Polymerase Chain Reaction (PCR) has become one of the routine tools used in most molecular biology laboratories today. To achieve a successful PCR reaction, a ‘high performance’ thermal cycler is an essential piece of equipment for complete and efficient utilization of the PCR mix. Biometra’s T-personal Thermal Cycler is extremely lightweight, compact and quiet, fitting into any corner of the lab thanks to its small footprint. The machine has a small thermal cycler block, providing space for 48-0.2 ml or 35-0.5 ml PCR vials. Though not compatible with 96-well plates, other versions are already available from Biometra to meet these requirements.
The display of the machine is easy to read and a large memory offers storage of over 900 programs in 10 different directories. All of the directories are scanned every time the machine is switched on. Each file represents one complete program and up to 24 different steps of the PCR reaction can be entered. Writing a program is simple and enables the user to set temperature increments and rates at every step. Such options are extremely useful when using primers with a low Tm for annealing with a given template.
The block temperature can reach 99C, which is sufficient for the melting step of any PCR reaction. Only block temperature can be set and it cannot be automatically calculated based on reaction volume or thickness of the PCR vial. If the reaction has already been standardized, then this is not a serious problem.
The lid has a unique clutch mechanism that provides optimal pressure on the PCR vials and the temperature can reach 110C, which aids in preventing moisture condensation within the caps of sample vials. It takes over 2 min for the lid to reach this temperature. The ramp rate of the machine (i.e. the rate of temperature change between any two steps of the PCR cycle) is extremely fast (4C per second), aiding in quick completion of the PCR reaction. This not only saves PCR time, but also contributes to primer specificity.
One of the drawbacks of the machine is that the thermal block, which holds the sample vials, is deeply seated. This morphology occasionally hinders proper placement of vials in the machine. The major hurdle with this instrument is the lack of a temperature gradient system that restricts the annealing step of PCR reaction to a fixed temperature. Hence, standardization of PCR reaction needs to be performed in a different machine.
Vikas Jain
Research Scholar
Indian Institute of Science
India