A sandwich amperometric immunosensor for the detection of fowl adenovirus group I based on bimetallic Pt/Ag nanoparticle-functionalized multiwalled carbon nanotubes

An enzyme-free sandwich amperometric immunosensor based on bimetallic Pt/Ag nanoparticle (Pt/AgNPs)-functionalized chitosan (Chi)-modified multiwalled carbon nanotubes (MWCNTs) as dual signal amplifiers and Chi-modified MWCNTs (MWCNTs-Chi) as substrate materials was developed for ultrasensitive detection of fowl adenovirus group I (FAdV-I). MWCNTs have a large specific surface area, and many accessible active sites were formed after modification with Chi. Hence, MWCNTs-Chi, as a substrate material for modifying glassy carbon electrodes (GCEs), could immobilize more antibodies (fowl adenovirus group I-monoclonal antibody, FAdV-I/MAb). Multiple Pt/AgNPs were attached to the surface of MWCNTs-Chi to generate MWCNTs-Chi-Pt/AgNPs with high catalytic ability for the reaction of H 2 O 2 and modified active sites for fowl adenovirus group I-polyclonal antibody (FAdV-I/PAb) binding. Amperometric i–t measurements were employed to characterize the recognizability of FAdV-I. Under optimal conditions, and the developed immunosensor exhibited a wide linear range (10 0.93 EID 50 mL −1 to 10 3.43 EID 50 mL −1 ), a low detection limit (10 0.67 EID 50 mL −1 ) and good selectivity, reproducibility and stability. This immunosensor can be used in clinical sample detection.