Label-free electrochemical detection of cancer biomarkers DNA and anti-p53 at tin oxide quantum dot-gold-DNA nanoparticle modified electrode

Abstract

Lung cancer is one of the deadliest types of cancer and accounts for 8.1% of all cancer related deaths. To prevent a growing death rate, it is crucial to identify lung cancer at an early stage by single polynucleotide morphism detection. In this paper, we present a novel label-free electrochemical biosensor based on composites of tin oxide quantum dots and gold nanoparticles (SnO2-QD-Au) for the sensitive and precise detection of lung cancer DNA. The SnO2-QD and SnO2-QD-Au nanoparticles were characterized using Scanning and Transmission Electron Microscopes (SEM and TEM), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), UV–Vis spectroscopy (UV), Fourier transmission infrared spectroscopy (FTIR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. Gold thiol covalent bonding was used for immobilising probe DNA on the surface of SnO2-QD-Au nanoparticles followed by target DNA hybridization and detected electrochemically in presence of 1 mM [Fe(CN6)]3−/4−as a redox couple probe. Under ideal circumstances, the sensor showed the lowest detection limit of 3.2 × 10−20 M with a linear range of 1 × 10−6 − 1 × 10−20 M. Additionally, the sensing method was applied to find a cancer biomarker, Anti-P53 antibody.