Development of an Electrochemical Sensing Technique for Rapid Genotyping of Hepatitis B Virus

OBJECTIVE To develop a convenient; sensitive; accurate; and economical technique for genotyping of hepatitis B viruses (HBVs). METHODS The mercapto-modified B1; B2; C1; and C2-specific genotyping probes consisted of two probes for each HBV genotype that served as a double verification system. These probes were fixed on the surface of No. 1; 2; 3; and 4 gold electrodes; respectively; via Au-S bonds. Different charge generated by the binding of RuHex to phosphate groups of the DNA backbone before and after hybridization was used for distinguishing the different genotypes. RESULTS During hybridization with genotype B; the charges detected at the No. 1 and 2 electrodes were significantly increased; while the charge at the No. 3 and 4 electrodes did not change significantly. During hybridization with genotype C; the charges detected at No. 3 and 4 electrodes were significantly increased; while the signals remained unchanged at the No. 1 and 2 electrodes. During hybridization with mixed genotypes (B and C); the charges detected at all four electrodes were significantly increased. The linear range of detection was 10(-7) to 10(-10) mol/L and the sensitivity for detecting mixed B (10%) or C (10%). CONCLUSIONS Rapid genotyping of HBVs based on electrochemical sensing is simple, has good specificity; and can greatly reduce the cost. This method can be used for sensitive detection of mixed B and C HBV genotypes.