Highly sensitive amperometric detection of genomic DNA in animal tissues

A simple and highly sensitive method for the detection of genomic DNA in tissue samples is described. It is based on amperometric detection of target DNA by forming an analyte/polymeric activator bilayer on a gold electrode. The biotinylated target DNA is hybridized to oligonucleotide capture probes immobilized on the gold electrode, forming the first layer. A subsequent binding of glucose oxidase– avidin conjugate to the target DNA and the introduction of a second layer of a redox polymer to the electrode, via layer‐by‐layer electrostatic self‐assembly, allow for electrochemical detection of the catalytic oxidation current of glucose in a PBS solution. Less than 2.0 fg of rat genomic DNA, for both regulated and house‐keeping genes, can be easily detected in 2.5 µl droplets. The proposed procedure shows very high specificity for genomic DNA in a RT–PCR mixture.