Thermal cyclers are ubiquitous in the molecular biology world. There are multiple options and many different companies offering their products. Among the top are Eppendorf, Applied Biosystems, Invitrogen and Bio-Rad, each with models of varying sizes and features. Coming from a lab that does a lot of genotyping, we were most interested in high-throughput and the ability to troubleshoot PCR protocols. For this reason, I tried out the Bio-Rad iCycler. It has the option of interchanging the 96-well upper block with a dual 48-well block. The dual option allows one to run two PCR reactions side by side on one machine, increasing throughput and making good use of time when a smaller number of samples are required. The other great feature is the optimization mode with the gradient feature (although this only works with the 96-well block). There are 8 different temperature options, from top to bottom, for varying the annealing temperature of the PCR reaction. The machine allows you to set your upper and lower temperature limits and then assigns the temperatures in between. It would be more useful if one was allowed to pick the exact temperatures, but the in betweens are usually pretty approximate to what is needed. Another nice feature is the ability to tell when the reaction will be finished, allowing even more control over setup and timing.
We have several ABI 9700s in our lab, but I was looking for a new machine with a gradient function and the ability to use one PCR machine for two reactions was a plus. So far, I have been pretty well pleased by the iCycler. One problem is that the programs do seem to report exceptions every other day or so but I’ve never really been able to figure out what they were or noticed that they affected the results of the PCR. I have also noticed that when using the dual 48 well blocks, occasionally when starting a new cycle on the opposite block, it will cause the cycle that is already running to stop or pause. I haven’t been able to figure out why this happens or how it is triggered but it can be annoying when it occurs and the PCR has to be repeated. So there definitely are a few drawbacks to the system.
The price for the thermal cycler was very reasonable and competitive with other models. I have seen lately that Applied Biosystems has come out with a new machine that allows one to program specific annealing temperatures with its own gradient block, but I have not yet tried the machine out. For a lab that runs multiple PCRs, sometimes requiring large and sometimes smaller sample sizes, the option to use the same machine for two separate PCR reactions comes in handy. The thermal cycler seems to be pretty reliable with constant use. There is an additional option to upgrade to real-time PCR. For the price and the features, this machine has come in pretty handy, even with the occasional quirks and setbacks in the programming.
iCycler Thermal Cycler From Bio-Rad
Interchangeable dual 48-well or 96-well blocks; thermal gradient feature; interactive screen with graphical interface.
Machine has occasional exceptions and errors, big footprint.
The Bottom Line
Good thermal cycler with PCR and machine optimization features, reasonable price and high-throughput analysis.