Abstract:In this study, a nano-immunosensor was constructed through using chitosan, graphene and gold nanoparticles as the composite modification material to immobilize β-lactoglobulin (β-LG) antibody, to establish a rapid method for the determination of β-LG. The nano-immunosensor was characterized by cyclic voltammetry, using 1.0 mmol/L K3[Fe(CN)6] as the probe, and the experimental conditions were optimized. The optimal conditions were as follows: amount of the composite modification solution, 5 μL; pH of electrolyte solution, 7.0; loading amount of antibody, 40 ng; incubation temperature, 37 ℃; incubation time, 30 min. There was a good linear relationship between the immune-response current of the nano-immunosensor and the logarithm of β-lactoglobulin mass concentration at 2.5~100 ng/mL, with a limit of detection of 0.75 ng/mL. The nano-immunosensor exhibited good stability, specificity and reproducibility, and had a recovery rate of the spiked standard between 88.59% to 97.64% when it was applied to the determination of lactoglobulin in dairy products. The recovery rate was good, and the results were more accurate than those obtained by ELISA. Therefore, this methods can be used for rapid and accurate determination of β-lactoglobulin allergen in dairy products.
