Thermal design of integrated heating for lab-on-a-chip systems

The transient thermal behavior of heating in a Lab-on-a-Chip (LoC) system is important for biological processes that require temperature treatment. A technology platform for LoCs that provides integrated heating functionality has been previously described. For a better understanding of the underlying mechanisms of its thermal dynamics a test system has been set up consisting of a printed circuit board, adhesive tape, integrated heater and microfluidic substrate. The focus of this contribution is the modelling of a transient thermal behavior model of non-integrated and integrated nonlinear heater and its experimental validation. A thermal model of a heating element in a polymer-based system's environment is developed with Finite Element Method. The thermal performance of both, integrated and non-integrated heating elements, is compared. The resulting design considerations are described in detail. Furthermore, the test assembly is investigated experimentally with electrical characterization of the heaters and by infrared camera to verify the simulation results. The thermal model will be the basis for design optimization and the development of a stable control loop in the future.