Development of the Au@Pt-Labeled Nanobody Lateral-Flow Nanozyme Immunoassay for Visual Detection of 3-Phenoxybenzoic Acid in Milk and Lake Water
Can Zhang, Jinnuo Hu, Xiaoxiao Wu, Jiyong Shi, Bruce D. Hammock
Abstract
As a major metabolite of pyrethroid pesticides, 3-phenoxybenzoic acid (3-PBA) can be an indicator of health risk and human exposure assessment. A gold–platinum (Au@Pt) nanozyme is a kind of mimic enzyme with unique properties of nanomaterials and catalytic activity. The anti-3-PBA nanobodies were labeled with Au@Pt (Au@Pt-Nbs) by electrostatic adsorption. The Au@Pt-Nbs lateral-flow nanozyme immunoassay was established for the visual and rapid detection of 3-PBA. The visualization results were quantitatively analyzed by Adobe Photoshop CC and got a cutoff value of 0.005 ng/mL. The samples of milk- and lake water-spiked 3-PBA were also analyzed, and the recoveries ranged from 102 to 108% and 95 to 112%, respectively. The results were also validated by liquid chromatography–mass spectrometry and got good correlation (R2 = 0.945). The Au@Pt-Nbs lateral-flow nanozyme immunoassay was developed by the combination of nanobodies and nanozymes, which will be a promising application in the field of safety inspection.