Journal of Analytical & Bioanalytical Techniques
Open Access

Abstract

Investigation of biomolecules at the single-molecule level is an important research area. Quantum dots (QDs) and fluorescence cross-correlation spectroscopy (FCCS) could be applied in this area because of their unique properties. In the present study, dual-color QD-labeled DNA probes were prepared by streptavidin-biotin conjugation. The labeled DNA probes on 3? and 5? terminals were hybridized with the target DNA, and then analyzed by FCCS with one laser excitation (488 nm). The effective volume of FCCS was 1.53 fL and the concentration and diffusion coefficient of the double-stranded DNA molecules were 4.3�10 - 11 mol L ?1 and 3.9�10-12 m2s -1 , respectively. The efficiency of hybridization was about 9% at 37�C. These results indicate that QDs broke the bottleneck of traditional FCCS and could be used in FCCS with one-laser beam for investigations on the single-molecule scale. Compared with traditional methods, QDs-based FCCS is simpler and less expensive because of the photo-properties of QDs. This technique is promising for detection of target biomolecules.

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