A dual-signal ECL-RET immunosensor based on VC-g-C3N4 and Ru-Zr-MOF for the detection of β2-MG

This work proposes a novel dual-signal electrochemiluminescence ( ECL) immunosensor based on energy resonance transfer (RET) for the detection of β2-Microglobulin (β2-MG). Introducing carbon vacancy into g-C 3 N 4 (V C -g-C 3 N 4 ) can lead to the narrowing of the band gap and the reduction of LUMO, thereby significantly enhancing the ECL efficiency of the material. Meanwhile, Zr-MOF can effectively load Ru(bpy) 3 2+ (Ru-Zr-MOF), enabling its stable existence on the electrode. The ECL emission spectrum of V C -g-C 3 N 4 overlaps well with the fluorescence excitation spectrum of Ru-Zr-MOF, indicating an effective ECL-RET effect between them. As the concentration of β2-MG increases, the intensity of anodic ECL signal gradually increases, while the intensity of cathodic ECL signal gradually decreases. The difference between the cathodic and anodic ECL signals has a good linear relationship within the concentration range from 0.2 pg/mL to 200 ng/mL, with a detection limit of 27.73 fg/mL. The constructed immunosensor can be used for practical analysis in human serum. The proposed sensor has great potential in clinical detection of β2-MG, providing new insights for biomolecular detection and disease diagnosis.