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Research Project: Prevention of Obesity Related Metabolic Diseases by Bioactive Components of Food Processing Waste Byproducts and Mitigation of Food Allergies

Location: Healthy Processed Foods Research

Title: Usage of nanobody-beta-galactosidase fusion in immunoassays and its application in detecting a peanut allergen

Author
item Zhang, Yuzhu
item Bhardwaj, Shilpa
item CARRERE, MATHIS - School Of Engineers Of Purpan
item He, Xiaohua
item JIN, TENGCHUAN - Hefei University
item Xu, Yixiang

Submitted to: Food Chemistry: Molecular Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/17/2026
Publication Date: 1/18/2026
Citation: Zhang, Y., Bhardwaj, S.R., Carrere, M., He, X., Jin, T., Xu, Y. 2026. Usage of nanobody-beta-galactosidase fusion in immunoassays and its application in detecting a peanut allergen. Food Chemistry: Molecular Sciences. 12. Article 100357. https://doi.org/10.1016/j.fochms.2026.100357.
DOI: https://doi.org/10.1016/j.fochms.2026.100357

Interpretive Summary: The presence of undeclared food allergens continues to be one of the main reasons for food recalls in the US. Immunoassays are essential methods for detecting allergens in packaged food. Horseradish peroxidase and alkaline phosphatase are the two most widely used enzymes in immunoassays, and nanobodies, a single protein domain of certain camelids and cartilaginous fish antibodies, have become favorite tools for research and applications in the medical and food industries. This study reports the utilization of beta-galactosidase to generate detection signals in immunoassays for the first time. The result may lead to the easy generation of immunoassay reagents for many research fields, including detecting food allergens and foodborne toxins.

Technical Abstract: Small-sized nanobodies (Nb) have many advantages compared to conventional antibodies and antibody fragments. However, the single valence of an antibody may impact its usage. This study fused a previously isolated Nb specific to peanut allergen Ara h 3 (Nb16) to the tetrameric Escherichia coli beta-galactosidase (ß-gal). The results showed that tagging an Nb to the N-terminus of ß-gal does not affect its activity. The data also showed that tagging ß-gal to the C-terminus of a nanobody does not affect its association with its cognate antigen. In ELISA experiments, peanut allergen Ara h 3 was successfully detected using the Nb16-ß-gal with a detection limit no higher than 0.3 ppm. The ease of recombinantly producing nanobody-ß-gal chimeras may accelerate ß-gal’s joining horseradish peroxidase and alkaline phosphatase to become a widely used detection enzyme in immunoassays.