Nowadays, the possibility to work on the whole genome in real time is achievable. However, new tools are necessary for high throughput analysis and cost reduction. In such a way, microarrays and lab-on-a-chip systems are going to fulfil these new requirements, including the miniaturization of biological assays as well as the parallelization of analysis. Both sensitivity and reliability of microarray devices are key points for the future. The optical enhancement of the fluorescence signal is particularly addressed in this issue, where it is shown that a significant increase in sensitivity can be reached. Concerning the technology of electrophoresis in microfluidic devices, remarkable developments have been achieved, especially in the DNA separation area. In particular, a specifically designed microfluidic device has been implemented for high throughput genotyping and its stability has been validated on a set of 150 thermally cycled biochemical reactions. (C) 2002 Elsevier Science B.V. All rights reserved.