Background and aims: Clinical symptoms of patients infected with Escherichia coli O157:H7 is a wide range and diagnosis of the symptoms is difficult. to detect conventional methods of biological agents have many disadvantages. The aim of the current study was detection of rfbE gene in real samples of Escherichia coli O157 by by DNA hybridization-based nanobiosensor.

Methods: In this experimental study, for sample preparation prior to the measurement by the biosensor, the genome of the Escherichia coli O157 was extracted by the CTAB-NaCl method and DynaBio^TM DNA Extraction Mini Kit. Enzymatic digestion of genomic DNA of Escherichia coli O157 was perform at 37°C for 4 minutes and thermal denaturation. To be sure, rfbE gene Escherichia coli O157:H7 was detected by PCR. The rfbE gene sequence in real samples of Escherichia coli O157:H7 was measured by DNA hybridization-based nanobiosensor.

Results: The results of the charge transfer resistance indicate proper interaction between ssDNA immobilized on the electrode with the DNA digested genomic of Escherichia coli O157:H7 and PCR product that is represents of successful detection of the rfbE gene Escherichia coli O157:H7. The nanobiosensor was able to detect bacteria digested genome to 10-6 dilution that this dilution is corresponding to the concentration of 102 of Bacterium Escherichia coli.

Conclusion: In this study, the nanobiosensor based on DNA hybridization was used for the detection of rfbE gene sequences in the real sample of Escherichia coli O157:H7 with high sensitivity and accuracy that could be a basis for making DNA detection tool.