Enhancement in PDMS-Based Microfluidic Network for On-Chip Thermal Treatment of Biomolecules

In this paper, we present an improved microfluidic network based on polydimethylsiloxane (PDMS) and thin film heaters for thermal treatment of biomolecules in lab-on-chip systems. It relies on the series connection of two thermally actuated valves, at both inlet and outlet of the network, in order to reduce leakage of sample when its process temperature approaches 100 °C. The spatial arrangement of valves and microfluidic channels in between has been optimized using COMSOL Multiphysics, through the investigation of the system thermal behavior. Taking into account the simulation results, the geometries of the heaters have been defined following standard microelectronic technologies and the microfluidic network has been fabricated by soft lithography. The experiments demonstrate that with the proposed configuration the liquid evaporation is strongly reduced since more than 80% of the sample is recovered after a practical thermal treatment experiment.