A Simple and Sensitive Electrochemical DNA Biosensor of the Bacteria Chlamydia Trachomatis

Document Type : Research Paper


1 Department of Biology, Medical Biotechnology Research Center, Ashkezar Branch, Islamic Azad University, Ashkezar, Yazd, Iran

2 Department of Textile and Polymer Engineering, Yazd Branch, Islamic Azad University, Yazd, Iran

3 Stem Cell Biology Research Center, Yazd Reproductive Sciences Institute, Shahid Sadoughi University of Medical Sciences, P. O. Box: 89195-999, Yazd, Iran. Department of Advanced Medical Sciences and Technologies, School of Paramedicine, Shahid Sadoughi University of Medical Sciences, Yazd 8916188635, Iran


Bacterial infection is a global problem, and detection of bacteria is the first step for solving such a problem. Herein, we developed an electrochemical biosensor for the detection of the bacteria Chlamydia Trachomatis. The hybridization-based biosensor was made by modifying the screen-printed gold electrode (SPGE) with the thiolated specific detection probes, which were complementary sequences to the target DNA molecule of the bacteria. The Oracet blue was used as an electrochemical label which was intercalated between two DNA sequences, and its reduction peak current was recorded by DPV method as an output signal of the biosensor. Conventional electrochemical characterization techniques, including cyclic voltammetry (CV) and Electrochemical impedance spectroscopy (EIS), were used to confirm the fabrication of the modified electrode. In addition, the Atomic Force Microscopy (AFM) imaging was performed to assess the electrode surface. The dynamic range of the biosensor was from 4 to 3000 pM with a detection limit of 1.3 pM. The simplicity and performance mentioned above of the biosensor, alongside the low cost and repeatability of the production, make it a great candidate for clinical applications for Chlamydia Trachomatis detection. Plus, it can be used for another species of bacteria with just a change of the thiolated probe.