Nanostructured zirconia@reduced graphene oxide based ultraefficient nanobiosensing platform for food toxin detection

Abstract

In this work, we report zirconia nanoparticle (∼17 nm) decorated reduced graphene oxide nanocomposite (nZrO₂@RGO) based nanobiosensing platform for label-free and efficient detection of food toxin (aflatoxin B1, AFB1). A simple hydrothermal approach was followed for the synthesis of the nZrO₂@RGO nanocomposite, which was further functionalized with 3-aminopropyltriethoxy silane (APTES) and made to adhere electrophoretically onto an indium tin oxide (ITO) coated glass substrate (15 V, 180 s). The immobilization of monoclonal antibodies of aflatoxin B1 (anti-AFB1) and bovine serum albumin (BSA) was achieved through EDC–NHS chemistry and drop-casting method, respectively. The structural, morphological, and electrochemical attributes of nZrO₂@RGO and the fabricated bioelectrodes were characterized by spectroscopic, microscopic and electrochemical (cyclic voltammetry and differential pulse voltammetry) techniques. Here, the large surface area of RGO support helps in increasing the dispersibility of nZrO₂ which imparts synergistic effects to the nZrO₂@RGO nanocomposite and as result, accelerates the electron transfer process. Thus, the fabricated immunoelectrode (BSA/anti-AFB1/APTES/nZrO₂@RGO/ITO) efficiently detects AFB1 covering wider linear detection range between 1.5–18 ng mL⁻¹ with lower limit of detection of 2.54 ng mL⁻¹ and durability of 49 days.