Nanoparticle based DNA biosensor for tuberculosis detection using thermophilic helicase-dependent isothermal amplification

The present study describes the development of a DNA based biosensor to detect Mycobacterium tuberculosis using thermophilic helicase-dependent isothermal amplification (tHDA) and dextrin coated gold nanoparticles (AuNPs) as electrochemical reporter. The biosensor is composed of gold nanoparticles (AuNPs) and amine-terminated magnetic particles (MPs) each functionalized with a different DNA probe that specifically hybridize with opposite ends of a fragment within the IS16110 gene, which is M. tuberculosis complex (MTC) specific. After hybridization, the formed complex (MP-target-AuNP) is magnetically separated from the solution and the AuNPs are electrochemically detected on a screen printed carbon electrode (SPCE) chip. The obtained detection limit is 0.01 ng/mu l of isothermally amplified target (105 bp). This biosensor system can be potentially implemented in peripheral laboratories with the use of a portable, handheld potentiostat. (C) 2011 Elsevier B.V. All rights reserved.