Influence of micro‑tube tilt angle on the temperature profile in convective PCR: Numerical simulation and statistical analysis

Abstract

The study investigates how the tilt angle of a standard 50 µL polypropylene micro-tube affects the temperature regime of convective polymerase chain reaction (PCR). The fluid flow is modeled using the Boussinesq approximation as implemented in the OpenFOAM suite. Water serves as the working medium. DNA molecule motion is simulated with a Monte Carlo approach: randomly placed particles are advected through the computed velocity field, and their temperature is recorded at each tracking step. For the range of tilt angles from −90° to +90°, computational-experiment data were obtained, histograms of particle residence times within specified temperature intervals were constructed, and a heat map was generated. The results show that tilting the tube to the right (positive angles) lowers the dominant temperatures, whereas tilting it to the left (negative angles) shifts the temperature range upward. These findings enable optimization of convective PCR parameters simply by adjusting the micro-tube’s tilt angle and boundary temperatures, potentially enhancing the sensitivity and reliability of portable PCR systems. DOI: 10.33184/bulletin-bsu-2025.4.1