Detecção eletroquímica indireta do DNA genômico do vírus da hepatite B em eletrodos de ouro modificados

Hepatitis B is a disease caused by a viral infection in liver cells, and occurs through percutaneous and mucosal membrane exposure to contaminated blood and body fluids, including serum, semen and saliva1. Biosensors are great alternatives to the current diagnosis methods, since they can be used as real time diagnostic devices, requiring no professional handling, with a quick response, low cost, potentially miniaturized and portable2.This work describes a new detection strategieof hepatitis B virus (HBV) genomic DNA. The electrochemical platform consisted of a single-stranded DNA probe immobilized on a gold electrode modified with reduced graphene oxide, a conductive nanomaterial, which optimizes the immobilization process by increasing the surface area. Figure 1 shows the differential pulse voltammogram relative to the oxidation of ethidium bromide, an DNA intercalator molecule. It can be observed that the oxidation peak of ethidium bromide occurs at +0.6 V. When Escherichiacoligenomic DNA was added, the observed current values were similar to the probe. However, with the addition of HBV genomic DNA (ip = 4.09 μA ± 0.19 μA), an increase of about 1.4 times was observed when compared to the probe (ip = 2.93 μA ± 0.24 μA), indicating that the hybridization process occurred, asethidium bromide is a double helix DNA intercalator3, and thus accumulated on the surface of the electrode.With this plataform, the hepatitis B virus genomic DNA extracted from patients samples was successfully detected. Thus, novel biosensors based on DNA hybridization can be constructed, aiming new devices for the rapid diagnosis of this pathology. Figure1: Differential pulse voltammograms (baseline subtracted) of the ethidium bromide oxidation in the gold electrode surface modified with reduced graphene oxide. (v= 30 mV.s-1, phosphate buffer 0,5 mol.L-1ph = 7,3).