Studying of quantum dot luminescence quenching effect caused by covalent conjugation with protein.

The characterization of quantum dots (QDs) and their conjugates with bovine serum albumin was done using on-a-chip electrophoresis. Under optimal conditions, bioconjugated QDs were successfully separated from free QDs within ≈10 min. Influence of coupling agent on a quenching of QD fluorescence intensity caused by conjugation to a protein was studied. When using two-step procedure combining 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide with N-hydroxysulfosuccinimide, the highest quenching effect was notable. We showed that QDs and capillary electrophoresis on a chip can be applied as a sensitive technique for the detection of biological molecules. The characteristics of this method are simplicity, small sample and reagent requirements, and high efficiency of separation. Graphical abstract: [ABSTRACT FROM AUTHOR]