The application of quantum dots as fluorescent label to glycoarray

A sensitive, specific, and rapid method for the detection of carbohydrate-protein interactions was demonstrated using quantum dots (QDs) as a fluorescence label coupled with protein. 1,3-Dipolar cycloaddition between azide and alkyne was exploited to attach alpha-d-glucopyranoside to a C(14) hydrocarbon chain that noncovalently binds to the microtiter well surface, and the product formation was detected by both electrospray ionization-mass spectrometry (ESI-MS) and QD- (or fluorescein isothiocyanate (FITC))-conjugated lectin binding. It indicated that the peak intensity of the fluorescence emission was proportional to the initial concanavalin A (Con A) concentration in the range of 2 x 10(-3) micromol/L to 2 x 10(-2)mmol/L with a detection limit at least 100 times lower than that of the FITC-based method.