LAUSR

A novel dual-signal electrochemiluminescence immunosensor with high sensitivity was successfully constructed for the sensitive detection of gastric cancer biomarker CA 72-4. The superior performance of the electrochemiluminescence immunosensor came from the self-calibration function of the dual-signal system "Ru(bpy)32+@3D-foam graphene/TPA" and "SnS2 dots/K2S2O8". 3D-foam graphene not only has good electrical conductivity and ideal surface area, but also contains amino groups on its surface, which facilitate electron transfer and can carry a large number of luminous reagents. Furthermore, immobilized Ru(bpy)3Cl2·6H2O on 3D-foam graphene to construct an ECL immunosensor, which can reduce the distance between the illuminant and the surface of electrode, thus highly increasing the ECL intensity. Additionally, the SnS2 dot with excellent stability and outstanding biocompatibility is an ideal candidate for efficient cross-linking to the anti-CA 72-4. The dual-signal immunosensor is prepared by linking SnS2 dots-Ab2 and CA 72-4 through specific recognition. Generally, the ECL intensity of electrochemiluminescence immunosensor changes linearly with the logarithm of CA 72-4 concentration in the range from 5 × 10-5 to 5 × 102 U mL-1 and the detection limit of 1.48 × 10-5 U mL-1 (S/N = 3). Furthermore, the experiment results show that the constructed CA 72-4 immunosensor has excellent reproducibility and can be used for the sensitive detection of CA 72-4 in human serum. The approach opens up the new way for clinical bioassays.