Development of a sandwich-type electrochemical DNA sensor based on CeO2/AuPt nanoprobes for highly sensitive detection of hepatitis B virus DNA.

To provide accurate diagnostic evidence for early hepatitis B virus (HBV) infection-related diseases, this study targeted HBV DNA as an analyte, where a sandwich-type electrochemical DNA sensor based on gold nanoparticles/reduced graphene oxide (Au NPs/ERGO) and cerium oxide/gold-platinum nanoparticles (CeO₂/AuPt NPs) was constructed. Au NPs/ERGO composite nanomaterials were first synthesized on the surface of a glass carbon electrode using electrochemical co-reduction, which significantly improved the specific surface area and electrical conductivity of the electrode. Further specific hybridization of target HBV-DNA was performed by combining capture probe DNA (S1-DNA) bound to AuNPs/ERGO with CeO₂/AuPt modified signal probe DNA (S2-DNA). Leveraging the excellent H₂O₂ catalytic activity of the CeO₂/AuPt nanocomposite, the constructed sandwich-type electrochemical DNA sensor was used to detect HBV DNA. By optimizing the detection conditions, the sensor showed a good linear response in the range of 1 fmol/L to 1 nmol/L, with a detection limit as low as 0.36 fmol/L. The sensor had good specificity, repeatability, and stability. Further, spiked recovery experiments of actual serum samples showed recoveries ranging from 98.7 % to 102.7 %, and the relative standard deviations were all lower than 4.77 %. This study provides a new method for the detection of HBV DNA with potential clinical applications.