A signal enhanced lateral flow immunoassay based on core-shell quantum dots labeled antibody and antigen for sensitive detection of CP4-EPSPS protein

A signal enhanced lateral flow immunochromatographic test strip (ICS) using CdSe/ZnS core-shell quantum dots (QDs) labeled antigen and antibody for the rapid and sensitive detection of CP4-EPSPS protein in genetically modified crops was successfully developed. In the ICS, signal amplification was realized based on aminated CdSe/ZnS QDs labeled CP4-EPSPS antigen protein and carboxylated QDs labeled anti-CP4-EPSPS monoclonal antibody 2, respectively, which were forming two fluorescent probes. The CP4-EPSPS test antibody 1 and the goat anti-mouse IgG were coated on test area and control area of the nitrocellulose membrane to form the test line and control line. The visual detection limits of the test strip were 0.01 % for soybean RRS, 0.05 % for maize NK603, 0.001 % for labeled soybean RRS, and 0.005 % for labeled maize NK603. Compared with carboxylated QDs based ICS and gold nanoparticles based ICS, the signal enhanced ICS succeeded in increasing sensitivity by 10 similar to 20 times with the same detection time and operation steps. Consequently, it could be a potential tool for sensitive, on-site screening genetically modified crops.