Quantum Dot-Labeled Immunochromatographic Test Strip for Rapid Detection of Ochratoxin A in Cereals

Abstract

Objective:A quantum dot-labeled immunochromatographic test strip for the determination of ochratoxin A(OTA)in cereals was developed based on the competitive inhibition principle. Methods:Quantum dot antibody conjugates(QD-Ab)were prepared by coupling an carboxy-functionalized quantum dot(QD)with an ochratoxin A polyclonal antibody(Antibody,Ab)via the activated ester method;Different amounts of QD-Ab and working fluid were used to optimize the working conditions of the quantum dot-labeled immunochromatographic test strip;The effectiveness of the method was verified by a commercial kit. Results:When the molar ratio of QD to Ab was 1:10,the fluorescence characteristics of QD-Ab were the best;when QD-Ab and working fluid were added at 1,10 μL,respectively,the best results of quantum dot-labeled immunochromatographic test strips were obtained;The detection limit of the quantum dot-labeled immunochromatographic test strip in the assay buffer was 0.5 μg/L,and the detection limit of OTA in the cereal sample was 5 μg/kg,the entire detection process could be completed within 10 min;The quantum dot-labeled immunochromatographic test strip had good specificity and effectiveness. Conclusion:This assay is simple,rapid,and sensitivity. It can meet the requirements of on-site rapid detection of ochratoxin A in cereals.