DEVELOPMENT OF BIOFUNCTIONALIZED NANOCOMPOSITE BASED BIOSENSOR FOR ORAL CANCER DETECTION

Abstract

This dissertation deals with the results of studies relating to the fabrication of a novel biosensing platform based on yttria stabilized zirconia decorated reduced graphene oxide (nY2O3-nZrO2-rGO) nanocomposite, for sensitive label-free detection of oral cancer biomarker CYFRA-21-1. One step, hydrothermal method has been used to synthesize nY2O3-nZrO2-rGO nanocomposite and 3-aminopropyl triethoxysilane (APTES) has been utilized for functionalization of the synthesized nY2O3-nZrO2-rGO nanocomposite. Thin films of the APTES/nY2O3-nZrO2-rGO nanocomposite have been obtained onto ITO electrodes via electrophoretic deposition (45 V; 180 s). Monoclonal anti-CYFRA-21-1 antibodies immobilized on to this APTES/nY2O3-nZrO2-rGO/ITO platform via EDC-NHS mediated covalent conjugation and BSA was used for blocking of non-specific sites yielding the BSA/anti-CYFRA-21-1/APTES/nY2O3-nZrO2-rGO/ITO immunoelectrode. Structural, morphological and electrochemical characterization of the synthesized nanocomposite and the fabricated electrodes was conducted via X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, differential pulse voltammetry (DPV) and cyclic voltammetry (CV). Electrochemical response studies revealed that the proposed immunosensor can efficiently detect CYFRA-21-1 in a wide linear detection range of 0.25-22 ng mL-1 with excellent sensitivity of 9.6 μA mL ng-1cm-2 and detection limit of 0.1 ng mL-1.