PCR Thermal Cyclers: Behind the technology

Thermal cyclers, also known as PCR machines or thermocyclers, are essential for any laboratory that relies on molecular biology. An indispensable tool for DNA amplification, the thermal cycler often becomes a nonstop workhorse that lab workers expect to function properly and efficiently. Due to the wide range of choices available from manufacturers, a good thermal cycler is not hard to find, as long as the lab first identifies what it needs in a thermal cycler, and then seeks the type that can best rise to the occasion.

Behind the technology

The basic idea of a thermal cycler is that it provides a thermally controlled environment for PCR samples. A thermal cycler usually contains a heating block with holes or depressions in it that receive sample tubes (though other types of sample vessels are now possible also; see below). For the PCR reactions to work properly, the block must change temperature at specific times, and spend specific durations of time at specific temperatures. The researcher programs the temperature cycling information into the thermal cycler either by computer or via a console on the instrument, or uses a preprogrammed routine built into the machine.

Applications of thermocyclers

Thermal cyclers are used in a range of disciplines. The majority of thermocyclers reside in research laboratories, where they are mainly used for amplifying DNA. In addition, researchers take advantage of thermal cyclers for cloning DNA and sequencing genes. Clinical facilities also house thermal cyclers for genetic tests that are used in diagnosing diseases.

Types of thermal cyclers

Thermal cyclers are available in a variety of sizes and models. You can choose from among the larger sizes of traditional models, smaller compact models designed to save lab space, and even “mini” or “personal” models that can be placed atop a desk. For the number-crunching capacity of much larger systems, some manufacturers make thermal cyclers that can be linked together to create a larger PCR system controlled by a central computer. Labs wanting to maximize their throughput capabilities may benefit from the linked PCR machine system.