Detection of LAMP products using CNT array electrode

Abstract

We described here a novel strategy for discriminating target gene by integrating loop-mediated isothermal amplification (LAMP) and differential pulse voltammetry (DPV). After a successful LAMP reaction, the anodic peak current (ipa) of the free 2′-deoxyguanosine 5′-triphosphate (dGTP) decreased remarkably at a carbon nanotubes array working electrode, owing to the consumption of free dGTPas one of reactive substrates. Thus, the change of current response was used to characterize the result of LAMP reaction. And hence the presence of the target gene in template DNA could be discriminated easily. The malB gene extracted from Escherichia coli cells was tested as a model. After the reaction for 30 min, the LAMP mix was scanned directly. Then the information of the target gene in 0.8 picogram template DNA was obtained accurately. The result was in good accordance with that obtained with optical-basedmethods (gel electrophoresis and fluorescent dye). The new strategy has the advantages of being very simple to perform, rapid response, elimination of post-amplification processing, avoidance of auxiliary reagents and low cost (there was almost no cost for the detection step). Therefore, it was quite promising for use in miniaturized devices and in the development of point-of-care applications.