A simple and sensitive electrochemical sensor for rapid detection of Clostridium tetani based on multi-walled carbon nanotubes

Tetanus is a common disease caused by anaerobic bacteria called Clostridium tetani in deep tissue infections. Once the vulnus is infected with C. tetani, the risk for amputation and mortality increases greatly. Therefore, it is necessary to design a rapid and sensitive detection method for the early diagnosis and clinical treatment of tetanus. In this research, we developed a detection method for C. tetani using an electrochemical biosensor on the basis of an improved rolling circle amplification (iRCA) assay, wherein the tetanus toxin gene was used as the target gene. The biosensor was coated by probes that capture C. tetani DNA after amplification; then, the sensor was hybridized with detection probes that are combined with methylene blue (MB). Compared with the culture method, PCR technology and the traditional loop-mediated isothermal amplification (LAMP) method, this method is not only simple and rapid, but can also be identified through an electrochemical analyser. Additionally, this method has good stability, strong specificity, and high sensitivity with a detection limit of 1.0 x 10(-16) M, and quantitative analysis could be realized. Therefore, this method is ideal and rapid in detecting C. tetani, thus broadening the use of the DNA amplification method and holding great promise for future ultrasensitive bioassays.