CdS quantum dots as a fluorescent sensing platform for nucleic acid detection.

We demonstrate that CdS quantum dots (QDs) can be applied to fluorescence-enhanced detection of nucleic acids in a two-step protocol. In step one, a fluorescently labeled single-stranded DNA probe is adsorbed on the QDs to quench its luminescence. In step two, the hybridization of the probe with its target ssDNA produces a double-stranded DNA which detaches from the QD. This, in turn, leads to the recovery of the fluorescence of the label. The lower detection limit of the assay is as low as 1 nM. The scheme (that was applied to detect a target DNA related to the HIV) is simple and can differentiate between perfectly complementary targets and mismatches. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]