Rapid, sequence-specific detection of unpurified PCR amplicons via a reusable, electrochemical sensor

*Center for Polymers and Organic Solids, Departments of
^†Chemistry and Biochemistry,
^‡Physics, and
^¶Mechanical Engineering,
^§Biomolecular Science and Engineering Program, and
^‖Materials Department, University of California, Santa Barbara, CA 93106

Contributed by Alan J. Heeger, January 3, 2006

Abstract

We report an electrochemical method for the sequence-specific detection of unpurified amplification products of the gyrB gene of Salmonella typhimurium. Using an asymmetric PCR and the electrochemical E-DNA detection scheme, single-stranded amplicons were produced from as few as 90 gene copies and, without subsequent purification, rapidly identified. The detection is specific; the sensor does not respond when challenged with control oligonucleotides based on the gyrB genes of either Escherichia coli or various Shigella species. In contrast to existing sequence-specific optical- and capillary electrophoresis-based detection methods, the E-DNA sensor is fully electronic and requires neither cumbersome, expensive optics nor high voltage power supplies. Given these advantages, E-DNA sensors appear well suited for implementation in portable PCR microdevices directed at, for example, the rapid detection of pathogens.

Footnotes

**To whom correspondence may be addressed. E-mail: kwp{at}chem.ucsb.edu or ajhe{at}physics.ucsb.edu
Author contributions: R.Y.L., E.T.L., and K.W.P. designed research; R.Y.L., E.T.L., and S.-H.L. performed research; R.Y.L. and E.T.L. analyzed data; and R.Y.L., E.T.L., H.T.S., K.W.P., and A.J.H. wrote the paper.
Conflict of interest statement: No conflicts declared.
Abbreviation:

MB,

methylene blue