Iranian Scientists Develop Genosensor for Detection of Gastrointestinal Infections
The sensor, which was developed under the form of a doctoral thesis by Sepideh Ziayee and the guidance Hedayatollah Qourchian, a faculty member of the Biochemistry and Biophysics Research Center of the University of Tehran, can identify C. difficile bacteria with high accuracy and non-invasively.
“This electrochemical genosensor has been designed and built to identify different strains of C. difficile bacteria with high sensitivity and specificity. In this sensor, the gene expressing the surface protein of this bacteria (called the SlpA protein) is identified,” said Qourchian.
“This genosensor operates non-invasively, meaning that it does not harm the patient during sampling, because the gene under investigation is extracted from the patient's stool sample. By placing a drop of the extracted genome on the sensor surface, a strong electrochemical signal is generated if C. difficile bacteria are present, and a weak signal is generated otherwise,” he added.
“This genosensor is capable of detecting the gene levels of this bacteria at very low concentrations of 0.2 femtomolar (10-16×2 M). The response of this genosensor is linear in the range of 0.5 to 1900 femtomolar of the gene concentration of this bacteria. This genosensor also provided significant responses to the concentration of 102 to 107 colonies per gram of this bacteria,” Qourchian noted.
Genosensors, also known as nucleotide-based sensing (NABs), are biological devices that recognize target nucleic acids (RNA or DNA) through hybridization.
An electrochemical genosensor was constructed for detection of specific DNA sequence of the hepatitis B virus, based on graphite electrodes modified with poly(4-aminophenol) and incorporating a specific oligonucleotide probe.
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