Melamine-Modified Metal–Organic Framework as Novel Electrochemiluminescence Enhancer for Single-Electrode Multiplex cTnI Immunosensor

The single-electrode electrochemical system (SEES) has emerged as a significant advancement in electrochemiluminescence (ECL), offering enhanced multiplexing efficiency, simplified operation, and reduced fabrication costs. In this study, melamine-modified naphthalene-substituted UiO-66 nanocrystal (Me-UiO-66-NDC) was used as a novel enhancer of Ru(bpy)₃²⁺ ECL based on a SEES. The modification of the electrode with Me-UiO-66-NDC remarkably enhanced Ru(bpy)₃²⁺ anodic ECL. Amino groups in Me-UiO-66-NDC are found to play an important role in the enhancement of Ru(bpy)₃²⁺ ECL. The label-free platform based on the Me-UiO-66-NDC-modified electrode enables the multiplex detection of cardiac troponin I (cTnI) over a linear range of 0.01-1000 ng/mL with a detection limit of 1.9 pg/mL. The integration of immunomagnetic separation simplifies the capture and isolation of target biomolecules from complex serum samples, reducing the need for extensive pretreatment and significantly reducing the total detection time. The efficient ECL performance shows strong potential for biosensing applications.