Analysis of Thermal Performance in a Bidirectional Thermocycler by Including Thermal Contact Characteristics

Abstract

This paper illustrates an application of a technique for predicting the thermal characteristics of a bidirectional thermocycling device for polymerase chain reaction (PCR). The micromilling chamber is oscillated by a servo motor and contacted with different isothermal heating blocks to successfully amplify the DNA templates. Because a comprehensive database of contact resistance factors does not exist, it causes researchers to not take thermal contact resistance into consideration at all. We are motivated to accurately determine the thermal characteristics of the reaction chamber with thermal contact effects existing between the heater surface and the chamber surface. Numerical results show that the thermal contact effects between the heating blocks and the reaction chamber dominate the temperature variations and the ramping rates inside the PCR chamber. However, the influences of various temperatures of the ambient conditions on the sample temperature during three PCR steps can be negligible. The experimental temperature profiles are compared well with the numerical simulations by considering the thermal contact conductance coefficient which is empirical by the experimental fitting. To take thermal contact conductance coefficients into consideration in the thermal simulation is recommended to predict a reasonable temperature profile of the reaction chamber during various thermal cycling processes. Finally, the PCR experiments present that Hygromycin B DNA templates are amplified successfully. Furthermore, our group is the first group to OPEN ACCESS Micromachines 2014, 5 1446 introduce the thermal contact effect into theoretical study that has been applied to the design of a PCR device, and to perform the PCR process in a bidirectional thermocycler.

Fabrication of an Oscillating Thermocycler to Analyze the Canine Distemper Virus by Utilizing Reverse Transcription Polymerase Chain Reaction

“…PCR experiments presented that Hygromycin B DNA templates were amplified successfully [9]. In the present study, the RNA mixtures are pipetted in a fixed reaction chamber.…”

“…This can convert the output of the microcontroller to the RS232 output level and vice versa. A temperature drop is experienced at the interface between the heating block and the reaction chamber in contact [9]. The phenomenon resulting from the thermal contact resistance existing between the real contacting surfaces is diminished by applying some thermal grease.…”

“…Our group was the first group to introduce the thermal contact effect into a theoretical study that had been applied to the design of a PCR device. The PCR experiments presented that Hygromycin B DNA templates were amplified successfully [9]. In the present study, the RNA mixtures are pipetted in a fixed reaction chamber.…”

“…By keeping the temperatures constant over time at different locations (ranging from one to three) in the device, the reaction mixture moves through the individual isothermal zones to finish the reaction stages. Not only is the residence time in which a sample is exposed to each isothermal region, but also the number of thermal cycles is determined by the arrangement of heating zones [9]. Each type has its own merits.…”

“…The design concepts of the oscillating thermocycler we use in the present work are the continuation of our previously presented bidirectional thermocycler [9,23]. The reaction chamber with the DNA mixture was driven by the moving stage, which is connected to the linear motor.…”