Thermal cycler

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title: "Thermal cycler" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["molecular-biology-laboratory-equipment", "polymerase-chain-reaction"] description: "Laboratory equipment for cycling temperature" topic_path: "science/biology" source: "https://en.wikipedia.org/wiki/Thermal_cycler" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Laboratory equipment for cycling temperature ::

History

::figure[src="https://upload.wikimedia.org/wikipedia/commons/d/db/Baby_Blue_-a_prototype_polymerase_chain_reaction(PCR),c_1986.(9663810586).jpg" caption="Baby Blue, a prototype automated thermal cycler built around 1986"] ::

::figure[src="https://upload.wikimedia.org/wikipedia/commons/2/2f/Primitive_PCR_machine_for_scrap.JPG" caption="water baths]] at constant temperatures between which samples are moved with a [[robotic arm"] ::

The earliest thermal cyclers were designed for use with the Klenow fragment of DNA polymerase I. Since this enzyme is destroyed during each heating step of the amplification process, new enzyme had to be added every cycle. This led to a cumbersome machine based on an automated pipettor, with open reaction tubes. Later, the PCR process was adapted to the use of thermostable DNA polymerase from Thermus aquaticus, which greatly simplified the design of the thermal cycler. While in some old machines the block is submerged in an oil bath to control temperature, in modern PCR machines a Peltier element is commonly used. Quality thermal cyclers often contain silver blocks to achieve fast temperature changes and uniform temperature throughout the block. Other cyclers have multiple blocks with high heat capacity, each of which is kept at a constant temperature, and the reaction tubes are moved between them by means of an automated process. Miniaturized thermal cyclers have been created in which the reaction mixture moves via channel through hot and cold zones on a microfluidic chip. Thermal cyclers designed for quantitative PCR have optical systems which enable fluorescence to be monitored during reaction cycling.

Modern innovation

Modern thermal cyclers are equipped with a heated lid that presses against the lids of the reaction tubes. This prevents condensation of water from the reaction mixtures on the insides of the lids. Traditionally, a layer of mineral oil was used for this purpose. Some thermal cyclers are equipped with a fully adjustable heated lid to allow for nonstandard or diverse types of PCR plasticware.

Some thermal cyclers are equipped with multiple blocks allowing several different PCRs to be carried out simultaneously. Some models also have a gradient function to allow for different temperatures in different parts of the block. This is particularly useful when testing suitable annealing temperatures for PCR primers. ::figure[src="https://upload.wikimedia.org/wikipedia/commons/e/e1/Working_model_of_thermal_cycler_machines_v2.webm" caption="language=en}} uses this technology."] ::

::data[format=table]

Peltier based	Resistive Heating Element	Air Chamber
Commercially available machines	Eppendorff Mastercycler X50s	miniPCR mini 16x QP-1000-16
Thermal Elements	Peltier Element	Resistive Heating
Lid Heater	yes	no
Heating Rate
Cooling Rate
Gradient Temperature	yes	no
Temperature uniformity	0.15 °C	0.5 °C
Power consumption
::

References

References

1. Weier, HU. (Jul–Aug 1988). "A programmable system to perform the polymerase chain reaction.". DNA (Mary Ann Liebert, Inc.).
2. Higgins, James A.. (1 August 2003). "A handheld real time thermal cycler for bacterial pathogen detection". Biosensors and Bioelectronics.
3. (2014-09-29). "The Most "Advanced" Thermal Cycler Yet - Get Informed". Get Informed.
4. "Mastercycler® X50 - PCR Thermocycler".
5. "Bot Verification".
6. "Rotor-Gene Q MDx 5plex HRM (CA)".
7. "Mastercycler® X50 - PCR Thermocycler".
8. "Bot Verification".
9. "Rotor-Gene Q MDx 5plex HRM (CA)".

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::