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National Institute of Environmental Health Sciences

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Your Environment. Your Health.

Publication Detail

Title: Investigation of the Small Size of Nanobodies for a Sensitive Fluorescence Polarization Immunoassay for Small Molecules: 3-Phenoxybenzoic Acid, an Exposure Biomarker of Pyrethroid Insecticides as a Model.

Authors: Wang, Yulong; Li, Zhenfeng; Barnych, Bogdan; Huo, Jingqian; Wan, Debin; Vasylieva, Natalia; Xu, Junli; Li, Pan; Liu, Beibei; Zhang, Cunzheng; Hammock, Bruce D

Published In J Agric Food Chem, (2019 Oct 16)

Abstract: Limited reports on the use of nanobodies (Nbs) in fluorescence polarization immunoassay (FPIA) aroused us to explore if the small size of Nbs is a drawback for the development of sensitive FPIA to small molecular compounds, particularly since FPIA is a technology strongly dependent on molecular weight. In the present work, three different molecular weight Nbs against 3-phenoxybenzoic acid (3-PBA), an exposure biomarker of pyrethroid insecticides, including bare Nbs (15 kDa), Nbs-Avidin (Nbs-AV, 60 kDa), and Nbs-Alkaline phosphatase (Nbs-AP, 130 kDa) were specifically generated to cover distinct regions on the polarization and molecular weight relationship curve for a fluorescein tracer. In competitive FPIA, similar half-maximal inhibitory concentrations (IC50) of 3-PBA of 16.4, 12.2, and 14.8 ng mL-1 were obtained for Nbs, Nbs-AV, and Nbs-AP, respectively, indicating that the size of Nbs in the range tested had no significant effect on the sensitivity of the resulting competitive FPIA. An IC50 of 20.2 ng mL-1 for an anti-3-PBA polyconal antibody based FPIA further demonstrated the performance of Nbs, which was comparable to that of traditional antibodies in FPIA. Spike-recovery studies showed good and reproducible recovery of 3-PBA in urine samples, demonstrating the applicability of Nb-based FPIA. Overall, our results show that Nb-based FPIA achieves sensitivity levels of FPIA based on conventional antibodies and further indicate that Nb absolutely meets the sensitivity requirement of FPIA.

PubMed ID: 31589045 Exiting the NIEHS site

MeSH Terms: Benzoates/urine*; Biomarkers/urine; Environmental Exposure/analysis; Fluorescence Polarization Immunoassay/instrumentation; Fluorescence Polarization Immunoassay/methods*; Humans; Insecticides/analysis; Insecticides/toxicity*; Pyrethrins/analysis; Pyrethrins/toxicity*; Sensitivity and Specificity; Single-Domain Antibodies/chemistry*

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