Fig. 1. Mechanism for encapsulation of graphene oxide with AuNS

Fig. 2. Fabrication of the EGO-AuNS-LPFG immunosensor. (a) Surface pre-treatment; (b) hydroxylation; (c) silylation; (d) modification with EGO-AuNS; (e) activation of carboxyl group; (f) surface modification with AIV-MAbs and sealing of redundant binding sites; (g) detection for AIV antigens

Fig. 3. Schematic diagram of the experimental system

Fig. 4. FESEM graphs of the EGO-AuNS-LPFG images. (a) 5000×; (b) 10000×; (c) 50000×

Fig. 5. Energy spectrum of the EGO-AuNS-LPFG

Fig. 6. Transmission spectrum of the EGO-AuNS-LPFG

Fig. 7. Transmission spectra of the bare LPFG and the EGO-AuNS coated LPFG immersed in different sucrose concentrations. (a) Bare LPFG; (b) EGO-AuNS coated LPFG

Fig. 8. Resonant wavelength of the bare LPFG and EGO-AuNS coated LPFG against RI of different sucrose solutions

Fig. 9. Spectral evolution and the corresponding wavelength shift of the immunosensor for AIV detection against time. (a) Spectral evolution;(b)corresponding wavelength shift

Fig. 10. Wavelength shift of the GO-AuNS-LPFG immunosensor for different AIV concentration levels (Inset corresponds to the linear fitting area)

Fig. 11. Wavelength shift for specificity and clinical assays of the EGO-AuNS-LPFG immunosensor