Development of a nano-biosensor for direct detection of Helicobacter pylori

Background and Aim : Helicobacter pylori is the leading cause of gastritis, stomach ulcers, gastric cancer, and mucosa-associated lymphoid tissue (MALT). However, it is still diagnosed by conventional methods and urea breath test (UBT) is often considered as the gold standard. Due to the importance of rapid specific diagnosis of H. pylori, we developed a nanoprobe-based method for direct detection of the target in the cells. Methods : A specific target region in the genomic DNA of the microorganism was selected and a specific complementary probe was designed and modified for further particle attachment. The probe was used to functionalize gold nanoparticles. The genomic DNA contents of the samples were accessed by the boiling method. The nucleic acid content of the cells was used for the further detection procedure. After a denaturation and annealing stage, magnesium chloride salt was used for induction in the colorimetric assay. The specificity and limit of detection were analyzed.Results : The results show that the designed Au-nanoprobe could attach to the target region specifically among ten different bacteria, providing a specific colorimetric detection approach in less than six minutes. Furthermore, the optimized concentration of the salt yields an optimum color differentiation between the positive and the negative samples. In positive samples, the nanoparticles stayed dispersed (red) due to a successful hybridization while in negative samples, aggregation occurred due to the absence of a complementary sequence resulting in a blue shift.Conclusion : The direct gold nanoprobe-based method could be employed as a simple, rapid, and affordable method to nano-diagnosis of H. pylori and help restraining the spread of H. pylori infection.

کلیدواژه ها:

Helicobacter pylori ، Amplification-free ، Rapid diagnostic test ، gold nanoparticle ، biosensing