One-step electrochemiluminescence immunoassay for breast cancer biomarker CA 15-3 based on Ru(bpy)62+-coated UiO-66-NH2 metal-organic framework

[Display omitted] •An ECL immunosensor based on UiO-66-NH2 for sensitive detection of CA 15-3 has been constructed.•The UiO-66-NH2 can provide a large specific surface area for enhancing ECL signal responses.•The proposed ECL immunosensor displays a wide linear range, low detection limit and favorable recovery. By virtue of the metal organic framework UiO-66-NH2, an ingenious electrochemiluminescence immunosensor was successfully constructed for subtle exploration of the breast cancer biomarker CA 15-3. In this protocol, Ru(bpy)3Cl2·6H2O (Ru(bpy)32+), as a conventional luminescent reagent, provides a stable and strong luminescent signal. The UiO-66-NH2 serves as a carrier to provide a large specific surface area for enhancing the electrochemical luminescence signal response of Ru(bpy)32+. UiO-66-NH2, Ru(bpy)32+ are fixed together with Nafion membrane, and CA 15-3 antibody is covalently conjugated onto the membrane through the amide reaction. Ru(bpy)32+@UiO-66-NH2 is used as the detection system. The experimental results reveal that the ECL signal decreased obviously after the CA 15-3 antigen molecule is captured on the immunosensor, with the capture of manifesting the principle of electrochemical luminescence quenching detection. Under optimal conditions, the sensor is sensitive and selective for detecting CA 15-3 with the detection range from 5 × 10−4 to 5 × 102 U mL-1 and the low LOD (1.7705 × 10-5 U mL-1). Furthermore, multiple experiments elucidate that the as-prepared sensor could be used for susceptibly detect CA 15-3 in actual samples, which has underlying application prospects in biological analysis.