DNA Chips: from elaboration to application

The Nucleic Acids (DNA and RNA) are molecules holding the genetic information in all life cells and constitute the crucial and fundamental component of genes monitoring the working of living organisms. The scientific projects actually put in place through the world indicate clearly the strategic importance of the complete gene knowledge of wide varieties of live materials (Human Genomic Sequencing, Genoplant, Bacteriology and Environment). In this way, a key point is the development of tools allowing the multiparametric analysis. Based on the molecular hybridization principle, DNA chips are considered as new and powerful tools combining the large integration ability of microelectronic devices with the properties of biological interaction for simultaneous analysis of several thousands nucleic acids. Compared with the microarrays on high-density membranes, the advantages of such devices hold in their miniaturisation allowing to collect an impressive number of information and the robotic process of the elaboration leading to a best reproducibility. Moreover, the very small size of each active area on DNA chips requires small amounts of biologic materials. Sequence analysis, genotyping and gene expression monitoring are some examples of potential applications in broad areas: biomedical research, genomics and clinical diagnostics, pharmacology, environment and food industry and give an idea of scientific and economic stakes. The importance of this tool for future gene studies leads to a strong competition between several teams which proposed different technological choices. Although issued from very simple concept, DNA Chip technology is complex because wide complementary competencies such as surface chemistry, micro-technology, electronics, molecular biology and data processing must be gathered.