Interface Self-Assembly of Au10 Nanoclusters for Enhanced Electrochemiluminescence and Alzheimer's Disease Biomarker Detection.

Atomically precise metal nanoclusters (NCs), as ultrasmall materials with well-defined composition and structure, exceptional biocompatibility, and unique optical properties, position them as strong candidates in the field of electrochemiluminescence (ECL). However, the ECL efficiency of NCs is relatively low, which dramatically constrained their applications due to the demands of detection sensitivity and brightness. In this study, we report the interface self-assembly of Au10 nanoclusters for the first time, and ultimately formed a fibrous structure with a high aspect ratio, Au10-Fiber, which is an innovative approach that significantly enhances the ECL activity of Au10 NCs. By employing time-dependent and in situ spectroscopic techniques, we visually monitored the dynamic assembly process, and elucidated the interface self-assembly mechanism mediated by aurophilic interaction and π-π stacking. The increase in local electronic density, enhanced conductivity of the ordered structure, and accelerated electron transfer within the π-conjugated system collectively contributed to the significant enhancement of the ECL performance, thereby revealing the key structural factors responsible for ECL enhancement. As a proof of concept, we successfully constructed an ECL immunosensor based on Au10-Fiber for the detection of Alzheimer's disease biomarker Aβ1-42, achieving a detection limit below 3.33 fg/mL.