Applications of electrochemiluminescence resonance energy transfer between CdSe/ZnS quantum dots and cyanine dye (Cy5) molecules in evaluating interactions and conformational changes of DNA molecules

In this work, electrochemiluminescence resonance energy transfer (ECRET) between CdSe/ZnS quantum dot (QD) as the donor and cyanine dye (Cy5) as the acceptor in the conjugates consisting of QD, DNA and Cy5 was studied in detail. When a negative potential was applied to the conjugates immobilized on an Au electrode, QDs emitted a light with a maximum emission (λm) of 590 nm or transfered energy to proximal ground-state Cy5 molecules in 0.1 mol/L phosphate buffer (pH 7.4) containing 0.1 mol/L K2S2O8 and 0.1 mol/L KNO3. The excited state Cy5 molecules relaxed to their ground state by emitting a light with a λm of 675 nm. ECRET between QD and Cy5 in the conjugates could be used to evaluate the interactions between DNAs and to measure the conformational changes of DNAs as well as the distances between groups in DNAs. For the ECRET system, ECRET efficiency was high due to high Cy5-to-QD ratio and low Förster distance.

Graphical abstractElectrochemiluminescence resonance energy transfer in the conjugates consisting of CdSe/ZnS QD, DNA and Cy5 dye.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Electrochemiluminescence resonance energy transfer (ECRET) between QD and Cy5. ► Evaluation of the interactions between DNAs using ECRET between QD and Cy5. ► Measurement of the conformational changes of DNAs using the ECRET system. ► Measurement of distances between groups in DNAs using the ECRET system.