Evaluation a gold nanorods based nanobiosensor for rapid detection of Mycobacterium Tuberculosis

Background and Aim : Mycobacterium tuberculosis (MTB) is a deadly pathogen, causing the disease tuberculosis (TB) in human. The IS۶۱۱۰ gene is specific to members of the Mycobacterium tuberculosis complex (MTBC). MTB diagnosis has been increasingly relying on the molecular identification. Today, the use of biosensors based on metal nanoparticles, especially gold nanoparticles due to their optical properties in the detection of bacteria has become widespread. In this study a gold nanoparticle (AuNPs) probes to detect IS۶۱۱۰ of MTB, that based on the colorimetric differentiation of specific DNA sequences aggregation in the presence or absence of specific target hybridization.Methods : At first, gold nanoparticles were synthesized by the seed mediated growth method, and confirmed with transmission electron microscope (TEM) and Dynamic Light Scattering (DLS). The ssDNA probes designed for IS۶۱۱۰ were attached to the gold nanoparticles. By preparing serial dilutions from recombinant plasmid (pUc۵۷/IS۶۱۱۰), the Limit Of Detection (LOD) was determined for biosensor and TaqMan-Real Time PCR. In this study, ۲۲۰ sputum specimen of subjects suspected tuberculosis was used. Final biosensor results were compared with TaqMan Real-time PCR method.Results : The size and morphology of the synthesized Gold Nanorods (GNRs) were confirmed by TEM and DLS techniques. From ۲۲۰ sputum specimen of subjects suspected tuberculosis, ۴۲ cases by TaqMan- Real Time technique and ۴۱ cases by nanobiosensor method, were detected. Based on the vector used, limit of detection for biosensor ۱۰-۷ng/μl and This value for TaqMan real-time assay ۱۰-۱۰ng/μl was determined. Also, the specificity of both methods was ۱۰۰%.Conclusion : It was received that sensitivity of IS۶۱۱۰ TaqMan real-time PCR assay more than biosensor. But the specificity of both methods was the same. High speed and simplicity of biosensor method are its advantages. The DNA biosensor provides a new strategy for clinical MTB diagnostics and probably also for pathogenic bacteria. According to the importance of rapid diagnosis of tuberculosis, this technique can play an important role in developing novel optical biosensors for MTB detection.

کلیدواژه ها:

Mycobacterium tuberculosis ، gold nanoparticles ، biosensor ، detection