Smartphone-integrated cascade immunosensing platform based on antibody-enzyme-inorganic hybrid nanoflowers for highly sensitive detection of zearalenone.

Zearalenone (ZEN), a toxic non-steroidal mycotoxin with strong bioaccumulation potential, poses severe threats to food and public health, while conventional detection methods suffer from poor stability, exogenous reagent dependence, or limited on-site applicability. Herein, we report a cascade catalysis-driven, smartphone-integrated immunosensing platform based on antibody-enzyme-inorganic hybrid nanoflower (IgG-GOx-Pt@NiO/CoO HNFs) for highly sensitive and on-site detection of ZEN. The unique hierarchical architecture of the hybrid nanoflower dramatically boosts enzymatic activity and long-term stability, enabling efficient signal amplification via glucose oxidase (GOx)-mediated oxidation of glucose and subsequent H₂O₂-triggered colorimetric reaction of 3,3',5,5'-tetramethylbenzidine (TMB). Under optimal conditions, the colorimetric immunoassay exhibits a broad linear range of 0.125-100 ng/mL and a low detection limit (LOD) of 0.04 ng/mL. Furthermore, by integrating a smartphone app for colorimetric readout, we constructed a portable sensing platform with a linear range of 5-100 ng/mL and LOD of 1.67 ng/mL. This work highlights the synergistic enhancement achieved through an integrated hybrid nanoflower architecture and the smartphone-based mode enables instrument-free, on-site analysis with results obtained in under 10 min. The results of 15 naturally contaminated real samples showed good correlation between HPLC-MS/MS and the developed system. The proposed strategy exhibited great potential for the rapid monitoring of mycotoxins or other small molecule hazards.