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

A composite film that contained CeO2–ZrO2 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 CeO2–ZrO2 nanospheres into the chitosan gel during electrodeposition. Furthermore, an electrochemical DNA biosensor was fabricated based on the synergistic affinity of CeO2–ZrO2 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 CeO2–ZrO2 nanospheres and chitosan in DNA electrochemical biosensing analysis.