Electrophoretically deposited reduced graphene oxide platform for foodtoxin detection

Abstract

Reduced graphene oxide (RGO) due to its excellent electrochemical properties and large surface area, has recently aroused much interest for electrochemical biosensing application. Here, the chemically active RGO has been synthesized and deposited onto an indium tin oxide (ITO) coated glass substrate by the electrophoretic deposition technique. This novel platform has been utilized for covalent attachment of the monoclonal antibodies of aflatoxin B₁ (anti-AFB₁) for food toxin (AFB₁) detection. The electron microscopy, X-ray diffraction, and UV-visible studies reveal successful synthesis of reduced graphene oxide while the XPS and FTIR studies suggest its carboxylic functionalized nature. The electrochemical sensing results of the anti-AFB₁/RGO/ITO based immunoelectrode obtained as a function of aflatoxin concentration show high sensitivity (68 μA ng⁻¹ mL cm⁻²) and improved detection limit (0.12 ng mL⁻¹). The association constant (k_a) for antigen–antibody interaction obtained as 5 × 10⁻⁴ ng mL⁻¹ indicates high affinity of antibodies toward the antigen (AFB₁).