Characterization of temperature distribution in microfluidic chip for DNA amplification

This work focuses on the temperature monitoring inside a polydimethylsiloxane microfluidic chip, suitable for DNA amplification. In order to achieve this aim, the microfluidic chip has been thermally coupled with a labonchip integrating, on a single glass substrate, temperature sensors and thin film heater. The wells of the chip have been filled with thermochromic liquid crystals, that change their optical properties at a precise transition temperature (TT). Experiments have been performed cycling the chip temperatures between 90 °C and 50 °C, two temperatures very close to the annealing and denaturation steps of the standard Polymerase Chain Reaction (PCR), utilized for DNA amplification. Results state that the temperature distribution inside the wells follows values and spatial uniformity required by the PCR cycles, guaranteeing an effective heat transfer from the thin film resistor to the microfluidic chip. Gel electrophoresis of amplified samples showed the presence of the amplifications and thus the successful implementation of the PCR in our lab-on-chip.