An ultrasensitive biosensor for DNA detection based on hybridization chain reaction coupled with the efficient quenching of a ruthenium complex to CdTe quantum dots.

A highly sensitive and selective DNA biosensor based on hybridization chain reaction is described, which combines CdTe quantum dots (QDs) and a ruthenium complex. Based on the variation of fluorescence signals of the CdTe QDs, the target DNA is determined.