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Gold nanoparticle probe-based diagnostic system for rapid and sensitive detection of Mycobacterium tuberculosis

Abstract number: p1109

Koziol-Montewka  M., Paluch-Oles  J., Baptista  P.

Tuberculosis has re-emerged as a major infectious disease in several areas in the world and M. tuberculosis (MTb) infections continue to increase worldwide with an estimated annual growing rate of 3%. The application of new methods based on nanotechnology can simplify the bacterial DNA detection and improve MTb identification making the diagnosis of infections caused by this pathogen faster and less expensive than conventional methods. Here we describe a rapid and sensitive colorimetric method based on the use of gold nanoparticles functionalised with thiolated oligonucleotides for MTb detection directly from clinical samples without the prior DNA amplification.

Objectives: 

The aim of our work was to screen clinical specimens for the presence of MTb using approved INNO-LiPA RifTB kit and a novel gold nanoprobe-based method.

Methods: 

The used gold nanoprobe-based method consisted on visual and spectrophotometric comparison of the blank (containing the gold nanoprobes alone), negative (containing DNA from samples previously tested and confirmed as negative for MTb) and positive (containing DNA from samples positive for MTb) solutions. After the NaCl addition blank and negative samples turned from the initial pink to a blue–purple colour, denoting gold nanoprobes aggregation. In case of positive samples, the solutions maintained their original pink colour after the NaCl addition. The presence/absence of gold nanoprobe aggregation was corroborated by UV/visible spectra.

Results: 

We tested 47 clinical samples from patients with the suspicion of pulmonary and extra pulmonary tuberculosis. The gold nanoprobe method proved to give consistent positive or negative results with validated INNO-LiPA RifTB kit for the MTb DNA detection in 42 out of 47 samples. Five out of 47 samples were interpreted as "non-consistent" possibly due to the DNA content being under the threshold of the method.

Conclusion: 

The results indicate that DNA-derivatives gold nanoparticles hybridization is a sensitive and specific tool for the identification of MTb directly in clinical samples without prior amplification by PCR.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Subject:
Location: Oxford, UK
Presentation type:
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