DNA chips – Integrated Chemical Circuits for DNA Diagnosis and DNA computers

DNA chips are sil iconor glass-based small surfaces on which many DNA oligonucleotides are integrated. There are two photolithography methods for making DNA chips. The lightdirected oligonucleotide synthesis method is based on the combinatorial strategy. It is suitable for making a high-density 2-D array of DNA oligonucleotides. On the other hand, the lightdirected oligonucleotide immobilization method can be easily combined with the fabrication of a micro integrated fluid system. Therefore, it is suitable for making the next-generation DNA chips, which include not only DNA integrated circuits but also micro valves, pumps, detectors, and their controller. DNA chips have been applied to DNA diagnosis of infectious diseases and cancer genes, and monitoring gene expressions. Their needs are increasing with the rapid progress of the genome projects. DNA chips will also provide basic devices for DNA computers, which is an ultra-parallel c omputer using DNA molecules.