In by admin

NameChristopher Martin
OrganizationUniversity of Central Florida
TopicAnalytical Chemistry

Electrochemical Detection of Mycobacterium Tuberculosis Using a Four-Way Junction DNA Stem-Loop Probe


Christopher P. Martin, Jeffer Pinzon, Dawn M. Mills, Dr. Percy Calvo-Marzal, and Dr. Karin Y. Chumbimuni-Torres

Author Location(s)

University of Central Florida


Tuberculosis is an infectious disease caused by the microorganism Mycobacterium tuberculosis that can exist in a latent or active form within the human body.  In its latent form, it does not show symptoms, making diagnosis difficult; the only test in use today is highly susceptible to false positives.  The appearance of multiple-drug resistant forms of tuberculosis demands the development of a sensor that is both rapid and accurate so that appropriate medical action can be taken.

As a bacterium, tuberculosis contains genetic material (DNA) that can be detected and correlated to a particular form of the organism.  The sensor presented in this work utilizes a DNA stem-loop probe immobilized to a gold disc electrode where the native conformation is a closed hairpin structure.  Short adaptor strands complementary to both the probe and the target of interest are used to create a four-way junction structure.  This conformation change moves a redox marker (methylene blue) attached to one of the adaptor strands close to the electrode surface where electron transfer is made possible, giving rise to a current measurable by techniques such as square wave voltammetry.  Previous studies of the above sensor have demonstrated that the system is highly selective for the target of interest and thus would make the current test nearly obsolete.  The entire detection process takes well under 4 hours, making it rapid when compared to the multi-day long test available today.