaviors of Au–Ag Nanoclusters Based on Synergistic and Ligand Effects

This study developed a dual-mode aptamer sensor based on methionine (Met)-stabilized Au-Ag nanoclusters (Au-Ag NCs) for the simultaneous electrochemical (EC) and electrochemiluminescence (ECL) detection of alternariol (AOH) at trace levels. Compared to traditional stabilizers for nanoclusters, Met not only improves the storage stability and conductivity of Au-Ag NCs but also enhances their overall EC/ECL performance. The synergistic effect of bimetallic Au-Ag further boosts the EC/ECL behavior of the nanoclusters. First, it balances lattice mismatch, reduces surface-state defects, and increases the ECL efficiency by up to 163%. Second, it narrows the bandgap, facilitating electron transfer and significantly enhancing the EC response. Moreover, the dual-mode EC/ECL sensor enables cross-validation across a wide AOH concentration range (0.001-100 ng/mL), effectively minimizing false-positive or false-negative results. In summary, the superior EC/ECL properties of Met/Au-Ag NCs provide a novel design strategy for dual-mode aptamer sensors, advancing their application in highly reliable detection systems.