When you perform thousands of PCR reactions a week, a reliable thermal cycler is an absolute necessity. For this reason, our laboratory chose to purchase the DNA Engine Tetrad from MJ Research (now Bio-Rad). This device is a large capacity thermal cycler specifically designed for high-throughput amplifications.
The DNA Engine Tetrad consists of four sample-block/heat-pump modules suitable for amplifications in either 96- or 384-well format. The temperature control is provided by Peltier-Joule heat pumps which samples thermal profiles every 50 milliseconds. The temperature of the heatings blocks can be easily modulated at a rate of 3.0°C/sec within a range from –5.0°C to 105°C. We perform our amplifications in 384-well plates, but as mentioned above, it is also possible to use 96-well plates. Since my research projects require the amplification of thousands of cDNA clones, the option of having four 384-well format blocks in one machine made scaling up easier. We have now purchased four of these machines, which allows us to amplify an arrayed cDNA library of 50,000 clones within a week.
We purchased our Tetrad machines over one year ago and since then we have not had any technical problem with the instruments. What is very practical is the fact that the thermal blocks operate independently, not only in terms of PCR protocols, but also because they can still operate even if one or more of the blocks is out of order. Another very useful feature, that we fortunately have not had to use, is that technical service from Bio-Rad will provide a replacement machine within 24 hours if yours needs to be serviced.
The one thing I wish I could change on this machine, however, has to do with the lids for the sample blocks. Opening the lid must be performed manually and it is sometimes difficult. The reason being that the closing screw for the lid is impractically designed for easy handling. Although this is a small problem, if you have to open sixteen lids per run it can become difficult.
In summary, the DNA Engine Tetrad is one of the very few high-throughput PCR machines available on the market and I think it is a good one. It’s compact design and modular structure facilitate performing large scale experiments. I recommend this device to any researcher planning to start large-scale genomics projects.
Michal Janitz, M.D.
Groupleader
Max Planck Institute for Molecular Genetics
Berlin, Germany