Recording the Reaction Process of Loop-Mediated Isothermal Amplification (LAMP) by Monitoring the Voltammetric Response of 2′-Deoxyguanosine 5′-Triphosphate

We describe here a novel strategy for recording the reaction process of loop-mediated isothermal amplification (LAMP) by monitoring the voltammetric response of 2'-deoxyguanosine 5'-triphosphate (dGTP). Unlike the other three kinds of reactive substrates for DNA synthesis in LAMP reaction, dGTP exhibits sensitive voltammetric response at the carbon nanotube array electrode. When the LAMP reaction occurs, the concentration of dGTP decreases accordingly, bringing forth the decrease of the anodic peak current (i(pa)). In inversion, the decrease of the i(pa) of dGTP was used to characterize the reaction process of LAMP. The relationships among the LAMP reaction time, the initial quantity of template DNA and the value change of the i(pa) were studied. The results indicate that the protocol integrated LAMP and voltammetric techniques can be used for not only qualitative gene discrimination but also quantitative gene assay in a wide range. The malB gene extracted from common strains of Escherichia coli cells was tested as a model. The detecting results of LAMPs obtained by voltammetric method were in good agreement with those by optical-based methods (gel electrophoresis and fluorescent dye).