Phage-displayed nanobody based double antibody sandwich chemiluminescent immunoassay for the detection of Cry2A toxin in cereals

• Main Authors: Yulou Qiu, Pan Li, Beibei Liu, Yuan Liu, Yulong Wang, Tingting Tao, Junli Xu, Bruce D. Hammock, Xianjin Liu, Rongfa Guan, Cunzheng Zhang
• Format: Article
• Language: English
• Published: Taylor & Francis Group 2019-01-01
• Series: Food and Agricultural Immunology
• Subjects: cry2a toxin; phage-displayed nanobody; chemiluminescence; sandwich immunoassay
• Online Access: http://dx.doi.org/10.1080/09540105.2019.1642307
• ISSN: 0954-0105; 1465-3443

In this study, we developed a double antibody sandwich chemiluminescent immunoassay (DAS-CLIA) based on phage-displayed nanobodies for the determination of Cry2A toxin. Nine phage-displayed nanobodies specifically to Cry2A were obtained from a naive nanobody library after four rounds of biopanning. The phage-displayed nanobody P2 with high affinity binding was selected as the detection antibody for the sensitive DAS-CLIA development. The proposed method exhibited high sensitivity with a limit of detection of 0.09 ng/mL, has a wide linear range for Cry2A toxin detection, in the range of 0.1–1000 ng/mL and negligible cross-reactivities to the other Bt toxins. The recoveries of Cry2A toxin spiked in cereal samples (rice, wheat, and corn) ranged from 82.7% to 118%, with a coefficient of variation of less than 10%. This study demonstrated that the DAS-CLIA procedure based on phage-displayed nanobodies may provide an alternative sensitive method for the detection of Bt toxins in agri-products.