ABSTRACT
A core-shell cerium oxide nanorod@polypyrrole (CeO2-NR@Ppy) nanocomposite-based electrochemical DNA biosensor was studied for Salmonella detection. The core-shell CeO2-NR@Ppy nanocomposite was prepared by in situ chemical oxidative polymerization of pyrrole monomer on CeO2-NRs, which provided a suitable platform for electrochemical DNA biosensor fabrication. The immobilization of ss-DNA sequences onto nanocomposite-coated microelectrode was performed via covalent attachment method. DNA biosensor electrochemical responses were studied by cyclic voltammetry and electrochemical impedance spectroscopy with [Fe (CN)6]3-/4- as redox probe. Under optimal conditions, DNA biosensor response showed good linearity in the range of 0.01-0.4â¯nM with sensitivity of 593.7â¯Ω·nM-1·cm-2. The low limit of detection and limit of quantification for the DNA biosensor were 0.084 and 0.28â¯nM, respectively. The proposed DNA biosensor also showed good results when used in detecting actual Salmonella samples.
