Ultrasensitive label-free electrochemical immunosensors for detecting marine medaka (Oryzias melastigma) vitellogenin based on novel Cu2O–BSA nanoparticles and anti-lipovitellin monoclonal antibody

Vitellogenin (Vtg) is a biomarker for environmental estrogens, and its sensitive detection method is vital for the detection of weak estrogenic activity. This study aimed to develop sensitive electrochemical immunosensors for marine medaka ( Oryzias melastigma ) Vtg based on novel nanomaterials. Firstly, Cu 2 O–BSA nanoparticles (NPs) with a diameter of 120−150 nm was synthesized, and monoclonal antibody against lipovitellin (anti-Lv mAb) was prepared. Then two simple and efficient label-free immunosensors for the detection of Vtg were established using Cu 2 O–BSA NPs and gold nanoparticle (Au NPs) as signal amplification elements and anti-Lv mAb as the detection probe. These two immunosensors have good sensitivity, selectivity, reproducibility for Vtg quantification, and are easy to use. Moreover, the BSA/Anti-Lv mAb/Au/Cu 2 O–BSA/GCE immunosensor exhibited a linear range from 0.128 to 5 × 10 4 pg/mL, with the lowest detection limit (LOD) of 0.09 pg/mL, which is considerably lower than those of the previously reported Vtg detection techniques. Finally, the performance of the immunosensor was evaluated by quantifying Vtg concentrations in plasma of male marine medaka exposed three estrogenic bisphenols. The results demonstrated that the BSA/Anti-Lv mAb/Au/Cu 2 O–BSA/GCE immunosensor was an easily-operated, ultrasensitive and accurate detection method for weak estrogenic activity.