Detection of Matrix Metalloproteinase 2 by a Polypeptide Cleavable Split-Type Sensor Based on Atomically Precise Bimetallic Nanocluster Au3Ag5(MSA)3

In this study, a split-type electrochemiluminescence (ECL) sensor based on polypeptide cleavage was proposed for the sensitive detection of matrix metalloproteinase 2 (MMP 2). The bimetallic nanoclusters were protected by mercaptosuccinic acid (MSA), named Au₃Ag₅(MSA)₃, serving as a signal probe. Owing to the synergistic effect of the bimetal composition, the clusters exhibited enhanced ECL properties. Polypeptide chains (PLGVR) that can be specifically cleaved by MMP 2 were selected from the MMP 2 domain. Additionally, the antifouling segment (PPEKEK) and the binding segment (CCC) were incorporated into the polypeptide chain design. In the presence of MMP 2, a specific cleavage site on the polypeptide was targeted, resulting in the detachment of Au₃Ag₅(MSA)₃ and subsequent generation of an ECL signal. Compared to conventional detection methods, this approach exhibited enhanced sensitivity and improved stability. This method provides a valuable reference for detecting members of the matrix metalloproteinase family and holds promising prospects for future development.