Electrochemiluminescence Sensor for Uric Acid Based on Two-dimensional MOF Nanosheet-Modified Indium Tin Oxide Electrodes

Two-dimensional conductive metal–organic frameworks (2D c-MOFs) hold great promise for electrochemical applications due to their π-conjugated structures and high conductivity, but their application in electrochemiluminescence (ECL) sensing remains largely unexplored. In this study, we synthesized 2D c-MOF Cu3(benzenehexathiol) nanosheets (CuBHT NSs) with lateral dimensions of 2–10 μm and a thickness of 24 nm and immobilized them on indium tin oxide (ITO) electrodes. This platform facilitated the first study of luminol’s cathodic ECL behavior. CuBHT NSs exhibited exceptional oxygen reduction reaction (ORR) catalytic activity, significantly enhancing the generation of reactive oxygen species (ROS) and thereby increasing the luminol’s cathodic ECL response. Mechanistic studies confirmed that unsaturated Cu sites in CuBHT play a crucial role, as Uric acid (UA) can bind to unsaturated Cu sites, inhibiting ROS production. This outcome enabled a highly sensitive and selective ECL sensor for UA with a wide linear range (10 nM–0.1 mM) and a low detection limit (3.5 nM, S/N = 3). The sensor was successfully applied to detect UA in serum samples.