DNA microchips: Technical and practical considerations

The development of high throughput techniques, such as DNA microarrays, eng ages interest in many biomedical research fields. They are becoming one of the preferred methods for large-scale expression analyses. The power of thi s technology is that it allows the profiling of thousands of genes in one s ingle experiment. There are two main array-based technologies: cDNA and oli gonucleotide arrays. cDNA arrays consist of microscope slides or nylon memb ranes containing hundreds to thousands of immobilized DNA probes, which are hybridized to fluorescent or radioactive complementary cDNA obtained from a target sample. Oligonucleotide chips differ in that probes are 20-25 mer selected oligonucleotides, which are bound to glass substrates and that the DNA obtained from a target sample can only be fluorescently labeled. In th is review, we describe the different types of DNA-chips, the steps involved in the production of microchips, the methodological and technical aspects of microchip utilization, and their potential applications including some p ractical considerations utilizing clinical material.