Detection of glyphosate by quantitative analysis of fluorescence and single DNA using DNA-labeled fluorescent magnetic core-shell nanoparticles

Biosensors based on antibody recognition have a wide range of monitoring applications with applications to environmental and food problems. In an effort to improve the limit of detection, novel Co-B/SiO₂/dye nanoparticles were prepared in a water-in-oil microemulsion and subsequently surface modified. The fluorescence magnetic nanoparticle (FMP) based detection method for quantitatively fluorescence intensity and specific DNA-based application is described. A sandwich format consisting of conjugated glyphosate-double target/probe DNA-FMP was fabricated. Results were measured based on the fluorescence intensity obtained by comparing the free glyphosates at concentrations of 1-10,000 nM for detecting the binding of glyphosate-double DNA-FMP nanoparticles. Moreover, quantitative information concerning the free glyphosate analysis was translated into a single probe DNA signal with a good linear correlation in the concentration range of 1-10,000 nM (R² = 0.98) and a limit of detection of 0.27 nM. Therefore, detection of glyphosate could easily and quantitatively be measured using confocal laser scanning microscopy and low-cost UV photometric analysis. These results indicate that this method is a very simple and economic strategy for detecting glyphosate.