Cobalt Oxide Porous Nanocubes-Based Electrochemical Immunobiosensing of Hepatitis B Virus DNA in Blood Serum and Urine Samples

In this work, we report a new biosensing platform for hepatitis B virus (HBV) DNA genosensing using cobalt oxide (Co3O4) nanostructures. The tunable morphologies of Co3O4 nanostructures such as porous nanocubes (PNCs), nanooctahedra (NOHs), and nanosticks (NSKs) are synthesized, and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) patterns, nitrogen adsorption/desorption isotherms (BET), and electrochemical impedance spectral (EIS) methods. The HBV probe DNA (ssDNA) is immobilized on the Co3O4 nanostructures through coordinate bond formation between nucleic acid of ssDNA and Co metal, which results in highly stable nanostructured biosensing platform. To the best of our knowledge, first time the target cDNA of HBV is detected using ssDNA/Co3O4PNCs/GCE electrode by EIS method with a limit of detection (LOD) of 0.38 pM (signal-to-noise ratio (S/N) = 3). Moreover, the ssDNA/Co3O4PNCs/GCE has shown excellent specificity to HBV target cDNA, compared with noncomplementary DNA, and 1- and 3-mismatch DNAs. Finally, we explore ssDNA/Co3O4PNCs/GCE as potential electrode to test HBV DNA in blood serum and urine samples for practical applications.