A biocompatible serine functionalized nanostructured zirconia based biosensing platform for non-invasive oral cancer detection

Abstract

We report results of studies relating to the fabrication of nontoxic, biocompatible serine functionalized nanostructured zirconia (serine/nZrO₂) for oral cancer detection. The hydrothermally synthesized ZrO₂ nanoparticles (∼4.5 nm) have been characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The cytotoxicity studies of serine/nZrO₂ carried out using MTT assay on the HEK 293 human cell line reveal biocompatibility of the serine/nZrO₂. The serine functionalized nZrO₂ are electrophoretically deposited onto a hydrolysed indium tin oxide (ITO) coated glass electrode (serine/nZrO₂/ITO). Furthermore, monoclonal antibodies (anti-CYFRA-21-1) were covalently immobilized onto the serine/nZrO₂/ITO electrode and BSA was been used for blocking of the non-specific binding sites. The fabricated BSA/anti-CYFRA-21-1/serine/nZrO₂/ITO immunoelectrode was used for label free, non-invasive and efficient detection of an oral cancer biomarker (CYFRA-21-1). The electrochemical response studies of this immunoelectrode exihibited a wider linear detection range (0.01–29 ng mL⁻¹) with a remarkable detection limit (0.01 ng mL⁻¹) and a quick response time (6 min) for detection of the CYFRA-21-1 antigen. The results of validation studies conducted on the fabricated immunoelectrode (BSA/anti-CYFRA-21-1/serine/nZrO₂/ITO) using saliva samples of oral cancer patients indicate a good agreement with the results obtained via enzyme linked immunosorbent assay (ELISA).