文摘
Capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection was used to separate differentbioconjugated CdSe/ZnS quantum dots (QDs). The QDnanocrystals studied were conjugated to the biomoleculesstreptavidin, biotin, and immunoglobulin G. The bioconjugated QDs showed different electrophoretic mobilities,which appear to depend upon the biomolecule that isattached to the QD and the buffer solution used. The useof a polymeric additive into the CE run buffer improvedthe resolution of the bioconjugates. Under CE conditions,the interaction between QD bioconjugates containingstreptavidin (QDSt) and biotin (QDBi) was monitored.Under a given set of experimental conditions, the fluorescence intensity of QDSt and QDBi emitting light at 655nm indicated that about 90% of QDBi complexed with70% of QDSt. A two-color experiment that made use oftwo different sizes of QD (i.e., 585 and 655 nm) indicatedthat 30% of the 655 nm QDBi complexed with 53% ofthe 585 nm QDSt. The use of QDs with different emissionproperties allows the selective monitoring of two differentwavelengths while using one single excitation source. This,in turn, allowed the monitoring of overlapping peaks inthe electropherogram when newly formed products resulting from the interaction of the two bioconjugated QDsappeared.