Electrochemical characterization and DNA sensing application of a sphere-like CeO2–ZrO2 and chitosan nanocomposite formed on a gold electrode by one-step electrodeposition

Abstract A composite film that contained CeO 2 –ZrO 2 hollow nanospheres and chitosan was deposited on a gold electrode using a one-step electrodeposition based on the pH-dependent solubility of chitosan. Electrochemical characterization experiments showed that the electroactive surface of the modified electrode was significantly enhanced by the introduction of the CeO 2 –ZrO 2 nanospheres into the chitosan gel during electrodeposition. Furthermore, an electrochemical DNA biosensor was fabricated based on the synergistic affinity of CeO 2 –ZrO 2 and chitosan in the nanocomposite film to probe DNA. DNA hybridization assays suggested that the target DNA could be quantified over a wide dynamic range of 1.63 × 10 −13  M–1.63 × 10 −8  M with a detection limit of 1.0 × 10 −13  M using methylene blue as an electrochemical indicator. This work describes a simple strategy for the preparation of a stable and conductive interface for electrochemical detection of DNA hybridization and opens a path for the application of CeO 2 –ZrO 2 nanospheres and chitosan in DNA electrochemical biosensing analysis.