( a time considerablyshorter than that...)Rapid PCR* Using Active Tube Temperature Control On Thermo's PCR Machines

The method of choice for monitoring any thermal cycling reaction is to measure the actual temperature the reaction mix achieves during PCR and adjust the heating or cooling accordingly. In this way, the researcher can be assured that the temperatures and dwell times they have set are actually achieved by the sample and not just the block. This control mode, which all Thermo thermal cyclers can use, is termed Active Tube Control (figure 2).

The improved accuracy in Active Tube Controlled protocols allows reaction conditions to be more stringent and subsequently overall run time can be significantly reduced.

Successful PCR using Block Control

While Block Control is less than ideal for performing PCRs, protocols can be written to compensate for inaccuracies in the PCR machine and it is ultimately possible to successfully amplify a gene fragment (figure 3).

Comparison of Block Control and Active Tube Control

The results of a PCR using the standard 30 second dwell time PCR with Block Control can be directly compared with those of a PCR performed using Active Tube Control (figure 4). Using Active Tube Control in this way caused an increase in the run time on both the MBS and the Px2 (table 1). In these equivalent protocols, the faster run time of the block controlled reaction occurs because the dwell time clock starts counting down as soon as the block achieves the set temperature, irrespective of the sample temperature. In the case of the Active Tube Controlled protocol, the unit more accurately monitors the in-sample temperature and the dwell time clock will not count down until it has achieved the set temperature.
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