Unfortunately, because of the geometry of the heating elements and metal blocks, even the steady-state condition may not produce uniform temperatures across all samples. At best, these machines suffer from temperature imbalance during the long wait for equilibrium conditions. At worst, the imbalance is permanent. While other manufacturers have partially addressed these issues, the RapidCycler is the only thermal cycler fast enough to approach the kinetic limits of amplification reactions. The RapidCycler uses micro-capillary tubes or thin walled microcentrifuge tubes, which are ideally suited to temperature cycling since they have very thin walls and extremely high surface area to volume ratio.
Capillary tubes cut sample temperature lag to less than a second.
The use of air as the cycling medium results in high temperature ramp rates. Tornado-like conditions inside the cylindrical reaction chamber ensure both temperature uniformity and rapid heat exchange with the sample. This allows the RapidCycler to spend less than one second at the high and low temperatures and still be certain that each sample has reached the target temperature. A fraction of a second is adequate for the reaction. A 536 BP product, from the human b-globin gene is visible in lane 2.