Competitive electrochemical immunosensor for the detection of histamine based on horseradish peroxidase initiated deposition of insulating film

• We reported competitive electrochemical immunosensor for histamine.
• We conjugated histamine with horseradish peroxidase.
• Horseradish peroxidase initiated deposit of insulating film onto the electrode.
• The insulating film resulted in decrease of response current of the immunosensor.
• The current decrease was proportional to the concentration of histamine detected.

Competitive electrochemical immunosensor for the detection of histamine based on graphene modified electrode and horseradish peroxidase (HRP) initiated deposition of insulating film was developed. After the immobilization of anti-histamine antibodies onto graphene surface, free histamine and HRP tagged histamine molecules will compete to bind with the antibodies. The captured HRP could then catalyze the polymerization of 3,3′-dimethoxybenzidine (DB) in the presence of H2O2 to produce the deposition of an insulating polymer film, poly(3,3′-dimethoxybenzidine) (PDB) onto electrode surface. The deposited insulating PDB film resulted in the decrease of the electrochemical current of the electrode in Fe(CN)63−/4− solution, and the current change is proportional to the concentration of histamine detected. The proposed immunosensor displays wide linear range towards histamine detection (1 pg/mL–1 ng/mL) with a detection limit of 0.5 pg/mL. The immunosensor was applied to the detection of histamine in serum samples with satisfactory results.