Nanobody multimerization strategy to enhance the sensitivity of competitive ELISA for detection of ochratoxin A in coffee samples. (September 2021)

• Record Type: Journal Article
• Authors: Bao, Kunlu; Liu, Xing; Xu, Qi; Su, Bencao; Liu, Zilong; Cao, Hongmei; Chen, Qi
• Is Part Of: Food control. Volume 127(2021)
• Publication Date: 2021-09
• Subjects: Nanobody multimerization -- Heptamer -- Competitive ELISA -- Sensitivity enhancement strategy; Food -- Quality -- Periodicals; Food -- Analysis -- Periodicals; Food handling -- Periodicals; Food industry and trade -- Quality control -- Periodicals; Aliments -- Industrie et commerce -- Qualité -- Contrôle -- Périodiques; Aliments -- Qualité -- Périodiques; Aliments -- Analyse -- Périodiques; Hygiène alimentaire -- Périodiques; Food -- Analysis; Food handling; Food -- Quality; Periodicals; Electronic journals; 664.07
• DOI: 10.1016/j.foodcont.2021.108167
• Languages: English
• ISSNs: 0956-7135

Abstract

Abstract: Enzyme-linked immunosorbent assay (ELISA) is an ideal immunoassay technique for large scale screening detection of various chemical contaminants in food due to its high throughput, low cost and ease of automation. However, the widespread use of traditional colorimetric ELISA has been hindered by the relatively low sensitivity. In this paper, the OTA-specific nanobody (Nb28) was fused with the C4-binding protein (C4bp) C-terminal fragment to form a self-assembled heptamer fusion protein (Nb28-C4bpα). In addition, the heptamer with higher affinity was employed to develop an ultrasensitive competitive ELISA for the detection of OTA in coffee samples. The effect of this sensitivity enhancement strategy was demonstrated with the IC50 of 0.13 ng/mL and LOD of 0.009 ng/mL for the heptamer-based ELISA, which is 26.54-fold and 175.56-fold lower than that of the monomer-based ELISA, respectively. The proposed nanobody multimerization can be a particularly appealing strategy to enhance the sensitivity or analytical signals in various immunoassays. Highlights: A heptameric nanobody was developed for enhance the sensitivity of competitive ELISA. The effect of nanobody multimerization strategy on the sensitivity of competitive ELISA was studied. The heptamer-based ELISA ELISA has an LOD of 0.009 ng/mL for OTA in coffee samples.