Fumed silica nanoparticles–chitosan nanobiocomposite for ochratoxin-A detection

Fumed silica nanoparticles (NanoSiO2) and chitosan (CH) based nanobiocomposite film have been used to co-immobilize rabbit-immunoglobulin antibodies (r-IgGs) and bovine serum albumin (BSA) for ochratoxin-A (OTA) detection. The observed three-dimensional (3D) arrangement of NanoSiO2 in CH matrix via hydrogen bonding, available NH2/OH groups and excellent film-forming ability of CH results in increased effective surface area of CH–NanoSiO2 nanobiocomposite for r-IgGs immobilization. Electrochemical studies suggest that presence of NanoSiO2 leads to enhanced electrochemical behaviour of CH resulting in increased electron transport between the medium and the electrode. BSA/r-IgGs/CH–NanoSiO2/ITO immunoelectrode exhibits improved sensing characteristics such as linearity (0.5–6 ng/dL), detection limit (0.3 ng/dL), response time (25 s) and sensitivity (18 μA ng/dL cm−2) with correlation coefficient as 0.98.