Published online 20 January 2004
Nucleic Acids Research, 2004, Vol. 32, No. 2 e15
© 2004 Oxford University Press
Highly sensitive amperometric detection of genomic DNA in animal tissues
Institute of Bioengineering and Nanotechnology, 51 Science Park Road, Singapore 117586, Republic of Singapore
*To whom correspondence should be addressed. Tel: +65 6874 9386; Fax: +65 6874 9341; Email: zqgao{at}ibn.a-star.edu.sg
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 RTPCR mixture.