Electrochemiluminescent competitive immunosensor based on polyethyleneimine capped SiO nanomaterials as labels to release Ru(bpy) fixed in 3D Cu/Ni oxalate for the detection of aflatoxin B1.

In this work, a highly-efficient competitive method-based electrochemiluminescence (ECL) immunosensor was proposed based on {[Ru(bpy)][CuNi(ox)]} (Cu/Ni/Ru) as luminophor to efficiently detect aflatoxins B1 (AFB1). Cu/Ni/Ru exhibited excellent ECL behavior. While polyethyleneimine capped silicon dioxide (PEI@SiO) could decrease the ECL performance of Cu/Ni/Ru due that PEI could destroy the structure of Cu/Ni/Ru via producing the complex between PEI and metal ions (Cu(II)/Ni(II)), inducing the release of Ru(bpy). Since Au nanoparticles can directly combine with antibody and antigen, the Cu/Ni/Ru and PEI@SiO was functionalized by Au nanoparticles. The quantitative detection of AFB1 was based on the competitive binding between AFB1-bovine serum albumin labeled Au-PEI@SiO (Au-PEI@SiO-AFB1-BSA) and free AFB1 with antibody-AFB1 which immobilized on Au-Cu/Ni/Ru. The ECL signal increased with augmenting the concentrations of the free AFB1 due to less Au-PEI@SiO-AFB1-BSA combining with antibodies. Under optimal conditions, the proposed immunosensor exhibited a wide linear range from 0.01ngmL to 100ngmL with a detection limit of 0.0039ngmL (S/N = 3). The proposed immunosensor also provides a promising approach for ultrasensitive detection of other mycotoxins.