Embedded DNA-polypyrrole biosensor for rapid detection of Escherichia Coli

The principal objective of this paper was to present the design and fabrication of a single-strand (ss) DNA biosensor for the detection of Escherichia coli (E. coli) DNA synthetic oligonucleotides as a model of rapid detection of bacterial select bioterrorism agents. Molecular biology and chemical electrodeposition techniques, such as cyclic voltammetry (CV), were combined to develop and test a model DNA-based biosensor on a platinum (Pt) electrode electropolimerized with polypyrrole (PPY). The hybridization on embedded DNA into PPY with complementary DNA samples was determined. The recognition element was a 25 base pair (bp) oligonucleotide specific for E. coli derived from the uidA gene that codes for the enzyme β-D glucuronidase. CV scans between 0.0 and +0.70 V at a 50-mV/s scanning rate generated current versus potential graphs. A standard DNA concentration of 1 μg/μL was used to determine the hybridization signal of the biosensor. The model biosensor generated distinctive CV signals between complementary and noncomplementary DNA oligonucleotides. The biosensor proved to be effective in the detection of complementary uidA 25-bp oligonucleotide for E. coli K-12.