Sequence-specific electrochemical detection of nucleic acids in real samples

This paper reviews past and current developments in the field of electrochemical biosensors with a focus on the sequence-specific detection of nucleic acids in real samples. After electrochemical hybridization sensors had been first described in 1993, it took nearly a decade until some of the many proposed protocols were indeed applied to real samples like blood or tissue. Electrochemical transduction schemes used either rely on electroactive moieties such as intercalators, groove binders, covalently attached labels, and products of enzyme markers or they are completely indicator free like impedance-based detection principles. Most detection schemes require a polymerase chain reaction amplification step to allow for sufficient selectivity and sensitivity. Today, several companies develop electrochemical microarrays able to detect dozens to many thousands of sequences in a single experiment.