US Patent 7291457 Electrochemical detection of mismatch nucleic acids

A method and system for specifically detecting perfectly matched probe-target hybrids by annealing a hairpin-based probe to a nucleic acid target under conditions favoring the formation of perfectly matched targets over mismatched targets, and electrochemically detecting the annealed probe. Sensitivity of detection can be enhanced by catalyzed reporter deposition of probe signal prior to electrochemical detection. Specificity can be enhanced by including hairpin-based competitor probes in the annealing step. The detection assay is particularly applicable to typing single nucleotide polymorphisms by DNA sandwich hybridization.