Methyl orange-enhanced DNA hybridization: A gene sensor approach for hepatitis delta detection

Hepatitis delta is an infection triggered by the hepatitis delta virus (HDV), a defective virus that requires the hepatitis B virus (HBV) to replicate. Coinfection with both viruses can result in more severe complications, including progressive chronic liver damage. In this study, we present the development of an electrochemical device for molecular diagnosis of HDV in the blood serum of infected patients, employing screen-printed carbon electrodes functionalized with ethylenediamine and sensitized through the use of a specific DNA probe. The interaction with specific genomic RNA was evaluated using Differential Pulse Voltammetry, Electrochemical Spectroscopy Impedance, Scanning Electron Microscopy, Atomic Force Microscopy and molecular docking. The genosensor efficiently detected genomic RNA within a linear range from 9 copies/mL to 3 × 10⁵ copies/mL, with a detection limit of 9 copies/mL. EIS revealed that the sensor's resistance to charge transfer increased exponentially with increasing concentration of the target genomic RNA. This platform offers several advantages for application in real samples, including high sensitivity, selectivity, and low sample volume requirements, making it particularly suitable for the diagnosis of hepatitis delta virus in blood serum samples. Furthermore, the simple and low-cost modification via direct drop-casting highlights the potential of this platform for integration into portable point-of-care devices.