Electrochemical Biosensor for Sensitive Detection of Hepatitis B in Human Plasma

In this work we report the construction of an electrochemical device for molecular diagnosis of hepatitis B virus in the blood plasma of infected patients, using graphite electrodes functionalized with poly(4-aminophenol) and sensitized with specific DNA probe. The recognition of genomic DNA was evaluated by electrochemical techniques (DPV and EIS) and scanning electron microscopy. The genosensor was efficient in detecting genomic DNA with a linear range from 1.176 μg.ml-1 to 4.825 μg.ml-1 and detection limit of 35.69 ng.ml-1 (4.63 UI.ml-1 or 25.93 copies.ml-1), which is better than 10.00 UI.ml-1 limit of reference method, real- time PCR, used in point of care. EIS analysis shows that the genosensor resistence increased exponentially with the concentration of the genomic DNA target. The developed platform has inherent advantages to its applicability in real samples, such as good sensitivity, selectivity, and low sample volume, being interesting for application in diagnosis of hepatitis B virus in blood plasma.