Abstract:

A novel electrochemical immunosensor was developed by modifying the electrode with gold nanoparticles/
graphene composite material. The immunogen was prepared by conjugating dienestrol (hapten) to the carrier protein (bovine
serum albumin) and used to generate polyclonal antibodies. Cyclic voltammetry and differential pulse voltammetry were
employed to monitor the fabrication process of immunoreaction system in solutions containing the redox probe K3Fe(CN)6.
The results revealed that gold nanoparticle/grapheme composites could effectively modify the electrode and enhance its
sensitivity. The biosensor showed excellent detection performance with a broad linear range of 1–6 000 ng/mL and a
supersensitive detection limit of 0.05 ng/mL. In addition, the biosensor modified with the small molecule of dienestrol had
the advantages of simplicity, reproducibility and stability. Good recoveries in the range of 96.5%–103.7% were obtained in
the detection of pork, dunk, beef and milk powder samples.

Key words: gold nanoparticles, graphene, composite materials, electrochemical biosensor, dienestrol