A conductive metal-organic framework-modified electrode for sensitive electrochemiluminescent detection of cardiac Troponin I

Abstract

The design of a sensitive and accurate electrochemiluminescence (ECL) immunosensor for the early detection of cardiac biomarkers at low concentrations is essential to improve patient outcomes. In this study, a conductive metal-organic framework (c-MOF), Cu3(HHTP)2, was drop-coated onto a screen-printed carbon electrode (SPCE) to produce an ultra-efficient electrochemical sensing platform which was subsequently functionalized with cTnI antibodies (Ab) and bovine serum albumin (BSA) for selective detection of the cardiac Troponin I. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) confirmed the successful stepwise fabrication of the immunosensor. We investigated the ECL behaviour of the Cu3(HHTP)2-modified SPCE using [Ru(bpy)3]2+ as the luminophore and found that a significant increase in ECL intensity was achieved compared to that of the unmodified SPCE. This enhancement was attributed to the high conductivity, porous structure, the increased surface area of the c-MOF and crucially the HHTP ligand plays a critical role in enabling ECL generation in this system. The analytical performance of the immunosensor was evaluated by monitoring the ECL responses at varying cTnI concentrations. The immunosensor achieved a detection limit of 10.23 ± 1.06 pg/mL in vitro, well below the clinically relevant cTnI thresholds, highlighting its potential for rapid and early-stage cardiac biomarker detection. These findings suggest the Cu3(HHTP)2-based ECL immunosensor represents a viable sensing platform that significantly increases conductivity and ECL efficiency without the need of additional coreactant species.