Ultrasensitive Detection of the Hepatitis E Virus by Electrocatalytic Water Oxidation Using Pt-Co₃O₄ Hollow Cages

A sensitive virus detection method applicable for an early stage increases the probability of survival. Here, we develop a simple and rapid detection strategy for the detection of the hepatitis E virus (HEV) by an electrocatalytic water oxidation reaction (WOR) using a platinum (Pt)-incorporated cobalt (Co)-based zeolite imidazole framework (ZIF-67). The surface cavity of ZIF-67 enables the rich loading of Pt NPs, and subsequent calcination etches the cavity, promoting the electrocatalytic activity of Pt-Co₃O₄ HCs. The Pt-Co₃O₄ HCs show excellent behavior for the WOR due to the synergistic interaction of Pt and Co₃O₄, evaluated by voltammetry and chronoamperometry. The synthesized Pt-Co₃O₄ HCs are conjugated with anti-HEV antibody (Ab@Pt-Co₃O₄ HCs); the electrocatalytic activity of Ab@Pt-Co₃O₄ HCs is combined with that of antibody-conjugated magnetic nanoparticles (MNPs) for HEV detection by a magneto-and-nanocomposite sandwich immunoassay. The sensor is challenged to detect the HEV in spiked serum samples and HEV G7 genotypes collected from the cell culture supernatant, reaching a low limit of detection down to 61 RNA copies mL^-1. This work establishes a free-indicator one-step approach with the controlled design of Pt-Co₃O₄ HCs, which presents an effective WOR technique for virus detection in a neutral pH solution, which can be extended to electrocatalytic studies in the future integrated biosensing systems.