Escherichia coli genosensor based on polyaniline

Avidin-modified polyaniline (PANI) electrochemically deposited onto a Pt disk electrode has been utilized for direct detection of Escherichia coli by immobilizing a 5'-biotin-labeled E. coli probe (BdE) using a differential pulse voltammetric technique in the presence of methylene blue as a DNA hybridization indicator. Depending on the target sample and the sonication time, this BdEavidin-PANI bioelectrode can be utilized to electrochemically detect a complementary target probe (0.009 ng/mu L), E. coli genomic DNA (0.01 ng/mu L) and 11 E. coli cells/ mL in 60 s to 14 min (hybridization time) without using PCR and can be used 5-7 times at temperatures of 30-45 degrees C.