Conjugation behaviours of CdTe quantum dots and antibody by a novel immunochromatographic method

Three water-soluble CdTe quantum dots (QDs) (green-emitting, yellow-emitting and red-emitting) were synthesised for different refluxing time with 3-mercaptopropionic acid (MPA) as stabiliser. Then the red-emitting CdTe QDs and mouse immunoglobulin G (IgG) were taken as the representative to study the conjugation behaviour of QDs and antibody by a novel immunochromatographic method. After comparing with several methods, that is, direct conjugation, 1-ethyl-3(3-dimethylaminopropyl) carbodiimides hydrochloride (EDC)-mediated conjugation, N-hydroxysuccinimide (NHS)-mediated conjugation, EDC/NHS-mediated conjugation by immunochromatographic strips, EDC and NHS were selected together as coupling agents to conjugate QDs with antibody efficiently. Finally, the K562 leukaemia cells were incubated with the EDC/NHS-mediated conjugates to evaluate the performance in practical application, and the result from fluorescence images showed that it was successfully applied to label cells. The immunochromatographic strip was a superior method to study the conjugation of the fluorophore and antibody.