Electrochemiluminescent competitive immunoassay for zearalenone based on the use of a mimotope peptide, Ru(II)(bpy)3-loaded NiFe2O4 nanotubes and TiO2 mesocrystals.

An ultrasensitive competitive-type electrochemiluminescence immunoassay for the mycotoxin zearalenone is described. The method is based on the use of (a) a mimotope peptide that was selected from a phage displayed peptide library and used to substitute ZEN for designing the competitive assay; (b) NiFe2O4 nanotubes with large specific surface area loaded with the ECL probe Ru(bpy)32+; and (c) poly(vinylpyrrolidone) (PVP)-assisted synthesis of TiO2 mesocrystals that acts as the sensing platform and support for antibody immobilization. Under the optimized conditions and at an ECL working potential of 1.1 V, a linear response is found for ZEN in the 0.1 to 1.0 × 10-5 ng·mL-1 concentration range with a detection limit as low as 3.3 fg·mL-1. Graphical abstract An ultrasensitive competitive-type electrochemiluminescence (ECL) immunosensor based on mimotope peptide was constructed for the detection of Zearalenone.