Abstract: A current-type nano-immunosensor was developed for the specific determination of immunoglobulin G (IgG) content in colostrum products and bovine IgG-containing products. The chitosan with excellent film-forming capability and biocompatibility was used as the medium to connect nano-gold and glassy carbon electrode. Due to its large surface area, strong adsorption capacity and good biocompatibility, nano-gold was used to immobilize rabbit anti-bovine IgG-HRP. Electrochemical properties of electrode surface during each fabrication procedure were characterized by cyclic voltammetry and alternating current impedance method and standard bovine IgG in phosphate buffer was determined by chronoamperometry. The results revealed that the current-type nano-immuosensor had an excellent linear relationship between the concentration of bovine IgG in the range of 0.1－10000 ng/mL and the change rate of stable current before and after immunization with a correlation coefficient of 0.9976. Moreover, this immunosensor proved stable, reproducible, easy to use and inexpensive, thus being applicable for the quality control of bovine IgG products.

Key words: bovine immunoglobulin G, immunosensor, nano-gold, chronoamperometry