96-Well PCR Machines

PCR machines, which often accommodate the standard 96-well sample format, are fundamental lab instruments that carry out PCR-based amplification or real-time detection. Thermocyclers operate by cycling through temperatures instantly, but in practice, temperature changes depend on factors such as the composition of the heating block in which the reaction tubes are incubated. Most thermocyclers are heated with a Peltier device, which changes electric current into heat. Many temperature blocks are made of silver because it changes temperature relatively quickly and uniformly. Some thermocyclers offer a gradient option, which results in a range of set temperatures across the block. This is useful when optimizing conditions such as the annealing temperatures of primers. Alternatively, other thermocyclers may contain multiple smaller blocks, each kept at a single, and different, temperature, among which the reaction tubes are switched by automation. Some PCR machines come with a standard 96-well block that can be easily replaced with a block of another format, such as a 48-well or 384-well. Another important option is a heated lid, which reduces condensation that can form on the insides of the sample tube lids. Many modern thermocyclers also offer the capability to upgrade to a real-time thermocycler (for quantitative PCR, or qPCR), and offer optional conveniences such as smaller, space-saving footprints, and touch-screen operation.