A disposable and cost efficient microfluidic device for the rapid chip-based electrical detection of DNA

Requirements for a point-of-care device are an easy and robust read-out and - above all - a simple handling. We integrated an established robust electrical read-out for DNA-chips into a microfluidic device, thereby creating an automated analysis system that combines the necessary steps for a chip-based analysis. It is based on the electrical detection of biotin-labeled DNA in a gap between two microstructured electrodes on the surface of a DNA-chip. The biotin serves as binding molecule for streptavidin-conjugated horseradish peroxidase. A following enzyme-induced silver deposition bridges the gap by a conductive layer. The miniaturized chip gives the possibility to realize a durable system suitable for point-of-care applications. To enable an initial automation, all corresponding process steps were executed in a miniaturized silicone flow cell. The required defined temperatures for the hybridization and the washing steps can be adjusted by a heating foil. This paper characterizes the performance of the flow cell based system in terms of reaction speed and analysis time, sensitivity as well as specificity, and the comparison to a conventional system, without flow cell. These first steps of automation and integration will help to realize a laboratory-independent bioanalytical tool, for the use outside of specialized laboratories for fast analysis of different chemical and biological applications. (C) 2009 Elsevier B.V. All rights reserved.