•A nanohybrid of platinum nanoparticles-porous ZnO spheres-hemin was synthesized.•Hemin was adsorbed onto Pt–pZnO by ester-like binding between hemin and ZnO.•Alkaline phosphatase catalyzed 1-naphthyl phosphate and in situ produce electroactive substance 1-naphthol.•Pt–pZnO–hemin exhibited electrocatalytic activity toward 1-naphthol.In this work, a nanohybrid of platinum nanoparticles-porous ZnO spheres-hemin (Pt–pZnO–hemin) was synthesized for construction of alkaline phosphatase-based immunosensor for detection of influenza. Briefly, porous ZnO spheres (pZnO) were prepared using soluble starches as the capping agent, followed by surface functionalization of platinum nanoparticles via a hydrothermal method (Pt–pZnO). Then, hemin with carboxylic functionality was spontaneously adsorbed onto Pt–pZnO by ester-like binding between carboxylic group of hemin and ZnO. Compared with platinum nanoparticles and hemin, the resulting Pt–pZnO–hemin nanohybrid showed more excellent electrocatalysis activity toward 1-naphthol (1-NP). Taking advantage of the Pt–pZnO–hemin, we have developed an amplified electrochemical immunosensor based on in situ generation of redox probe by alkaline phosphatase (ALP) and Pt–pZnO–hemin as signal enhancer. Herein, electrochemically active 1-NP was generated by enzymatic hydrolysis of inactive 1-naphthyl phosphate by ALP, then Pt–pZnO–hemin was used as catalyst to catalytically oxidize 1-NP, resulting in electrochemical signal amplification. Furthermore, in comparison with other nanomaterials including Au–pZnO, Pt–pZnO and Au–pZnO–hemin, the excellent catalytical property of Pt–pZnO–hemin make it a promising nanohybrid material for ALP-based immunosensor for signal amplification.

•ALP catalyzed p-NPP hydrolysis and in situ produce electroactive substance.•Pt/CeO2/GO were used to oxide 1-naphthol, resulting in signal amplification.•GO and Pt were used to functionalized CeO2 to improveits properties.•Pt/CeO2/GO with a large of area increased the immobilized amount of ALP and Ab2.In this work, an amplified electrochemical immunosensor based on 1-naphthol as electroactive substance and Pt/CeO2/GO composites as catalytic amplifier was constructed for sensitive detection influenza. Through “sandwich” reaction, the Pt/CeO2/GO functionalized bioconjugates were captured on electrode surface and the electrochemical signal directly originated from 1-naphthol, which was in situ produced with high local concentration though the hydrolysis of 1-naphthyl phosphate catalyzed by ALP. Then, 1-naphthol as new reactant was oxidized by Pt/CeO2/GO composites with outstanding catalytic performance, resulting in detection signal amplification. In addition, as compared to label electroactive substance to antibodies, a simplified preparative step of immunosensor could be achieved because the signal probe get rid of introducation other electroactive substances. The proposed immunosensor achieved a linear range of 1.0×10−3–1.0 ng mL−1 and 5.0 to 1.0×102 ng mL−1 with a detection limit of 0.43 pg mL−1 (defined as S/N=3).