Highly sensitive biofunctionalized nickel oxide nanowires for nanobiosensing applications

Abstract

We report results of the studies relating to the fabrication of nickel oxide nanowires (NwNiOs) with an enhanced aspect ratio of ∼100 for biosensing applications. Anti Vibrio cholerae monoclonal antibodies were used to functionalize the nickel oxide nanowire (20–80 nm) surfaces fabricated on indium tin oxide coated glass plate for Vibrio cholerae detection. The results of the impedance response studies conducted using this immunoelectrode as a function of the Vibrio cholerae concentration revealed a detection range of 37–350 ng ml⁻¹ and a low detection limit of 0.553 ng ml⁻¹ using the 3σ_b/m criteria. The high sensitivity (11.12 Ω (ng ml⁻¹)⁻¹ cm⁻²) of this fabricated sensor is attributed to the excellent electronic properties of NiO nanowires which facilitate the efficient transfer of electrons between the electrode and the antibody molecules through electron channeling effects. Besides this, the nanostructured NiO nanowire based immunosensor exhibits interesting supercapacitive behaviour towards the detection of CT. This immunosensor showed values of association constant (K_a) of 4.5 × 10⁷ ng ml⁻¹ and dissociation constant (K_d) of 2.22 × 10⁻⁶ ng ml⁻¹.