Label-free DNA detection using the narrow side of funnel-type etched nanopores.

A sensitive; simple and label-free method for DNA detection is presented. Irradiated polyethylene terephthalate foils were etched to present conical tracks at a density of approximately 5×107 tracks per cm². Probe DNA was immobilized at the narrow opening of the tracks (2-4 nm diameter). The presence of target DNA resulted in changes in both conductance and rectification ratios in a concentration-dependent manner. DNA concentrations as low as 2 nM could be detected using this simple two-step detection scheme.

Chemiluminescent DNA optical fibre sensor for Brettanomyces bruxellensis detection.

Food and beverage industries require rapid tests to limit economic losses and one way to do so is via molecular tests. In the present work, DNA capture and secondary probes, were designed to target the ITS (Internal Transcribed) sequences of Brettanomyces bruxellensis, a yeast responsible for the production of off flavours in both wine and beer. ITS1 and ITS2 were found to contain distinct regions with sufficient sequence divergence to make them suitable as specific identification target sites. The dot blot technique was used to determine the sensitivity and specificity of the capture probe. Both probes were, thereafter, adapted to construct an optical fibre genosensor, which produced neither false positives nor false negatives, and was both repeatable and faster with respect to traditional methods, the latter requiring at least one week to detect B. bruxellensis.