A quantitative PCR-electrochemical genosensor test for the screening of biotech crops

The design of screening methods for the detection of genetically modified organisms (GMOs) in food would improve the efficiency in their control. We report here a PCR amplification method combined with a sequence-specific electrochemical genosensor for the quantification of a DNA sequence characteristic of the 35S promoter derived from the cauliflower mosaic virus (CaMV). Specifically, we employ a genosensor constructed by chemisorption of a thiolated capture probe and p-aminothiophenol gold surfaces to entrap on the sensing layer the unpurified PCR amplicons, together with a signaling probe labeled with fluorescein. The proposed test allows for the determination of a transgene copy number in both hemizygous (maize MON810 trait) and homozygous (soybean GTS40-3-2) transformed plants, and exhibits a limit of quantification of at least 0.25% for both kinds of GMO lines

The catalytic polarographic pre-wave of nickel(II) induced by 2-methylbenzimidazole

A comprehensive study of the prewave of NiII induced by 2-methylbenzimidazole in sodium barbital/nitric acid/potassium sulfate media was carried out by using various polarographic techniques in order to establish the mechanism via which the underlying electrode reaction proceeds. Based in the proposed mechanism, the formation of the catalytic complexes is a surface process involving deprotonated 2-methylbenzimidazole; the adsorption of this compound over the catalyst concentration where the prewaves are well-defined conforms to a Langmuir isotherm. Accordingly, a plot of the reciprocal of the limiting current for the prewave against the reciprocal of the ligand-catalyst concentration is a straight line. This finding was exploited for the determination of 2-methylbenzimidazole at concentrations from 5 × 10−7 to 5 × 10−5 M from NiII prepeaks recorded by differential pulse polarography and square-wave voltammetr

Helicase-Dependent Isothermal DNA Amplification Coupled with an Electrochemical Genomagnetic Assay to Detect Pathogens

International Conference on Bio-Sensing Technology (BITE 2013) (3º. 2013. Sitges, España