ABSTRACT
The advent of analytical microchips (i.e., microfabricated devices that perform some form of analytical function) has provided the molecular biologist with many new opportunities for performing nucleic acid amplification. These devices provide a special type of environment for amplification that was absent in the more conventional equipment that has served this purpose over the past decade. Today, it seems relatively obvious that nucleic acid amplification would be one of the applications of the growing plethora of analytical functions carried out on microchips. In reality, the first publications in this area only date from 1994, showing how reticent developmental scientists were to investigate miniaturization of a procedure that was showing marked inconsistencies and reliability problems using conventional tubes and thermocycling equipment. In addition to this, there appeared little benefit at that time, other than potential savings in terms of reagent, to embark on development programs for nucleic acid amplification when efforts to miniaturize more common assays such as immunoassay-based tests, colorimetry, and electrophoresis were showing little progress. It was only when breakthroughs in fabrication techniques occurred that provided the ability to construct microchip-based devices incorporating channels and chambers with evidence of fluidic control that the realization occurred. The early work showed elementary devices with chambers that could be subjected to thermocycling and thus laid the foundation for microchip-based amplification.
