Dual-functionalized gold nanoparticles probe based bio-barcode immuno-PCR for the detection of glyphosate

Glyphosate (GLYP) was the most widely used broad-spectrum herbicide in the world. Herein, a gold nanoparticle (AuNP) probe dual-functionalized with anti-GLYP antibody and double-stranded oligonucleotides was synthesized. An AuNP-based bio-barcode immuno-PCR (AuNP-BB-iPCR) based on the probe was developed for sensitive detection of GLYP in food samples without high-cost and time-consuming experiments. GLYP detection was accomplished with a linear range from 61.1 pg g^-1 to 31.3 ng g^-1 and a detection limit of 4.5 pg g^-1 which was 7 orders of magnitude lower than that of conventional ELISA (70 μg g^-1) developed using the same antibody. The recoveries of GLYP from soybean, cole and maize samples were 99.8%, 102.6% and 103.7%, respectively, and all relative standard deviation values were below 12.9%. The assay time (including food samples preparation) of AuNP-BB-iPCR was 4 h. The proposed AuNP-BB-iPCR exhibits potential for sensitive detection of GLYP in foodstuffs and environment.