Anodic Electrochemiluminescence Platform for Domoic Acid Detection Utilizing AuCu Bimetallic Nanoclusters with Low Trigger Potential

Gold nanoclusters (Au NCs) have demonstrated significant potential in electrochemiluminescence (ECL) due to their unique quantum size effect. However, Au NCs are not only expensive but also exhibit high anodic emission potentials, which cause false-positive signals in sensing systems. To overcome these limitations, a central atom regulation strategy was developed. By employing short peptides as a stabilizing ligand and precisely controlling the atomic ratio of Au to copper (Cu), exceptional ECL properties were observed in the synthesized AuCu bimetallic nanoclusters (GSH-AuCu NCs). Notably, when N,N-diisopropylethylamine (DIPEA) was employed as a coreactant, the ECL response of GSH-AuCu NCs was 2.83 times stronger than that of GSH-Au NCs and photon emission was generated at a low applied potential of +0.20 V. Moreover, the synthesized GSH-AuCu NCs exhibited four distinct ECL emissions, thereby establishing a foundation for the advancement of probe-based multiplexing methodologies. To enhance the applicability of GSH-AuCu NCs in biosensing applications, we implemented them as signal probes and employed a high-affinity domoic acid (DA) aptamer as the recognition probe. By utilizing selective activation strategies based on ECL signals, the ECL detection platform enabled the highly sensitive identification of DA. This work not only advances the application of nanoclusters in ECL systems but also introduces a novel approach for designing efficient methodologies for DA detection.