It is now possible to miniaturize numerous 'macroscale' processes and develop microfabricated devices to replace conventional equipment. Such advances have lead to the development of arrays of immobilized oligonuceotides useful for basic research, diagnostic studies, sequence analysis and a number of novel applications. Additionally, standard laboratory equipment has been redesigned on a microscale level to increase efficiency many processes have been integrated onto one chip since miniaturization call be readily achieved. (C) 1996 Elsevier Science B.V.