A sensitive electrochemical biosensor for specific DNA sequence detection based on flower-like VS2, graphene and Au nanoparticles signal amplification

• VS2 nanoflowers was prepared by a simple hydrothermal method.
• VS2 nanoflowers, Gr and AuNPs were employed to construct biosensing platform.
• Avian influenza virus H5N1 gene sequence was chosen as the target DNA.
• The developed biosensor can detect target DNA down to 52 fM.

Flower-like VS2 was prepared by a simple one-step hydrothermal strategy. A highly sensitive and label-free electrochemical aptasensor was developed by employing self-assembly of DNA aptamers on flower-like VS2, graphene and Au nanoparticles (AuNPs)-modified glassy carbon electrodes. Avian influenza virus H5N1 gene sequence was chosen as the target DNA and [Fe(CN)6]3−/4− solution was used as the electrochemical indicator. AuNPs were coated onto VS2-graphene modified electrode and used as a platform for the immobilization of the aptamers. This VS2-graphene composite offered a nanostructure with a large effective surface area, highly electrocatalytic activities and electronic conductivity. Therefore, the amount of aptamer immobilized onto the electrode was increased while the accessibility of the detection target was maintained. The decrease in the peak current was linear with the logarithm of the concentration of the H5N1 specific sequence from 5.0 × 10−13 to 5.0 × 10−10 M (R = 0.9912) with a detection limit of 5.2 × 10−14 M. The proposed method also showed acceptable stability and reproducibility. This work provides a promising immobilization strategy for the fabrication of biosensors and offers an alternative and sensitive method for DNA detection.