CdTe/CdS quantum dot-labeled fluorescent immunochromatography test strips for rapid detection of Escherichia coli O157:H7

Abstract

Immunochromatography test strips have been widely used to detect foodborne pathogens due to their high sensitivity, stability and specificity, and the selection of the label is an important factor. In this study, CdTe/CdS quantum dots with a high fluorescence were synthesized as a fluorescence label to conjugate with antibodies to prepare an immunochromatography test strip for the detection of Escherichia coli O157:H7 (E. coli O157:H7). Antibody-quantum dot conjugation was coated onto a glass fiber membrane, which played the role of the conjugate pad. E. coli O157:H7 polyclonal antibodies and goat anti-rabbit immunoglobulin G (Ig G) were used to create the test line and the control line, respectively. The detection limit was determined as 10⁴ CFU mL⁻¹ and no cross-reactions were discovered with other Escherichia coli and other strains. In addition, the strips detected effectively after storing at room temperature in the dark for 35 d. The detection was easy to perform, rapidly and sensitively, and the total detection time was less than 12 min to obtain accurate results, and this method has the potential to be a powerful tool to detect bacteria quantitatively.