Target-induced structure switching of DNA for label-free and ultrasensitive electrochemiluminescent detection of proteins.

The association of the target thrombin with the corresponding aptamer leads to structure switching of the dsDNA probes and the formation of nicking sites for exonuclease III, which causes cyclic cleavage of the dsDNA probes and highly reduced intercalation of the electrochemiluminescent signal indicators for label-free and sensitive detection of thrombin at the femtomolar level.