Nanoconfinement catalysis-enhanced electrochemiluminescence aptasensor for the sensitive detection of matrix...

Matrix metalloproteinase-9 (MMP-9) detection is crucial for the early screening and treatment monitoring of infantile hemangioma. Herein, a nanoconfinement catalysis-enhanced electrochemiluminescence (ECL) aptasensor was fabricated for the sensitive detection of MMP-9. Co₃O₄ nanoparticles were electrochemically deposited onto an ordered silica nanochannel film (SNF), which not only exhibited electrocatalytic oxidation activity toward luminol and H₂O₂ but also possessed peroxidase (POD)-like activity. The synergistic effect between Co₃O₄ and the confinement effect of SNF remarkably amplified ECL from the luminol-H₂O₂ system. After functionalizing the electrode surface with epoxy groups, MMP-9 aptamers were covalently immobilized to construct the aptasensor. ECL signal quenching, attributable to the spatial hindrance and elevated interfacial resistance following the specific MMP-9/aptamer binding, served as the basis for the quantitative detection of MMP-9. The sensor displayed a wide linear response range (0.001 to 100 ng mL^-1), a low detection limit of 0.1 pg mL^-1, and high selectivity, reproducibility, and stability.