One-pot Synthesis of Quencher Labeled Hairpin DNA-CdTe QDs Conjugate for Target DNA and Deoxyribonuclease I Detection.

A black-hole quencher (BHQ-2) labeled DNA (Q-DNA) with a phosphorothioate backbone was covalently conjugated to the CdTe QDs during the QDs synthesis procedure. The hairpin structure of Q-DNA shortened the distance of the CdTe QDs and the BHQ-2 group, which resulted in fluorescence quenching of the QDs. The addition of target DNA or deoxyribonuclease I (DNase I) could move the BHQ-2 group away from the QDs. As a result, the fluorescence of the CdTe QDs recovered. This work provides a new way for target DNA and DNase I detection.