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An abrupt decrease in egg production and quality in laying hens can be brought on by the avian adenovirus known as the egg drop syndrome virus (EDSV). So far, there are no efficient commercial diagnostic approaches for EDSV. In the present study, we first purified two monoclonal antibodies (mAbs 5G4 and 6G6) specifically against the EDSV fibre protein. The mAb 5G4 was then employed as capture antibody. Additionally, the detection antibody 6G6 (HRP-6G6) was conjugated with horseradish peroxidase. Consequently, based on these two mAbs, we developed a sandwich enzyme-linked immunosorbent assay (ELISA) for EDSV detection. Specificity evaluation demonstrated that only EDSV gave a positive result while other avian viruses showed negative results. Sensitivity investigation showed that the limit of detection of EDSV was 102.9 TCID50/ml and the limit of detection of the purified His-Fiber was 5 ng/ml. Furthermore, the screening of samples from infected chickens showed that this method was very effective and could be applied to the detection of EDSV in infected samples. In summary, the sandwich enzyme-linked immunosorbent assay developed here provides an efficient, sensitive, and large-scale method for the specific diagnosis of EDSV. A sandwich ELISA was developed to detect EDSV using the mAbs 5G4 and HRP-6G6. The sandwich ELISA maintained high specificity and sensitivity. The sandwich ELISA had equivalent consistency with real-time PCR assay. [ABSTRACT FROM AUTHOR]

Maduramicin (MD) is a type of monoglycoside polyether ionophore antibiotic that can effectively treat coccidiosis and facilitate animal growth. However, its extensive and excessive use brings potential risk to human health. Herein, an electrochemical immunosensor based on indirect competitive format was fabricated for analysis of MD residue in eggs by a multiple signal amplification system. Initially, Au nanoparticles were deposited onto glassy carbon electrode surface to load the coating antigen MD-BSA and to improve conductivity. Then the signal amplification platform was constructed by encapsulating hemin into Fe-MIL-88 NH 2 metal-organic frameworks (hemin@MOFs), and then the obtained composites were decorated with AuPt nanoparticles. The synthesized hemin@MOFs/AuPt was not only used as a signal amplification mediator, but also utilized as a carrier for immobilization of horseradish peroxidase-conjugated affinipure goat anti-mouse antibody (Ab 2 -HRP) and horseradish peroxidase (HRP). The constructed hemin@MOFs/AuPt-Ab 2 -HRP bioconjugates could effectively amplify the current signal since hemin@MOFs, AuPt and HRP all exhibited high catalytic activity towards the hydrogen peroxide. Moreover, the established immunosensor showed high sensitivity and stability during the detection procedure. With the synergistic catalytic effect of hemin@MOFs, AuPt and HRP, a wide detection range of 0.1–50 ng mL−1 and a low detection limit of 0.045 ng mL−1 were achieved (S/N = 3), respectively. Ultimately, the developed method displayed excellent performance in practical applications, providing a promising probability to detect other veterinary drug residues to guarantee food safety. • An ultrasensitive biosensor for MD detection was constructed by using hemin@MOFs/AuPt-Ab 2 -HRP/HRP as bioprobes. • A linear calibration curve of MD ranged from 0.1 ng mL−1 to 50 ng mL−1 was obtained with LOD as low as 0.045 ng mL−1. • A multiple signal amplification strategy was triggered by the co-synergistic effect of hemin@MOFs, AuPt and HRP. • The proposed immunosensor shows a great potential for sensitive detection of small molecule drug residues. [ABSTRACT FROM AUTHOR]