A Modified Electrochemical Electrode for Development of Nanobiosensor for the Detection of rfbE Gene of Escherichia Coli O157:H7

Nanobiosensors could be used instead of traditional detection methods of Escherichia coli O157:H7. In this paper, a nanobiosensor for detection of rfbE gene of the Escherichia coli O157:H7 has been studied by immobilization and hybridization single strand DNA (ssDNA) sequences on the electrode surface modified with gold nanoparticles. Electrochemical impedance spectroscopy technique was used to study the properties of the sensing modified electrode. The working electrode surface was modified by electrochemical method with gold nanoparticles. The single-stranded DNA sequence using self-assembled monolayer was immobilized on the gold electrode for two hours. A mixed monolayer comprising both mercaptohexanol (MCH) and mercaptopropionic acid (MPA) were used as blocking layer. The hybridization DNA/DNA was performed by immersion of the modified gold electrode into ssDNA at a concentration of 1 μM target DNA. The results showed that the electrode modified with gold nanoparticles after immobilizing ssDNA effectively detected rfbE gene of Escherichia coli O157:H7 by DNA hybridization. The nanobiosiosensor showed suitable selectivity for the detection of target DNA complementary sequence compared with the mismatched oligonucleotides sequence and the noncomplementary oligonucleotides sequence. According to the results obtained and similar studies, the electrochemical nanobiosensor based on DNA hybridization has advantages such as low cost, simplicity, and miniaturization and can provide a basis for the development of genomic detection tools.