Determination of Subgroup J Avian Leukosis Virus by Surface Plasmon Resonance Immunosensor

Abstract

Two novel Fourier transform-surface plasmon resonance immunosensors were fabricated for the determination of the subgroup J avian leukosis virus. The immunosensors were based on a functionalized gold substrate and immobilized gold–silver nanoparticles. For the first immunosensor, the gold substrate was functionalized with a dense self-assembled monolayer of 3-mercaptopropionic acid through gold–sulfur bonds, and then protein A which can combine subgroup J avian leucosis virus antibody on the antigen nonbinding site was modified on the sensor chip surface via covalent bonds formed between the amino groups and the activated carboxyl groups of 3-mercaptopropionic acid. After inactivation by ethanolamine, the sensor chip immobilized the antibody by the combination with protein A to produce a sensor. For the second immunosensor, 1,6- hexanedithiol formed a self-assembled monolayer on the sensor chip surface through gold–sulfur bonds. Then gold–silver nanoparticles were immobilized on the sensor chip by gold–sulfur and silver–sulfur bonds. The modification by various reagents and determination of the subgroup J avian leukosis virus antigen were the same as in the first immunosensor. The immunosensors determined the subgroup J avian leukosis virus antigen to analyte concentrations of 659 TCID 50 ·mL− 1 and 1054 TCID 50 ·mL− 1 , respectively. The result suggested that introducing gold–silver nanoparticles to the Fourier transform-surface plasmon resonance immunosensor is beneficial to effectively improving the sensitivity of the immunosensor. Moreover, the contrast experiment presented that the immunosensors showed high specificity for the subgroup J avian leucosis virus detection.