Homogeneous electrochemical detection of carcinoembryonic antigen based on target-controlled catalytical reaction of platinum/UiO-66 MOFs nanozyme integrated with aptamer

Abstract

In this work, a novel homogeneous electrochemical (HEC) sensing strategy was developed for carcinoembryonic antigen (CEA) detection, addressing limitations of traditional electrochemical platforms that necessitate complex electrode modifications and receptor immobilization protocols. This approach integrates platinum nanoparticle-loaded UiO-66 metal-organic frameworks (Pt/UiO) as an oxidase-like nanozyme with CEA-specific aptamer (Apt) as recognition element, establishing a target-responsive catalytic mechanism. In solution-phase operation, the Pt/UiO nanozyme facilitates the oxidation of 1,2-diaminobenzene into electroactive diaminophenazine (DAP), generating measurable reduction current at unmodified electrode. Apt adsorption onto Pt/UiO surfaces effectively inhibits this enzymatic activity through steric hindrance, resulting in current suppression proportional to Apt coverage. The presence of CEA induces specific Apt-CEA binding, resulting Apt away from the nanozyme surface and restoring catalytic activity in a concentration-dependent manner. Optimization of experimental parameters (e.g., nanozyme concentration, incubation time) enabled the sensor to achieve a detection limit of 3 pg mL⁻¹ with a linear range spanning 0.01–11 ng mL⁻¹, demonstrating potential for point-of-care applications in tumor biomarker analysis.