AlphaHelix - Accurate Temperature Control


While all other PCR and qPCR instruments estimate sample temperature by measuring the block temperature or, in the case of LightCycler 2.0 and Rotor-Gene 6000, the air temperature, QuanTyper-48 continuously monitor sample temperature in real-time (throughout the run) using in-tube temperature measurement and temperature sensitive resistors. Figures 1-3 below highlight the benefits of in-tube temperature measurement. The problem when estimating sample temperature from block or air temperature is that, since temperature ramping is slower the larger the reaction volume is, it is often impossible to get a PCR reaction and temperature profile to work equally well for different reaction volumes. AlphaHelix's in-tube temperature measurement technology safely avoids this problem and ensures that the result will be the same, regardless of the total reaction volume.

Figure 1. 100 µl PCR 8 µl of a crude bacterial DNA preparation (Mycobacterium avium subspecies paratuberculosis) was run in duplicates at two different dilutions, amplifying a 120 bp bacterial gene segment. qPCR reactions were performed in the presence of SYBR Green I using the following temperature profile: an initial denaturation of 95 ºC for two minutes, followed by 40 cycles of 96 ºC for 0 s; 62 ºC for 6 s; and 74 ºC for 3 s. The samples were subsequently subjected to a melt gradient from 65 ºC to 95 ºC heating 0.3°C/sec continuously.

Figure 2. 100 µl PCR – longer hold times Same samples and volume as in Figure 2. but with longer hold times (to see if it may compensate for the slower ramping rates that hampers larger reaction volumes in RG6000).

Figure 3. 20 µl PCR Same samples as in Figure 1. but with a 20 µl PCR reaction volume. This run shows that the PCR reaction works equally well in both instruments at 20 µl.