▎ 摘　　要

In this paper, an electrochemical DNA biosensor was prepared using electroreduced graphene oxide, titanium dioxide nanowires and chitosan modified carbon ionic liquid electrode as the substrate electrode, which was further used for the electrochemical detection of the specific tlh gene sequence from Vibrio parahaemolyticus. The presence of nanocomposite on the electrode surface can increase the surface area and fix the ssDNA probe sequence by electrostatic attraction. After the hybridization with the target ssDNA sequence under the selected conditions, methylene blue (MB) was used as the electrochemical indicator for monitoring the hybridization reaction. Under the optimal conditions, the reduction peak current of MB was proportional to the concentration of tlh gene sequence in the range from 1.0 x 10(-12) to 1.0 x 10(-6) mol L-1 with a detection limit as 3.17 x 10(-13) mol L-1 (3 sigma). This electrochemical DNA sensor exhibited good ability to discriminate between one-base and three-base mismatched ssDNA sequences, and the polymerase chain reaction amplification product of the tlh gene from oyster samples was further detected with satisfactory results.