Fig. 4

A Amperometric i–t current response of the immunosensor towards the addition of 10 mM H₂O₂ for detecting the following different concentrations of AIV H9 at − 0.4 V versus SCE: (a) 10^0.37 EID₅₀ mL⁻¹, (b) 10^1.37 EID₅₀ mL⁻¹, (c) 10^2.37 EID₅₀ mL⁻¹, (d) 10^3.37 EID₅₀ mL⁻¹, (e) 10^4.37 EID₅₀ mL⁻¹, (f) 10^5.37 EID₅₀ mL⁻¹ and (g) 10^6.37 EID₅₀ mL⁻¹. B Calibration curve of the immunosensor response to different concentrations of AIV H9. Error bar = RSD (n = 5). B Calibration curve of the immunosensor response to different concentrations of AIV H9 (n = 5). C Specificity of the immunosensor towards the target AIV H9 and other interfering substances. D Reproducibility of the developed immunosensor in the presence of 10^6.37 EID₅₀ mL⁻¹ AIV H9. E Long-term stability of the proposed immunosensor