Rapid Immunochromatographic Assay for <i>Escherichia coli</i> O157:H7 in Bovine Milk Using IgY Labeled by Fe₃O₄/Au Composite Nanoparticles

• DOI: 10.3136/fstr.22.53
• Publication Date: 2016-02-29T22:07:23Z
• Authors: Haiyan Xue; Baoyan Zhang; Baoyuan He; Zhanyong Wang; Chao Chen
• Keywords: Conjugate; Bovine milk

A rapid pretreatment-free immunochromatographic assay (ICA) was developed for the screen of Escherichia coli O157:H7 (E. O157:H7) in bovine milk. Anti-E. immunoglobins yolk (IgY) conjugated with a core/shell-structured super-paramagnetic Fe3O4/Au composite nanoparticle (GoldMag) and showed high coupling ratio 8 µg IgY mL−1 nanoparticles at pH 8.0. The conditions ICA strips using this conjugate were optimized could be used to measure spiked E. samples detection limit 103 CFU obtained by visual detection. Additionally, magnetic signal intensities can quantitatively concentration range 102 – 105 both phosphate buffer solution (pH 7.4) milk mL−1.