Electrochemical DNA Biosensor Based on Platinum-gold Bimetal Decorated Graphene Modified Electrode for the Detection of Vibrio parahaemolyticus Specific tlh Gene Sequence

Background: By using bimetal nanocomposite modified electrode, the electrochemical DNA biosensor showed the advantages of high sensitivity, low cost, rapid response and convenient operation, which was applied for disease diagnosis, food safety, and biological monitoring. Objective: A nanocomposite consisting of platinum (Pt)-gold (Au) bimetal and two-dimensional graphene (GR) was synthesized by hydrothermal method, which was modified on the surface of carbon ionic liquid electrode and further used for the immobilization of probe ssDNA related to Vibrio parahaemolyticus tlh gene to construct an electrochemical DNA sensor. Method: Potassium ferricyanide was selected as electrochemical indicator, cyclic voltammetry was used to study the electrochemical behaviours of different modified electrodes and differential pulse voltammetry was employed to test the analytical performance of this biosensor for the detection of target gene sequence. Results: This electrochemical DNA biosensor could detect the Vibrio parahaemolyticus tlh gene sequence as the linear concentration in the range from 1.0×10-¹³ mol L^-1 to 1.0×10^-6 mol L^-1 with the detection limit as 2.91×10^-14 mol L^-1 (3σ). Conclusion: This proposed electrochemical DNA biosensor could be used to identify the special gene sequence with good selectivity, low detection limit and wide detection range.