The thermal circulator is an instrument used in molecular biology, medicine, food industry, judicial science, biotechnology, environmental science, microbiology, clinical diagnosis, epidemiology, genetics, gene chip, gene detection, gene cloning, gene expression and other fields to amplify DNA/RNA, characterized by polymerase chain reaction. Therefore, it is widely used in all walks of life, and is a necessary instrument in many industrial laboratories.
The thermal circulator, also known as the gene amplification instrument or the PCR instrument for short, provides accurate temperature conditions for the PCR process by controlling the periodic rapid heating and cooling of the PCR tube containing the reaction liquid. Although the instrument structure of the thermal circulator has become more and more complex compared with the previous three temperature water bath, it is still an instrument used for heating and cooling in the final analysis.
At present, most of the thermal cycle meters on the market are constant temperature calorimeters, but it should be noted that constant temperature calorimeters can be divided into static and isothermal types. Their difference is that static constant temperature means that there is no control device for the temperature of the outer cylinder water, and the temperature of the outer cylinder water is maintained by increasing the water volume and keeping the indoor ambient temperature as constant as possible. The temperature of the water in the outer cylinder of the isothermal calorimeter is maintained by the temperature control device, and there is circulating water on the inner cylinder cover and the cylinder bottom to communicate with the water in the outer cylinder.
Although the functional characteristics of different thermal circulators are different, as a thermal circulator, the most important thing is the accuracy of temperature control. Moreover, PCR is a geometric progression amplification process, and temperature control is particularly important for annealing, because it is necessary to accurately control the temperature whether it is denaturation, annealing or extension. Sometimes, the annealing temperature difference of 1 º C can lead to very different results. Therefore, in addition to distinguishing the functional characteristics of the thermal circulator, the accuracy of temperature control is also an important aspect that needs to be considered. Only when the thermal circulator is selected correctly, can the correct data be obtained in the experiment and reliable conclusions be drawn.
