Quasi-Solid-State ECL Immunosensor Based on Adenine-Incorporated MOFs Adsorption and Electrochemical Release of Ru(bpy)₃²⁺ for Signal Enhancement

Electrochemiluminescence (ECL) immunosensors are widely used for cancer marker detection due to their high selectivity, but their reuse is limited by the need for electrode reconditioning after each assay, hindering large-scale application. In our work, a novel quasi-solid-state ECL immunosensor is designed. A gel-cast cellulose membrane is used as our sensor platform, providing a new location for biomolecular-specific identification. Separating the specific identification process from the electrode surface greatly reduces the cost of using disposable electrodes. To accommodate the above assumptions, we independently designed a novel quasi-solid-state ECL auxiliary device and fabricated it by three dimensional printing. In addition, we synthesized Zinc-based metal–organic frameworks (ZnMOFs) using adenine. It has a good loading capacity for tris(2,2′-bipyridine)ruthenium(II) ion (Ru(bpy)32+). At the same time, adenine can be decomposed in the electrochemical process to release Ru(bpy)32+ and produce a signal-enhancing effect. To obtain better performance, we optimized the test conditions of the sensor. Finally, various performance parameters of the sensor were tested. Our research provides a novel strategy for the detection of Alpha-Fetoprotein, and the quasi-solid-state sensor also provides a universal model for the detection of other biomarkers.